1
|
Herbst R, Huijbers MG, Oury J, Burden SJ. Building, Breaking, and Repairing Neuromuscular Synapses. Cold Spring Harb Perspect Biol 2024; 16:a041490. [PMID: 38697654 PMCID: PMC11065174 DOI: 10.1101/cshperspect.a041490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
A coordinated and complex interplay of signals between motor neurons, skeletal muscle cells, and Schwann cells controls the formation and maintenance of neuromuscular synapses. Deficits in the signaling pathway for building synapses, caused by mutations in critical genes or autoantibodies against key proteins, are responsible for several neuromuscular diseases, which cause muscle weakness and fatigue. Here, we describe the role that four key genes, Agrin, Lrp4, MuSK, and Dok7, play in this signaling pathway, how an understanding of their mechanisms of action has led to an understanding of several neuromuscular diseases, and how this knowledge has contributed to emerging therapies for treating neuromuscular diseases.
Collapse
Affiliation(s)
- Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Centre LUMC, 2300 RC Leiden, the Netherlands
- Department of Neurology, Leiden University Medical Centre LUMC, 2333 ZA Leiden, the Netherlands
| | - Julien Oury
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, New York 10016, USA
| | - Steven J Burden
- Neurology Department, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| |
Collapse
|
2
|
Li J, Wu X, Chu T, Tan X, Wang S, Qu R, Chen Z, Wang Z. The efficacy and safety of FcRn inhibitors in patients with myasthenia gravis: a systematic review and meta-analysis. J Neurol 2024; 271:2298-2308. [PMID: 38431900 DOI: 10.1007/s00415-024-12247-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND Myasthenia gravis (MG) is an autoimmune disease that causes local or generalized muscle weakness. Complement inhibitors and targeting of the neonatal Fc receptor (FcRn) to block IgG cycling are two novel and successful mechanisms. METHODS PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov were systematically searched to identify relevant studies published before May 18, 2023. Review Manager 5.3 software was used to assess the data. RESULTS We pooled 532 participants from six randomized controlled trials (RCTs). Compared to the placebo, the FcRn inhibitors were more efficacy in Myasthenia Gravis Activities of Daily Living (MG-ADL) (MD = - 1.69 [- 2.35, - 1.03], P < 0.00001), MG-ADL responder (RR = 2.01 [1.62, 2.48], P < 0.00001), Quantitative Myasthenia Gravis (QMG) (MD = - 2.45 [- 4.35, - 0.55], P = 0.01), Myasthenia Gravis Composite (MGC) (MD = - 2.97 [- 4.27, - 1.67], P < 0.00001), 15-item revised version of the Myasthenia Gravis Quality of Life (MGQoL15r) (MD = - 2.52 [- 3.54, - 1.50], P < 0.00001), without increasing the risk of safety. The subgroup analysis showed that efgartigimod was more effective than placebo in MG-ADL responders. Rozanolixizumab was more effective than the placebo except in QMG, and batoclimab was more effective than the placebo except in MG-ADL responder. Nipocalizumab did not show satisfactory efficacy in all outcomes. With the exception of rozanolixizumab, all drugs showed non-inferior safety profiles to placebo. CONCLUSION FcRn inhibitors have good efficacy and safety in patients with MG. Among them, efgartigimod and nipocalimab were effective without causing an increased safety risk. Rozanolixizumab, despite its superior efficacy, caused an increased incidence of adverse events. Current evidence does not suggest that nipocalimab is effective in patients with MG.
Collapse
Affiliation(s)
- Jiaxuan Li
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China
| | - Xin Wu
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China
| | - Tianchen Chu
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China
| | - Xin Tan
- Department of Neurology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Suzhou, Jiangsu Province, China
| | - Shixin Wang
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China
| | - Ruisi Qu
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China
| | - Zhouqing Chen
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China.
| | - Zhong Wang
- Department of Neurosurgery and Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, Jiangsu Province, China.
| |
Collapse
|
3
|
Koneczny I, Mané-Damas M, Zong S, De Haas S, Huda S, van Kruining D, Damoiseaux J, De Rosa A, Maestri M, Guida M, Molenaar P, Van Damme P, Fichtenbaum A, Perkmann T, De Baets M, Lazaridis K, Zouvelou V, Tzartos S, Ricciardi R, Losen M, Martinez-Martinez P. A retrospective multicenter study on clinical and serological parameters in patients with MuSK myasthenia gravis with and without general immunosuppression. Front Immunol 2024; 15:1325171. [PMID: 38715598 PMCID: PMC11074957 DOI: 10.3389/fimmu.2024.1325171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/25/2024] [Indexed: 06/19/2024] Open
Abstract
Introduction Muscle-specific kinase (MuSK)- myasthenia gravis (MG) is caused by pathogenic autoantibodies against MuSK that correlate with disease severity and are predominantly of the IgG4 subclass. The first-line treatment for MuSK-MG is general immunosuppression with corticosteroids, but the effect of treatment on IgG4 and MuSK IgG4 levels has not been studied. Methods We analyzed the clinical data and sera from 52 MuSK-MG patients (45 female, 7 male, median age 49 (range 17-79) years) from Italy, the Netherlands, Greece and Belgium, and 43 AChR-MG patients (22 female, 21 male, median age 63 (range 2-82) years) from Italy, receiving different types of immunosuppression, and sera from 46 age- and sex-matched non-disease controls (with no diagnosed diseases, 38 female, 8 male, median age 51.5 (range 20-68) years) from the Netherlands. We analyzed the disease severity (assessed by MGFA or QMG score), and measured concentrations of MuSK IgG4, MuSK IgG, total IgG4 and total IgG in the sera by ELISA, RIA and nephelometry. Results We observed that MuSK-MG patients showed a robust clinical improvement and reduction of MuSK IgG after therapy, and that MuSK IgG4 concentrations, but not total IgG4 concentrations, correlated with clinical severity. MuSK IgG and MuSK IgG4 concentrations were reduced after immunosuppression in 4/5 individuals with before-after data, but data from non-linked patient samples showed no difference. Total serum IgG4 levels were within the normal range, with IgG4 levels above threshold (1.35g/L) in 1/52 MuSK-MG, 2/43 AChR-MG patients and 1/45 non-disease controls. MuSK-MG patients improved within the first four years after disease onset, but no further clinical improvement or reduction of MuSK IgG4 were observed four years later, and only 14/52 (26.92%) patients in total, of which 13 (93.3%) received general immunosuppression, reached clinical remission. Discussion We conclude that MuSK-MG patients improve clinically with general immunosuppression but may require further treatment to reach remission. Longitudinal testing of individual patients may be clinically more useful than single measurements of MuSK IgG4. No significant differences in the serum IgG4 concentrations and IgG4/IgG ratio between AChR- and MuSK-MG patients were found during follow-up. Further studies with larger patient and control cohorts are necessary to validate the findings.
Collapse
Affiliation(s)
- Inga Koneczny
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Marina Mané-Damas
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Shenghua Zong
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Sander De Haas
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Saif Huda
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- Department of Neurology, Walton Centre National Health Service (NHS) Foundation Trust, Liverpool, United Kingdom
| | - Daan van Kruining
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands
| | - Jan Damoiseaux
- Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, Netherlands
| | - Anna De Rosa
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Michelangelo Maestri
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Melania Guida
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Peter Molenaar
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Philip Van Damme
- Neurology Department, University Hospital, Leuven, Belgium
- Department of Neurosciences, Center for Brain & Disease Research, VIB, Leuven, Belgium
| | - Andreas Fichtenbaum
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Thomas Perkmann
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Marc De Baets
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | | | - Vasiliki Zouvelou
- 1stNeurology Department, National and Kapodistrian University of Athens, Athens, Greece
| | - Socrates Tzartos
- Department of Immunology, Hellenic Pasteur Institute, Athens, Greece
- Department of Neuroimmunology, Tzartos NeuroDiagnostics, Athens, Greece
| | - Roberta Ricciardi
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
- Cardio Thoracic and Vascular Surgery Department, University of Pisa, Pisa, Italy
| | - Mario Losen
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Pilar Martinez-Martinez
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| |
Collapse
|
4
|
Ünlü S, Sánchez Navarro BG, Cakan E, Berchtold D, Meleka Hanna R, Vural S, Vural A, Meisel A, Fichtner ML. Exploring the depths of IgG4: insights into autoimmunity and novel treatments. Front Immunol 2024; 15:1346671. [PMID: 38698867 PMCID: PMC11063302 DOI: 10.3389/fimmu.2024.1346671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/29/2024] [Indexed: 05/05/2024] Open
Abstract
IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.
Collapse
Affiliation(s)
- Selen Ünlü
- Koç University Research Center for Translational Medicine (KUTTAM), İstanbul, Türkiye
- Koç University School of Medicine, Istanbul, Türkiye
| | - Blanca G. Sánchez Navarro
- Department of Neurology with Experimental Neurology, Integrated Myasthenia Gravis Center, Neuroscience Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Elif Cakan
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, United States
| | - Daniel Berchtold
- Department of Neurology with Experimental Neurology, Integrated Myasthenia Gravis Center, Neuroscience Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Rafael Meleka Hanna
- Department of Neurology with Experimental Neurology, Integrated Myasthenia Gravis Center, Neuroscience Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Secil Vural
- Koç University Research Center for Translational Medicine (KUTTAM), İstanbul, Türkiye
- Department of Dermatology and Venereology, Koç University School of Medicine, İstanbul, Türkiye
| | - Atay Vural
- Koç University Research Center for Translational Medicine (KUTTAM), İstanbul, Türkiye
- Department of Neurology, Koç University School of Medicine, İstanbul, Türkiye
| | - Andreas Meisel
- Department of Neurology with Experimental Neurology, Integrated Myasthenia Gravis Center, Neuroscience Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Miriam L. Fichtner
- Koç University Research Center for Translational Medicine (KUTTAM), İstanbul, Türkiye
- Department of Neurology with Experimental Neurology, Integrated Myasthenia Gravis Center, Neuroscience Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
5
|
Motta RV, Culver EL. IgG4 autoantibodies and autoantigens in the context of IgG4-autoimmune disease and IgG4-related disease. Front Immunol 2024; 15:1272084. [PMID: 38433835 PMCID: PMC10904653 DOI: 10.3389/fimmu.2024.1272084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 01/25/2024] [Indexed: 03/05/2024] Open
Abstract
Immunoglobulins are an essential part of the humoral immune response. IgG4 antibodies are the least prevalent subclass and have unique structural and functional properties. In this review, we discuss IgG4 class switch and B cell production. We review the importance of IgG4 antibodies in the context of allergic responses, helminth infections and malignancy. We discuss their anti-inflammatory and tolerogenic effects in allergen-specific immunotherapy, and ability to evade the immune system in parasitic infection and tumour cells. We then focus on the role of IgG4 autoantibodies and autoantigens in IgG4-autoimmune diseases and IgG4-related disease, highlighting important parallels and differences between them. In IgG4-autoimmune diseases, pathogenesis is based on a direct role of IgG4 antibodies binding to self-antigens and disturbing homeostasis. In IgG4-related disease, where affected organs are infiltrated with IgG4-expressing plasma cells, IgG4 antibodies may also directly target a number of self-antigens or be overexpressed as an epiphenomenon of the disease. These antigen-driven processes require critical T and B cell interaction. Lastly, we explore the current gaps in our knowledge and how these may be addressed.
Collapse
Affiliation(s)
- Rodrigo V. Motta
- Translational Gastroenterology and Liver Unit, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Emma L. Culver
- Translational Gastroenterology and Liver Unit, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Gastroenterology and Hepatology, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| |
Collapse
|
6
|
Chen BH, Lin ZY, Zeng XX, Jiang YH, Geng F. LRP4-related signalling pathways and their regulatory role in neurological diseases. Brain Res 2024; 1825:148705. [PMID: 38065285 DOI: 10.1016/j.brainres.2023.148705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/17/2023] [Accepted: 12/03/2023] [Indexed: 01/28/2024]
Abstract
The mechanism of action of low-density lipoprotein receptor related protein 4 (LRP4) is mediated largely via the Agrin-LRP4-MuSK signalling pathway in the nervous system. LRP4 contributes to the development of synapses in the peripheral nervous system (PNS). It interacts with signalling molecules such as the amyloid beta-protein precursor (APP) and the wingless type protein (Wnt). Its mechanisms of action are complex and mediated via interaction between the pre-synaptic motor neuron and post-synaptic muscle cell in the PNS, which enhances the development of the neuromuscular junction (NMJ). LRP4 may function differently in the central nervous system (CNS) than in the PNS, where it regulates ATP and glutamate release via astrocytes. It mayaffect the growth and development of the CNS by controlling the energy metabolism. LRP4 interacts with Agrin to maintain dendrite growth and density in the CNS. The goal of this article is to review the current studies involving relevant LRP4 signaling pathways in the nervous system. The review also discusses the clinical and etiological roles of LRP4 in neurological illnesses, such as myasthenia gravis, Alzheimer's disease and epilepsy. In this review, we provide a theoretical foundation for the pathogenesis and therapeutic application of LRP4 in neurologic diseases.
Collapse
Affiliation(s)
- Bai-Hui Chen
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Ze-Yu Lin
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Xiao-Xue Zeng
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Yi-Han Jiang
- Department of Physiology, Shantou University Medical College, Shantou 515041, China
| | - Fei Geng
- Department of Physiology, Shantou University Medical College, Shantou 515041, China; Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China.
| |
Collapse
|
7
|
Kersten R, Trampert DC, Hubers LM, Tolenaars D, Vos HR, van de Graaf SFJ, Beuers U. Galectin-3 and prohibitin 1 are autoantigens in IgG4-related cholangitis without clear-cut protective effects against toxic bile acids. Front Immunol 2024; 14:1251134. [PMID: 38332916 PMCID: PMC10851949 DOI: 10.3389/fimmu.2023.1251134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/15/2023] [Indexed: 02/10/2024] Open
Abstract
Background and aims IgG4-related cholangitis (IRC) is the hepatobiliary manifestation of IgG4-related disease, a systemic B cell-driven fibro-inflammatory disorder. Four autoantigens have recently been described in IgG4-RD: annexin A11, galectin-3, laminin 511-E8, and prohibitin 1. We have previously reported a protective role of annexin A11 and laminin 511-E8 in human cholangiocytes against toxic bile acids. Here, we explored the potentially protective role of the carbohydrate-binding lectin galectin-3 and the scaffold proteins prohibitins 1 and 2. Methods Anti-galectin-3, anti-prohibitin 1 and 2 autoantibody positivity in IRC and healthy and disease (primary sclerosing cholangitis (PSC)) control sera was assessed by ELISA/liquid chromatography-tandem mass spectrometry (LC-MS/MS). Human H69 cholangiocytes were subjected to short hairpin RNA (shRNA) knockdown targeting galectin-3 (LGALS3), prohibitin 1 (PHB1), and prohibitin 2 (PHB2). H69 cholangiocytes were also exposed to recombinant galectin-3, the inhibitor GB1107, recombinant prohibitin 1, and the pan-prohibitin inhibitor rocaglamide. Protection against bile acid toxicity was assessed by intracellular pH (pHi) measurements using BCECF-AM, 22,23-3H-glycochenodeoxycholic acid (3H-GCDC) influx, and GCDC-induced apoptosis using Caspase-3/7 assays. Results Anti-galectin-3 autoantibodies were detected in 13.5% of individuals with IRC but not in PSC. Knockdown of LGALS3 and galectin-3 inhibition with GB1107 did not affect pHi, whereas recombinant galectin-3 incubation lowered pHi. LGALS3 knockdown increased GCDC-influx but not GCDC-induced apoptosis. GB1107 reduced GCDC-influx and GCDC-induced apoptosis. Recombinant galectin-3 tended to decrease GCDC-influx and GCDC-induced apoptosis. Anti-prohibitin 1 autoantibodies were detected in 61.5% and 35.7% of individuals with IRC and PSC, respectively. Knockdown of PHB1, combined PHB1/2 KD, treatment with rocaglamide, and recombinant prohibitin 1 all lowered pHi. Knockdown of PHB1, PHB2, or combined PHB1/2 did not alter GCDC-influx, yet knockdown of PHB1 increased GCDC-induced apoptosis. Conversely, rocaglamide reduced GCDC-influx but did not attenuate GCDC-induced apoptosis. Recombinant prohibitin 1 did not affect GCDC-influx or GCDC-induced apoptosis. Finally, anti-galectin-3 and anti-prohibitin 1 autoantibody pretreatment did not lead to increased GCDC-influx. Conclusions A subset of individuals with IRC have autoantibodies against galectin-3 and prohibitin 1. Gene-specific knockdown, pharmacological inhibition, and recombinant protein substitution did not clearly disclose a protective role of these autoantigens in human cholangiocytes against toxic bile acids. The involvement of these autoantibodies in processes surpassing epithelial secretion remains to be elucidated.
Collapse
Affiliation(s)
- Remco Kersten
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - David C. Trampert
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - Lowiek M. Hubers
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - Dagmar Tolenaars
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - Harmjan R. Vos
- Oncode Institute and Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, Netherlands
| | - Stan F. J. van de Graaf
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - Ulrich Beuers
- Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism (AGEM), Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
8
|
Liu Y, Wang Y, Hu M, Xu S, Jiang F, Han Y, Liu Z. The role of IgG4 in systemic lupus erythematosus: Implications for pathogenesis and therapy. J Biochem Mol Toxicol 2024; 38:e23626. [PMID: 38229315 DOI: 10.1002/jbt.23626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/16/2023] [Accepted: 12/14/2023] [Indexed: 01/18/2024]
Abstract
Immunoglobulin (Ig) G4 has a distinctive nature, and its involvement in autoimmune disorders is a subject of ongoing debate and uncertainty. A growing body of evidence indicates that IgG4 may play a pathogenic role in the development of systemic lupus erythematosus (SLE). The IgG4 autoantibodies have the capability to bind autoantigens in a competitive manner with other Ig classes, thereby forming immune complexes (ICs) that are noninflammatory in nature. This is due to the low affinity of IgG4 for both the Fc receptors and the C1 complement molecule, which results in a diminished inflammatory response in individuals with SLE. The present study aims to elucidate the significance of IgG4 in SLE. The present discourse pertains to the nascent and suggested modalities through which IgG4 might participate in the pathogenesis of SLE and the potential ramifications for therapeutic interventions in SLE.
Collapse
Affiliation(s)
- Yanyan Liu
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yingjian Wang
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Mengsi Hu
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shoufang Xu
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feiyu Jiang
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yetao Han
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zhiwei Liu
- Department of Blood Transfusion, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| |
Collapse
|
9
|
Tannemaat MR, Huijbers MG, Verschuuren JJGM. Myasthenia gravis-Pathophysiology, diagnosis, and treatment. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:283-305. [PMID: 38494283 DOI: 10.1016/b978-0-12-823912-4.00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.
Collapse
Affiliation(s)
- Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | |
Collapse
|
10
|
Paardekooper LM, Fillié-Grijpma YE, van der Sluijs-Gelling AJ, Zlei M, van Doorn R, Vermeer MH, Paunovic M, Titulaer MJ, van der Maarel SM, van Dongen JJM, Verschuuren JJ, Huijbers MG. Autoantibody subclass predominance is not driven by aberrant class switching or impaired B cell development. Clin Immunol 2023; 257:109817. [PMID: 37925120 DOI: 10.1016/j.clim.2023.109817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/25/2023] [Accepted: 10/25/2023] [Indexed: 11/06/2023]
Abstract
A subset of autoimmune diseases is characterized by predominant pathogenic IgG4 autoantibodies (IgG4-AID). Why IgG4 predominates in these disorders is unknown. We hypothesized that dysregulated B cell maturation or aberrant class switching causes overrepresentation of IgG4+ B cells and plasma cells. Therefore, we compared the B cell compartment of patients from four different IgG4-AID with two IgG1-3-AID and healthy donors, using flow cytometry. Relative subset abundance at all maturation stages was normal, except for a, possibly treatment-related, reduction in immature and naïve CD5+ cells. IgG4+ B cell and plasma cell numbers were normal in IgG4-AID patients, however they had a (sub)class-independent 8-fold increase in circulating CD20-CD138+ cells. No autoreactivity was found in this subset. These results argue against aberrant B cell development and rather suggest the autoantibody subclass predominance to be antigen-driven. The similarities between IgG4-AID suggest that, despite displaying variable clinical phenotypes, they share a similar underlying immune profile.
Collapse
Affiliation(s)
| | | | | | - Mihaela Zlei
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands
| | - Remco van Doorn
- Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maarten H Vermeer
- Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Manuela Paunovic
- Department of Neurology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Maarten J Titulaer
- Department of Neurology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - Jacques J M van Dongen
- Department of Immunology, Leiden University Medical Center, Leiden, The Netherlands; Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CIC-IBMCC, USAL-CSIC-FICUS) and Department of Medicine, University of Salamanca, Salamanca, Spain
| | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands; Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
11
|
Rispens T, Huijbers MG. The unique properties of IgG4 and its roles in health and disease. Nat Rev Immunol 2023; 23:763-778. [PMID: 37095254 PMCID: PMC10123589 DOI: 10.1038/s41577-023-00871-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2023] [Indexed: 04/26/2023]
Abstract
IgG4 is the least abundant subclass of IgG in human serum and has unique functional features. IgG4 is largely unable to activate antibody-dependent immune effector responses and, furthermore, undergoes Fab (fragment antigen binding)-arm exchange, rendering it bispecific for antigen binding and functionally monovalent. These properties of IgG4 have a blocking effect, either on the immune response or on the target protein of IgG4. In this Review, we discuss the unique structural characteristics of IgG4 and how these contribute to its roles in health and disease. We highlight how, depending on the setting, IgG4 responses can be beneficial (for example, in responses to allergens or parasites) or detrimental (for example, in autoimmune diseases, in antitumour responses and in anti-biologic responses). The development of novel models for studying IgG4 (patho)physiology and understanding how IgG4 responses are regulated could offer insights into novel treatment strategies for these IgG4-associated disease settings.
Collapse
Affiliation(s)
- Theo Rispens
- Department of Immunopathology, Sanquin Research and Landsteiner Laboratory, Amsterdam, The Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
12
|
Huang X, Zhang Z, Wang Y, Xu M, Du X, Zhang Y. Circulating miRNAs drive personalized medicine based on subgroup classification in myasthenia gravis patients. Neurol Sci 2023; 44:3877-3884. [PMID: 37402938 DOI: 10.1007/s10072-023-06933-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 06/29/2023] [Indexed: 07/06/2023]
Abstract
Myasthenia gravis (MG) is a classic autoimmune neuromuscular disease with strong clinical heterogeneity. The concept of subgroup classification was proposed to guide the precise treatment of MG. Subgroups based on serum antibodies and clinical features include ocular MG, early-onset MG with AchR antibodies, late-onset MG with AchR antibodies, thymoma-associated MG, MuSK-associated MG, LRP4-associated MG, and seronegative MG. However, reliable objective biomarkers are still needed to reflect the individualized response to therapy. MicroRNAs (miRNAs) are small non-coding RNA molecules which can specifically bind to target genes and regulate gene expression at the post-transcriptional level, and then influence celluar biological processes. MiRNAs play an important role in the pathogenesis of autoimmune diseases, including MG. Several studies on circulating miRNAs in MG have been reported. However, there is rare systematic review to summarize the differences of these miRNAs in different subgroups of MG. Here, we summarize the potential role of circulating miRNAs in different subgroups of MG to promote personalized medicine.
Collapse
Affiliation(s)
- Xiaoyu Huang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhouao Zhang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China
| | - Yingying Wang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China
| | - Mingming Xu
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China
| | - Xue Du
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China
| | - Yong Zhang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical University, No. 99 Huaihai West Road, Quanshan Distric, Xuzhou, Jiangsu, China.
| |
Collapse
|
13
|
Cao M, Liu WW, Maxwell S, Huda S, Webster R, Evoli A, Beeson D, Cossins JA, Vincent A. IgG1-3 MuSK Antibodies Inhibit AChR Cluster Formation, Restored by SHP2 Inhibitor, Despite Normal MuSK, DOK7, or AChR Subunit Phosphorylation. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2023; 10:e200147. [PMID: 37582613 PMCID: PMC10427144 DOI: 10.1212/nxi.0000000000200147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/07/2023] [Indexed: 08/17/2023]
Abstract
BACKGROUND AND OBJECTIVES Up to 50% of patients with myasthenia gravis (MG) without acetylcholine receptor antibodies (AChR-Abs) have antibodies to muscle-specific kinase (MuSK). Most MuSK antibodies (MuSK-Abs) are IgG4 and inhibit agrin-induced MuSK phosphorylation, leading to impaired clustering of AChRs at the developing or mature neuromuscular junction. However, IgG1-3 MuSK-Abs also exist in MuSK-MG patients, and their potential mechanisms have not been explored fully. METHODS C2C12 myotubes were exposed to MuSK-MG plasma IgG1-3 or IgG4, with or without purified agrin. MuSK, Downstream of Kinase 7 (DOK7), and βAChR were immunoprecipitated and their phosphorylation levels identified by immunoblotting. Agrin and agrin-independent AChR clusters were measured by immunofluorescence and AChR numbers by binding of 125I-α-bungarotoxin. Transcriptomic analysis was performed on treated myotubes. RESULTS IgG1-3 MuSK-Abs impaired AChR clustering without inhibiting agrin-induced MuSK phosphorylation. Moreover, the well-established pathway initiated by MuSK through DOK7, resulting in βAChR phosphorylation, was not impaired by MuSK-IgG1-3 and was agrin-independent. Nevertheless, the AChR clusters did not form, and both the number of AChR microclusters that precede full cluster formation and the myotube surface AChRs were reduced. Transcriptomic analysis did not throw light on the pathways involved. However, the SHP2 inhibitor, NSC-87877, increased the number of microclusters and led to fully formed AChR clusters. DISCUSSION MuSK-IgG1-3 is pathogenic but seems to act through a noncanonical pathway. Further studies should throw light on the mechanisms involved at the neuromuscular junction.
Collapse
Affiliation(s)
- Michelangelo Cao
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Wei-Wei Liu
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Susan Maxwell
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Saif Huda
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Richard Webster
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Amelia Evoli
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - David Beeson
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Judith A Cossins
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Angela Vincent
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy.
| |
Collapse
|
14
|
Fish LA, Ewing MD, Jaime D, Rich KA, Xi C, Wang X, Feder RE, Wharton KA, Rich MM, Arnold WD, Fallon JR. The MuSK-BMP pathway regulates synaptic Nav1.4 localization and muscle excitability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563837. [PMID: 37961580 PMCID: PMC10634800 DOI: 10.1101/2023.10.24.563837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The neuromuscular junction (NMJ) is the linchpin of nerve-evoked muscle contraction. Broadly considered, the function of the NMJ is to transduce a nerve action potential into a muscle fiber action potential (MFAP). Efficient information transfer requires both cholinergic signaling, responsible for the generation of endplate potentials (EPPs), and excitation, the activation of postsynaptic voltage-gated sodium channels (Nav1.4) to trigger MFAPs. In contrast to the cholinergic apparatus, the signaling pathways that organize Nav1.4 and muscle fiber excitability are poorly characterized. Muscle-specific kinase (MuSK), in addition to its Ig1 domain-dependent role as an agrin-LRP4 receptor, is also a BMP co-receptor that binds BMPs via its Ig3 domain and shapes BMP-induced signaling and transcriptional output. Here we probed the function of the MuSK-BMP pathway at the NMJ using mice lacking the MuSK Ig3 domain ('ΔIg3-MuSK'). Synapses formed normally in ΔIg3-MuSK animals, but the postsynaptic apparatus was fragmented from the first weeks of life. Anatomical denervation was not observed at any age examined. Moreover, spontaneous and nerve-evoked acetylcholine release, AChR density, and endplate currents were comparable to WT. However, trains of nerve-evoked MFAPs in ΔIg3-MuSK muscle were abnormal as revealed by increased jitter and blocking in single fiber electromyography. Further, nerve-evoked compound muscle action potentials (CMAPs), as well as twitch and tetanic muscle torque force production, were also diminished. Finally, Nav1.4 levels were reduced at ΔIg3-MuSK synapses but not at the extrajunctional sarcolemma, indicating that the observed excitability defects are the result of impaired localization of this voltage-gated ion channel at the NMJ. We propose that MuSK plays two distinct roles at the NMJ: as an agrin-LRP4 receptor necessary for establishing and maintaining cholinergic signaling, and as a BMP co-receptor required for maintaining proper Nav1.4 density, nerve-evoked muscle excitability and force production. The MuSK-BMP pathway thus emerges as a target for modulating excitability and functional innervation, which are defective in conditions such as congenital myasthenic syndromes and aging.
Collapse
Affiliation(s)
- L. A. Fish
- Neuroscience Graduate Program, Brown University, Providence, RI 02912
- Carney Institute for Brain Science, Brown University, Providence, RI 02912
| | - M. D. Ewing
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - D. Jaime
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - K. A. Rich
- Neuroscience Graduate Program, Ohio State University, Columbus, OH 43210
| | - C. Xi
- Biotechnology Graduate Program, Brown University, Brown University, Providence, RI 02912
| | - X. Wang
- Department of Neuroscience Cell Biology and Physiology, Wright State University, Dayton, OH 45435
| | - R. E. Feder
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - K. A. Wharton
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - M. M. Rich
- Department of Neuroscience Cell Biology and Physiology, Wright State University, Dayton, OH 45435
| | - W. D. Arnold
- NextGen Precision Health Institute, University of Missouri, Columbia, MO 62511
| | - J. R. Fallon
- Carney Institute for Brain Science, Brown University, Providence, RI 02912
- Department of Neuroscience, Brown University, Providence, RI 02912
| |
Collapse
|
15
|
Collet R, Caballero-Ávila M, Querol L. Clinical and pathophysiological implications of autoantibodies in autoimmune neuropathies. Rev Neurol (Paris) 2023; 179:831-843. [PMID: 36907709 DOI: 10.1016/j.neurol.2023.02.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/28/2023] [Accepted: 02/02/2023] [Indexed: 03/13/2023]
Abstract
Autoimmune neuropathies are a heterogeneous group of rare and disabling diseases in which the immune system targets peripheral nervous system antigens and that respond to immune therapies. This review focuses on Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, polyneuropathy associated with IgM monoclonal gammopathy, and autoimmune nodopathies. Autoantibodies targeting gangliosides, proteins in the node of Ranvier, and myelin-associated glycoprotein have been described in these disorders, defining subgroups of patients with similar clinical features and response to therapy. This topical review describes the role of these autoantibodies in the pathogenesis of autoimmune neuropathies and their clinical and therapeutic importance.
Collapse
Affiliation(s)
- R Collet
- Department of Neurology, Hospital Santa Creu i Sant Pau, Barcelona, Spain
| | - M Caballero-Ávila
- Department of Neurology, Hospital Santa Creu i Sant Pau, Barcelona, Spain; Neuromuscular Diseases Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - L Querol
- Department of Neurology, Hospital Santa Creu i Sant Pau, Barcelona, Spain; Neuromuscular Diseases Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro para la Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Madrid, Spain.
| |
Collapse
|
16
|
Lv R, Duan L, Gao J, Si J, Feng C, Hu J, Zheng X. Bioinformatics-based analysis of the roles of basement membrane-related gene AGRN in systemic lupus erythematosus and pan-cancer development. Front Immunol 2023; 14:1231611. [PMID: 37841281 PMCID: PMC10570813 DOI: 10.3389/fimmu.2023.1231611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/07/2023] [Indexed: 10/17/2023] Open
Abstract
Introduction Systemic lupus erythematosus (SLE) is an autoimmune disease involving many systems and organs, and individuals with SLE exhibit unique cancer risk characteristics. The significance of the basement membrane (BM) in the occurrence and progression of human autoimmune diseases and tumors has been established through research. However, the roles of BM-related genes and their protein expression mechanisms in the pathogenesis of SLE and pan-cancer development has not been elucidated. Methods In this study, we applied bioinformatics methods to perform differential expression analysis of BM-related genes in datasets from SLE patients. We utilized LASSO logistic regression, SVM-RFE, and RandomForest to screen for feature genes and construct a diagnosis model for SLE. In order to attain a comprehensive comprehension of the biological functionalities of the feature genes, we conducted GSEA analysis, ROC analysis, and computed levels of immune cell infiltration. Finally, we sourced pan-cancer expression profiles from the TCGA and GTEx databases and performed pan-cancer analysis. Results We screened six feature genes (AGRN, PHF13, SPOCK2, TGFBI, COL4A3, and COLQ) to construct an SLE diagnostic model. Immune infiltration analysis showed a significant correlation between AGRN and immune cell functions such as parainflammation and type I IFN response. After further gene expression validation, we finally selected AGRN for pan-cancer analysis. The results showed that AGRN's expression level varied according to distinct tumor types and was closely correlated with some tumor patients' prognosis, immune cell infiltration, and other indicators. Discussion In conclusion, BM-related genes play a pivotal role in the pathogenesis of SLE, and AGRN shows immense promise as a target in SLE and the progression of multiple tumors.
Collapse
Affiliation(s)
- Rundong Lv
- Department of Clinical Pharmacy, Zibo Central Hospital, Zibo, Shandong, China
| | - Lei Duan
- Department of Clinical Pharmacy, Zibo Central Hospital, Zibo, Shandong, China
| | - Jie Gao
- Department of Clinical Pharmacy, Zibo Central Hospital, Zibo, Shandong, China
| | - Jigang Si
- Department of Clinical Pharmacy, Zibo Central Hospital, Zibo, Shandong, China
| | - Chen Feng
- Department of Pharmacy, Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Jun Hu
- Department of Children’s Health, Zibo Central Hospital, Zibo, Shandong, China
| | - Xiulan Zheng
- School of Pharmacy, Faculty of Medicine, Macau University of Science and Technology, Macao, Macao SAR, China
- Department of Rheumatology and Immunology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, China
| |
Collapse
|
17
|
Oh S, Mao X, Manfredo-Vieira S, Lee J, Patel D, Choi EJ, Alvarado A, Cottman-Thomas E, Maseda D, Tsao PY, Ellebrecht CT, Khella SL, Richman DP, O'Connor KC, Herzberg U, Binder GK, Milone MC, Basu S, Payne AS. Precision targeting of autoantigen-specific B cells in muscle-specific tyrosine kinase myasthenia gravis with chimeric autoantibody receptor T cells. Nat Biotechnol 2023; 41:1229-1238. [PMID: 36658341 PMCID: PMC10354218 DOI: 10.1038/s41587-022-01637-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 12/08/2022] [Indexed: 01/21/2023]
Abstract
Muscle-specific tyrosine kinase myasthenia gravis (MuSK MG) is an autoimmune disease that causes life-threatening muscle weakness due to anti-MuSK autoantibodies that disrupt neuromuscular junction signaling. To avoid chronic immunosuppression from current therapies, we engineered T cells to express a MuSK chimeric autoantibody receptor with CD137-CD3ζ signaling domains (MuSK-CAART) for precision targeting of B cells expressing anti-MuSK autoantibodies. MuSK-CAART demonstrated similar efficacy as anti-CD19 chimeric antigen receptor T cells for depletion of anti-MuSK B cells and retained cytolytic activity in the presence of soluble anti-MuSK antibodies. In an experimental autoimmune MG mouse model, MuSK-CAART reduced anti-MuSK IgG without decreasing B cells or total IgG levels, reflecting MuSK-specific B cell depletion. Specific off-target interactions of MuSK-CAART were not identified in vivo, in primary human cell screens or by high-throughput human membrane proteome array. These data contributed to an investigational new drug application and phase 1 clinical study design for MuSK-CAART for the treatment of MuSK autoantibody-positive MG.
Collapse
Affiliation(s)
- Sangwook Oh
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xuming Mao
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Silvio Manfredo-Vieira
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Eun Jung Choi
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Damian Maseda
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Patricia Y Tsao
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christoph T Ellebrecht
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sami L Khella
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David P Richman
- Department of Neurology, University of California - Davis, Davis, CA, USA
| | - Kevin C O'Connor
- Departments of Neurology and Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | | | | | - Michael C Milone
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Aimee S Payne
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
18
|
Vakrakou AG, Karachaliou E, Chroni E, Zouvelou V, Tzanetakos D, Salakou S, Papadopoulou M, Tzartos S, Voumvourakis K, Kilidireas C, Giannopoulos S, Tsivgoulis G, Tzartos J. Immunotherapies in MuSK-positive Myasthenia Gravis; an IgG4 antibody-mediated disease. Front Immunol 2023; 14:1212757. [PMID: 37564637 PMCID: PMC10410455 DOI: 10.3389/fimmu.2023.1212757] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/05/2023] [Indexed: 08/12/2023] Open
Abstract
Muscle-specific kinase (MuSK) Myasthenia Gravis (MG) represents a prototypical antibody-mediated disease characterized by predominantly focal muscle weakness (neck, facial, and bulbar muscles) and fatigability. The pathogenic antibodies mostly belong to the immunoglobulin subclass (Ig)G4, a feature which attributes them their specific properties and pathogenic profile. On the other hand, acetylcholine receptor (AChR) MG, the most prevalent form of MG, is characterized by immunoglobulin (Ig)G1 and IgG3 antibodies to the AChR. IgG4 class autoantibodies are impotent to fix complement and only weakly bind Fc-receptors expressed on immune cells and exert their pathogenicity via interfering with the interaction between their targets and binding partners (e.g. between MuSK and LRP4). Cardinal differences between AChR and MuSK-MG are the thymus involvement (not prominent in MuSK-MG), the distinct HLA alleles, and core immunopathological patterns of pathology in neuromuscular junction, structure, and function. In MuSK-MG, classical treatment options are usually less effective (e.g. IVIG) with the need for prolonged and high doses of steroids difficult to be tapered to control symptoms. Exceptional clinical response to plasmapheresis and rituximab has been particularly observed in these patients. Reduction of antibody titers follows the clinical efficacy of anti-CD20 therapies, a feature implying the role of short-lived plasma cells (SLPB) in autoantibody production. Novel therapeutic monoclonal against B cells at different stages of their maturation (like plasmablasts), or against molecules involved in B cell activation, represent promising therapeutic targets. A revolution in autoantibody-mediated diseases is pharmacological interference with the neonatal Fc receptor, leading to a rapid reduction of circulating IgGs (including autoantibodies), an approach already suitable for AChR-MG and promising for MuSK-MG. New precision medicine approaches involve Chimeric autoantibody receptor T (CAAR-T) cells that are engineered to target antigen-specific B cells in MuSK-MG and represent a milestone in the development of targeted immunotherapies. This review aims to provide a detailed update on the pathomechanisms involved in MuSK-MG (cellular and humoral aberrations), fostering the understanding of the latest indications regarding the efficacy of different treatment strategies.
Collapse
Affiliation(s)
- Aigli G. Vakrakou
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleni Karachaliou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Patras, Greece
| | - Vasiliki Zouvelou
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Tzanetakos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Stavroula Salakou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marianna Papadopoulou
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Department of Physiotherapy, University of West Attica, Athens, Greece
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Department of Pharmacy, University of Patras, Patras, Greece
| | - Konstantinos Voumvourakis
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Kilidireas
- First Department of Neurology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Department of Neurology, Henry Dunant Hospital Center, Athens, Greece
| | - Sotirios Giannopoulos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Tsivgoulis
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
- Department of Neurology, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - John Tzartos
- Second Department of Neurology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|
19
|
Zhou Y, Jiang S. Roles of FcRn in Antigen-Presenting Cells during Autoimmunity and a Clinical Evaluation of Efgartigimod as an FcRn Blocker. Pathogens 2023; 12:817. [PMID: 37375507 DOI: 10.3390/pathogens12060817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The immune system is a complex network of multiple cells, tissues, and organs that protects the body against foreign pathogenic invaders. However, the immune system may mistakenly attack healthy cells and tissues due to the cross-reactivity of anti-pathogen immunity, leading to autoimmunity by autoreactive T cells and/or autoantibody-secreting B cells. Autoantibodies can accumulate, resulting in tissue or organ damage. The neonatal crystallizable fragment receptor (FcRn) is an important factor in immune regulation through controlling the trafficking and recycling of immunoglobulin G (IgG) molecules, the most abundant antibody in humoral immunity. In addition to its role in IgG trafficking and recycling, FcRn is also involved in antigen presentation, which is a crucial step in the activation of the adaptive immune response via directing the internalization and trafficking of antigen-bound IgG immune complexes into compartments of degradation and presentation in antigen-presenting cells. Efgartigimod, an FcRn inhibitor, has shown promise in reducing the levels of autoantibodies and alleviating the autoimmune severity of myasthenia gravis, primary immune thrombocytopenia, and pemphigus vulgaris/foliaceus. This article aims to provide an overview of the importance of FcRn in antigen-presenting cells and its potential as a therapeutic target in autoimmune diseases, using efgartigimod as an example.
Collapse
Affiliation(s)
- Yihan Zhou
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
| | - Shisong Jiang
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
| |
Collapse
|
20
|
Madigan LA, Jaime D, Fallon JR. MuSK-BMP signaling in adult muscle stem cells maintains quiescence and regulates myofiber size. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.17.541238. [PMID: 37292636 PMCID: PMC10245747 DOI: 10.1101/2023.05.17.541238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A central question in the biology of adult stem cells is elucidating the signaling pathways regulating their dynamics and function in diverse physiological and age-related contexts. Adult muscle stem cells (Satellite Cells; SCs) are generally quiescent but can activate and contribute to muscle homeostasis and repair. Here we tested the role of the MuSK-BMP pathway in regulating adult SC quiescence and myofiber size. We attenuated MuSK-BMP signaling by deletion of the BMP-binding MuSK Ig3 domain ('ΔIg3-MuSK') and studied the fast TA and EDL muscles. In germ line mutants at 3 months of age SC and myonuclei numbers as well as myofiber size were comparable in ΔIg3-MuSK and WT animals. However, in 5-month-old ΔIg3-MuSK animals SC density was decreased while myofiber size, myonuclear number and grip strength were increased - indicating that SCs had activated and productively fused into the myofibers over this interval. Notably, myonuclear domain size was conserved. Following injury, the mutant muscle fully regenerated with restoration of myofiber size and SC pool to WT levels, indicating that ΔIg3-MuSK SCs maintain full stem cell function. Conditional expression of ΔIg3-MuSK in adult SCs showed that the MuSK-BMP pathway regulates quiescence and myofiber size in a cell autonomous fashion. Transcriptomic analysis revealed that SCs from uninjured ΔIg3-MuSK mice exhibit signatures of activation, including elevated Notch and epigenetic signaling. We conclude that the MuSK-BMP pathway regulates SC quiescence and myofiber size in a cell autonomous, age-dependent manner. Targeting MuSK-BMP signaling in muscle stem cells thus emerges a therapeutic strategy for promoting muscle growth and function in the settings of injury, disease, and aging.
Collapse
|
21
|
Lim JL, Augustinus R, Plomp JJ, Roya-Kouchaki K, Vergoossen DLE, Fillié-Grijpma Y, Struijk J, Thomas R, Salvatori D, Steyaert C, Blanchetot C, Vanhauwaert R, Silence K, van der Maarel SM, Verschuuren JJ, Huijbers MG. Development and characterization of agonistic antibodies targeting the Ig-like 1 domain of MuSK. Sci Rep 2023; 13:7478. [PMID: 37156800 PMCID: PMC10167245 DOI: 10.1038/s41598-023-32641-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/30/2023] [Indexed: 05/10/2023] Open
Abstract
Muscle-specific kinase (MuSK) is crucial for acetylcholine receptor (AChR) clustering and thereby neuromuscular junction (NMJ) function. NMJ dysfunction is a hallmark of several neuromuscular diseases, including MuSK myasthenia gravis. Aiming to restore NMJ function, we generated several agonist monoclonal antibodies targeting the MuSK Ig-like 1 domain. These activated MuSK and induced AChR clustering in cultured myotubes. The most potent agonists partially rescued myasthenic effects of MuSK myasthenia gravis patient IgG autoantibodies in vitro. In an IgG4 passive transfer MuSK myasthenia model in NOD/SCID mice, MuSK agonists caused accelerated weight loss and no rescue of myasthenic features. The MuSK Ig-like 1 domain agonists unexpectedly caused sudden death in a large proportion of male C57BL/6 mice (but not female or NOD/SCID mice), likely caused by a urologic syndrome. In conclusion, these agonists rescued pathogenic effects in myasthenia models in vitro, but not in vivo. The sudden death in male mice of one of the tested mouse strains revealed an unexpected and unexplained role for MuSK outside skeletal muscle, thereby hampering further (pre-) clinical development of these clones. Future research should investigate whether other Ig-like 1 domain MuSK antibodies, binding different epitopes, do hold a safe therapeutic promise.
Collapse
Affiliation(s)
- Jamie L Lim
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Roy Augustinus
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Kasra Roya-Kouchaki
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Dana L E Vergoossen
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Yvonne Fillié-Grijpma
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Josephine Struijk
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Rachel Thomas
- Department PDC-Pathologie, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniela Salvatori
- Veterinary Faculty, Department Clinical Sciences, Universiteit Utrecht, Utrecht, The Netherlands
| | | | | | | | | | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands
| | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2300 RC, Leiden, The Netherlands.
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
| |
Collapse
|
22
|
Prömer J, Barresi C, Herbst R. From phosphorylation to phenotype - Recent key findings on kinase regulation, downstream signaling and disease surrounding the receptor tyrosine kinase MuSK. Cell Signal 2023; 104:110584. [PMID: 36608736 DOI: 10.1016/j.cellsig.2022.110584] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/16/2022] [Accepted: 12/31/2022] [Indexed: 01/04/2023]
Abstract
Muscle-specific kinase (MuSK) is the key regulator of neuromuscular junction development. MuSK acts via several distinct pathways and is responsible for pre- and postsynaptic differentiation. MuSK is unique among receptor tyrosine kinases as activation and signaling are particularly tightly regulated. Initiation of kinase activity requires Agrin, a heparan sulphate proteoglycan derived from motor neurons, the low-density lipoprotein receptor-related protein-4 (Lrp4) and the intracellular adaptor protein Dok-7. There is a great knowledge gap between MuSK activation and downstream signaling. Recent studies using omics techniques have addressed this knowledge gap, thereby greatly contributing to a better understanding of MuSK signaling. Impaired MuSK signaling causes severe muscle weakness as described in congenital myasthenic syndromes or myasthenia gravis but the underlying pathophysiology is often unclear. This review focuses on recent advances in deciphering MuSK activation and downstream signaling. We further highlight latest break-throughs in understanding and treatment of MuSK-related disorders and discuss the role of MuSK in non-muscle tissue.
Collapse
Affiliation(s)
- Jakob Prömer
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Cinzia Barresi
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
23
|
Vanoli F, Mantegazza R. Ravulizumab for the treatment of myasthenia gravis. Expert Opin Biol Ther 2023; 23:235-241. [PMID: 36852670 DOI: 10.1080/14712598.2023.2185131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
INTRODUCTION Myasthenia gravis (MG) is a neurological B-cell mediated autoimmune disorder affecting the neuromuscular junction. MG therapeutics have always relied on nonselective immunosuppression with oral steroids and non-steroidal immunosuppressants, mainly with good clinical response. However, clinical stabilization is often reached at the cost of many troublesome side effects and up to 15% of MG patients are deemed as refractory to conventional immunosuppression. This highlights the need of a more targeted and efficacious therapeutic approach. Results from the randomized-controlled period of the CHAMPION study demonstrate a good safety, tolerability, and efficacy profile of ravulizumab compared to placebo. Like eculizumab, ravulizumab is an anti-C5 monoclonal antibody, but with an enhanced pharmacokinetic profile, that allows dosing every 8 weeks. AREAS COVERED We provide an overview of ravulizumab biological features and results from the phase III CHAMPION MG (NCT03920293) study. EXPERT OPINION Data of the CHAMPION MG trial demonstrate that ravulizumab is effective and safe in the treatment of generalized MG. Having a rapid clinical effect, with long-term clinical response, ravulizumab could represent a selective immunosuppressive drug of choice in the future therapeutic algorithm of MG, where conventional immunosuppressants slowly leave room for newer drugs with a more targeted mechanism of action.
Collapse
Affiliation(s)
- Fiammetta Vanoli
- Neuroimmunology and Neuromuscular Disease Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Renato Mantegazza
- Neuroimmunology and Neuromuscular Disease Department, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| |
Collapse
|
24
|
Sikorski PM, Kusner LL, Kaminski HJ. Myasthenia Gravis. Clin Immunol 2023. [DOI: 10.1016/b978-0-7020-8165-1.00065-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
|
25
|
Harsini S, Rezaei N. Autoimmune diseases. Clin Immunol 2023. [DOI: 10.1016/b978-0-12-818006-8.00001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
26
|
Meisel A, Baggi F, Behin A, Evoli A, Kostera-Pruszczyk A, Mantegazza R, Morales RJ, Punga AR, Sacconi S, Schroeter M, Verschuuren J, Crathorne L, Holmes K, Leite MI. Role of autoantibody levels as biomarkers in the management of patients with myasthenia gravis: A systematic review and expert appraisal. Eur J Neurol 2023; 30:266-282. [PMID: 36094738 DOI: 10.1111/ene.15565] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/26/2022] [Accepted: 09/04/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Although myasthenia gravis (MG) is recognized as an immunoglobulin G autoantibody-mediated disease, the relationship between autoantibody levels and disease activity in MG is unclear. We sought to evaluate this landscape through systematically assessing the evidence, testing the impact of predefined variables on any relationship, and augmenting with expert opinion. METHODS In October 2020, a forum of leading clinicians and researchers in neurology from across Europe (Expert Forum for Rare Autoantibodies in Neurology in Myasthenia Gravis) participated in a series of virtual meetings that took place alongside the conduct of a systematic literature review (SLR). RESULTS Forty-two studies were identified meeting inclusion criteria. Of these, 10 reported some correlation between a patient's autoantibody level and disease severity. Generally, decreased autoantibody levels (acetylcholine receptor, muscle-specific kinase, and titin) were positively and significantly correlated with improvements in disease severity (Quantitative Myasthenia Gravis score, Myasthenia Gravis Composite score, Myasthenia Gravis Activities of Daily Living score, Myasthenia Gravis Foundation of America classification). Given the limited evidence, testing the impact of predefined variables was not feasible. CONCLUSIONS This first SLR to assess whether a correlation exists between autoantibody levels and disease activity in patients with MG has indicated a potential positive correlation, which could have clinical implications in guiding treatment decisions. However, in light of the limited and variable evidence, we cannot currently recommend routine clinical use of autoantibody level testing in this context. For now, patient's characteristics, clinical disease course, and laboratory data (e.g., autoantibody status, thymus histology) should inform management, alongside patient-reported outcomes. We highlight the need for future studies to reach more definitive conclusions on this relationship.
Collapse
Affiliation(s)
- Andreas Meisel
- Department of Neurology, Integrated Myasthenia Gravis Center, NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Fulvio Baggi
- Neuroimmunology and Neuromuscular Diseases Unit, Scientific Institute for Research and Health Care Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Anthony Behin
- Department of Neuromyology, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Institute of Myology, Paris, France
| | - Amelia Evoli
- Catholic University of the Sacred Heart and Agostino Gemelli University Polyclinic Foundation, Scientific Institute for Research and Health Care, Rome, Italy
| | | | - Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, Scientific Institute for Research and Health Care Foundation Carlo Besta Neurological Institute, Milan, Italy
| | | | - Anna Rostedt Punga
- Department of Medical Science, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | | | - Michael Schroeter
- Department of Neurology, University Hospital Cologne, Cologne, Germany
| | - Jan Verschuuren
- Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | - Maria-Isabel Leite
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| |
Collapse
|
27
|
Fichtner ML, Hoehn KB, Ford EE, Mane-Damas M, Oh S, Waters P, Payne AS, Smith ML, Watson CT, Losen M, Martinez-Martinez P, Nowak RJ, Kleinstein SH, O'Connor KC. Reemergence of pathogenic, autoantibody-producing B cell clones in myasthenia gravis following B cell depletion therapy. Acta Neuropathol Commun 2022; 10:154. [PMID: 36307868 PMCID: PMC9617453 DOI: 10.1186/s40478-022-01454-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/12/2022] Open
Abstract
Myasthenia gravis (MG) is an autoantibody-mediated autoimmune disorder of the neuromuscular junction. A small subset of patients (<10%) with MG, have autoantibodies targeting muscle-specific tyrosine kinase (MuSK). MuSK MG patients respond well to CD20-mediated B cell depletion therapy (BCDT); most achieve complete stable remission. However, relapse often occurs. To further understand the immunomechanisms underlying relapse, we studied autoantibody-producing B cells over the course of BCDT. We developed a fluorescently labeled antigen to enrich for MuSK-specific B cells, which was validated with a novel Nalm6 cell line engineered to express a human MuSK-specific B cell receptor. B cells (≅ 2.6 million) from 12 different samples collected from nine MuSK MG patients were screened for MuSK specificity. We successfully isolated two MuSK-specific IgG4 subclass-expressing plasmablasts from two of these patients, who were experiencing a relapse after a BCDT-induced remission. Human recombinant MuSK mAbs were then generated to validate binding specificity and characterize their molecular properties. Both mAbs were strong MuSK binders, they recognized the Ig1-like domain of MuSK, and showed pathogenic capacity when tested in an acetylcholine receptor (AChR) clustering assay. The presence of persistent clonal relatives of these MuSK-specific B cell clones was investigated through B cell receptor repertoire tracing of 63,977 unique clones derived from longitudinal samples collected from these two patients. Clonal variants were detected at multiple timepoints spanning more than five years and reemerged after BCDT-mediated remission, predating disease relapse by several months. These findings demonstrate that a reservoir of rare pathogenic MuSK autoantibody-expressing B cell clones survive BCDT and reemerge into circulation prior to manifestation of clinical relapse. Overall, this study provides both a mechanistic understanding of MuSK MG relapse and a valuable candidate biomarker for relapse prediction.
Collapse
Affiliation(s)
- Miriam L Fichtner
- Department of Neurology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA
- Department of Immunobiology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA
| | - Kenneth B Hoehn
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Easton E Ford
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Marina Mane-Damas
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Sangwook Oh
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Patrick Waters
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Aimee S Payne
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Melissa L Smith
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Corey T Watson
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, KY, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, USA
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Richard J Nowak
- Department of Neurology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA
| | - Steven H Kleinstein
- Department of Immunobiology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
- Program in Computational Biology & Bioinformatics, Yale University, New Haven, CT, USA
| | - Kevin C O'Connor
- Department of Neurology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA.
- Department of Immunobiology, Yale University School of Medicine, 300 George Street - Room 353J, New Haven, CT, 06511, USA.
| |
Collapse
|
28
|
Jentzer A, Attal A, Roué C, Raymond J, Lleixà C, Illa I, Querol L, Taieb G, Devaux J. IgG4 Valency Modulates the Pathogenicity of Anti–Neurofascin-155 IgG4 in Autoimmune Nodopathy. NEUROLOGY - NEUROIMMUNOLOGY NEUROINFLAMMATION 2022; 9:9/5/e200014. [PMID: 35948442 PMCID: PMC9365386 DOI: 10.1212/nxi.0000000000200014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022]
Abstract
Background and Objectives IgG4 autoantibodies to neurofascin-155 (Nfasc155) are associated with a subgroup of patients with chronic inflammatory demyelinating polyneuropathy (CIDP), currently named autoimmune nodopathy. We previously demonstrated that those antibodies alter conduction along myelinated axons by inducing Nfasc155 depletion and paranode destruction. In blood, IgG4 have the potency to exchange their moiety with other unrelated IgG4 through a process called Fab-arm exchange (FAE). This process results in functionally monovalent antibodies and may affect the pathogenicity of autoantibodies. Here, we examined this issue and whether FAE is beneficial or detrimental for Nfasc155 autoimmune nodopathy. Methods The bivalency and monospecificity of anti-Nfasc155 were examined by sandwich ELISA in 10 reactive patients, 10 unreactive CIDP patients, and 10 healthy controls. FAE was induced in vitro using reduced glutathione and unreactive IgG4, and the ratio of the κ:λ light chain was monitored. To determine the pathogenic potential of bivalent anti-Nfasc155 IgG4, autoantibodies derived from patients were enzymatically cleaved into monovalent Fab and bivalent F(ab’)2 or swapped with unreactive IgG4 and then were injected in neonatal animals. Results Monospecific bivalent IgG4 against Nfasc155 were detected in the serum of all reactive patients, indicating that a fraction of IgG4 have not undergone FAE in situ. These IgG4 were, nonetheless, capable of engaging into FAE with unreactive IgG4 in vitro, and this decreased the levels of monospecific antibodies and modulated the ratio of the κ:λ light chain. When injected in animals, monovalent anti-Nfasc155 Fab did not alter the formation of paranodes; by contrast, both native anti-Nfasc155 IgG4 and F(ab’)2 fragments strongly impaired paranode formation. The promotion of FAE with unreactive IgG4 also strongly diminished the pathogenic potential of anti-Nfasc155 IgG4 in animals and decreased IgG4 clustering on Schwann cells. Discussion Our findings demonstrate that monospecific and bivalent anti-Nfasc155 IgG4 are detected in patients and that those autoantibodies are the pathogenic ones. The transformation of anti-Nfasc155 IgG4 into monovalent Fab or functionally monovalent IgG4 through FAE strongly decreases paranodal alterations. Bivalency thus appears crucial for Nfasc155 clustering and paranode destruction.
Collapse
Affiliation(s)
- Alexandre Jentzer
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Arthur Attal
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Clémence Roué
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Julie Raymond
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Cinta Lleixà
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Isabel Illa
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Luis Querol
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Guillaume Taieb
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain
| | - Jérôme Devaux
- From the Institute for Neurosciences of Montpellier (A.J., A.A., G.T., J.D.), INSERM U1051, Montpellier University, Hôpital Saint Eloi, France; Department of Immunology (A.J.), CHU Montpellier, France ; Department of Neurology (A.A., G.T.), CHU Montpellier, Hôpital Gui de Chauliac, France; Institut de Génomique Fonctionnelle (C.R., J.R., G.T., J.D.), CNRS UMR5203, France; and Neuromuscular Diseases Unit (C.L., I.I., L.Q.), Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Spain.
| |
Collapse
|
29
|
Cardiac troponin T and autoimmunity in skeletal muscle aging. GeroScience 2022; 44:2025-2045. [PMID: 35034279 PMCID: PMC9616986 DOI: 10.1007/s11357-022-00513-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/05/2022] [Indexed: 01/03/2023] Open
Abstract
Age-related muscle mass and strength decline (sarcopenia) impairs the performance of daily living activities and can lead to mobility disability/limitation in older adults. Biological pathways in muscle that lead to mobility problems have not been fully elucidated. Immunoglobulin G (IgG) infiltration in muscle is a known marker of increased fiber membrane permeability and damage vulnerability, but whether this translates to impaired function is unknown. Here, we report that IgG1 and IgG4 are abundantly present in the skeletal muscle (vastus lateralis) of ~ 50% (11 out of 23) of older adults (> 65 years) examined. Skeletal muscle IgG1 was inversely correlated with physical performance (400 m walk time: r = 0.74, p = 0.005; SPPB score: r = - 0.73, p = 0.006) and muscle strength (r = - 0.6, p = 0.05). In a murine model, IgG was found to be higher in both muscle and blood of older, versus younger, C57BL/6 mice. Older mice with a higher level of muscle IgG had lower motor activity. IgG in mouse muscle co-localized with cardiac troponin T (cTnT) and markers of complement activation and apoptosis/necroptosis. Skeletal muscle-inducible cTnT knockin mice also showed elevated IgG in muscle and an accelerated muscle degeneration and motor activity decline with age. Most importantly, anti-cTnT autoantibodies were detected in the blood of cTnT knockin mice, old mice, and older humans. Our findings suggest a novel cTnT-mediated autoimmune response may be an indicator of sarcopenia.
Collapse
|
30
|
Lenti MV, Rossi CM, Melazzini F, Gastaldi M, Bugatti S, Rotondi M, Bianchi PI, Gentile A, Chiovato L, Montecucco C, Corazza GR, Di Sabatino A. Seronegative autoimmune diseases: A challenging diagnosis. Autoimmun Rev 2022; 21:103143. [PMID: 35840037 DOI: 10.1016/j.autrev.2022.103143] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/10/2022] [Indexed: 12/19/2022]
Abstract
Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.
Collapse
Affiliation(s)
- Marco Vincenzo Lenti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Carlo Maria Rossi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Federica Melazzini
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Serena Bugatti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Mario Rotondi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Paola Ilaria Bianchi
- Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonella Gentile
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Luca Chiovato
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Carlomaurizio Montecucco
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Gino Roberto Corazza
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonio Di Sabatino
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy.
| |
Collapse
|
31
|
Jeon MY, Seok JM, Fujihara K, Kim BJ. Autoantibodies in central nervous system and neuromuscular autoimmune disorders: A narrative review. PRECISION AND FUTURE MEDICINE 2022. [DOI: 10.23838/pfm.2021.00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The discovery of novel autoantibodies in neurological disorders contributes to a better understanding of its pathogenesis, improves the accuracy of diagnosis, and leads to new treatment strategies. Advances in techniques for the screening and detection of autoantibodies have enabled the discovery of new antibodies in the central nervous system (CNS) and neuromuscular diseases. Cell-based assays using live or fixed cells overexpressing target antigens are widely used for autoantibody-based diagnosis in clinical practice. Common pathogenic autoantibodies are unknown in most patients with multiple sclerosis (MS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Novel pathogenic autoantibodies to aquaporin-4 and myelin oligodendrocyte glycoprotein (MOG) have been identified in neuromyelitis optica spectrum disorder and MOG antibody-associated disease, respectively. These diseases have clinical similarities to MS, but with the discovery of pathogenic autoantibodies, they are now recognized as distinct disease entities. Antibodies to paranodal membrane proteins such as neurofascin-155, contactin‑1, contactin‑associated protein‑1 in CIDP and muscle-specific kinase and low-density lipoprotein receptor–related protein 4 in myasthenia gravis were added to the profiles of autoantibodies in neurological disorders. Despite the relatively low frequency of seropositivity, autoantibody detection is currently essential for the clinical diagnosis of CNS and neuromuscular autoimmune disorders, and differential approaches to seropositive patients will contribute to more personalized medicine. We reviewed recent discoveries of autoantibodies and their clinical implications in CNS and neuromuscular disorders.
Collapse
|
32
|
Dalakas MC. Role of complement, anti-complement therapeutics, and other targeted immunotherapies in myasthenia gravis. Expert Rev Clin Immunol 2022; 18:691-701. [PMID: 35730504 DOI: 10.1080/1744666x.2022.2082946] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Several patients with myasthenia gravis (MG) do not adequately respond to available drugs or exhibit poor tolerance, necessitating the need for new therapies. AREAS COVERED The paper discusses the rapidly evolving target-specific immunotherapies that promise long-standing remissions in the management of MG. It is specifically focused on the role of complement, anti-complement therapeutics, and the anti-FcRn and B cell monoclonals. EXPERT OPINION Anti-AChR antibodies cause internalization of the receptors and activate complement leading to in situ MAC formation that damages the post-synaptic membrane of the neuromuscular junction. Inhibiting MAC formation by antibodies targeting key complements subcomponents is a reasonable therapeutic goal. Indeed, the anti-C5 monoclonal antibodies, Eculizumab, Ravulizumab, and Zilucoplan, have been successfully tested in MG with Eculizumab first and now Ravulizumab FDA-approved for refractory MG based on sustained long-term benefits. Among the biologics that inhibit FcRn, Efgartigimod caused rapid reduction of the circulating IgG in the lysosomes, and induced sustained clinical remission with good safety profile leading to FDA-approved indication. Anti-B cell agents, like Rituximab, can induce sustained long-term remissions, especially in IgG4 antibody-mediated Musk-MG, by targeting short-lived antibody-secreting plasmablasts. These biologics offer effective targeted immunotherapies with good tolerance promising to change the therapeutic algorithm in the chronic MG management.
Collapse
Affiliation(s)
- Marinos C Dalakas
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA.,Neuroimmunology Unit, National and Kapodistrian University, University of Athens Medical School, Athens, Greece
| |
Collapse
|
33
|
Novel treatment strategies for acetylcholine receptor antibody-positive myasthenia gravis and related disorders. Autoimmun Rev 2022; 21:103104. [PMID: 35452851 DOI: 10.1016/j.autrev.2022.103104] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/18/2022] [Indexed: 11/21/2022]
Abstract
The presence of autoantibodies directed against the muscle nicotinic acetylcholine receptor (AChR) is the most common cause of myasthenia gravis (MG). These antibodies damage the postsynaptic membrane of the neuromuscular junction and cause muscle weakness by depleting AChRs and thus impairing synaptic transmission. As one of the best-characterized antibody-mediated autoimmune diseases, AChR-MG has often served as a reference model for other autoimmune disorders. Classical pharmacological treatments, including broad-spectrum immunosuppressive drugs, are effective in many patients. However, complete remission cannot be achieved in all patients, and 10% of patients do not respond to currently used therapies. This may be attributed to production of autoantibodies by long-lived plasma cells which are resistant to conventional immunosuppressive drugs. Hence, novel therapies specifically targeting plasma cells might be a suitable therapeutic approach for selected patients. Additionally, in order to reduce side effects of broad-spectrum immunosuppression, targeted immunotherapies and symptomatic treatments will be required. This review presents established therapies as well as novel therapeutic approaches for MG and related conditions, with a focus on AChR-MG.
Collapse
|
34
|
Koneczny I, Tzartos J, Mané-Damas M, Yilmaz V, Huijbers MG, Lazaridis K, Höftberger R, Tüzün E, Martinez-Martinez P, Tzartos S, Leypoldt F. IgG4 Autoantibodies in Organ-Specific Autoimmunopathies: Reviewing Class Switching, Antibody-Producing Cells, and Specific Immunotherapies. Front Immunol 2022; 13:834342. [PMID: 35401530 PMCID: PMC8986991 DOI: 10.3389/fimmu.2022.834342] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 02/28/2022] [Indexed: 12/24/2022] Open
Abstract
Organ-specific autoimmunity is often characterized by autoantibodies targeting proteins expressed in the affected tissue. A subgroup of autoimmunopathies has recently emerged that is characterized by predominant autoantibodies of the IgG4 subclass (IgG4-autoimmune diseases; IgG4-AID). This group includes pemphigus vulgaris, thrombotic thrombocytopenic purpura, subtypes of autoimmune encephalitis, inflammatory neuropathies, myasthenia gravis and membranous nephropathy. Although the associated autoantibodies target specific antigens in different organs and thus cause diverse syndromes and diseases, they share surprising similarities in genetic predisposition, disease mechanisms, clinical course and response to therapies. IgG4-AID appear to be distinct from another group of rare immune diseases associated with IgG4, which are the IgG4-related diseases (IgG4-RLD), such as IgG4-related which have distinct clinical and serological properties and are not characterized by antigen-specific IgG4. Importantly, IgG4-AID differ significantly from diseases associated with IgG1 autoantibodies targeting the same organ. This may be due to the unique functional characteristics of IgG4 autoantibodies (e.g. anti-inflammatory and functionally monovalent) that affect how the antibodies cause disease, and the differential response to immunotherapies of the IgG4 producing B cells/plasmablasts. These clinical and pathophysiological clues give important insight in the immunopathogenesis of IgG4-AID. Understanding IgG4 immunobiology is a key step towards the development of novel, IgG4 specific treatments. In this review we therefore summarize current knowledge on IgG4 regulation, the relevance of class switching in the context of health and disease, describe the cellular mechanisms involved in IgG4 production and provide an overview of treatment responses in IgG4-AID.
Collapse
Affiliation(s)
- Inga Koneczny
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Inga Koneczny,
| | - John Tzartos
- Neuroimmunology, Tzartos NeuroDiagnostics, Athens, Greece
- 2nd Department of Neurology, “Attikon” University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Marina Mané-Damas
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Vuslat Yilmaz
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Maartje G. Huijbers
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden, Netherlands
| | - Konstantinos Lazaridis
- Department of Immunology, Laboratory of Immunology, Hellenic Pasteur Institute, Athens, Greece
| | - Romana Höftberger
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Erdem Tüzün
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Pilar Martinez-Martinez
- Research Group Neuroinflammation and Autoimmunity, Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Socrates Tzartos
- Neuroimmunology, Tzartos NeuroDiagnostics, Athens, Greece
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Frank Leypoldt
- Neuroimmunology, Institute of Clinical Chemistry and Department of Neurology, UKSH Kiel/Lübeck, Kiel University, Kiel, Germany
| |
Collapse
|
35
|
Berger B, Schröter N. Changes in antibody titers and clinical course in myasthenia gravis retrospective study. PROGRESS IN NEUROLOGY AND PSYCHIATRY 2022. [DOI: 10.1002/pnp.738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Benjamin Berger
- Dr Berger is a Senior Physician and Dr Schröter is an Assistant Physician at the Clinic of Neurology and Neurophysiology, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Nils Schröter
- Dr Berger is a Senior Physician and Dr Schröter is an Assistant Physician at the Clinic of Neurology and Neurophysiology, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| |
Collapse
|
36
|
Huijbers MG, Marx A, Plomp JJ, Le Panse R, Phillips WD. Advances in the understanding of disease mechanisms of autoimmune neuromuscular junction disorders. Lancet Neurol 2022; 21:163-175. [DOI: 10.1016/s1474-4422(21)00357-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/15/2021] [Accepted: 10/06/2021] [Indexed: 01/19/2023]
|
37
|
Maslinska M, Dmowska-Chalaba J, Jakubaszek M. The Role of IgG4 in Autoimmunity and Rheumatic Diseases. Front Immunol 2022; 12:787422. [PMID: 35145508 PMCID: PMC8821096 DOI: 10.3389/fimmu.2021.787422] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/23/2021] [Indexed: 12/15/2022] Open
Abstract
The distinguishing of the IgG4-related disease (IgG4-RD) from among other rheumatic diseases has brought attention to the IgG4 subclass of immunoglobulins. It is the least numerous subclass among immunoglobulins G. In general, IgG4 is considered to be non-inflammatory and tolerance inducing, due to its unique structure. However, in IgG4-RD this antibody plays a pathogenic role in activation of the fibrinogenesis and of the inflammatory process; there are also suggestions that it may be a marker of an abnormal inflammatory response. The importance of IgG4 for the pathogenesis of allergic diseases, with a vital role of its ratio to immunoglobulin E (IgE/IgG4 ratio), has been known for years. The role of IgG4 in the course and pathogenesis of rheumatic diseases is still being researched and is not yet fully understood. Increased IgG4 levels have been revealed in rheumatoid arthritis, although no clear link between this phenomenon and disease activity has been demonstrated. There are articles on the potential importance of IgG4 concentration (of both elevated and decreased serum levels) in Sjogren’s syndrome. Additionally, anti-nuclear IgG4 antibody significant titers have been detected in SLE patients, and it has been suggested that the effect of these antibodies on complement consumption and the production of proinflammatory cytokines may play a role in inhibiting the progression of SLE. IgG4 plays a role in autoimmune diseases other than rheumatic diseases, such as pemphigus, bullous pemphigoid, idiopathic membranous glomerulonephritis, or myasthenia gravis, but also in helmints infections. Research shows the importance of IgG4 in malignancy of neoplasms. Melanoma cells are known to stimulate IgG4 production through a modified Th2-based inflammatory response. The role of this immunoglobulin in cholangiocarcinoma is also considered as possible. The aim of this review article is to discuss the current knowledge of IgG4 not only from the perspective of the IgG4-RD but also from a point of view of other autoimmune diseases with particular emphasis on rheumatic diseases.
Collapse
|
38
|
Jiao L, Li H, Guo S. Eculizumab treatment for myasthenia gravis subgroups: 2021 update. J Neuroimmunol 2022; 362:577767. [PMID: 34823117 DOI: 10.1016/j.jneuroim.2021.577767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 01/21/2023]
Abstract
Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.
Collapse
Affiliation(s)
- Li Jiao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Honghao Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China.
| |
Collapse
|
39
|
Gomathy SB, Agarwal A, Vishnu VY. Molecular Therapy in Myasthenia Gravis. Neurology 2022. [DOI: 10.17925/usn.2022.18.1.49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disorder caused by antibodies that act against the myoneural junction. Conventional immunosuppressants such as corticosteroids, azathioprine and mycophenolate are associated with long-term side effects and many patients do not achieve remission and may become refractory. Thus, there is an unmet need for target-specific therapies that act faster, have fewer side effects and lead to stable disease remission. However, many of the novel therapeutic agents being described are not meeting their primary endpoints. We reviewed the current status of novel immunotherapies for MG, their mechanisms of action, along with the side effect profiles. Fast onset of action, sustained disease remission and relatively low frequency of side effects of the new agents are attractive. However, the unknown long-term safety and high cost are precluding factors. Better preclinical studies and more randomized trials are needed before novel agents are routinely employed.
Collapse
|
40
|
Wang S, Yang H, Guo R, Wang L, Zhang Y, Lv J, Zhao X, Zhang J, Fang H, Zhang Q, Zhang Y, Yang J, Cui X, Gao P, Chang T, Gao F. Antibodies to Full-Length Agrin Protein in Chinese Patients With Myasthenia Gravis. Front Immunol 2021; 12:753247. [PMID: 34956185 PMCID: PMC8692888 DOI: 10.3389/fimmu.2021.753247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
This study aimed to establish a cell-based assay (CBA) for the detection of agrin antibodies (Agrin-Ab) to explore the clinical features of agrin antibody-positive Chinese patients with myasthenia gravis (Agrin-MG). We developed a CBA based on the human full-length agrin protein expressed in HEK293T cells for the reliable and efficient detection of Agrin-Ab. Clinical data and serum samples were collected from 1948 MG patients in 26 provinces in China. The demographic and clinical features of Agrin-MG patients were compared with those of other MG patient subsets. Eighteen Agrin-MG cases were identified from 1948 MG patients. Nine patients were Agrin-Ab positive, and nine were AChR-Ab and Agrin-Ab double-positive (Agrin/AChR-MG). Eleven (61.11%) patients were males older than 40 years of age. The initial symptom in 13 (81.25%) cases was ocular weakness. Occasionally, the initial symptom was limb-girdle weakness (two cases) or bulbar muscle weakness (one case). Agrin-MG patients demonstrated slight improvement following treatment with either acetylcholinesterase inhibitor or prednisone; however, the combination of the two drugs could effectively relieve MG symptoms. In China, Agrin-MG demonstrated seropositivity rates of 0.92%. These patients were commonly middle-aged or elderly men. The patients usually presented weakness in the ocular, bulbar, and limb muscles, which may be combined with thymoma. These patients have more severe diseases, although the combination of pyridostigmine and prednisone was usually effective in relieving symptoms.
Collapse
Affiliation(s)
- Shumin Wang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Haonan Yang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,BGI College, Zhengzhou University, Zhengzhou, China
| | - Rongjing Guo
- Department of Neurology, Tangdu Hospital, The Air Force Medical University, Xi'an, China
| | - Lulu Wang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,Department of Neurology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yingna Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jie Lv
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Xue Zhao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jing Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Hua Fang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Qingyong Zhang
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yunke Zhang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of Traditional Chinese Medicine (TCM), Zhengzhou, China
| | - Junhong Yang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of Traditional Chinese Medicine (TCM), Zhengzhou, China
| | - Xinzheng Cui
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Peiyang Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Ting Chang
- Department of Neurology, Tangdu Hospital, The Air Force Medical University, Xi'an, China
| | - Feng Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| |
Collapse
|
41
|
Bortone F, Scandiffio L, Cavalcante P, Mantegazza R, Bernasconi P. Epstein-Barr Virus in Myasthenia Gravis: Key Contributing Factor Linking Innate Immunity with B-Cell-Mediated Autoimmunity. Infect Dis (Lond) 2021. [DOI: 10.5772/intechopen.93777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Epstein-Barr virus (EBV), a common human herpes virus latently infecting most of the world’s population with periodic reactivations, is the main environmental factor suspected to trigger and/or sustain autoimmunity by its ability to disrupt B-cell tolerance checkpoints. Myasthenia gravis (MG) is a prototypic autoimmune disorder, mostly caused by autoantibodies to acetylcholine receptor (AChR) of the neuromuscular junction, which cause muscle weakness and fatigability. Most patients display hyperplastic thymus, characterized by ectopic germinal center formation, chronic inflammation, exacerbated Toll-like receptor activation, and abnormal B-cell activation. After an overview on MG clinical features and intra-thymic pathogenesis, in the present chapter, we describe our main findings on EBV presence in MG thymuses, including hyperplastic and thymoma thymuses, in relationship with innate immunity activation and data from other autoimmune conditions. Our overall data strongly indicate a critical contribution of EBV to innate immune dysregulation and sustained B-cell-mediated autoimmune response in the pathological thymus of MG patients.
Collapse
|
42
|
Lim AH, Wong S, Nguyen NQ. Eosinophilic Esophagitis and IgG4: Is There a Relationship? Dig Dis Sci 2021; 66:4099-4108. [PMID: 33534011 DOI: 10.1007/s10620-020-06788-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/14/2020] [Indexed: 02/06/2023]
Abstract
Our knowledge of the pathophysiology of eosinophilic esophagitis is constantly evolving. There is significant association between eosinophilic esophagitis and atopy; however, multiple studies have refuted the role of IgE in its pathogenesis. Instead, new data have demonstrated an elevated IgG4 level in patients with eosinophilic esophagitis. We review the current understanding of eosinophilic esophagitis pathogenesis and highlight the increasing evidence for the role of IgG4.
Collapse
Affiliation(s)
- Amanda H Lim
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, North Terrace, 5000, Adelaide, SA, Australia
| | - Stephanie Wong
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, North Terrace, 5000, Adelaide, SA, Australia
| | - Nam Q Nguyen
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, North Terrace, 5000, Adelaide, SA, Australia. .,Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.
| |
Collapse
|
43
|
Beladakere Ramaswamy S, Singh S, Hooshmand S, Junsang C, Sweeney M, Govindarajan R. Current and Upcoming Treatment Modalities in Myasthenia Gravis. J Clin Neuromuscul Dis 2021; 23:75-99. [PMID: 34808650 DOI: 10.1097/cnd.0000000000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
ABSTRACT Myasthenia gravis (MG) is one of the extensively studied autoimmune disorder. There has been a dramatic increase in research to further understand molecular pathogenesis of MG and clinical trials for new drugs in MG treatment in the past decade. This review article is to consolidate the available information in simple terms with students, residents, and fellows as target audience for easy learning and help application of this knowledge to clinical practice.
Collapse
|
44
|
Wolfe GI, Ward ES, de Haard H, Ulrichts P, Mozaffar T, Pasnoor M, Vidarsson G. IgG regulation through FcRn blocking: A novel mechanism for the treatment of myasthenia gravis. J Neurol Sci 2021; 430:118074. [PMID: 34563918 DOI: 10.1016/j.jns.2021.118074] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 09/04/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
The neonatal Fc receptor (FcRn) is an MHC class I-like molecule that is widely distributed in mammalian organs, tissues, and cells. FcRn is critical to maintaining immunoglobulin G (IgG) and albumin levels through rescuing these molecules from lysosomal degradation. IgG autoantibodies are associated with many autoimmune diseases, including myasthenia gravis (MG), a rare neuromuscular autoimmune disease that causes debilitating and, in its generalized form (gMG), potentially life-threatening muscle weakness. IgG autoantibodies are directly pathogenic in MG and target neuromuscular junction proteins, causing neuromuscular transmission failure. Treatment approaches that reduce autoantibody levels, such as therapeutic plasma exchange and intravenous immunoglobulin, have been shown to be effective for gMG patients but are not indicated as ongoing maintenance therapies and can be associated with burdensome side effects. Agents that block FcRn-mediated recycling of IgG represent a rational and promising approach for the treatment of gMG. Blocking FcRn allows targeted reduction of all IgG subtypes without decreasing concentrations of other Ig isotypes; therefore, FcRn blocking could be a safe and effective treatment strategy for a broad population of gMG patients. Several FcRn-blocking antibodies and one antibody Fc fragment have been developed and are currently in various stages of clinical development. This article describes the mechanism of FcRn blockade as a novel approach for IgG-mediated disease therapy and reviews promising clinical data using such FcRn blockers for the treatment of gMG.
Collapse
Affiliation(s)
- Gil I Wolfe
- Department of Neurology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, SUNY, Buffalo, NY, USA.
| | - E Sally Ward
- Centre for Cancer Immunology, Faculty of Medicine, University of Southampton, SO16 6YD, UK
| | - Hans de Haard
- argenx, Zwijnaarde, Belgium, University of California, Irvine, CA, USA
| | - Peter Ulrichts
- argenx, Zwijnaarde, Belgium, University of California, Irvine, CA, USA
| | - Tahseen Mozaffar
- Department of Neurology, University of California, Irvine, CA, USA
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Gestur Vidarsson
- Sanquin Research, and Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
45
|
Ziogas DC, Mandellos D, Theocharopoulos C, Lialios PP, Bouros S, Ascierto PA, Gogas H. Neuromuscular Complications of Targeted Anticancer Agents: Can Tyrosine Kinase Inhibitors Induce Myasthenia Gravis? Getting Answers From a Case Report up to a Systematic Review. Front Oncol 2021; 11:727010. [PMID: 34722270 PMCID: PMC8554100 DOI: 10.3389/fonc.2021.727010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/23/2021] [Indexed: 11/29/2022] Open
Abstract
More than 40 tyrosine kinase inhibitors (TKIs) have received hematological or oncological indications over the past 20 years, following the approval of imatinib, and many others are currently being tested in clinical and preclinical level. Beyond their common toxicities, no certain agent from this large class of molecularly targeted therapies was strongly associated with “off-target” impairment of neuromuscular transmission, and although myasthenia gravis (MG) is a well-characterized autoimmune disorder, only few sporadic events proven by serologically detected causative autoantibodies and/or by positive electrophysiological tests are reported in the literature. Herein, we present the first case of anti-MUSK (+) MG in a woman with metastatic BRAF-mutant melanoma after long-term treatment with dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor). Triggered by this report, a systematic literature review was conducted, summarizing all other cancer cases that developed MG, after exposure to any type of targeted agent and regardless of the underlying malignancy. All available data on the clinical diagnosis, the potential of administered TKIs to induce a seropositive myasthenic syndrome, the immune and non-immune-mediated pathogenesis of postsynaptic damage, and the challenging management of this neuromuscular toxicity were collected and discussed. In the presented case, MG was confirmed by both autoantibodies and nerve-conduction tests, while its reactivation after TKIs rechallenge supports a more than coincidental association. The following review identified 12 cancer cases with TKI-related MG in six case reports and one case series. In most of them, the myasthenia diagnosis was challenging, since the clinical symptomatology of fatigable weakness was not corroborating with consistent laboratory and electrophysiological findings. In fact, anti-AchR titers were positive in five and anti-MuSK only in the abovementioned individual. The symptomatology corresponded to TKI discontinuation and standard treatment with pyridostigmine and prednisolone; intravenous immunoglobulin was added only in three, and two required mechanical ventilation. In an era where TKIs will be prescribed more frequently for various malignancies, even in combinations with immune-checkpoint inhibitors, this report synthesizes their risk for neuromuscular complications and increases the clinicians’ awareness in order to extend the on-treatment and overall survival of TKI-treated cancer patients.
Collapse
Affiliation(s)
- Dimitrios C Ziogas
- First Department of Medicine, National and Kapodistrian University of Athens, School of Medicine, Laiko General Hospital, Athens, Greece
| | | | - Charalampos Theocharopoulos
- First Department of Medicine, National and Kapodistrian University of Athens, School of Medicine, Laiko General Hospital, Athens, Greece
| | - Panagiotis-Petros Lialios
- First Department of Medicine, National and Kapodistrian University of Athens, School of Medicine, Laiko General Hospital, Athens, Greece
| | - Spyros Bouros
- First Department of Medicine, National and Kapodistrian University of Athens, School of Medicine, Laiko General Hospital, Athens, Greece
| | - Paolo A Ascierto
- Department of Melanoma, Cancer Immunotherapy and Development Therapeutics, Istituto Nazionale Tumori IRCCS Fondazione Pascale, Napoli, Italy
| | - Helen Gogas
- First Department of Medicine, National and Kapodistrian University of Athens, School of Medicine, Laiko General Hospital, Athens, Greece
| |
Collapse
|
46
|
Yu Z, Zhang M, Jing H, Chen P, Cao R, Pan J, Luo B, Yu Y, Quarles BM, Xiong W, Rivner MH, Mei L. Characterization of LRP4/Agrin Antibodies From a Patient With Myasthenia Gravis. Neurology 2021; 97:e975-e987. [PMID: 34233932 PMCID: PMC8448554 DOI: 10.1212/wnl.0000000000012463] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/22/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVE To determine whether human anti-LRP4/agrin antibodies are pathogenic in mice and to investigate underpinning pathogenic mechanisms. METHODS Immunoglobulin (Ig) was purified from a patient with myasthenia gravis (MG) with anti-LRP4/agrin antibodies and transferred to mice. Mice were characterized for body weight, muscle strength, twitch and tetanic force, neuromuscular junction (NMJ) functions including compound muscle action potential (CMAP) and endplate potentials, and NMJ structure. Effects of the antibodies on agrin-elicited muscle-specific tyrosine kinase (MuSK) activation and AChR clustering were studied and the epitopes of these antibodies were identified. RESULTS Patient Ig-injected mice had MG symptoms, including weight loss and muscle weakness. Decreased CMAPs, reduced twitch and tetanus force, compromised neuromuscular transmission, and NMJ fragmentation and distortion were detected in patient Ig-injected mice. Patient Ig inhibited agrin-elicited MuSK activation and AChR clustering. The patient Ig recognized the β3 domain of LRP4 and the C-terminus of agrin and reduced agrin-enhanced LRP4-MuSK interaction. DISCUSSION Anti-LRP4/agrin antibodies in the patient with MG is pathogenic. It impairs the NMJ by interrupting agrin-dependent LRP4-MuSK interaction.
Collapse
Affiliation(s)
- Zheng Yu
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Meiying Zhang
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Hongyang Jing
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Peng Chen
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Rangjuan Cao
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Jinxiu Pan
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Bin Luo
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Yue Yu
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Brandy M Quarles
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Wencheng Xiong
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Michael H Rivner
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH.
| | - Lin Mei
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH.
| |
Collapse
|
47
|
Basile U, Napodano C, Gulli F, Pocino K, Di Santo R, Todi L, Basile V, Provenzano C, Ciasca G, Marino M. Laboratory Investigation of Hybrid IgG4 k/λ in MuSK Positive Myasthenia Gravis. Int J Mol Sci 2021; 22:ijms22179142. [PMID: 34502051 PMCID: PMC8430634 DOI: 10.3390/ijms22179142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 08/03/2021] [Accepted: 08/14/2021] [Indexed: 12/29/2022] Open
Abstract
Myasthenia gravis with antibodies (Abs) against the muscle-specific tyrosine kinase (MuSK) is a rare autoimmune disorder (AD) of the neuromuscular junction (NMJ) and represents a prototype of AD with proven IgG4-mediated pathogenicity. Thanks to the mechanism of Fab-arm exchange (FAE) occurring in vivo, resulting MuSK IgG4 k/λ Abs increase their interference on NMJ and pathogenicity. The characterization of hybrid MuSK IgG4 as a biomarker for MG management is poorly investigated. Here, we evaluated total IgG4, hybrid IgG4 k/λ, and the hybrid/total ratio in 14 MuSK-MG sera in comparison with 24 from MG with Abs against acetylcholine receptor (AChR) that represents the not IgG4-mediated MG form. In both subtypes of MG, we found that the hybrid/total ratio reflects distribution reported in normal individuals; instead, when we correlated the hybrid/total ratio with specific immune-reactivity we found a positive correlation only with anti-MuSK titer, with a progressive increase of hybrid/total mean values with increasing disease severity, indirectly confirming that most part of hybrid IgG4 molecules are engaged in the anti-MuSK pathogenetic immune-reactivity. Further analysis is necessary to strengthen the significance of this less unknown biomarker, but we retain it is full of a diagnostic-prognostic powerful potential for the management of MuSK-MG.
Collapse
Affiliation(s)
- Umberto Basile
- Dipartimento di Scienze di Laboratorio e Infettivologiche, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
| | | | - Francesca Gulli
- Laboratorio di Patologia Clinica, Ospedale Madre Giuseppina Vannini, 00177 Rome, Italy;
| | - Krizia Pocino
- Unità Operativa Complessa Patologia Clinica, Ospedale Generale di Zona, San Pietro Fatebenefratelli, 00189 Rome, Italy;
| | - Riccardo Di Santo
- Dipartimento di Neuroscienze, Sezione di Fisica, Fondazione Policlinico “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (R.D.S.); (G.C.)
| | - Laura Todi
- Dipartimento di Medicina e Chirurgia Traslazionale, Sezione di Patologia Generale, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (L.T.); (C.P.)
| | - Valerio Basile
- Clinical Pathology Unit and Cancer Biobank, Department of Research, Advanced Diagnostics and Technological Innovation, IFO-Regina Elena National Cancer Institute, 00128 Rome, Italy;
| | - Carlo Provenzano
- Dipartimento di Medicina e Chirurgia Traslazionale, Sezione di Patologia Generale, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (L.T.); (C.P.)
| | - Gabriele Ciasca
- Dipartimento di Neuroscienze, Sezione di Fisica, Fondazione Policlinico “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (R.D.S.); (G.C.)
| | - Mariapaola Marino
- Dipartimento di Medicina e Chirurgia Traslazionale, Sezione di Patologia Generale, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy; (L.T.); (C.P.)
- Correspondence:
| |
Collapse
|
48
|
Myasthenia Gravis-An Analysis of Multimodal Evoked Potentials. Brain Sci 2021; 11:brainsci11081057. [PMID: 34439676 PMCID: PMC8392656 DOI: 10.3390/brainsci11081057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 11/16/2022] Open
Abstract
INTRODUCTION The aim of this study is a comprehensive analysis of the parameters of exogenous evoked potentials (visual, brainstem auditory, and somatosensory) in patients with myasthenia gravis (MG), a prototype of both neuromuscular junction disease and autoimmune disease. The study also seeks to isolate electrophysiological changes that may indicate disorders within the central and/or peripheral nervous system. METHODS A total of forty-two consecutive patients with myasthenia gravis (24 women, 18 men) were included in the study. All of the patients underwent EP examination. MR images were also analyzed. RESULTS In the group of MG patients, the latency of P100 (113.9 ± 13.9; p < 0.0001) VEP, wave III (3.92 ± 0.29; p = 0.015), wave V (5.93 ± 0.32; <0.0001), interlatency III-V (2.00 ± 0.12; p < 0.0001), interlatency I-V (4.20 ± 0.28; p < 0.001) BAEP, and all components of SEP (N9, P10, N13, P16, N20, P22) were significantly longer. Mean wave I and V amplitude BAEP were relatively lower. CONCLUSIONS The results of the study suggest the presence of disturbances in the bioelectric activities of the central and peripheral nervous system in MG patients.
Collapse
|
49
|
Evoli A, Spagni G, Monte G, Damato V. Heterogeneity in myasthenia gravis: considerations for disease management. Expert Rev Clin Immunol 2021; 17:761-771. [PMID: 34043932 DOI: 10.1080/1744666x.2021.1936500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Myasthenia gravis is a rare disease of the neuromuscular junction and a prototype of B cell-driven immunopathology. Pathogenic antibodies target post-synaptic transmembrane proteins, most commonly the nicotinic acetylcholine receptor and the muscle-specific tyrosine kinase, inducing end-plate alterations and neuromuscular transmission impairment. Several clinical subtypes are distinct on the basis of associated antibodies, age at symptom onset, thymus pathology, genetic factors, and weakness distribution. These subtypes have distinct pathogenesis that can account for different responses to treatment. Conventional therapy is based on the use of symptomatic agents, steroids, immunosuppressants and thymectomy. Of late, biologics have emerged as effective therapeutic options.Areas covered: In this review, we will discuss the management of myasthenia gravis in relation to its phenotypic and biological heterogeneity, in the light of recent advances in the disease immunopathology, new diagnostic tools, and results of clinical trialsExpert opinion: Clinical management is shaped on serological subtype, and patient age at onset, lifestyle and comorbidities, balancing therapeutic needs and safety. Although reliable biomarkers predictive of clinical and biologic outcome are still lacking, recent developments promise a more effective and safe treatment. Disease subtyping according to serological testing and immunopathology is crucial to the appropriateness of clinical management.
Collapse
Affiliation(s)
- Amelia Evoli
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy.,Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Gregorio Spagni
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Gabriele Monte
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Valentina Damato
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| |
Collapse
|
50
|
Zografou C, Vakrakou AG, Stathopoulos P. Short- and Long-Lived Autoantibody-Secreting Cells in Autoimmune Neurological Disorders. Front Immunol 2021; 12:686466. [PMID: 34220839 PMCID: PMC8248361 DOI: 10.3389/fimmu.2021.686466] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/28/2021] [Indexed: 12/24/2022] Open
Abstract
As B cells differentiate into antibody-secreting cells (ASCs), short-lived plasmablasts (SLPBs) are produced by a primary extrafollicular response, followed by the generation of memory B cells and long-lived plasma cells (LLPCs) in germinal centers (GCs). Generation of IgG4 antibodies is T helper type 2 (Th2) and IL-4, -13, and -10-driven and can occur parallel to IgE, in response to chronic stimulation by allergens and helminths. Although IgG4 antibodies are non-crosslinking and have limited ability to mobilize complement and cellular cytotoxicity, when self-tolerance is lost, they can disrupt ligand-receptor binding and cause a wide range of autoimmune disorders including neurological autoimmunity. In myasthenia gravis with predominantly IgG4 autoantibodies against muscle-specific kinase (MuSK), it has been observed that one-time CD20+ B cell depletion with rituximab commonly leads to long-term remission and a marked reduction in autoantibody titer, pointing to a short-lived nature of autoantibody-secreting cells. This is also observed in other predominantly IgG4 autoantibody-mediated neurological disorders, such as chronic inflammatory demyelinating polyneuropathy and autoimmune encephalitis with autoantibodies against the Ranvier paranode and juxtaparanode, respectively, and extends beyond neurological autoimmunity as well. Although IgG1 autoantibody-mediated neurological disorders can also respond well to rituximab induction therapy in combination with an autoantibody titer drop, remission tends to be less long-lasting and cases where titers are refractory tend to occur more often than in IgG4 autoimmunity. Moreover, presence of GC-like structures in the thymus of myasthenic patients with predominantly IgG1 autoantibodies against the acetylcholine receptor and in ovarian teratomas of autoimmune encephalitis patients with predominantly IgG1 autoantibodies against the N‐methyl‐d‐aspartate receptor (NMDAR) confers increased the ability to generate LLPCs. Here, we review available information on the short-and long-lived nature of ASCs in IgG1 and IgG4 autoantibody-mediated neurological disorders and highlight common mechanisms as well as differences, all of which can inform therapeutic strategies and personalized medical approaches.
Collapse
Affiliation(s)
- C Zografou
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - A G Vakrakou
- First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - P Stathopoulos
- First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| |
Collapse
|