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Spagni G, Vincent A, Sun B, Falso S, Jacobson LW, Devenish S, Evoli A, Damato V. Serological Markers of Clinical Improvement in MuSK Myasthenia Gravis. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2024; 11:e200313. [PMID: 39250722 PMCID: PMC11385952 DOI: 10.1212/nxi.0000000000200313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
BACKGROUND AND OBJECTIVES In this retrospective longitudinal study, we aimed at exploring the role of (a) MuSK-immunoglobulin G (IgG) levels, (b) predominant MuSK-IgG subclasses, and (c) antibody affinity as candidate biomarkers of severity and outcomes in MuSK-MG, using and comparing different antibody testing techniques. METHODS Total MuSK-IgGs were quantified with radioimmunoassay (RIA), ELISA, flow cytometry, and cell-based assay (CBA) serial dilutions using HEK293 cells transfected with MuSK-eGFP. MuSK-IgG subclasses were measured by flow cytometry. SAffCon assay was used for determining MuSK-IgG affinity. RESULTS Forty-three serum samples were obtained at different time points from 20 patients with MuSK-MG (median age at onset: 48 years, interquartile range = 27.5-72.5; women, 16/20), with 9 of 20 (45%) treated with rituximab. A strong correlation between MuSK-IgG levels measured by flow cytometry and RIA titers was found (rs = 0.74, 95% CI 0.41-0.89, p = 0.0003), as well as a moderate correlation between CBA end-point titers and RIA titers (rs = 0.47, 95% CI 0.01-0.77, p = 0.0414). A significant correlation was found between MuSK-IgG flow cytometry levels and disease severity (rs = 0.39, 95% CI 0.06-0.64, p = 0.0175; mixed-effects model estimate: 2.296e-06, std. error: 1.024e-06, t = 2.243, p = 0.032). In individual patients, clinical improvement was associated with decrease in MuSK-IgG levels, as measured by either flow cytometry or CBA end-point titration. In all samples, MuSK-IgG4 was the most frequent isotype (mean ± SD: 90.95% ± 13.89). A significant reduction of MuSK-IgG4 and, to a lesser extent, of MuSK-IgG2, was seen in patients with favorable clinical outcomes. A similar trend was confirmed in the subgroup of rituximab-treated patients. In a single patient, MuSK-IgG affinity increased during symptom exacerbation (KD values: 62 nM vs 0.6 nM) while total MuSK-IgG and IgG4 levels remained stable, suggesting that affinity maturation may be a driver of clinical worsening. DISCUSSION Our data support the quantification of MuSK antibodies by flow cytometry. Through a multimodal investigational approach, we showed that total MuSK-IgG levels, MuSK-IgG4 and MuSK-IgG2 levels, and MuSK-IgG affinity may represent promising biomarkers of disease outcomes in MuSK-MG.
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Affiliation(s)
- Gregorio Spagni
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Angela Vincent
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Bo Sun
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Silvia Falso
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Leslie W Jacobson
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Sean Devenish
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Amelia Evoli
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
| | - Valentina Damato
- From the Department of Neuroscience (G.S., S.F., A.E.), Università Cattolica del Sacro Cuore, Rome, Italy; German Center for Neurodegenerative Diseases (DZNE) Berlin (G.S.), Berlin, Germany; Nuffield Department of Clinical Neurosciences (A.V., B.S., L.W.J.), University of Oxford; Fluidic Analytics Ltd (S.D.), The Paddocks Business Centre, Cambridge, United Kingdom; and Department of Neurosciences (V.D.), Drugs and Child Health, University of Florence, Italy
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Butenko O, Jensen SM, Fillié-Grijpma YE, Verpalen R, Verschuuren JJ, van der Maarel SM, Huijbers MG, Plomp JJ. Change of voltage-gated sodium channel repertoire in skeletal muscle of a MuSK myasthenia gravis mouse model. Eur J Neurosci 2024; 59:3292-3308. [PMID: 38650308 DOI: 10.1111/ejn.16347] [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: 09/15/2023] [Revised: 03/11/2024] [Accepted: 03/23/2024] [Indexed: 04/25/2024]
Abstract
Muscle-specific kinase myasthenia gravis (MuSK MG) is caused by autoantibodies against MuSK in the neuromuscular junction (NMJ). MuSK MG patients have fluctuating, fatigable skeletal muscle weakness, in particular of bulbar muscles. Severity differs greatly between patients, in spite of comparable autoantibody levels. One explanation for inter-patient and inter-muscle variability in sensitivity might be variations in compensatory muscle responses. Previously, we developed a passive transfer mouse model for MuSK MG. In preliminary ex vivo experiments, we observed that muscle contraction of some mice, in particular those with milder myasthenia, had become partially insensitive to inhibition by μ-Conotoxin-GIIIB, a blocker of skeletal muscle NaV1.4 voltage-gated sodium channels. We hypothesised that changes in NaV channel expression profile, possibly co-expression of (μ-Conotoxin-GIIIB insensitive) NaV1.5 type channels, might lower the muscle fibre's firing threshold and facilitate neuromuscular synaptic transmission. To test this hypothesis, we here performed passive transfer in immuno-compromised mice, using 'high', 'intermediate' and 'low' dosing regimens of purified MuSK MG patient IgG4. We compared myasthenia levels, μ-Conotoxin-GIIIB resistance and muscle fibre action potential characteristics and firing thresholds. High- and intermediate-dosed mice showed clear, progressive myasthenia, not seen in low-dosed animals. However, diaphragm NMJ electrophysiology demonstrated almost equal myasthenic severities amongst all regimens. Nonetheless, low-dosed mouse diaphragms showed a much higher degree of μ-Conotoxin-GIIIB resistance. This was not explained by upregulation of Scn5a (the NaV1.5 gene), lowered muscle fibre firing thresholds or histologically detectable upregulated NaV1.5 channels. It remains to be established which factors are responsible for the observed μ-Conotoxin-GIIIB insensitivity and whether the NaV repertoire change is compensatory beneficial or a bystander effect.
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Affiliation(s)
- Olena Butenko
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stine Marie Jensen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Robyn Verpalen
- Department of Human Genetics, Leiden University Medical Center, 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, Leiden, The Netherlands
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
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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.
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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
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4
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Jaime D, Fish LA, Madigan LA, Xi C, Piccoli G, Ewing MD, Blaauw B, Fallon JR. The MuSK-BMP pathway maintains myofiber size in slow muscle through regulation of Akt-mTOR signaling. Skelet Muscle 2024; 14:1. [PMID: 38172960 PMCID: PMC10763067 DOI: 10.1186/s13395-023-00329-9] [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: 02/21/2023] [Accepted: 10/19/2023] [Indexed: 01/05/2024] Open
Abstract
Myofiber size regulation is critical in health, disease, and aging. MuSK (muscle-specific kinase) is a BMP (bone morphogenetic protein) co-receptor that promotes and shapes BMP signaling. MuSK is expressed at all neuromuscular junctions and is also present extrasynaptically in the mouse soleus, whose predominantly oxidative fiber composition is akin to that of human muscle. To investigate the role of the MuSK-BMP pathway in vivo, we generated mice lacking the BMP-binding MuSK Ig3 domain. These ∆Ig3-MuSK mice are viable and fertile with innervation levels comparable to wild type. In 3-month-old mice, myofibers are smaller in the slow soleus, but not in the fast tibialis anterior (TA). Transcriptomic analysis revealed soleus-selective decreases in RNA metabolism and protein synthesis pathways as well as dysregulation of IGF1-Akt-mTOR pathway components. Biochemical analysis showed that Akt-mTOR signaling is reduced in soleus but not TA. We propose that the MuSK-BMP pathway acts extrasynaptically to maintain myofiber size in slow muscle by promoting protein synthetic pathways including IGF1-Akt-mTOR signaling. These results reveal a novel mechanism for regulating myofiber size in slow muscle and introduce the MuSK-BMP pathway as a target for promoting muscle growth and combatting atrophy.
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Grants
- R41 AG073144 NIA NIH HHS
- T32 MH020068 NIMH NIH HHS
- U01 NS064295, R41 AG073144, R21 NS112743, R21 AG073743, P30 GM103410, P30 RR031153, P20 RR018728, S10 RR02763, R25GM083270, 2T32AG041688, and T32 MH20068 NIH HHS
- P30 GM103410 NIGMS NIH HHS
- T32 AG041688 NIA NIH HHS
- P30 RR031153 NCRR NIH HHS
- U01 NS064295 NINDS NIH HHS
- R21 NS112743 NINDS NIH HHS
- P20 RR018728 NCRR NIH HHS
- R21 AG073743 NIA NIH HHS
- R25 GM083270 NIGMS NIH HHS
- National Institutes of Health
- Carney Institute for Brain Sciences
- ALS Finding a Cure
- AFM-Téléthon
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Affiliation(s)
- Diego Jaime
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Lauren A Fish
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA
| | - Laura A Madigan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Chengjie Xi
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA
| | - Giorgia Piccoli
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Madison D Ewing
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA
| | - Bert Blaauw
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Justin R Fallon
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA.
- Carney Institute for Neuroscience, Brown University, Providence, RI, USA.
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5
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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.
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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
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Akhtar M, Islam MR, Khaton F, Soltana UH, Jafrin SA, Rahman SIA, Tauheed I, Ahmed T, Khan II, Akter A, Khan ZH, Islam MT, Khanam F, Biswas PK, Ahmmed F, Ahmed S, Rashid MM, Hossain MZ, Alam AN, Alamgir ASM, Rahman M, Ryan ET, Harris JB, LaRocque RC, Flora MS, Chowdhury F, Khan AI, Banu S, Shirin T, Bhuiyan TR, Qadri F. Appearance of tolerance-induction and non-inflammatory SARS-CoV-2 spike-specific IgG4 antibodies after COVID-19 booster vaccinations. Front Immunol 2023; 14:1309997. [PMID: 38173725 PMCID: PMC10763240 DOI: 10.3389/fimmu.2023.1309997] [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: 10/09/2023] [Accepted: 11/28/2023] [Indexed: 01/05/2024] Open
Abstract
Background Understanding the characteristics of the humoral immune responses following COVID-19 vaccinations is crucial for refining vaccination strategies and predicting immune responses to emerging SARS-CoV-2 variants. Methods A longitudinal analysis of SARS-CoV-2 spike receptor binding domain (RBD) specific IgG antibody responses, encompassing IgG subclasses IgG1, IgG2, IgG3, and IgG4 was performed. Participants received four mRNA vaccine doses (group 1; n=10) or two ChAdOx1 nCoV-19 and two mRNA booster doses (group 2; n=19) in Bangladesh over two years. Results Findings demonstrate robust IgG responses after primary Covishield or mRNA doses; declining to baseline within six months. First mRNA booster restored and surpassed primary IgG responses but waned after six months. Surprisingly, a second mRNA booster did not increase IgG levels further. Comprehensive IgG subclass analysis showed primary Covishield/mRNA vaccination generated predominantly IgG1 responses with limited IgG2/IgG3, Remarkably, IgG4 responses exhibited a distinct pattern. IgG4 remained undetectable initially but increased extensively six months after the second mRNA dose, eventually replacing IgG1 after the 3rd/4th mRNA doses. Conversely, initial Covishield recipients lack IgG4, surged post-second mRNA booster. Notably, mRNA-vaccinated individuals displayed earlier, robust IgG4 levels post first mRNA booster versus Covishield counterparts. IgG1 to IgG4 ratios decreased with increasing doses, most pronounced with four mRNA doses. This study highlights IgG response kinetics, influenced by vaccine type and doses, impacting immunological tolerance and IgG4 induction, shaping future vaccination strategies. Conclusions This study highlights the dynamics of IgG responses dependent on vaccine type and number of doses, leading to immunological tolerance and IgG4 induction, and shaping future vaccination strategies.
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Affiliation(s)
- Marjahan Akhtar
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Md. Rashedul Islam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Fatema Khaton
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Umma Hany Soltana
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Syeda Anoushka Jafrin
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Sadia Isfat Ara Rahman
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Imam Tauheed
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Tasnuva Ahmed
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Ishtiakul Islam Khan
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Afroza Akter
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Zahid Hasan Khan
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Md. Taufiqul Islam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Farhana Khanam
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Prasanta Kumar Biswas
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Faisal Ahmmed
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Shakeel Ahmed
- Bangladesh Institute of Tropical & Infectious Diseases, Chittagong, Bangladesh
| | - Md. Mamunur Rashid
- Bangladesh Institute of Tropical & Infectious Diseases, Chittagong, Bangladesh
| | - Md. Zakir Hossain
- Bangladesh Institute of Tropical & Infectious Diseases, Chittagong, Bangladesh
| | - Ahmed Nawsher Alam
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - A. S. M. Alamgir
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Mahbubur Rahman
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Edward T. Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, United States
- Department of Medicine, Harvard Medical School, Boston, MA, United States
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Jason B. Harris
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, United States
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| | - Regina C. LaRocque
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, United States
- Department of Medicine, Harvard Medical School, Boston, MA, United States
| | | | - Fahima Chowdhury
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Ashraful Islam Khan
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Sayera Banu
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Tahmina Shirin
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Taufiqur Rahman Bhuiyan
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
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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.
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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.
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8
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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: 45] [Impact Index Per Article: 45.0] [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.
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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.
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9
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Koral G, Ulusoy C, Cossins J, Lazaridis K, Türkoğlu R, Dong YY, Tüzün E, Yılmaz V. Silencing of FCRLB by shRNA ameliorates MuSK-induced EAMG in mice. J Neuroimmunol 2023; 383:578195. [PMID: 37660538 DOI: 10.1016/j.jneuroim.2023.578195] [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: 03/04/2023] [Revised: 05/18/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
INTRODUCTION Muscle specific kinase (MuSK) antibody positive myasthenia gravis (MG) often presents with a severe disease course and resistance to treatment. Treatment-refractory patients may respond to B cell depleting treatment methods. Our aim was to investigate whether inhibition of Fc receptor-like B (FCRLB) could effectively suppress autoimmunity without diminishing B cell counts in animal model of MG, a classical antibody-mediated autoimmune disease. METHODS Experimental autoimmune MG was induced in Balb/C mice with two s.c. immunizations with recombinant human MuSK in complete Freund's adjuvant. FCRLB was silenced with a lentiviral particle transported shRNA in myasthenic mice with a single i.p. injection during second MuSK-immunization. Control immunized mice received scrambled shRNA or saline. Mice were observed for clinical parameters for 28 days and at termination, anti-MuSK IgG, neuromuscular junction (NMJ) deposits, muscle AChR expression and lymph node B and T cell ratios were assessed by ELISA, immunofluorescence, immunoblotting and flow cytometry, respectively. RESULTS FCRLB shRNA-treated mice showed no muscle weakness or weight loss at termination. Also, they exhibited higher grip strength and muscle AChR levels, lower anti-MuSK IgG and NMJ IgG/C3 levels than control mice. Flow cytometry analysis showed that ratios of major effector lymph node B and T cell populations were not altered by FCRLB silencing. However, regulatory T and CD19 + CD5+ B cell ratios were decreased in FCRLB shRNA-group. CONCLUSION Our results provide evidence regarding involvement and therapeutic value of FCRLB in MuSK-MG. Silencing of FCRLB appears to substantially inhibit antibody production without interfering with survival of major lymphocyte populations.
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Affiliation(s)
- Gizem Koral
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Canan Ulusoy
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Judith Cossins
- Neuromuscular Disorders Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, Oxford, UK
| | | | - Recai Türkoğlu
- Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey
| | - Yin Yao Dong
- Neuromuscular Disorders Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, Oxford, UK
| | - Erdem Tüzün
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Vuslat Yılmaz
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey.
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10
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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: 41] [Impact Index Per Article: 41.0] [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.
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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.
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11
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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.
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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
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12
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Sun L, Su Y, Jiao A, Wang X, Zhang B. T cells in health and disease. Signal Transduct Target Ther 2023; 8:235. [PMID: 37332039 PMCID: PMC10277291 DOI: 10.1038/s41392-023-01471-y] [Citation(s) in RCA: 123] [Impact Index Per Article: 123.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 06/20/2023] Open
Abstract
T cells are crucial for immune functions to maintain health and prevent disease. T cell development occurs in a stepwise process in the thymus and mainly generates CD4+ and CD8+ T cell subsets. Upon antigen stimulation, naïve T cells differentiate into CD4+ helper and CD8+ cytotoxic effector and memory cells, mediating direct killing, diverse immune regulatory function, and long-term protection. In response to acute and chronic infections and tumors, T cells adopt distinct differentiation trajectories and develop into a range of heterogeneous populations with various phenotype, differentiation potential, and functionality under precise and elaborate regulations of transcriptional and epigenetic programs. Abnormal T-cell immunity can initiate and promote the pathogenesis of autoimmune diseases. In this review, we summarize the current understanding of T cell development, CD4+ and CD8+ T cell classification, and differentiation in physiological settings. We further elaborate the heterogeneity, differentiation, functionality, and regulation network of CD4+ and CD8+ T cells in infectious disease, chronic infection and tumor, and autoimmune disease, highlighting the exhausted CD8+ T cell differentiation trajectory, CD4+ T cell helper function, T cell contributions to immunotherapy and autoimmune pathogenesis. We also discuss the development and function of γδ T cells in tissue surveillance, infection, and tumor immunity. Finally, we summarized current T-cell-based immunotherapies in both cancer and autoimmune diseases, with an emphasis on their clinical applications. A better understanding of T cell immunity provides insight into developing novel prophylactic and therapeutic strategies in human diseases.
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Affiliation(s)
- Lina Sun
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
- Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, 710061, China
- Xi'an Key Laboratory of Immune Related Diseases, Xi'an, Shannxi, 710061, China
| | - Yanhong Su
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
- Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, 710061, China
- Xi'an Key Laboratory of Immune Related Diseases, Xi'an, Shannxi, 710061, China
| | - Anjun Jiao
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
- Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, 710061, China
- Xi'an Key Laboratory of Immune Related Diseases, Xi'an, Shannxi, 710061, China
| | - Xin Wang
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
- Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, 710061, China
- Xi'an Key Laboratory of Immune Related Diseases, Xi'an, Shannxi, 710061, China
| | - Baojun Zhang
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China.
- Institute of Infection and Immunity, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, 710061, China.
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, Shaanxi, 710061, China.
- Xi'an Key Laboratory of Immune Related Diseases, Xi'an, Shannxi, 710061, China.
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13
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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.
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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.
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14
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Jaime D, Fish LA, Madigan LA, Ewing MD, Fallon JR. The MuSK-BMP pathway maintains myofiber size in slow muscle through regulation of Akt- mTOR signaling. RESEARCH SQUARE 2023:rs.3.rs-2613527. [PMID: 36909467 PMCID: PMC10002845 DOI: 10.21203/rs.3.rs-2613527/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Myofiber size regulation is critical in health, disease, and aging. MuSK (muscle-specific kinase) is a BMP (bone morphogenetic protein) co-receptor that promotes and shapes BMP signaling. MuSK is expressed at all neuromuscular junctions and is also present extrasynaptically in the slow soleus muscle. To investigate the role of the MuSK-BMP pathway in vivo we generated mice lacking the BMP-binding MuSK Ig3 domain. These ΔIg3-MuSKmice are viable and fertile with innervation levels comparable to wild type. In 3-month-old mice myofibers are smaller in the slow soleus, but not in the fast tibialis anterior (TA). Transcriptomic analysis revealed soleus-selective decreases in RNA metabolism and protein synthesis pathways as well as dysregulation of IGF1-Akt-mTOR pathway components. Biochemical analysis showed that Akt-mTOR signaling is reduced in soleus but not TA. We propose that the MuSK-BMP pathway acts extrasynaptically to maintain myofiber size in slow muscle by promoting protein synthetic pathways including IGF1-Akt-mTOR signaling. These results reveal a novel mechanism for regulating myofiber size in slow muscle and introduce the MuSK-BMP pathway as a target for promoting muscle growth and combatting atrophy.
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15
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Pugliese A, Nicocia G, Messina S, Toscano A, Rodolico C. A very late onset AChR and MuSK double positive myasthenia gravis: a case description and literature review. Neuromuscul Disord 2023; 33:145-147. [PMID: 36628839 DOI: 10.1016/j.nmd.2022.12.004] [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: 04/19/2021] [Revised: 11/06/2022] [Accepted: 12/12/2022] [Indexed: 12/14/2022]
Abstract
AChR and MuSK double positive myasthenia gravis has been rarely reported. Generally, it occurs in children and adults after thymectomy or immunotherapy. Furthermore, in a few patients with bulbar or respiratory involvement, MuSK antibodies might be detected after clinical deterioration. We report a man with a very late onset myasthenia gravis (86-year-old) and the coexistence of both antibodies at the time of the diagnosis. Despite the presence of MuSK antibodies, he manifested no bulbar symptoms and had a favorable clinical outcome. However, side effects related to low dose pyridostigmine were evident. Hence, double positivity can also occur in elderly and in more benign forms of myasthenia gravis. Other cases of AChR and MuSK double positive myasthenia gravis could allow a better definition of this condition.
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Affiliation(s)
- A Pugliese
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - G Nicocia
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - S Messina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - A Toscano
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - C Rodolico
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.
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16
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Ujiie H. What's new in the pathogeneses and triggering factors of bullous pemphigoid. J Dermatol 2023; 50:140-149. [PMID: 36412277 PMCID: PMC10098684 DOI: 10.1111/1346-8138.16654] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/21/2022] [Indexed: 11/23/2022]
Abstract
Bullous pemphigoid (BP) is a subepidermal blistering disease induced by autoantibodies to type XVII collagen (COL17, also called BP180) and BP230. Previous studies using patients' samples and animal disease models elucidated the complement-dependent and complement-independent pathways of blister formation, the pathogenic roles of immune cells (T and B cells, macrophages, mast cells, neutrophils, eosinophils), and the pathogenicity of IgE autoantibodies in BP. This review introduces the recent progress on the mechanism behind the epitope-spreading phenomenon in BP, which is considered to be important to understand the chronic and intractable disease course of BP, and the pathogenicity of anti-BP230 autoantibodies, mainly focusing on studies that used active disease models. To clarify the pathogenesis of BP, the mechanism behind the breakdown of immune tolerance to BP antigens should be investigated. Recent studies using various experimental models have revealed important roles for regulatory T cells in the maintenance of self-tolerance to COL17 and BP230 as well as in the suppression of inflammation triggered by the binding of antibodies to COL17. Notably, physical stresses such as trauma, thermal burns, bone fractures, irradiation and ultraviolet exposure, some pathologic conditions such as neurological diseases and hematological malignancies, and the use of dipeptidyl peptidase-IV inhibitors and immune checkpoint inhibitors have been reported as triggering factors for BP. These factors and certain underlying conditions such as genetic background, regulatory T-cell dysfunction or aging might synergistically affect some individuals and eventually induce BP. Further studies on the breakdown of self-tolerance and on the identification of key molecules that are relevant to blister formation and inflammation may expand our understanding of BP's etiology and may lead to the development of novel therapeutic approaches.
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Affiliation(s)
- Hideyuki Ujiie
- Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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17
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Vergoossen DLE, Ruiter AM, Keene KR, Niks EH, Tannemaat MR, Strijbos E, Lipka AF, van der Zijde ECJ, van Tol MJD, Bakker JA, Wevers BA, Westerberg E, Borges LS, Tong OC, Richman DP, Illa I, Punga AR, Evoli A, van der Maarel SM, Verschuuren JJ, Huijbers MG. Enrichment of serum IgG4 in MuSK myasthenia gravis patients. J Neuroimmunol 2022; 373:577978. [PMID: 36240543 DOI: 10.1016/j.jneuroim.2022.577978] [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: 08/20/2022] [Revised: 09/26/2022] [Accepted: 10/05/2022] [Indexed: 11/05/2022]
Abstract
Muscle-specific kinase (MuSK) myasthenia gravis (MG) is a neuromuscular autoimmune disease belonging to a growing group of IgG4 autoimmune diseases (IgG4-AIDs), in which the majority of pathogenic autoantibodies are of the IgG4 subclass. The more prevalent form of MG with acetylcholine receptor (AChR) antibodies is caused by IgG1-3 autoantibodies. A dominant role for IgG4 in autoimmune disease is intriguing due to its anti-inflammatory characteristics. It is unclear why MuSK autoantibodies are predominantly IgG4. We hypothesized that MuSK MG patients have a general predisposition to generate IgG4 responses, therefore resulting in high levels of circulating IgG4. To investigate this, we quantified serum Ig isotypes and IgG subclasses using nephelometric and turbidimetric assays in MuSK MG and AChR MG patients not under influence of immunosuppressive treatment. Absolute serum IgG1 was increased in both MuSK and AChR MG patients compared to healthy donors. In addition, only MuSK MG patients on average had significantly increased and enriched serum IgG4. Although more MuSK MG patients had elevated serum IgG4, for most the IgG4 serum levels fell within the normal range. Correlation analyses suggest MuSK-specific antibodies do not solely explain the variation in IgG4 levels. In conclusion, although serum IgG4 levels are slightly increased, the levels do not support ubiquitous IgG4 responses in MuSK MG patients as the underlying cause of dominant IgG4 MuSK antibodies.
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Affiliation(s)
- Dana L E Vergoossen
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands
| | - Annabel M Ruiter
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Kevin R Keene
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Erik H Niks
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Ellen Strijbos
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Alexander F Lipka
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Els C Jol van der Zijde
- Willem-Alexander Children's Hospital, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maarten J D van Tol
- Willem-Alexander Children's Hospital, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Jaap A Bakker
- Department of Clinical Chemistry, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Brigitte A Wevers
- Department of Clinical Chemistry, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Elisabet Westerberg
- Clinical Neurophysiology, Department of Medical Sciences, Uppsala University, Akademiska sjukhuset, Ingång 85, 3rd floor, 751 85 Uppsala, Sweden
| | - Lúcia S Borges
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - Olivia C Tong
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - David P Richman
- Department of Neurology, University of California Davis, 1515 Newton Court, Davis, CA 95618, USA
| | - Isabel Illa
- Neuromuscular diseases Neurology department, Hospital Sant Pau UAB, Avenida Pare Claret N° 167, Barcelona 08025, Spain
| | - Anna Rostedt Punga
- Clinical Neurophysiology, Department of Medical Sciences, Uppsala University, Akademiska sjukhuset, Ingång 85, 3rd floor, 751 85 Uppsala, Sweden
| | - Amelia Evoli
- Department of Neurology, Università Cattolica del Sacro Cuore, Largo A. Gemelli 1, 00168 Rome, Italy
| | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands
| | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Centre LUMC, Einthovenweg 20, 2300 RC Leiden, the Netherlands; Department of Neurology, Leiden University Medical Centre LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands.
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18
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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]
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19
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Su M, Zhao C, Luo S. Therapeutic potential of chimeric antigen receptor based therapies in autoimmune diseases. Autoimmun Rev 2021; 21:102931. [PMID: 34481941 DOI: 10.1016/j.autrev.2021.102931] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/26/2021] [Accepted: 08/31/2021] [Indexed: 11/02/2022]
Abstract
Chimeric antigen receptor (CAR) based therapies have been adopted as an option for treating autoimmune diseases from the field of blood malignancies by targeting immune cells or rebalancing the pro-inflammatory milieu. Important questions still remained about the efficacy and safety regarding the dynamic and complex autoimmune pathological networks. We here reviewed the emerged developments in basic, translational, and clinical studies of the CAR based therapies in a wide spectrum of autoimmune diseases. The primary goal of the study is to provide some future perspectives on how to optimize the performance of CAR based therapies. The fundamental strategy is to engineer the recognition domains in CAR products for precisely targeting the components in the pro-inflammatory milieu. The second strategy is to incorporate multiple CARs in one carrier, or use fluorescein isothiocyanate (FITC)-CAR T cells for enhancing the therapeutic efficacy. In addition, we reviewed the preclinical evidence in disease-specific context. Overall, we aim to attract more attention in the field of developing future precision CAR based therapies to tailor medial decisions in autoimmune diseases.
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Affiliation(s)
- Manqiqige Su
- Department of Neurology, Huashan hospital Fudan University, 200040 Shanghai, China
| | - Chongbo Zhao
- Department of Neurology, Huashan hospital Fudan University, 200040 Shanghai, China
| | - Sushan Luo
- Department of Neurology, Huashan hospital Fudan University, 200040 Shanghai, China.
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20
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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.
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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
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21
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Functional monovalency amplifies the pathogenicity of anti-MuSK IgG4 in myasthenia gravis. Proc Natl Acad Sci U S A 2021; 118:2020635118. [PMID: 33753489 PMCID: PMC8020787 DOI: 10.1073/pnas.2020635118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
An expanding group of autoimmune diseases is now recognized to be hallmarked by pathogenic IgG4 autoantibodies. IgG4 has the unique ability to exchange Fab-arms, rendering it bispecific and functionally monovalent. Here we show that autoantibody functional monovalency significantly amplifies the pathogenicity of IgG4 autoantibodies using patient-derived monoclonal antibodies in an in vivo model of MuSK myasthenia gravis. Therefore, subclass switching to predominant IgG4 autoantibodies is a critical step in the development of MuSK myasthenia gravis. This new mechanism in autoimmunity is also potentially relevant to 29 other IgG4-mediated autoimmune diseases known to date, allergy and other disease settings where IgG4 antibodies contribute to pathology. Human immunoglobulin (Ig) G4 usually displays antiinflammatory activity, and observations of IgG4 autoantibodies causing severe autoimmune disorders are therefore poorly understood. In blood, IgG4 naturally engages in a stochastic process termed “Fab-arm exchange” in which unrelated IgG4s exchange half-molecules continuously. The resulting IgG4 antibodies are composed of two different binding sites, thereby acquiring monovalent binding and inability to cross-link for each antigen recognized. Here, we demonstrate that this process amplifies autoantibody pathogenicity in a classic IgG4-mediated autoimmune disease: muscle-specific kinase (MuSK) myasthenia gravis. In mice, monovalent anti-MuSK IgG4s caused rapid and severe myasthenic muscle weakness, whereas the same antibodies in their parental bivalent form were less potent or did not induce a phenotype. Mechanistically this could be explained by opposing effects on MuSK signaling. Isotype switching to IgG4 in an autoimmune response thereby may be a critical step in the development of disease. Our study establishes functional monovalency as a pathogenic mechanism in IgG4-mediated autoimmune disease and potentially other disorders.
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22
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Isotyping paranodal antibodies in inflammatory neuropathies. NEUROLOGY - NEUROIMMUNOLOGY NEUROINFLAMMATION 2020. [PMCID: PMC7413706 DOI: 10.1212/nxi.0000000000000843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Koneczny I. Update on IgG4-mediated autoimmune diseases: New insights and new family members. Autoimmun Rev 2020; 19:102646. [PMID: 32801046 DOI: 10.1016/j.autrev.2020.102646] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 03/08/2020] [Indexed: 12/23/2022]
Abstract
Antibodies of IgG4 subclass are exceptional players of the immune system, as they are considered to be immunologically inert and functionally monovalent, and as such may be part of classical tolerance mechanisms. IgG4 antibodies are found in a range of different diseases, including IgG4-related diseases, allergy, cancer, rheumatoid arthritis, helminth infection and IgG4 autoimmune diseases, where they may be pathogenic or protective. IgG4 autoimmune diseases are an emerging new group of diseases that are characterized by pathogenic, antigen-specific autoantibodies of IgG4 subclass, such as MuSK myasthenia gravis, pemphigus vulgaris and thrombotic thrombocytopenic purpura. The list of IgG4 autoantigens is rapidly growing and to date contains 29 candidate antigens. Interestingly, IgG4 autoimmune diseases are restricted to four distinct organs: 1) the central and peripheral nervous system, 2) the kidney, 3) the skin and mucous membranes and 4) the vascular system and soluble antigens in the blood circulation. The pathogenicity of IgG4 can be validated using our classification system, and is usually excerted by functional blocking of protein-protein interaction.
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Affiliation(s)
- Inga Koneczny
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Währingergürtel 18-20, 1090 Vienna, Austria.
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24
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Appeltshauser L, Brunder AM, Heinius A, Körtvélyessy P, Wandinger KP, Junker R, Villmann C, Sommer C, Leypoldt F, Doppler K. Antiparanodal antibodies and IgG subclasses in acute autoimmune neuropathy. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2020; 7:7/5/e817. [PMID: 32736337 PMCID: PMC7413710 DOI: 10.1212/nxi.0000000000000817] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/19/2020] [Indexed: 12/20/2022]
Abstract
Objective To determine whether IgG subclasses of antiparanodal autoantibodies are related to disease course and treatment response in acute- to subacute-onset neuropathies, we retrospectively screened 161 baseline serum/CSF samples and 66 follow-up serum/CSF samples. Methods We used ELISA and immunofluorescence assays to detect antiparanodal IgG and their subclasses and titers in serum/CSF of patients with Guillain-Barré syndrome (GBS), recurrent GBS (R-GBS), Miller-Fisher syndrome, and acute- to subacute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP). We evaluated clinical data retrospectively. Results We detected antiparanodal autoantibodies with a prevalence of 4.3% (7/161), more often in A-CIDP (4/23, 17.4%) compared with GBS (3/114, 2.6%). Longitudinal subclass analysis in the patients with GBS revealed IgG2/3 autoantibodies against Caspr-1 and against anti–contactin-1/Caspr-1, which disappeared at remission. At disease onset, patients with A-CIDP had IgG2/3 anti–Caspr-1 and anti–contactin-1/Caspr-1 or IgG4 anti–contactin-1 antibodies, IgG3 being associated with good response to IV immunoglobulins (IVIg). In the chronic phase of disease, IgG subclass of one patient with A-CIDP switched from IgG3 to IgG4. Conclusion Our data (1) confirm and extend previous observations that antiparanodal IgG2/3 but not IgG4 antibodies can occur in acute-onset neuropathies manifesting as monophasic GBS, (2) suggest association of IgG3 to a favorable response to IVIg, and (3) lend support to the hypothesis that in some patients, an IgG subclass switch from IgG3 to IgG4 may be the correlate of a secondary progressive or relapsing course following a GBS-like onset.
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Affiliation(s)
- Luise Appeltshauser
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany.
| | - Anna-Michelle Brunder
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Annika Heinius
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Peter Körtvélyessy
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Klaus-Peter Wandinger
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Ralf Junker
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Carmen Villmann
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Claudia Sommer
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Frank Leypoldt
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
| | - Kathrin Doppler
- From the Department of Neurology (L.A., A.-M.B., C.S., K.D.), University Hospital of Würzburg; Neuroimmunology Section (A.H., K.-P.W., R.J., F.L.), Institute of Clinical Chemistry, University Hospital of Schleswig-Holstein Campus Kiel; Department of Neurology (P.K.), University Hospital of Magdeburg; and Institute for Clinical Neurobiology (C.V.), University Hospital of Würzburg, Germany
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25
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Vergoossen DLE, Augustinus R, Huijbers MG. MuSK antibodies, lessons learned from poly- and monoclonality. J Autoimmun 2020; 112:102488. [PMID: 32505442 DOI: 10.1016/j.jaut.2020.102488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/28/2020] [Accepted: 05/06/2020] [Indexed: 11/25/2022]
Abstract
Muscle-specific kinase (MuSK) plays a critical role in establishing and maintaining neuromuscular synapses. Antibodies derived from immunizing animals with MuSK were important tools to help detect MuSK and its activity. The role of antibodies in MuSK-related research got an extra dimension when autoantibodies to MuSK were found to cause myasthenia gravis (MG) in 2001. Active immunization with MuSK or passive transfer of polyclonal purified IgG(4) fractions from patients reproduced myasthenic muscle weakness in a range of animal models. Polyclonal patient-purified autoantibodies were furthermore found to block agrin-Lrp4-MuSK signaling, explaining the synaptic disassembly, failure of neuromuscular transmission and ultimately muscle fatigue observed in vivo. MuSK autoantibodies are predominantly of the IgG4 subclass. Low levels of other subclass MuSK antibodies coexist, but their role in the pathogenesis is unclear. Patient-derived monoclonal antibodies revealed that MuSK antibody subclass and valency alters their functional effects and possibly their pathogenicity. Interestingly, recombinant functional bivalent MuSK antibodies might even have therapeutic potential for a variety of neuromuscular disorders, due to their agonistic nature on the MuSK signaling cascade. Thus, MuSK antibodies have proven to be helpful tools to study neuromuscular junction physiology, contributed to our understanding of the pathophysiology of MuSK MG and might be used to treat neuromuscular disorders. The source of MuSK antibodies and consequently their (mixed) polyclonal or monoclonal nature were important confounding factors in these experiments. Here we review the variety of MuSK antibodies described thus far, the insights they have given us and their potential for the future.
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Affiliation(s)
- Dana L E Vergoossen
- 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
| | - 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, Albinusdreef 2, 2333 ZA, Leiden, the Netherlands.
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26
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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27
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Abstract
Thirty to fifty percent of patients with acetylcholine receptor (AChR) antibody (Ab)-negative myasthenia gravis (MG) have Abs to muscle specific kinase (MuSK) and are referred to as having MuSK-MG. MuSK is a 100 kD single-pass post-synaptic transmembrane receptor tyrosine kinase crucial to the development and maintenance of the neuromuscular junction. The Abs in MuSK-MG are predominantly of the IgG4 immunoglobulin subclass. MuSK-MG differs from AChR-MG, in exhibiting more focal muscle involvement, including neck, shoulder, facial and bulbar-innervated muscles, as well as wasting of the involved muscles. MuSK-MG is highly associated with the HLA DR14-DQ5 haplotype and occurs predominantly in females with onset in the fourth decade of life. Some of the standard treatments of AChR-MG have been found to have limited effectiveness in MuSK-MG, including thymectomy and cholinesterase inhibitors. Therefore, current treatment involves immunosuppression, primarily by corticosteroids. In addition, patients respond especially well to B cell depletion agents, e.g., rituximab, with long-term remissions. Future treatments will likely derive from the ongoing analysis of the pathogenic mechanisms underlying this disease, including histologic and physiologic studies of the neuromuscular junction in patients as well as information derived from the development and study of animal models of the disease.
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Affiliation(s)
| | - David P. Richman
- Department of Neurology, University of California, Davis, Davis, CA, United States
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28
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Guarino SR, Canciani A, Forneris F. Dissecting the Extracellular Complexity of Neuromuscular Junction Organizers. Front Mol Biosci 2020; 6:156. [PMID: 31998752 PMCID: PMC6966886 DOI: 10.3389/fmolb.2019.00156] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/13/2019] [Indexed: 12/20/2022] Open
Abstract
Synapse formation is a very elaborate process dependent upon accurate coordination of pre and post-synaptic specialization, requiring multiple steps and a variety of receptors and signaling molecules. Due to its relative structural simplicity and the ease in manipulation and observation, the neuromuscular synapse or neuromuscular junction (NMJ)-the connection between motor neurons and skeletal muscle-represents the archetype junction system for studying synapse formation and conservation. This junction is essential for survival, as it controls our ability to move and breath. NMJ formation requires coordinated interactions between motor neurons and muscle fibers, which ultimately result in the formation of a highly specialized post-synaptic architecture and a highly differentiated nerve terminal. Furthermore, to ensure a fast and reliable synaptic transmission following neurotransmitter release, ligand-gated channels (acetylcholine receptors, AChRs) are clustered on the post-synaptic muscle cell at high concentrations in sites opposite the presynaptic active zone, supporting a direct role for nerves in the organization of the post-synaptic membrane architecture. This organized clustering process, essential for NMJ formation and for life, relies on key signaling molecules and receptors and is regulated by soluble extracellular molecules localized within the synaptic cleft. Notably, several mutations as well as auto-antibodies against components of these signaling complexes have been related to neuromuscular disorders. The recent years have witnessed strong progress in the understanding of molecular identities, architectures, and functions of NMJ macromolecules. Among these, prominent roles have been proposed for neural variants of the proteoglycan agrin, its receptor at NMJs composed of the lipoprotein receptor-related protein 4 (LRP4) and the muscle-specific kinase (MuSK), as well as the regulatory soluble synapse-specific protease Neurotrypsin. In this review we summarize the current state of the art regarding molecular structures and (agrin-dependent) canonical, as well as (agrin-independent) non-canonical, MuSK signaling mechanisms that underscore the formation of neuromuscular junctions, with the aim of providing a broad perspective to further stimulate molecular, cellular and tissue biology investigations on this fundamental intercellular contact.
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Affiliation(s)
| | | | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department Biology and Biotechnology, University of Pavia, Pavia, Italy
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29
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Herbst R. MuSk function during health and disease. Neurosci Lett 2019; 716:134676. [PMID: 31811897 DOI: 10.1016/j.neulet.2019.134676] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 02/06/2023]
Abstract
The receptor tyrosine kinase MuSK (muscle-specific kinase) is the key signaling molecule during the formation of a mature and functional neuromuscular junction (NMJ). Signal transduction events downstream of MuSK activation induce both pre- and postsynaptic differentiation, which, most prominently, includes the clustering of acetylcholine receptors (AChRs) at synaptic sites. MuSK activation requires a complex interplay between its co-receptor Lrp4 (low-density lipoprotein receptor-related protein-4), the motor neuron-derived heparan-sulfate proteoglycan Agrin and the intracellular adaptor protein Dok-7. A tight regulation of MuSK kinase activity is crucial for proper NMJ development. Defects in MuSK signaling are the cause of muscle weakness as reported in congenital myasthenic syndromes and myasthenia gravis. This review focuses on recent structure-based analyses of MuSK, Agrin, Lrp4 and Dok-7 interactions and their function during MuSK activation. Conclusions about the regulation of the MuSK kinase that were derived from molecular structures will be highlighted. In addition, the role of MuSK during development and disease will be discussed.
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Affiliation(s)
- Ruth Herbst
- Medical University of Vienna, Center for Pathophysiology, Infectiology and Immunology, Kinderspitalgasse 15, 1090 Vienna, Austria.
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30
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Tea F, Lopez JA, Ramanathan S, Merheb V, Lee FXZ, Zou A, Pilli D, Patrick E, van der Walt A, Monif M, Tantsis EM, Yiu EM, Vucic S, Henderson APD, Fok A, Fraser CL, Lechner-Scott J, Reddel SW, Broadley S, Barnett MH, Brown DA, Lunemann JD, Dale RC, Brilot F. Characterization of the human myelin oligodendrocyte glycoprotein antibody response in demyelination. Acta Neuropathol Commun 2019; 7:145. [PMID: 31481127 PMCID: PMC6724269 DOI: 10.1186/s40478-019-0786-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/09/2019] [Indexed: 12/14/2022] Open
Abstract
Over recent years, human autoantibodies targeting myelin oligodendrocyte glycoprotein (MOG Ab) have been associated with monophasic and relapsing central nervous system demyelination involving the optic nerves, spinal cord, and brain. While the clinical relevance of MOG Ab detection is becoming increasingly clear as therapeutic and prognostic differences from multiple sclerosis are acknowledged, an in-depth characterization of human MOG Ab is required to answer key challenges in patient diagnosis, treatment, and prognosis. Herein, we investigated the epitope, binding sensitivity, and affinity of MOG Ab in a cohort of 139 and 148 MOG antibody-seropositive children and adults (n = 287 patients at baseline, 130 longitudinal samples, and 22 cerebrospinal fluid samples). MOG extracellular domain was also immobilized to determine the affinity of MOG Ab. MOG Ab response was of immunoglobulin G1 isotype, and was of peripheral rather than intrathecal origin. High affinity MOG Ab were detected in 15% paediatric and 18% adult sera. More than 75% of paediatric and adult MOG Ab targeted a dominant extracellular antigenic region around Proline42. MOG Ab titers fluctuated over the progression of disease, but affinity and reactivity to Proline42 remained stable. Adults with a relapsing course intrinsically presented with a reduced immunoreactivity to Proline42 and had a more diverse MOG Ab response, a feature that may be harnessed for predicting relapse. Higher titers of MOG Ab were observed in more severe phenotypes and during active disease, supporting the pathogenic role of MOG Ab. Loss of MOG Ab seropositivity was observed upon conformational changes to MOG, and this greatly impacted the sensitivity of the detection of relapsing disorders, largely considered as more severe. Careful consideration of the binding characteristics of autoantigens should be taken into account when detecting disease-relevant autoantibodies.
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Rivner MH, Pasnoor M, Dimachkie MM, Barohn RJ, Mei L. Muscle-Specific Tyrosine Kinase and Myasthenia Gravis Owing to Other Antibodies. Neurol Clin 2019; 36:293-310. [PMID: 29655451 DOI: 10.1016/j.ncl.2018.01.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Around 20% of patients with myasthenia gravis are acetylcholine receptor antibody negative; muscle-specific tyrosine kinase antibodies (MuSK) were identified as the cause of myasthenia gravis in 30% to 40% of these cases. Anti MuSK myasthenia gravis is associated with specific clinical phenotypes. One is a bulbar form with fewer ocular symptoms. Others show an isolated head drop or symptoms indistinguishable from acetylcholine receptor-positive myasthenia gravis. These patients usually respond well to immunosuppressive therapy, but not as well to cholinesterase inhibitors. Other antibodies associated with myasthenia gravis, including low-density lipoprotein receptor-related protein 4, are discussed.
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Affiliation(s)
- Michael H Rivner
- EMG Lab, Augusta University, 1120 15th Street, BP-4390, Augusta, GA 30912, USA.
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Mazen M Dimachkie
- Department of Neurology, University of Kansas Medical Center, 3599 Rainbow Boulevard, Mail Stop 2012, Kansas City, KS 66103, USA
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 4017, Kansas City, KS 66160, USA
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Augusta University, 1120 15th Street, CA-2014, Augusta, GA 30912, USA
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Myasthenia Gravis: Pathogenic Effects of Autoantibodies on Neuromuscular Architecture. Cells 2019; 8:cells8070671. [PMID: 31269763 PMCID: PMC6678492 DOI: 10.3390/cells8070671] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/26/2019] [Accepted: 06/28/2019] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ). Autoantibodies target key molecules at the NMJ, such as the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low-density lipoprotein receptor-related protein 4 (Lrp4), that lead by a range of different pathogenic mechanisms to altered tissue architecture and reduced densities or functionality of AChRs, reduced neuromuscular transmission, and therefore a severe fatigable skeletal muscle weakness. In this review, we give an overview of the history and clinical aspects of MG, with a focus on the structure and function of myasthenic autoantigens at the NMJ and how they are affected by the autoantibodies' pathogenic mechanisms. Furthermore, we give a short overview of the cells that are implicated in the production of the autoantibodies and briefly discuss diagnostic challenges and treatment strategies.
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Takata K, Stathopoulos P, Cao M, Mané-Damas M, Fichtner ML, Benotti ES, Jacobson L, Waters P, Irani SR, Martinez-Martinez P, Beeson D, Losen M, Vincent A, Nowak RJ, O'Connor KC. Characterization of pathogenic monoclonal autoantibodies derived from muscle-specific kinase myasthenia gravis patients. JCI Insight 2019; 4:127167. [PMID: 31217355 PMCID: PMC6629167 DOI: 10.1172/jci.insight.127167] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/10/2019] [Indexed: 12/15/2022] Open
Abstract
Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by muscle weakness and caused by pathogenic autoantibodies that bind to membrane proteins at the neuromuscular junction. Most patients have autoantibodies against the acetylcholine receptor (AChR), but a subset of patients have autoantibodies against muscle-specific tyrosine kinase (MuSK) instead. MuSK is an essential component of the pathway responsible for synaptic differentiation, which is activated by nerve-released agrin. Through binding MuSK, serum-derived autoantibodies inhibit agrin-induced MuSK autophosphorylation, impair clustering of AChRs, and block neuromuscular transmission. We sought to establish individual MuSK autoantibody clones so that the autoimmune mechanisms could be better understood. We isolated MuSK autoantibody-expressing B cells from 6 MuSK MG patients using a fluorescently tagged MuSK antigen multimer, then generated a panel of human monoclonal autoantibodies (mAbs) from these cells. Here we focused on 3 highly specific mAbs that bound quantitatively to MuSK in solution, to MuSK-expressing HEK cells, and at mouse neuromuscular junctions, where they colocalized with AChRs. These 3 IgG isotype mAbs (2 IgG4 and 1 IgG3 subclass) recognized the Ig-like domain 2 of MuSK. The mAbs inhibited AChR clustering, but intriguingly, they enhanced rather than inhibited MuSK phosphorylation, which suggests an alternative mechanism for inhibiting AChR clustering. A fluorescent tetrameric antigen allows isolation of human myasthenia gravis monoclonal antibodies that interrupt acetylcholine receptor signaling.
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Affiliation(s)
- Kazushiro Takata
- Department of Neurology and.,Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Panos Stathopoulos
- Department of Neurology and.,Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Michelangelo Cao
- Neurosciences Group, Weatherall Institute of Molecular Medicine and Nuffield Department of Clinical Neurosciences, Oxford, England
| | - Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Miriam L Fichtner
- Department of Neurology and.,Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Erik S Benotti
- Department of Neurology and.,Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Leslie Jacobson
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, England
| | - Patrick Waters
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, England
| | - Sarosh R Irani
- Oxford Autoimmune Neurology Group, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, England
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine and Nuffield Department of Clinical Neurosciences, Oxford, England
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Angela Vincent
- Neurosciences Group, Weatherall Institute of Molecular Medicine and Nuffield Department of Clinical Neurosciences, Oxford, England
| | | | - Kevin C O'Connor
- Department of Neurology and.,Department of Immunobiology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
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Ujiie H, Yoshimoto N, Natsuga K, Muramatsu K, Iwata H, Nishie W, Shimizu H. Immune Reaction to Type XVII Collagen Induces Intramolecular and Intermolecular Epitope Spreading in Experimental Bullous Pemphigoid Models. Front Immunol 2019; 10:1410. [PMID: 31275329 PMCID: PMC6593113 DOI: 10.3389/fimmu.2019.01410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/04/2019] [Indexed: 01/18/2023] Open
Abstract
Bullous pemphigoid (BP), the most common autoimmune blistering disease, is induced by autoantibodies to type XVII collagen (COL17). Previous studies demonstrated that COL17 harbors several epitopes targeted by autoreactive T and B cells and that the target epitopes change sequentially during the disease course. To elucidate the details of the humoral immune response to COL17, we used an active BP mouse model in which BP is induced by the adoptive transfer of spleen cells from wild-type mice immunized with human COL17-expressing skin grafting to immunodeficient COL17-humanized (Rag-2-/-, mouse Col17-/-, human COL17+) mice. By immunoblot analysis, antibodies to the NC16A domain and other extracellular domains (ECDs) of COL17 were detected earlier than antibodies to intracellular domains (ICDs) in the active BP model. Time course analysis by enzyme-linked immunosorbent assay demonstrated a delayed peak of antibodies to ICD epitopes in active BP model. The blockade of CD40-CD40 ligand interaction soon after the adoptive transfer suppressed the production of antibodies to the non-collagenous 16A (NC16A) domain but not to an ICD epitope, suggesting the sequential activation from T and B cells against the ECD epitopes including the NC16A domain to those against ICD epitopes in vivo. Both wild-type mice immunized with a fragment of the NC16A domain and the recipients of those spleen cells produced IgG antibodies to ICD and ECD epitopes, showing intramolecular epitope spreading from the NC16A domain to other epitopes of COL17. Furthermore, we found that a portion of the active BP model mice show intermolecular epitope spreading from human COL17 to murine BP230. The appearance of antibodies to ICD epitopes of COL17 or of antibodies to murine BP230 did not correlate with the skin changes in the mice, suggesting that those antibodies have low pathogenicity. These results suggest that the immune response to the ECD epitopes of COL17, especially to the NC16A domain, triggers intramolecular, and intermolecular epitope spreading to ICD epitopes of COL17 and to murine BP230. These novel findings provide insight into the mechanism of epitope spreading in organ-specific, antibody-mediated autoimmune disorders.
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Affiliation(s)
- Hideyuki Ujiie
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies against the acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or other AChR-related proteins in the postsynaptic muscle membrane. Localized or general muscle weakness is the predominant symptom and is induced by the antibodies. Patients are grouped according to the presence of antibodies, symptoms, age at onset and thymus pathology. Diagnosis is straightforward in most patients with typical symptoms and a positive antibody test, although a detailed clinical and neurophysiological examination is important in antibody-negative patients. MG therapy should be ambitious and aim for clinical remission or only mild symptoms with near-normal function and quality of life. Treatment should be based on MG subgroup and includes symptomatic treatment using acetylcholinesterase inhibitors, thymectomy and immunotherapy. Intravenous immunoglobulin and plasma exchange are fast-acting treatments used for disease exacerbations, and intensive care is necessary during exacerbations with respiratory failure. Comorbidity is frequent, particularly in elderly patients. Active physical training should be encouraged.
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Cognitive dysfunction in mice with passively induced MuSK antibody seropositive myasthenia gravis. J Neurol Sci 2019; 399:15-21. [DOI: 10.1016/j.jns.2019.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/23/2019] [Accepted: 02/01/2019] [Indexed: 11/19/2022]
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Huijbers MG, Plomp JJ, van Es IE, Fillié-Grijpma YE, Kamar-Al Majidi S, Ulrichts P, de Haard H, Hofman E, van der Maarel SM, Verschuuren JJ. Efgartigimod improves muscle weakness in a mouse model for muscle-specific kinase myasthenia gravis. Exp Neurol 2019; 317:133-143. [PMID: 30851266 DOI: 10.1016/j.expneurol.2019.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/24/2019] [Accepted: 03/04/2019] [Indexed: 12/30/2022]
Abstract
Myasthenia gravis is hallmarked by fatigable muscle weakness resulting from neuromuscular synapse dysfunction caused by IgG autoantibodies. The variant with muscle-specific kinase (MuSK) autoantibodies is characterized by prominent cranial and bulbar weakness and a high frequency of respiratory crises. The majority of MuSK MG patients requires long-term immunosuppressive treatment, but the result of these treatments is considered less satisfactory than in MG with acetylcholine receptor antibodies. Emergency treatments are more frequently needed, and many patients develop permanent facial weakness and nasal speech. Therefore, new treatment options would be welcome. The neonatal Fc receptor protects IgG from lysosomal breakdown, thus prolonging IgG serum half-life. Neonatal Fc receptor antagonism lowers serum IgG levels and thus may act therapeutically in autoantibody-mediated disorders. In MuSK MG, IgG4 anti-MuSK titres closely correlate with disease severity. We therefore tested efgartigimod (ARGX-113), a new neonatal Fc receptor blocker, in a mouse model for MuSK myasthenia gravis. This model involves 11 daily injections of purified IgG4 from MuSK myasthenia gravis patients, resulting in overt myasthenic muscle weakness and, consequently, body weight loss. Daily treatment with 0.5 mg efgartigimod, starting at the fifth passive transfer day, reduced the human IgG4 titres about 8-fold, despite continued daily injection. In muscle strength and fatigability tests, efgartigimod-treated myasthenic mice outperformed control myasthenic mice. Electromyography in calf muscles at endpoint demonstrated less myasthenic decrement of compound muscle action potentials in efgartigimod-treated mice. These substantial in vivo improvements of efgartigimod-treated MuSK MG mice following a limited drug exposure period were paralleled by a tendency of recovery at neuromuscular synaptic level (in various muscles), as demonstrated by ex vivo functional studies. These synaptic improvements may well become more explicit upon longer drug exposure. In conclusion, our study shows that efgartigimod has clear therapeutic potential in MuSK myasthenia gravis and forms an exciting candidate drug for many autoantibody-mediated neurological and other disorders.
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Affiliation(s)
- Maartje G Huijbers
- Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands; Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands.
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Inge E van Es
- Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands
| | | | - Samar Kamar-Al Majidi
- Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands; Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands
| | - Peter Ulrichts
- argenx BVBA, Industriepark Zwijnaarde 7, 9052, Zwijnaarde, Gent, Belgium
| | - Hans de Haard
- argenx BVBA, Industriepark Zwijnaarde 7, 9052, Zwijnaarde, Gent, Belgium
| | - Erik Hofman
- argenx BVBA, Industriepark Zwijnaarde 7, 9052, Zwijnaarde, Gent, Belgium
| | | | - Jan J Verschuuren
- Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
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Huijbers MG, Vergoossen DL, Fillié-Grijpma YE, van Es IE, Koning MT, Slot LM, Veelken H, Plomp JJ, van der Maarel SM, Verschuuren JJ. MuSK myasthenia gravis monoclonal antibodies: Valency dictates pathogenicity. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2019; 6:e547. [PMID: 30882021 PMCID: PMC6410930 DOI: 10.1212/nxi.0000000000000547] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/14/2019] [Indexed: 12/18/2022]
Abstract
Objective To isolate and characterize muscle-specific kinase (MuSK) monoclonal antibodies from patients with MuSK myasthenia gravis (MG) on a genetic and functional level. Methods We generated recombinant MuSK antibodies from patient-derived clonal MuSK-specific B cells and produced monovalent Fab fragments from them. Both the antibodies and Fab fragments were tested for their effects on neural agrin-induced MuSK phosphorylation and acetylcholine receptor (AChR) clustering in myotube cultures. Results The isolated MuSK monoclonal antibody sequences included IgG1, IgG3, and IgG4 that had undergone high levels of affinity maturation, consistent with antigenic selection. We confirmed their specificity for the MuSK Ig-like 1 domain and binding to neuromuscular junctions. Monovalent MuSK Fab, mimicking functionally monovalent MuSK MG patient Fab-arm exchanged serum IgG4, abolished agrin-induced MuSK phosphorylation and AChR clustering. Surprisingly, bivalent monospecific MuSK antibodies instead activated MuSK phosphorylation and partially induced AChR clustering, independent of agrin. Conclusions Patient-derived MuSK antibodies can act either as MuSK agonist or MuSK antagonist, depending on the number of MuSK binding sites. Functional monovalency, induced by Fab-arm exchange in patient serum, makes MuSK IgG4 antibodies pathogenic.
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Affiliation(s)
- Maartje G Huijbers
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Dana L Vergoossen
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Yvonne E Fillié-Grijpma
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Inge E van Es
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Marvyn T Koning
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Linda M Slot
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Hendrik Veelken
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Jaap J Plomp
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Silvère M van der Maarel
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
| | - Jan J Verschuuren
- Department of Neurology (M.G.H., Y.E.F.-G., I.E.v.E., J.J.P., J.J.V.), Department of Human Genetics (M.G.H., D.L.V., Y.F.-G., I.E.v.E., S.M.v.d.M.), Department of Hematology (M.T.K., H.V.), and Department of Rheumatology (L.M.S.), Leiden University Medical Center, The Netherlands
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Galassi G, Mazzoli M, Ariatti A, Kaleci S, Valzania F, Nichelli PF. Antibody profile may predict outcome in ocular myasthenia gravis. Acta Neurol Belg 2018; 118:435-443. [PMID: 29858757 DOI: 10.1007/s13760-018-0943-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/15/2018] [Indexed: 02/04/2023]
Abstract
An unsolved issue remains whether there are clinical and immunological features to predict in a single patient the risk of conversion from ocular Myasthenia Gravis (OMG) to generalized disease (GMG) as 50-60% of patients may progress within 1-2 years since onset. Anti-acetylcholine receptor antibodies (AChR Abs) are found in up to 50% of OMG patients; muscle-specific tyrosine kinase antibodies (MuSK-Abs) are present in about 70% of the whole seronegative (SN), who usually develop a severe disease with bulbar involvement. We surveyed a cohort of 175 OMG patients with purely ocular symptoms and we compare the outcome of patients with antibodies to AChR or to MuSK with those seronegative for both Abs (DSN). All patients had purely ocular signs for at least 24 months. Gender, age at onset, time to generalization or to worsening in quantitative ocular QMG scores, electrophysiological results were analyzed. Males were 58.9%, females 41.1%. Patients with late onset of symptoms after 50 years (LOMG) were 78.3%. We assayed anti-MuSK-Abs in 4.7%, anti-AChR Abs in 38.5%; 57.3% were defined DSN. Thirty-seven patients (21.1%) progressed to GMG during the observational time: 23 were females, 62% of the whole group of the generalized subjects, 75% of MuSK-positive OMG converted to GMG versus the 26.2% of AChR positive and 13.7% of DSN. Statistical analysis showed that gender and presence of antibodies either to AChR or to MuSK were independent predictors of worse outcome; the DSN subjects had lower risk of conversion to GMG.
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Affiliation(s)
- Giuliana Galassi
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy.
| | - Marco Mazzoli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Alessandra Ariatti
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Shaniko Kaleci
- Department of Diagnostic Clinical Medicine and Public Health, University of Modena, Modena, Italy
| | - Franco Valzania
- Department of Neurology, Arcispedale S. Maria Nuova, Reggio Emilia, Italy
| | - Paolo F Nichelli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
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Wang S, Breskovska I, Gandhy S, Punga AR, Guptill JT, Kaminski HJ. Advances in autoimmune myasthenia gravis management. Expert Rev Neurother 2018; 18:573-588. [PMID: 29932785 PMCID: PMC6289049 DOI: 10.1080/14737175.2018.1491310] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Myasthenia gravis (MG) is an autoimmune neuromuscular disorder with no cure and conventional treatments limited by significant adverse effects and variable benefit. In the last decade, therapeutic development has expanded based on improved understanding of autoimmunity and financial incentives for drug development in rare disease. Clinical subtypes exist based on age, gender, thymic pathology, autoantibody profile, and other poorly defined factors, such as genetics, complicate development of specific therapies. Areas covered: Clinical presentation and pathology vary considerably among patients with some having weakness limited to the ocular muscles and others having profound generalized weakness leading to respiratory insufficiency. MG is an antibody-mediated disorder dependent on autoreactive B cells which require T-cell support. Treatments focus on elimination of circulating autoantibodies or inhibition of effector mechanisms by a broad spectrum of approaches from plasmapheresis to B-cell elimination to complement inhibition. Expert commentary: Standard therapies and those under development are disease modifying and not curative. As a rare disease, clinical trials are challenged in patient recruitment. The great interest in development of treatments specific for MG is welcome, but decisions will need to be made to focus on those that offer significant benefits to patients.
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Affiliation(s)
- Shuhui Wang
- Department of Neurology, George Washington University, Washington DC 20008
| | - Iva Breskovska
- Department of Neurology, George Washington University, Washington DC 20008
| | - Shreya Gandhy
- Department of Neurology, George Washington University, Washington DC 20008
| | - Anna Rostedt Punga
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | - Jeffery T. Guptill
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
| | - Henry J. Kaminski
- Department of Neurology, George Washington University, Washington DC 20008
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Abstract
PURPOSE OF REVIEW Myasthenia gravis, a rare disorder of the neuromuscular transmission, is increasingly acknowledged as a syndrome more than as a single disease. This review summarizes recent advances in pathophysiology which confirm the disease heterogeneity, and may help find disease-targeted and patient-targeted therapies. RECENT FINDINGS Antibodies to the acetylcholine receptor, the muscle-specific tyrosine kinase and the lipoprotein receptor protein 4, characterize disease subtypes with distinct clinical traits and immune-pathogenic mechanisms. Genome-wide approaches have identified susceptibility loci within genes that participate in the immune response. Regulatory T and B cells appear to be defective in myasthenia gravis. In patients with acetylcholine receptor antibodies, thymectomy associated with prednisone proved more effective than prednisone alone in a multicenter randomized trial. New therapeutic options target B cells, B-cell growth factors and complement inhibition, and are currently reserved for patients with refractory disease. SUMMARY In the recent past, there has been an active search for new antigens in myasthenia gravis, whereas clinical and experimental studies have provided new insights of crucial pathways in immune regulation, which might become the targets of future therapeutic interventions.
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Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Roma, Italy
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Morren J, Li Y. Myasthenia gravis with muscle-specific tyrosine kinase antibodies: A narrative review. Muscle Nerve 2018; 58:344-358. [DOI: 10.1002/mus.26107] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/09/2018] [Accepted: 02/18/2018] [Indexed: 12/14/2022]
Affiliation(s)
- John Morren
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
| | - Yuebing Li
- Neuromuscular Center, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Desk S90; Cleveland Ohio 44195 USA
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Huijbers MG, Plomp JJ, van der Maarel SM, Verschuuren JJ. IgG4-mediated autoimmune diseases: a niche of antibody-mediated disorders. Ann N Y Acad Sci 2018; 1413:92-103. [PMID: 29377160 DOI: 10.1111/nyas.13561] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/19/2017] [Accepted: 10/30/2017] [Indexed: 12/11/2022]
Abstract
Immunoglobulin 4 (IgG4) is one of four human IgG subclasses and has several unique functional characteristics. It exhibits low affinity for complement and for most Fc receptors. It furthermore has generally high affinity for its antigen, with binding occurring in a monovalent fashion, as IgG4 can exchange Fab-arms with other IgG4 molecules. Because of these characteristics, IgG4 is believed to block its targets and prevent inflammation, which, depending on the setting, can have a protective or pathogenic effect. One example of IgG4 pathogenicity is muscle-specific kinase (MuSK) myasthenia gravis (MG), in which patients develop IgG4 MuSK autoantibodies, resulting in muscle weakness. As a consequence of the distinct IgG4 characteristics, the pathomechanism of MuSK MG is very different from IgG1-and IgG3-mediated autoimmune diseases, such as acetylcholine receptor MG. In recent years, new autoantibodies in a spectrum of autoimmune diseases have been discovered. Interestingly, some were found to be predominantly IgG4. These IgG4-mediated autoimmune diseases share many pathomechanistic aspects with MuSK MG, suggesting that IgG4-mediated autoimmunity forms a separate niche among the antibody-mediated disorders. In this review, we summarize the group of IgG4-mediated autoimmune diseases, discuss the role of IgG4 in MuSK MG, and highlight interesting future research questions for IgG4-mediated autoimmunity.
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Affiliation(s)
- Maartje G Huijbers
- Departments of Neurology, Leiden University Medical Centre, Leiden, the Netherlands.,Department of Human Genetics, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jaap J Plomp
- Departments of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | | | - Jan J Verschuuren
- Departments of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
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Verschuuren JJGM, Plomp JJ, Burden SJ, Zhang W, Fillié-Grijpma YE, Stienstra-van Es IE, Niks EH, Losen M, van der Maarel SM, Huijbers MG. Passive transfer models of myasthenia gravis with muscle-specific kinase antibodies. Ann N Y Acad Sci 2018; 1413:111-118. [PMID: 29356029 DOI: 10.1111/nyas.13543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/02/2017] [Accepted: 10/05/2017] [Indexed: 12/20/2022]
Abstract
Myasthenia gravis (MG) with antibodies to muscle-specific kinase (MuSK) is characterized by fluctuating fatigable weakness. In MuSK MG, involvement of bulbar muscles, neck, and shoulder and respiratory weakness are more prominent than in acetylcholine receptor (AChR) MG. MuSK autoantibodies are mainly of the IgG4 subclass, and as such are unable to activate complement, have low affinity for Fc receptors, and are functionally monovalent. Therefore, the pathogenicity of IgG4 MuSK autoantibodies was initially questioned. A broad collection of in vitro active immunization and passive transfer models has been developed that have shed light on the pathogenicity of MuSK autoantibodies. Passive transfer studies with purified IgG4 from MuSK MG patients confirmed that IgG4 is sufficient to reproduce clear clinical, electrophysiological, and histological signs of myasthenia. In vitro experiments revealed that MuSK IgG4 autoantibodies preferably bind the first Ig-like domain of MuSK, correlate with disease severity, and interfere with the association between MuSK and low-density lipoprotein receptor-related protein 4 and collagen Q. Some patients have additional IgG1 MuSK autoantibodies, but their role in the disease is unclear. Altogether, this provides a rationale for epitope-specific or IgG4-specific treatment strategies for MuSK MG and emphasizes the importance of the development of different experimental models.
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Affiliation(s)
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | - Steve J Burden
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Medical School, New York, New York
| | - Wei Zhang
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University Medical School, New York, New York
| | | | | | - Erik H Niks
- Department of Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | | | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, the Netherlands
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Evoli A, Alboini PE, Damato V, Iorio R, Provenzano C, Bartoccioni E, Marino M. Myasthenia gravis with antibodies to MuSK: an update. Ann N Y Acad Sci 2017; 1412:82-89. [PMID: 29266255 DOI: 10.1111/nyas.13518] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 02/06/2023]
Abstract
Myasthenia gravis with antibodies to the muscle-specific tyrosine kinase (MuSK+ MG) is a rare disease with distinctive pathogenic mechanisms and clinical features. An acute onset and predominant bulbar muscle weakness are very common and highly suggestive of the disease. On the other hand, a more indolent course, atypical ocular presentation, and signs of cholinergic hyperactivity may complicate the diagnosis. Though MuSK+ MG is still a severe disease, over the years we have observed a steady reduction in the rate of respiratory crisis and a significant improvement in the clinical outcome, both likely related to earlier diagnosis and timely treatment. Despite the improved management, MuSK+ MG patients tend to remain dependent on long-term immunosuppressive treatment and may develop permanent disabling weakness. In uncontrolled studies, B cell depletion with rituximab proved effective in most patients with refractory disease, inducing prolonged clinical responses associated with a sustained reduction of serum antibody levels. Promising results from experimental studies and case reports suggest that both 3,4-diaminopyridine and albuterol may be effective as symptomatic agents.
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Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Paolo E Alboini
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Valentina Damato
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Raffaele Iorio
- Institute of Neurology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Carlo Provenzano
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Emanuela Bartoccioni
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
| | - Mariapaola Marino
- Institute of General Pathology, Catholic University, Fondazione Policlinico Gemelli, Rome, Italy
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Autoantibodies in chronic inflammatory neuropathies: diagnostic and therapeutic implications. Nat Rev Neurol 2017; 13:533-547. [PMID: 28708133 DOI: 10.1038/nrneurol.2017.84] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The chronic inflammatory neuropathies (CINs) are rare, very disabling autoimmune disorders that generally respond well to immune therapies such as intravenous immunoglobulin (IVIg). The most common forms of CIN are chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy, and polyneuropathy associated with monoclonal gammopathy of unknown significance. The field of CIN has undergone a major advance with the identification of IgG4 autoantibodies directed against paranodal proteins in patients with CIDP. Although these autoantibodies are only found in a small subset of patients with CIDP, they can be used to guide therapeutic decision-making, as these patients have a poor response to IVIg. These observations provide proof of concept that identifying the target antigens in tissue-specific antibody-mediated autoimmune diseases is important, not only to understand their underlying pathogenic mechanisms, but also to correctly diagnose and treat affected patients. This state-of-the-art Review focuses on the role of autoantibodies against nodes of Ranvier in CIDP, a clinically relevant emerging field of research. The role of autoantibodies in other immune-mediated neuropathies, including other forms of CIN, primary autoimmune neuropathies, neoplasms, and systemic diseases that resemble CIN, are also discussed.
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Takamori M. Synaptic Homeostasis and Its Immunological Disturbance in Neuromuscular Junction Disorders. Int J Mol Sci 2017; 18:ijms18040896. [PMID: 28441759 PMCID: PMC5412475 DOI: 10.3390/ijms18040896] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/04/2017] [Accepted: 04/19/2017] [Indexed: 12/14/2022] Open
Abstract
In the neuromuscular junction, postsynaptic nicotinic acetylcholine receptor (nAChR) clustering, trans-synaptic communication and synaptic stabilization are modulated by the molecular mechanisms underlying synaptic plasticity. The synaptic functions are based presynaptically on the active zone architecture, synaptic vesicle proteins, Ca2+ channels and synaptic vesicle recycling. Postsynaptically, they are based on rapsyn-anchored nAChR clusters, localized sensitivity to ACh, and synaptic stabilization via linkage to the extracellular matrix so as to be precisely opposed to the nerve terminal. Focusing on neural agrin, Wnts, muscle-specific tyrosine kinase (a mediator of agrin and Wnts signalings and regulator of trans-synaptic communication), low-density lipoprotein receptor-related protein 4 (the receptor of agrin and Wnts and participant in retrograde signaling), laminin-network (including muscle-derived agrin), extracellular matrix proteins (participating in the synaptic stabilization) and presynaptic receptors (including muscarinic and adenosine receptors), we review the functional structures of the synapse by making reference to immunological pathogenecities in postsynaptic disease, myasthenia gravis. The synapse-related proteins including cortactin, coronin-6, caveolin-3, doublecortin, R-spondin 2, amyloid precursor family proteins, glia cell-derived neurotrophic factor and neurexins are also discussed in terms of their possible contribution to efficient synaptic transmission at the neuromuscular junction.
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Affiliation(s)
- Masaharu Takamori
- Neurological Center, Kanazawa-Nishi Hospital, Kanazawa, Ishikawa 920-0025, Japan.
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Sinmaz N, Nguyen T, Tea F, Dale RC, Brilot F. Mapping autoantigen epitopes: molecular insights into autoantibody-associated disorders of the nervous system. J Neuroinflammation 2016; 13:219. [PMID: 27577085 PMCID: PMC5006540 DOI: 10.1186/s12974-016-0678-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/17/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Our knowledge of autoantibody-associated diseases of the central (CNS) and peripheral (PNS) nervous systems has expanded greatly over the recent years. A number of extracellular and intracellular autoantigens have been identified, and there is no doubt that this field will continue to expand as more autoantigens are discovered as a result of improved clinical awareness and methodological practice. In recent years, interest has shifted to uncover the target epitopes of these autoantibodies. MAIN BODY The purpose of this review is to discuss the mapping of the epitope targets of autoantibodies in CNS and PNS antibody-mediated disorders, such as N-methyl-D-aspartate receptor (NMDAR), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), leucine-rich glioma-inactivated protein 1 (Lgi1), contactin-associated protein-like 2 (Caspr2), myelin oligodendrocyte glycoprotein (MOG), aquaporin-4 (AQP4), 65 kDa glutamic acid decarboxylase (GAD65), acetylcholine receptor (AChR), muscle-specific kinase (MuSK), voltage-gated calcium channel (VGCC), neurofascin (NF), and contactin. We also address the methods used to analyze these epitopes, the relevance of their determination, and how this knowledge can inform studies on autoantibody pathogenicity. Furthermore, we discuss triggers of autoimmunity, such as molecular mimicry, ectopic antigen expression, epitope spreading, and potential mechanisms for the rising number of double autoantibody-positive patients. CONCLUSIONS Molecular insights into specificity and role of autoantibodies will likely improve diagnosis and treatment of CNS and PNS neuroimmune diseases.
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Affiliation(s)
- Nese Sinmaz
- Brain Autoimmunity Group, Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Locked Bag 4001, Westmead, NSW, 2145, Australia
| | - Tina Nguyen
- Brain Autoimmunity Group, Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Locked Bag 4001, Westmead, NSW, 2145, Australia
| | - Fiona Tea
- Brain Autoimmunity Group, Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Locked Bag 4001, Westmead, NSW, 2145, Australia
| | - Russell C Dale
- Brain Autoimmunity Group, Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Locked Bag 4001, Westmead, NSW, 2145, Australia
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Fabienne Brilot
- Brain Autoimmunity Group, Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Locked Bag 4001, Westmead, NSW, 2145, Australia.
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia.
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