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Kowar M, Frackowiak M, Kaufhold C, Jacobs AH. [Fiber endoscopic evaluation of swallowing (FEES) - an important tool for diagnosing myasthenia gravis]. Dtsch Med Wochenschr 2024; 149:997-1001. [PMID: 39146745 DOI: 10.1055/a-2352-5193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
HISTORY AND ADMISSION FINDINGS A 76-year old man was admitted with a globus sensation and weight loss for further investigations to our geriatric ward. A gastroscopic evaluation executed before had been unremarkable. INVESTIGATIONS Physical examination was unremarkable, including a neurological examination. TREATMENT AND COURSE All radiological findings (computer tomography of chest, abdomen and neck) were unremarkable. In a FEES investigation we found retentions and a reduction of frequency of swallowing after a while. During the investigation the patient complained about a muscular weakness in his neck. The assumed diagnosis of a myasthenia gravis was confirmed by antibodies against acetylcholine receptors and a decrement in repetitive irritation of the orbicularis and trapezius muscle. CONCLUSION FEES can be a valid diagnosis tool for a pharyngeal type of a myasthenia gravis.
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Affiliation(s)
- Michael Kowar
- Klinik für Geriatrie mit Neurologie und Tagesklinik, Johanniter gGmbH, Johanniter-Krankenhaus Bonn
| | - Monika Frackowiak
- Klinik für Geriatrie mit Neurologie und Tagesklinik, Johanniter gGmbH, Johanniter-Krankenhaus Bonn
| | - Christiane Kaufhold
- Klinik für Geriatrie mit Neurologie und Tagesklinik, Johanniter gGmbH, Johanniter-Krankenhaus Bonn
| | - Andreas H Jacobs
- Klinik für Geriatrie mit Neurologie und Tagesklinik, Johanniter gGmbH, Johanniter-Krankenhaus Bonn
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Oeztuerk M, Henes A, Schroeter CB, Nelke C, Quint P, Theissen L, Meuth SG, Ruck T. Current Biomarker Strategies in Autoimmune Neuromuscular Diseases. Cells 2023; 12:2456. [PMID: 37887300 PMCID: PMC10605022 DOI: 10.3390/cells12202456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/09/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Inflammatory neuromuscular disorders encompass a diverse group of immune-mediated diseases with varying clinical manifestations and treatment responses. The identification of specific biomarkers has the potential to provide valuable insights into disease pathogenesis, aid in accurate diagnosis, predict disease course, and monitor treatment efficacy. However, the rarity and heterogeneity of these disorders pose significant challenges in the identification and implementation of reliable biomarkers. Here, we aim to provide a comprehensive review of biomarkers currently established in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), and idiopathic inflammatory myopathy (IIM). It highlights the existing biomarkers in these disorders, including diagnostic, prognostic, predictive and monitoring biomarkers, while emphasizing the unmet need for additional specific biomarkers. The limitations and challenges associated with the current biomarkers are discussed, and the potential implications for disease management and personalized treatment strategies are explored. Collectively, biomarkers have the potential to improve the management of inflammatory neuromuscular disorders. However, novel strategies and further research are needed to establish clinically meaningful biomarkers.
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Affiliation(s)
| | | | | | | | | | | | | | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.O.); (A.H.); (P.Q.)
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Myllynen C, Sarkkinen J, Atula S, Tienari P, Kekäläinen E, Laakso SM. A skewed ratio of free light chains is more common in patients with late-onset than early-onset myasthenia gravis. Immunol Lett 2023; 260:S0165-2478(23)00113-X. [PMID: 37414259 DOI: 10.1016/j.imlet.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/25/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023]
Abstract
Myasthenia gravis (MG) is an autoantibody-mediated neuromuscular disease with an unpredictable clinical course. Serum free light chains (FLCs) have risen as a promising biomarker for MG, but their role in different subtypes of MG and in predicting disease progression is still uncharted. We investigated plasma from 58 generalized MG patients during post-thymectomy follow-up to determine κ and λ FLC and κ/λ ratio. In a subcohort of 30 patients, we examined the expression of 92 proteins associated with immuno-oncology using Olink. We further studied the ability of FLCs or proteomic markers to differentiate disease severity. Patients with late-onset MG (LOMG) displayed significantly higher mean κ/λ ratio than patients with early-onset MG (P=0.004). Inducible T-cell co-stimulator ligand (ICOSLG), matrix metalloproteinase 7 (MMP7), hepatocyte growth factor (HGF), and arginase 1 (ARG1) were differentially expressed in MG patients compared to healthy controls. There were no significant associations between clinical outcomes and FLCs or the assayed proteins. In conclusion, an elevated κ/λ ratio suggests long-lasting aberrant clonal plasma cell function in LOMG. Immuno-oncology-related proteomic analysis showed alterations in immunoregulatory pathways. Our findings pinpoint the FLC ratio as a biomarker for LOMG and call for further investigation of the immunoregulatory pathways in MG.
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Affiliation(s)
- Chris Myllynen
- Department of Neurosciences, University of Helsinki, Helsinki, Finland.
| | - Joona Sarkkinen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Sari Atula
- Department of Neurosciences, University of Helsinki, Helsinki, Finland; Department of Neurology, Neurocenter, Helsinki University Hospital, Helsinki, Finland
| | - Pentti Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Neurocenter, Helsinki University Hospital, Helsinki, Finland
| | - Eliisa Kekäläinen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; HUS Diagnostic Center, HUSLAB Clinical Microbiology, Helsinki University Hospital, Helsinki, Finland
| | - Sini M Laakso
- Department of Neurosciences, University of Helsinki, Helsinki, Finland; Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Neurocenter, Helsinki University Hospital, Helsinki, Finland
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4
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Menghesha H, Schroeter M, Nelke C, Ruck T, Schlachtenberger G, Welskop C, Camo A, Heldwein M, Bennink G, Wahlers T, Bölükbas S, Doerr F, Hekmat K. The impact of thymectomy in subgroups of Myasthenia gravis patients: a single center longitudinal observation. Neurol Res Pract 2023; 5:24. [PMID: 37316910 DOI: 10.1186/s42466-023-00252-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/24/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Myasthenia gravis (MG) is a rare neuromuscular disorder. Symptoms can range from ptosis only to life threatening myasthenic crisis. Thymectomy is recommended for anti-acetylcholine receptor-antibody positive patients with early-onset MG. Here, we investigated prognostic factors shaping therapeutic outcomes of thymectomy to improve patient stratification. METHODS We retrospectively collected single-center data from a specialized center for MG from all consecutive adult patients that underwent thymectomy from 01/2012 to 12/2020. We selected patients with thymoma-associated and non-thymomatous MG for further investigations. We analyzed the patient collective regarding perioperative parameters in relation to the surgical approach. Furthermore, we investigated the dynamics of the anti-acetylcholine receptor-antibody titers and concurrent immunosuppressive therapies, as well as the therapeutic outcomes in dependence of clinical classifications. RESULTS Of 137 patients 94 were included for further analysis. We used a minimally invasive approach in 73 patients, whereas 21 patients underwent sternotomy. A total of 45 patients were classified as early-onset MG (EOMG), 28 as late-onset MG (LOMG) and 21 as thymoma-associated MG (TAMG). The groups differed in terms of age at diagnosis (EOMG: 31.1 ± 12.2 years; LOMG: 59.8 ± 13.7 years; TAMG: 58.6 ± 16.7 years; p < 0.001). Patients with EOMG and TAMG were more often female than patients in the LOMG group (EOMG: 75.6%; LOMG: 42.9%; TAMG: 61.9%; p = 0.018). There were no significant differences in outcome scores (quantitative MG; MG activities of daily living; MG Quality of Live) with a median follow-up of 46 months. However, Complete Stable Remission was achieved significantly more frequently in the EOMG group than in the other two groups (p = 0.031). At the same time, symptoms seem to improve similarly in all three groups (p = 0.25). CONCLUSION Our study confirms the benefit of thymectomy in the therapy of MG. Both, the concentration of acetylcholine receptor antibodies and the necessary dosage of cortisone therapy show a continuous regression after thymectomy in the overall cohort. Beyond EOMG, groups of LOMG and thymomatous MG responded to thymectomy as well, but therapy success was less pronounced and delayed compared to the EOMG subgroup. Thymectomy is a mainstay of MG therapy to be considered in all subgroups of MG patients investigated.
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Affiliation(s)
- Hruy Menghesha
- Department of Thoracic Surgery, University Medical Center Essen - Ruhrlandclinic, Tüschener Weg 40, 45239, Essen, Germany.
| | - Michael Schroeter
- Faculty of Medicine, Department of Neurology, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
| | - Christopher Nelke
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Dusseldorf, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Dusseldorf, Germany
| | - Georg Schlachtenberger
- Faculty of Medicine, Department of Cardiothoracic Surgery, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
| | - Clara Welskop
- Faculty of Medicine, University of Cologne, Joseph-Stelzmann-Strasse 20, 50931, Cologne, Germany
| | - Amina Camo
- Faculty of Medicine, University of Cologne, Joseph-Stelzmann-Strasse 20, 50931, Cologne, Germany
| | - Matthias Heldwein
- Faculty of Medicine, Department of Cardiothoracic Surgery, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
| | - Gerardus Bennink
- Faculty of Medicine, Department of Cardiothoracic Surgery, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
| | - Thorsten Wahlers
- Faculty of Medicine, Department of Cardiothoracic Surgery, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
| | - Servet Bölükbas
- Department of Thoracic Surgery, University Medical Center Essen - Ruhrlandclinic, Tüschener Weg 40, 45239, Essen, Germany
| | - Fabian Doerr
- Department of Thoracic Surgery, University Medical Center Essen - Ruhrlandclinic, Tüschener Weg 40, 45239, Essen, Germany
| | - Khosro Hekmat
- Faculty of Medicine, Department of Cardiothoracic Surgery, University of Cologne, University Hospital Cologne, Kerpener Strasse 62, 50937, Cologne, Germany
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Meisel A, Baggi F, Behin A, Evoli A, Kostera-Pruszczyk A, Mantegazza R, Morales RJ, Punga AR, Sacconi S, Schroeter M, Verschuuren J, Crathorne L, Holmes K, Leite MI. Role of autoantibody levels as biomarkers in the management of patients with myasthenia gravis: A systematic review and expert appraisal. Eur J Neurol 2023; 30:266-282. [PMID: 36094738 DOI: 10.1111/ene.15565] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/26/2022] [Accepted: 09/04/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Although myasthenia gravis (MG) is recognized as an immunoglobulin G autoantibody-mediated disease, the relationship between autoantibody levels and disease activity in MG is unclear. We sought to evaluate this landscape through systematically assessing the evidence, testing the impact of predefined variables on any relationship, and augmenting with expert opinion. METHODS In October 2020, a forum of leading clinicians and researchers in neurology from across Europe (Expert Forum for Rare Autoantibodies in Neurology in Myasthenia Gravis) participated in a series of virtual meetings that took place alongside the conduct of a systematic literature review (SLR). RESULTS Forty-two studies were identified meeting inclusion criteria. Of these, 10 reported some correlation between a patient's autoantibody level and disease severity. Generally, decreased autoantibody levels (acetylcholine receptor, muscle-specific kinase, and titin) were positively and significantly correlated with improvements in disease severity (Quantitative Myasthenia Gravis score, Myasthenia Gravis Composite score, Myasthenia Gravis Activities of Daily Living score, Myasthenia Gravis Foundation of America classification). Given the limited evidence, testing the impact of predefined variables was not feasible. CONCLUSIONS This first SLR to assess whether a correlation exists between autoantibody levels and disease activity in patients with MG has indicated a potential positive correlation, which could have clinical implications in guiding treatment decisions. However, in light of the limited and variable evidence, we cannot currently recommend routine clinical use of autoantibody level testing in this context. For now, patient's characteristics, clinical disease course, and laboratory data (e.g., autoantibody status, thymus histology) should inform management, alongside patient-reported outcomes. We highlight the need for future studies to reach more definitive conclusions on this relationship.
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Affiliation(s)
- Andreas Meisel
- Department of Neurology, Integrated Myasthenia Gravis Center, NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Fulvio Baggi
- Neuroimmunology and Neuromuscular Diseases Unit, Scientific Institute for Research and Health Care Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Anthony Behin
- Department of Neuromyology, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Institute of Myology, Paris, France
| | - Amelia Evoli
- Catholic University of the Sacred Heart and Agostino Gemelli University Polyclinic Foundation, Scientific Institute for Research and Health Care, Rome, Italy
| | | | - Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, Scientific Institute for Research and Health Care Foundation Carlo Besta Neurological Institute, Milan, Italy
| | | | - Anna Rostedt Punga
- Department of Medical Science, Clinical Neurophysiology, Uppsala University, Uppsala, Sweden
| | | | - Michael Schroeter
- Department of Neurology, University Hospital Cologne, Cologne, Germany
| | - Jan Verschuuren
- Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | | | | | - Maria-Isabel Leite
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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ADAMTS13 conformation and immunoprofiles in Japanese patients with immune-mediated thrombotic thrombocytopenic purpura. Blood Adv 2022; 7:131-140. [PMID: 36306339 PMCID: PMC9830168 DOI: 10.1182/bloodadvances.2022008885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/13/2022] [Accepted: 09/30/2022] [Indexed: 01/18/2023] Open
Abstract
Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is an ultrarare thrombotic disease caused by autoantibody-induced ADAMTS13 deficiency. Open ADAMST13 conformation, induced by autoantibodies, was identified as a novel biomarker for iTTP. Determining immunoprofiles in patients with iTTP has been shown to guide the development of novel targeted therapies. However, these studies were done in mainly Caucasian iTTP cohorts. To validate those findings across other ethnic cohorts, we investigated 195 acute TTP plasma samples from the Japanese iTTP registry. Seventy-six of the 195 samples had detectable ADAMTS13 antigen levels, of which 94.7% were shown to have an open ADAMTS13 conformation. A positive correlation was observed between ADAMTS13 inhibitor titers (a diagnostic parameter in Japan) and anti-ADAMTS13 immunoglobulin G autoantibody titers. Studying anti-M, anti-DT, anti-CS, anti-T2-T5, anti-T6-T8, anti-CUB1-2 autoantibodies and the corresponding immunoprofile showed that 73% of the patients had anti-CS autoantibodies and 25.8% had anti-M autoantibodies, with the latter being higher than in Caucasians. Stratifying patients according to their immunoprofiles revealed that the profile with only anti-CS autoantibodies was the most common immunoprofile similar to that in Caucasians (28.9%). Although this profile did not affect the 1-year TTP-related mortality rate, patients with autoantibodies against all 6 ADAMTS13 fragments had a higher risk for TTP-related death than other patients (P = .02). We here validated open ADAMTS13 as a novel biomarker for acute iTTP and determined the dominant immunoprofiling in the Japanese cohort, contributing to setting up the diagnosis and managing guidelines across different ethnic cohorts and developing ADAMTS13 variants that do not bind to the anti-CS autoantibodies.
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Novel treatment strategies for acetylcholine receptor antibody-positive myasthenia gravis and related disorders. Autoimmun Rev 2022; 21:103104. [PMID: 35452851 DOI: 10.1016/j.autrev.2022.103104] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/18/2022] [Indexed: 11/21/2022]
Abstract
The presence of autoantibodies directed against the muscle nicotinic acetylcholine receptor (AChR) is the most common cause of myasthenia gravis (MG). These antibodies damage the postsynaptic membrane of the neuromuscular junction and cause muscle weakness by depleting AChRs and thus impairing synaptic transmission. As one of the best-characterized antibody-mediated autoimmune diseases, AChR-MG has often served as a reference model for other autoimmune disorders. Classical pharmacological treatments, including broad-spectrum immunosuppressive drugs, are effective in many patients. However, complete remission cannot be achieved in all patients, and 10% of patients do not respond to currently used therapies. This may be attributed to production of autoantibodies by long-lived plasma cells which are resistant to conventional immunosuppressive drugs. Hence, novel therapies specifically targeting plasma cells might be a suitable therapeutic approach for selected patients. Additionally, in order to reduce side effects of broad-spectrum immunosuppression, targeted immunotherapies and symptomatic treatments will be required. This review presents established therapies as well as novel therapeutic approaches for MG and related conditions, with a focus on AChR-MG.
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Hamouri S, Syaj S, Al-Kraimeen L, Al-Smady M, Alhadidi H, Barakat F. Thymolipoma and its Association with Myasthenia Gravis: a Multi-center Experience. Med Arch 2022; 75:375-381. [PMID: 35169361 PMCID: PMC8740664 DOI: 10.5455/medarh.2021.75.375-381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 08/21/2021] [Indexed: 11/03/2022] Open
Abstract
Background Thymolipoma is a rare benign thymic tumor that arises in the anterior mediastinum. It presents with non-specific symptoms such as chest pain and dyspnea due to compression of the tumor on surrounding structures. In addition, this tumor is associated with paraneoplastic syndromes, including myasthenia gravis. Such a relationship is still not understood and requires investigation. Objective Investigate the significance of myasthenia gravis in thymolipoma patients. Methods We present a series of 16 thymolipoma cases from multiple medical centers. Data extraction included demographic, diagnostic, radiological and laboratory, and clinical outcome variables. We also used the modified Osserman score to assess the severity of myasthenia gravis. Results Ten patients were males, and six were females; the sample mean age was 39.9 years (SD = 16.7). Upon presentation, 7/16 patients were asymptomatic, 4/16 patients had chest pain, and 2/16 had dyspnea. Seven patients were having myasthenia gravis; they experience generalized weakness (3/7), diplopia (2/7), ptosis (1/7), and bulbar weakness (1/7). Serum acetylcholine receptor antibody (AChRAb) was positive in 4 patients. All patients underwent thymectomy either via sternotomy or thoracotomy. After proper follow-up, only 2/7 of myasthenic patients had a complete remission of symptoms, no tumor recurrence was observed. Conclusion Although the effect of using steroids in myasthenic patients on thymolipomic transformation still needs confirmation, diagnosis of thymolipoma should be kept in mind in myasthenic patients presenting with relevant symptoms and taking steroids. Furthermore, complete remission of myasthenic symptoms after removal of thymolipoma needs further investigation.
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Affiliation(s)
- Shadi Hamouri
- Department of General Surgery and Urology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Sebawe Syaj
- Department of General Surgery and Urology, Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Leen Al-Kraimeen
- Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Moaath Al-Smady
- Department of General Surgery, School of Medicine, The University of Jordan, Amman, Jordan
| | - Hani Alhadidi
- King Hussein Medical Centre, Royal Medical Services, Amman, Jordan
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Anti-ADAMTS13 autoantibody profiling in patients with immune-mediated thrombotic thrombocytopenic purpura. Blood Adv 2021; 5:3427-3435. [PMID: 34495312 DOI: 10.1182/bloodadvances.2020004172] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 05/30/2021] [Indexed: 12/27/2022] Open
Abstract
Anti-A Disintegrin and Metalloproteinase with a ThromboSpondin type 1 motif, member 13 (ADAMTS13) autoantibodies cause a severe ADAMTS13 deficiency in immune-mediated thrombotic thrombocytopenic purpura (iTTP). ADAMTS13 consists of a metalloprotease (M), a disintegrin-like (D) domain, 8 thrombospondin type 1 repeats (T1-T8), a cysteine-rich (C), a spacer (S), and 2 CUB domains (CUB1-2). We recently developed a high-throughput epitope mapping assay based on small, nonoverlapping ADAMTS13 fragments (M, DT, CS, T2-T5, T6-T8, CUB1-2). With this assay, we performed a comprehensive epitope mapping using 131 acute-phase samples and for the first time a large group of remission samples (n = 50). Next, samples were stratified according to their immunoprofiles, a field that is largely unexplored in iTTP. Three dominant immunoprofiles were found in acute-phase samples: profile 1: only anti-CS autoantibodies (26.7%); profile 2: both anti-CS and anti-CUB1-2 autoantibodies (12.2%); and profile 3: anti-DT, anti-CS, anti-T2-T5, anti-T6-T8, and anti-CUB1-2 autoantibodies (8.4%). Interestingly, profile 1 was the only dominant immunoprofile in remission samples (52.0%). Clinical data were available for a relatively small number of patients with acute iTTP (>68), and no correlation was found between immunoprofiles and disease severity. Nevertheless, profile 1 was linked with younger and anti-T2-T5 autoantibodies with older age and the absence of anti-CUB1-2 autoantibodies with cerebral involvement. In conclusion, identifying acute phase and remission immunoprofiles in iTTP revealed that anti-CS autoantibodies seem to persist or reappear during remission providing further support for the clinical development of a targeted anti-CS autoantibody therapy. A large cohort study with acute iTTP samples will validate possible links between immunoprofiles or anti-domain autoantibodies and clinical data.
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Ursache von Muskelschwäche: Spektrum neuromuskulärer Erkrankungen und diagnostisches Vorgehen. AKTUEL RHEUMATOL 2021. [DOI: 10.1055/a-1548-8821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
ZusammenfassungDas Leitsymptom der muskulären Schwäche kann auf das Vorliegen einer neuromuskulären Erkrankung zurückzuführen sein, findet sich jedoch auch bei einer Reihe anderer Faktoren wie Elektrolytveränderungen, Vitaminmangel, Schilddrüsenerkrankungen, Bewegungsmangel oder bei unerwünschten Arzneimittelnebenwirkungen. Einer gründlichen Anamnese und körperlichen Untersuchung kommt daher in der differentialdiagnostischen Abklärung eine große Bedeutung zu. Die zeitliche Entwicklung, das Verteilungsmuster sowie Begleitsymptome erlauben oftmals bereits eine erste diagnostische Einordnung. Bei begründetem Verdacht auf das Vorliegen einer neuromuskulären Erkrankung sollte die weiterführende Diagnostik durch einen Neurologen oder ein neuromuskuläres Zentrum erfolgen. Zu den wichtigsten neuromuskulären Erkrankungen mit Leitsymptom einer muskulären Schwäche gehören die neuromuskulären Übertragungsstörungen, Neuropathien, erbliche und erworbene Myopathien sowie Motoneuronerkrankungen. Diese Übersicht stellt die wichtigsten Ursachen für eine muskuläre Schwäche zusammen und zeigt das zu empfehlende diagnostische Vorgehen auf.
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Forgash JT, Chang YM, Mittelman NS, Petesch S, Benedicenti L, Galban E, Hammond JJ, Glass EN, Barker JR, Shelton GD, Luo J, Garden OA. Clinical features and outcome of acquired myasthenia gravis in 94 dogs. J Vet Intern Med 2021; 35:2315-2326. [PMID: 34331481 PMCID: PMC8478050 DOI: 10.1111/jvim.16223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 06/25/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Background Factors known to be associated with outcome of acquired myasthenia gravis (MG) in dogs are limited. Hypothesis/Objectives Of dogs with MG, advancing age and comorbid neoplasia are associated with poor long‐term prognosis and low rates of remission. Animals Ninety‐four client‐owned dogs with MG diagnosed by acetylcholine receptor antibody (AChR Ab) assay between 2001 and 2019 from a university clinic and 3 private clinics in the United States. Methods Cases were retrospectively evaluated and data were collected to determine clinical signs, treatment, and response to therapy defined by means of a clinical scoring rubric. Immunological remission was defined as a return of the AChR Ab concentration to <0.6 nmol/L. Multivariable binary logistic regression analysis was used to identify clinical criteria predicting remission. Results An anticholinesterase drug was used to treat 90/94 (96%) dogs, which in 63/94 (67%) was the sole treatment; other drugs included immune modulators. Clinical remission (lack of clinical signs ≥4 weeks after treatment cessation) was observed in 29 (31% [95% confidence interval (CI): 22.4‐40.8%]) dogs, clinical response (lack of clinical signs on treatment) in 14 (15% [95% CI: 9.0‐23.6%]) dogs, clinical improvement (on treatment) in 24 (26% [95% CI: 17.8‐35.2%]) dogs, and no clinical improvement in 27 (29% [95% CI: 20.5‐38.6%]) dogs. Immunological remission was observed in 27/46 (59%) dogs, with clinical remission in all 27. Younger age (P = .04) and comorbid endocrine disease (P = .04) were associated with clinical remission. Initial AChR Ab concentration (P = .02) and regurgitation (P = .04) were negatively associated with clinical remission. Conclusions and Clinical Importance Clinical remission in MG is less likely in older dogs and dogs presenting with regurgitation or high initial AChR Ab concentration, but more likely in younger dogs and dogs with comorbid endocrine disease.
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Affiliation(s)
- Jennifer T Forgash
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu-Mei Chang
- Research Support Office, Royal Veterinary College, University of London, London, United Kingdom
| | - Neil S Mittelman
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Scott Petesch
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Leontine Benedicenti
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Evelyn Galban
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James J Hammond
- Department of Neurology and Neurosurgery, Pieper Memorial Veterinary Center, Middletown, Connecticut, USA
| | - Eric N Glass
- Section of Neurology and Neurosurgery, Red Bank Veterinary Hospital, Tinton Falls, New Jersey, USA
| | - Jessica R Barker
- Department of Neurology and Neurosurgery, Bush Veterinary Neurology Service, Springfield, Virginia, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jie Luo
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Oliver A Garden
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Wang L, Wang S, Yang H, Han J, Zhao X, Han S, Zhang Y, Lv J, Zhang J, Li M, Ji Y, Zhou S, He X, Fang H, Yang J, Zhang Y, Zhang Q, Gao P, Gao F. No correlation between acetylcholine receptor antibody concentration and individual clinical symptoms of myasthenia gravis: A systematic retrospective study involving 67 patients. Brain Behav 2021; 11:e02203. [PMID: 34075720 PMCID: PMC8323040 DOI: 10.1002/brb3.2203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/06/2021] [Accepted: 05/11/2021] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To investigate the correlation between acetylcholine receptor antibodies (AChR-Ab) concentration levels and individualized clinical symptoms in patients with AChR myasthenia gravis (AChR-MG) in China. METHODS ELISA was used to determine the concentration of AChR-Ab in patients with MG. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, Quantitative Myasthenia Gravis (QMG) score, and MG-specific activities of daily living (MG-ADL) scoring systems were used to evaluate the clinical status of patients. Spearman correlation analysis was used to determine the correlation between the AChR-Ab concentration and clinical score. The changes in the antibody concentration and clinical score are shown in MGFA-antibody concentration-treatment plots. RESULTS Autoantibody detection tests were performed in 67 patients, and their clinical scores were recorded. Forty-nine patients received immunosuppressive therapy, 17 patients received pyridostigmine only, and 1 patient under thymectomy without any medication. The AChR-Ab concentration correlated with the MGFA Classification in 5 (29.4%) patients in the pyridostigmine-only group and 15 (30.6%) patients in the immunosuppressive drug group. The changes in the MGFA Classification preceded the changes in the AChR-Ab concentration in 4 (23.5%) patients treated with pyridostigmine and 10 (20.4%) patients on immunosuppressive drugs. In patients on oral non-steroidal immunosuppressants, the AChR-Ab concentration changed by more than 50%, whereas the MGFA Classification did not increase. The AChR-Ab concentration decreased in 17/32 (53.1%) patients after thymectomy, and then increased, whereas the AChR-Ab concentration increased in 15/32 (46.9%) patients and the MGFA Classification decreased in 27/32 (81.8%) patients after thymectomy. The AChR-Ab concentration presented a slight correlation with the corresponding MGFA, QMG, and MG-ADL in patients with thymoma. DISCUSSION In the Chinese AChR-MG population, the Changes in the AChR-Ab concentration in individuals with AChR-MG did not consistently correlate with the severity of clinical symptoms.
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Affiliation(s)
- Lulu Wang
- Department of NeurologyThe Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Shumin Wang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- Basic Medical CollegeZhengzhou UniversityZhengzhouChina
| | - Haonan Yang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- BGI CollegeZhengzhou UniversityZhengzhouChina
| | - Jiaojiao Han
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- Basic Medical CollegeZhengzhou UniversityZhengzhouChina
| | - Xue Zhao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Sensen Han
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- BGI CollegeZhengzhou UniversityZhengzhouChina
| | - Yingna Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Jie Lv
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Jing Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Mingqiang Li
- Department of NeurologyThe Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Ying Ji
- Department of NeurologyThe Second Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Shuxian Zhou
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- Basic Medical CollegeZhengzhou UniversityZhengzhouChina
| | - Xiaoxiao He
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
- BGI CollegeZhengzhou UniversityZhengzhouChina
| | - Hua Fang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Junhong Yang
- Department of EncephalopathyFirst Affiliated Hospital of Henan University of TCMZhengzhouChina
| | - Yunke Zhang
- Department of EncephalopathyFirst Affiliated Hospital of Henan University of TCMZhengzhouChina
| | - Qingyong Zhang
- Myasthenia Gravis Comprehensive Diagnosis and Treatment CenterHenan Provincial People’s HospitalZhengzhouChina
| | - Peiyang Gao
- Department of Clinical MedicineXinxiang Medical University Sanquan Medical CollegeXinxiangChina
| | - Feng Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
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13
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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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Gastaldi M, Scaranzin S, Businaro P, Mobilia E, Benedetti L, Pesce G, Franciotta D. Improving laboratory diagnostics in myasthenia gravis. Expert Rev Mol Diagn 2021; 21:579-590. [PMID: 33970749 DOI: 10.1080/14737159.2021.1927715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Myasthenia gravis (MG) is a prototypical autoimmune disease, characterized by pathogenic autoantibodies targeting structures of the neuromuscular junction. Radioimmunoprecipitation assays (RIPAs) represent the gold standard for their detection. However, new methods are emerging to complement, or overcome RIPAs, also with the perspective of eliminating the use of radioactive reagents.Areas covered: We discuss advances in laboratory methods, prompted especially by cell-based assays (CBAs), for the detection of the autoantibodies of MG diagnostics, above all those to the nicotinic acetylcholine receptor (AChR), muscle-specific kinase (MuSK), and low molecular-weight receptor-related low-density lipoprotein-4 (LRP4).Expert opinion: CBA technology makes AChRs aggregate on cell membranes, thus allowing to detect autoantibodies to clustered AChRs, with reduction of seronegative MG cases. The diagnostic relevance of RIPA/CBA-measurable LRP4 antibodies is still unclear, in Caucasian patients at least. Live CBAs for the detection of AChR, MuSK, and LRP4 antibodies might represent an alternative to RIPAs, but first require full validation. CBAs could be used as screening tests, limiting RIPAs for antibody quantification. To this end, ELISAs might be an alternative.Fixation procedures preserving enough degree of antigen conformationality could yield AChR and MuSK CBAs suitable for a wide use in clinical-chemistry laboratories.
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Affiliation(s)
- Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Silvia Scaranzin
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Pietro Businaro
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Emanuela Mobilia
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Luana Benedetti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - Giampaola Pesce
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy.,Department of Internal Medicine (Dimi), University of Genova, Genova, Italy
| | - Diego Franciotta
- Autoimmunity Laboratory, IRCCS Ospedale Policlinico San Martino, Genova, Italy
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15
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De Rosa A, Fornili M, Maestri Tassoni M, Guida M, Baglietto L, Petrucci L, Chella A, Melfi F, Lucchi M, Ricciardi R. Thymoma-associated myasthenia gravis: Clinical features and predictive value of antiacetylcholine receptor antibodies in the risk of recurrence of thymoma. Thorac Cancer 2020; 12:106-113. [PMID: 33142021 PMCID: PMC7779191 DOI: 10.1111/1759-7714.13724] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 01/03/2023] Open
Abstract
Background Thymoma‐associated myasthenia gravis (TAMG) is one of the subtypes of myasthenia gravis with autoantibodies against the acetylcholine receptor (AChR‐Ab). We analyzed the clinical features of our cohort of TAMG patients and the changes in AChR‐Ab titer before and after thymectomy in order to identify factors predicting thymoma relapses. Methods We retrospectively assessed: age of MG onset, MG clinical status according to MGFA (Myasthenia Gravis Foundation of America), epoch of thymectomy, post‐thymectomy status, oncological features and surgical approach. AChR‐Ab dosages were measured both before and after thymectomy. Linear regression models were applied to identify clinical determinants of AChR‐Ab titers and the Cox regression model was fitted to estimate the factors associated with the risk of thymoma recurrence. Results The study sample included 239 MG patients, 27 of whom experienced one or more recurrences (median follow‐up time: 4.8 years). The AChR‐Ab titers decreased after first thymectomy (P < 0.001); the decrease was more pronounced in female patients (P = 0.05), in patients diagnosed with MG at an older age (P = 0.003), and in those who had lower MG stage before surgery (P = 0.02) or higher Masaoka‐Koga stage (P = 0.005). The risk of relapse was closely linked with the age of the patient, the Masaoka‐Koga stage and the surgical approach. Conclusions Presurgery levels of AChR‐Ab or their change after surgery were not associated with thymoma recurrence. The reduction of AChR‐Ab titers after thymectomy confirms an immunological role of thymoma in the pathogenesis of MG. Key points Significant findings of the study: Young MG patients with an advanced Masaoka staging score of the primary tumor who underwent thymectomy with approaches different from sternotomy and VATS should be monitored for high risk of recurrence. What this study adds: No other study has ever investigated the changes in AChR‐Ab titers before and after thymectomy in a large cohort of TAMG patients. The reduction of AChR‐Ab titers after thymectomy suggests an immunological role of thymoma in the pathogenesis of MG.
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Affiliation(s)
- Anna De Rosa
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Marco Fornili
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | - Melania Guida
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Laura Baglietto
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Loredana Petrucci
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy
| | - Antonio Chella
- Department of Cardiology Thoracic and Vascular Medicine, Unit of Pneumology, University Hospital of Pisa, Pisa, Italy
| | - Franca Melfi
- Department of Cardiology Thoracic and Vascular Medicine, Minimally Invasive and Robotic Thoracic Surgery, Robotic Multispecialty Center for Surgery, University of Pisa, Pisa, Italy
| | - Marco Lucchi
- Department of Cardiology Thoracic and Vascular Medicine, University Hospital of Pisa, Pisa, Italy
| | - Roberta Ricciardi
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Pisa, Italy.,Department of Cardiology Thoracic and Vascular Medicine, University Hospital of Pisa, Pisa, Italy
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16
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Aguirre F, Manin A, Fernandez VC, Justo ME, Leoni J, Paz ML, Villa AM. C3, C5a and anti-acetylcholine receptor antibody as severity biomarkers in myasthenia gravis. Ther Adv Neurol Disord 2020; 13:1756286420935697. [PMID: 32843900 PMCID: PMC7418469 DOI: 10.1177/1756286420935697] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 05/12/2020] [Indexed: 12/16/2022] Open
Abstract
Background Although the pathogenesis of myasthenia gravis (MG) is well known, prognostic markers are not yet available. We assessed the utility of anti-acetylcholine receptor (AChR) antibody (AChR-ab) titer and concentration of C3, C4, and C5a as potential severity biomarkers in MG. Methods Levels of C3, C4, C5a, and AChR-ab were measured in 60 AChR-ab-positive patients with MG. Their relationship with clinical severity was analyzed using the activities of daily living (ADL) and MG composite (MGC) scales. Results AChR-ab titer correlated with severity of MG according to ADL (p = 0.002) and MGC scales (p = 0.001). When patients were classified according to disease duration, a statistically significant correlation between AChR-ab titer and clinical severity was only found in the subgroup of patients with fewer than 5 years from symptoms onset. C5a levels showed a positive correlation with MG severity according to the ADL scale (p = 0.041; τb = 0.18), although C5a levels were not different from the control group. Discussion AChR-ab titers and C5a levels could potentially be considered markers of severity in patients with MG.
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Affiliation(s)
- Florencia Aguirre
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Analisa Manin
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Victoria C Fernandez
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
| | - Mariano E Justo
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología. CONICET - Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Juliana Leoni
- CONICET - Universidad de Buenos Aires, Instituto de Estudios de la, Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Mariela L Paz
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología. CONICET - Universidad de Buenos Aires, Instituto de Estudios de la Inmunidad Humoral (IDEHU), Buenos Aires, Argentina
| | - Andres M Villa
- Sección de Neuroinmunología y Electrofisiología, División Neurología, Hospital José María Ramos Mejía. Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina - Universidad de Buenos Aires, Argentina
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17
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Lazaridis K, Tzartos SJ. Autoantibody Specificities in Myasthenia Gravis; Implications for Improved Diagnostics and Therapeutics. Front Immunol 2020; 11:212. [PMID: 32117321 PMCID: PMC7033452 DOI: 10.3389/fimmu.2020.00212] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and fatiguability of skeletal muscles. It is an antibody-mediated disease, caused by autoantibodies targeting neuromuscular junction proteins. In the majority of patients (~85%) antibodies against the muscle acetylcholine receptor (AChR) are detected, while in 6% antibodies against the muscle-specific kinase (MuSK) are detected. In ~10% of MG patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG), making the improvement of methods for the detection of known autoantibodies or the discovery of novel antigenic targets imperative. Over the past years, using cell-based assays or improved highly sensitive immunoprecipitation assays, it has been possible to detect autoantibodies in previously SN-MG patients, including the identification of the low-density lipoprotein receptor-related protein 4 (LRP4) as a third MG autoantigen, as well as AChR and MuSK antibodies undetectable by conventional methods. Furthermore, antibodies against other extracellular or intracellular targets, such as titin, the ryanodine receptor, agrin, collagen Q, Kv1.4 potassium channels and cortactin have been found in some MG patients, which can be useful biomarkers. In addition to the improvement of diagnosis, the identification of the patients' autoantibody specificity is important for their stratification into respective subgroups, which can differ in terms of clinical manifestations, prognosis and most importantly their response to therapies. The knowledge of the autoantibody profile of MG patients would allow for a therapeutic strategy tailored to their MG subgroup. This is becoming especially relevant as there is increasing progress toward the development of antigen-specific therapies, targeting only the specific autoantibodies or immune cells involved in the autoimmune response, such as antigen-specific immunoadsorption, which have shown promising results. We will herein review the advances made by us and others toward development of more sensitive detection methods and the identification of new antibody targets in MG, and discuss their significance in MG diagnosis and therapy. Overall, the development of novel autoantibody assays is aiding in the more accurate diagnosis and classification of MG patients, supporting the development of advanced therapeutics and ultimately the improvement of disease management and patient quality of life.
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Affiliation(s)
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.,Tzartos NeuroDiagnostics, Athens, Greece
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18
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Finsterer J, Scorza FA, Fiorini AC, Scorza CA. Comment on: Factors Affecting Generalization of Ocular Myasthenia Gravis in Patients With Positive Acetylcholine Receptor Antibodies. Am J Ophthalmol 2020; 210:193-194. [PMID: 31753417 DOI: 10.1016/j.ajo.2019.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 11/28/2022]
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19
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Finsterer J. Viability of electro-oculogram signal processing for diagnosing myasthenia remains elusive. Clin Neurophysiol 2020; 131:347. [DOI: 10.1016/j.clinph.2019.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 11/30/2022]
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20
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Beatmung bei neuromuskulären Erkrankungen. NEUROLOGISCHE BEATMUNGSMEDIZIN 2020. [PMCID: PMC7236064 DOI: 10.1007/978-3-662-59014-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neuromuskuläre Erkrankungen betreffen das erste und zweite Motoneuron, die peripheren Nerven, die neuromuskulären Übertragung und die Muskelzelle. Es handelt sich um eine heterogene Gruppe von erblichen, degenerativen und autoimmunen Erkrankungen. Eine korrekte diagnostische Einordnung ist erforderlich, da zentralnervöse, kardiale, endokrine und weitere Begleitsymptome vorliegen können und für einige Erkrankungen bereits medikamentöse Therapien zur Verfügung stehen. Neuromuskuläre Erkrankungen haben eine große Bedeutung in der neuromuskulären Beatmungsmedizin. Die respiratorische Symptomatik resultiert in der Regel aus Paresen der am Atmen, Schlucken oder Husten beteiligten Muskulatur mit konsekutiver ventilatorischer Insuffienz, Dysphagie bis hin zur Speichelaspiration und Sekretretention. Mittels eines strukturierte Sekretmanagements und einer effektive nichtinvasive oder invasive Beatmungstherapie können neuromuskuläre Patienten viele Jahre mit guter Lebensqualität überleben. Themen dieses Kapitels sind ein Überblick über die neuromuskulären Erkrankungen, die Indikationen und Strategien der nichtinvasiven und der invasiven Beatmung und eine ausführliche Darstellung beatmungsmedizinisch besonders relevanter neuromuskulärer Erkrankungen wie der amyotrophe Lateralsklerose, des Guillain-Barré-Syndroms, der Myasthenia gravis und der Critical-Illness-Polyneuropathie/-Myopathie.
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21
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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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22
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Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Università Cattolica del Sacro Cuore, Roma, Italy
- Fondazione Policlinico Gemelli, IRCCS, Roma, Italy
| | - Elisa Meacci
- Fondazione Policlinico Gemelli, IRCCS, Roma, Italy
- Institute of Thoracic Surgery, Università Cattolica del Sacro Cuore, Roma, Italy
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23
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Schelpe AS, Roose E, Joly BS, Pareyn I, Mancini I, Biganzoli M, Deckmyn H, Voorberg J, Fijnheer R, Peyvandi F, De Meyer SF, Coppo P, Veyradier A, Vanhoorelbeke K. Generation of anti-idiotypic antibodies to detect anti-spacer antibody idiotopes in acute thrombotic thrombocytopenic purpura patients. Haematologica 2018; 104:1268-1276. [PMID: 30523052 PMCID: PMC6545854 DOI: 10.3324/haematol.2018.205666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/30/2018] [Indexed: 12/22/2022] Open
Abstract
In autoantibody-mediated autoimmune diseases, autoantibody profiling allows patients to be stratified and links autoantibodies with disease severity and outcome. However, in immune-mediated thrombotic thrombocytopenic purpura (iTTP) patients, stratification according to antibody profiles and their clinical relevance has not been fully explored. We aimed to develop a new type of autoantibody profiling assay for iTTP based on the use of anti-idiotypic antibodies. Anti-idiotypic antibodies against 3 anti-spacer autoantibodies were generated in mice and were used to capture the respective anti-spacer idiotopes from 151 acute iTTP plasma samples. We next deciphered these anti-spacer idiotope profiles in iTTP patients and investigated whether these limited idiotope profiles could be linked with disease severity. We developed 3 anti-idiotypic antibodies that recognized particular idiotopes in the anti-spacer autoantibodies II-1, TTP73 or I-9, that are involved in ADAMTS13 binding; 35%, 24% and 42% of patients were positive for antibodies with the II-1, TTP73 and I-9 idiotopes, respectively. Stratifying patients according to the corresponding 8 anti-spacer idiotope profiles provided a new insight into the anti-spacer II-1, TTP73 and I-9 idiotope profiles in these patients. Finally, these limited idiotope profiles showed no association with disease severity. We successfully developed 3 anti-idiotypic antibodies that allowed us to determine the profiles of the anti-spacer II-1, TTP73 and I-9 idiotopes in iTTP patients. Increasing the number of patients and/or future development of additional anti-idiotypic antibodies against other anti-ADAMTS13 autoantibodies might allow idiotope profiles of clinical, prognostic value to be identified.
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Affiliation(s)
- An-Sofie Schelpe
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
| | - Elien Roose
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
| | - Bérangère S Joly
- Service d'Hématologie Biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, France.,EA3518, Institut Universitaire d'Hématologie Saint-Louis, Université Paris Diderot, France
| | - Inge Pareyn
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
| | - Ilaria Mancini
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Università degli Studi di Milano, Italy.,Department of Pathophysiology and Transplantation, Fondazione Luigi Villa, Milan, Italy
| | - Marina Biganzoli
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Università degli Studi di Milano, Italy.,Department of Pathophysiology and Transplantation, Fondazione Luigi Villa, Milan, Italy
| | - Hans Deckmyn
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
| | - Jan Voorberg
- Department of Molecular and Cellular Hemostasis, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - Rob Fijnheer
- Department of Internal Medicine, Meander Medical Center, Amersfoort, the Netherlands
| | - Flora Peyvandi
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Università degli Studi di Milano, Italy.,Department of Pathophysiology and Transplantation, Fondazione Luigi Villa, Milan, Italy
| | - Simon F De Meyer
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
| | - Paul Coppo
- Sorbonne Universités, Service d'Hématologie et Centre de Référence des Microangiopathies Thrombotiques (CNR-MAT), Hôpital Saint Antoine, Assistance Publique-Hôpitaux de Paris, France
| | - Agnès Veyradier
- Service d'Hématologie Biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, France.,EA3518, Institut Universitaire d'Hématologie Saint-Louis, Université Paris Diderot, France
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Belgium
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Heterogeneity of auto-antibodies against nAChR in myasthenic serum and their pathogenic roles in experimental autoimmune myasthenia gravis. J Neuroimmunol 2018; 320:64-75. [PMID: 29759142 DOI: 10.1016/j.jneuroim.2018.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 11/20/2022]
Abstract
Many myasthenia gravis (MG) patients have auto-antibodies against the nicotinic acetylcholine receptor (nAChR), and monoclonal antibodies against the main immunogenic region (MIR) of nAChR can induce experimental autoimmune MG (EAMG). We investigated whether Fab fragment of MIR antibody (Fab35) could block the pathogenicity of polyclonal antibodies. Fab35 partially inhibited nAChR downmodulation, blocked EAMG serum-induced binding of polyclonal antibodies and complement deposition in vitro. Moreover, Fab35 did not ameliorate the EAMG serum-induced EAMG phenotype in rats. These results suggested that the EAMG serum possessed several different pathogenic antibodies that might be sufficient to induce the EAMG phenotype.
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25
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Radovich M, Pickering CR, Felau I, Ha G, Zhang H, Jo H, Hoadley KA, Anur P, Zhang J, McLellan M, Bowlby R, Matthew T, Danilova L, Hegde AM, Kim J, Leiserson MDM, Sethi G, Lu C, Ryan M, Su X, Cherniack AD, Robertson G, Akbani R, Spellman P, Weinstein JN, Hayes DN, Raphael B, Lichtenberg T, Leraas K, Zenklusen JC, Fujimoto J, Scapulatempo-Neto C, Moreira AL, Hwang D, Huang J, Marino M, Korst R, Giaccone G, Gokmen-Polar Y, Badve S, Rajan A, Ströbel P, Girard N, Tsao MS, Marx A, Tsao AS, Loehrer PJ. The Integrated Genomic Landscape of Thymic Epithelial Tumors. Cancer Cell 2018; 33:244-258.e10. [PMID: 29438696 PMCID: PMC5994906 DOI: 10.1016/j.ccell.2018.01.003] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/15/2017] [Accepted: 01/09/2018] [Indexed: 12/31/2022]
Abstract
Thymic epithelial tumors (TETs) are one of the rarest adult malignancies. Among TETs, thymoma is the most predominant, characterized by a unique association with autoimmune diseases, followed by thymic carcinoma, which is less common but more clinically aggressive. Using multi-platform omics analyses on 117 TETs, we define four subtypes of these tumors defined by genomic hallmarks and an association with survival and World Health Organization histological subtype. We further demonstrate a marked prevalence of a thymoma-specific mutated oncogene, GTF2I, and explore its biological effects on multi-platform analysis. We further observe enrichment of mutations in HRAS, NRAS, and TP53. Last, we identify a molecular link between thymoma and the autoimmune disease myasthenia gravis, characterized by tumoral overexpression of muscle autoantigens, and increased aneuploidy.
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Affiliation(s)
- Milan Radovich
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | | | - Ina Felau
- National Cancer Institute, Bethesda, MD 20892, USA
| | - Gavin Ha
- Broad Institute, Cambridge, MA 02142, USA
| | | | - Heejoon Jo
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Katherine A Hoadley
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pavana Anur
- Oregon Health & Science University, Portland, OR 97239, USA
| | - Jiexin Zhang
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mike McLellan
- McDonnell Genome Institute at Washington University, St. Louis, MO 63108, USA
| | - Reanne Bowlby
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, BC V5Z 4S6, Canada
| | - Thomas Matthew
- University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | | | | | - Jaegil Kim
- Broad Institute, Cambridge, MA 02142, USA
| | - Mark D M Leiserson
- Department of Computer Science & Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
| | - Geetika Sethi
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Charles Lu
- McDonnell Genome Institute at Washington University, St. Louis, MO 63108, USA
| | - Michael Ryan
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaoping Su
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | | | - Gordon Robertson
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, BC V5Z 4S6, Canada
| | - Rehan Akbani
- MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Paul Spellman
- Oregon Health & Science University, Portland, OR 97239, USA
| | | | - D Neil Hayes
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ben Raphael
- Department of Computer Science & Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
| | | | | | | | | | | | | | - David Hwang
- University Health Network, Toronto, ON M5G 2C4, Canada
| | - James Huang
- Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Mirella Marino
- Department of Pathology, Regina Elena National Cancer Institute, Rome 00144, Italy
| | | | | | - Yesim Gokmen-Polar
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Sunil Badve
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA
| | - Arun Rajan
- National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Nicolas Girard
- Institute of Oncology, Cardiobiotec, Hospices Civils de Lyon, Lyon 69002, France
| | - Ming S Tsao
- Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Alexander Marx
- University Medical Centre Mannheim, University of Heidelberg, Mannheim 68167, Germany
| | - Anne S Tsao
- MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Patrick J Loehrer
- Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN 46202, USA.
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Chigurupati K, Gadhinglajkar S, Sreedhar R, Nair M, Unnikrishnan M, Pillai M. Criteria for Postoperative Mechanical Ventilation After Thymectomy in Patients With Myasthenia Gravis: A Retrospective Analysis. J Cardiothorac Vasc Anesth 2018; 32:325-330. [DOI: 10.1053/j.jvca.2017.06.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Indexed: 11/11/2022]
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Analysis of peripheral B cells and autoantibodies against the anti-nicotinic acetylcholine receptor derived from patients with myasthenia gravis using single-cell manipulation tools. PLoS One 2017; 12:e0185976. [PMID: 29040265 PMCID: PMC5645109 DOI: 10.1371/journal.pone.0185976] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 09/23/2017] [Indexed: 11/23/2022] Open
Abstract
The majority of patients with myasthenia gravis (MG), an organ-specific autoimmune disease, harbor autoantibodies that attack the nicotinic acetylcholine receptor (nAChR-Abs) at the neuromuscular junction of skeletal muscles, resulting in muscle weakness. Single cell manipulation technologies coupled with genetic engineering are very powerful tools to examine T cell and B cell repertoires and the dynamics of adaptive immunity. These tools have been utilized to develop mAbs in parallel with hybridomas, phage display technologies and B-cell immortalization. By applying a single cell technology and novel high-throughput cell-based binding assays, we identified peripheral B cells that produce pathogenic nAChR-Abs in patients with MG. Although anti-nAChR antibodies produced by individual peripheral B cells generally exhibited low binding affinity for the α-subunit of the nAChR and great sequence diversity, a small fraction of these antibodies bound with high affinity to native-structured nAChRs on cell surfaces. B12L, one such Ab isolated here, competed with a rat Ab (mAb35) for binding to the human nAChR and thus considered to recognize the main immunogenic region (MIR). By evaluating the Ab in in vitro cell-based assays and an in vivo rat passive transfer model, B12L was found to act as a pathogenic Ab in rodents and presumably in humans.These findings suggest that B cells in peripheral blood may impact MG pathogenicity. Our methodology can be applied not only to validate pathogenic Abs as molecular target of MG treatment, but also to discover and analyze Ab production systems in other human diseases.
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Noridomi K, Watanabe G, Hansen MN, Han GW, Chen L. Structural insights into the molecular mechanisms of myasthenia gravis and their therapeutic implications. eLife 2017; 6. [PMID: 28440223 PMCID: PMC5404922 DOI: 10.7554/elife.23043] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 03/29/2017] [Indexed: 12/05/2022] Open
Abstract
The nicotinic acetylcholine receptor (nAChR) is a major target of autoantibodies in myasthenia gravis (MG), an autoimmune disease that causes neuromuscular transmission dysfunction. Despite decades of research, the molecular mechanisms underlying MG have not been fully elucidated. Here, we present the crystal structure of the nAChR α1 subunit bound by the Fab fragment of mAb35, a reference monoclonal antibody that causes experimental MG and competes with ~65% of antibodies from MG patients. Our structures reveal for the first time the detailed molecular interactions between MG antibodies and a core region on nAChR α1. These structures suggest a major nAChR-binding mechanism shared by a large number of MG antibodies and the possibility to treat MG by blocking this binding mechanism. Structure-based modeling also provides insights into antibody-mediated nAChR cross-linking known to cause receptor degradation. Our studies establish a structural basis for further mechanistic studies and therapeutic development of MG. DOI:http://dx.doi.org/10.7554/eLife.23043.001 Myasthenia gravis is a disease that causes chronic weakness in muscles. It affects more than 20 in every 100,000 people and diagnosis is becoming more common due to increased awareness of the disease. However, most current treatments only temporarily relieve symptoms so there is a need to develop more effective therapies. The disease occurs when the immune system produces molecules called antibodies that bind to and destroy a receptor protein called nAChR. This receptor is normally found at the junctions between nerve cells and muscle cells, and its destruction disrupts communication between the nervous system and the muscle. However, it is not known exactly how these antibodies bind to nAChR, partly due to the lack of a detailed three-dimensional structure of the antibodies and nAChR together. The human nAChR protein is made up of several subunits, including one called alpha1 that is the primary target of Myasthenia gravis antibodies. Noridomi et al. used a technique known as X-ray crystallography to generate a highly detailed three-dimensional model of the structure of the alpha1 subunit with an antibody from rats that acts as in a similar way to human Myasthenia gravis antibodies. The structure reveals the points of contact between the antibodies and a core region of the nAChR alpha1 subunit and suggests that many different Myasthenia gravis antibodies may bind to nAChR in the same way. These findings may aid the development of drugs that bind to and disable Myasthenia gravis antibodies to relieve the symptoms of the disease. DOI:http://dx.doi.org/10.7554/eLife.23043.002
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Affiliation(s)
- Kaori Noridomi
- Department of Chemistry, University of Southern California, Los Angeles, United States
| | - Go Watanabe
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Melissa N Hansen
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
| | - Gye Won Han
- Department of Chemistry, Bridge Institute, University of Southern California, Los Angeles, United States
| | - Lin Chen
- Department of Chemistry, University of Southern California, Los Angeles, United States.,USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, United States.,Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, United States
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Hinge-deleted IgG4 blocker therapy for acetylcholine receptor myasthenia gravis in rhesus monkeys. Sci Rep 2017; 7:992. [PMID: 28428630 PMCID: PMC5430546 DOI: 10.1038/s41598-017-01019-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 03/28/2017] [Indexed: 11/08/2022] Open
Abstract
Autoantibodies against ion channels are the cause of numerous neurologic autoimmune disorders. Frequently, such pathogenic autoantibodies have a restricted epitope-specificity. In such cases, competing antibody formats devoid of pathogenic effector functions (blocker antibodies) have the potential to treat disease by displacing autoantibodies from their target. Here, we have used a model of the neuromuscular autoimmune disease myasthenia gravis in rhesus monkeys (Macaca mulatta) to test the therapeutic potential of a new blocker antibody: MG was induced by passive transfer of pathogenic acetylcholine receptor-specific monoclonal antibody IgG1-637. The effect of the blocker antibody (IgG4Δhinge-637, the hinge-deleted IgG4 version of IgG1-637) was assessed using decrement measurements and single-fiber electromyography. Three daily doses of 1.7 mg/kg IgG1-637 (cumulative dose 5 mg/kg) induced impairment of neuromuscular transmission, as demonstrated by significantly increased jitter, synaptic transmission failures (blockings) and a decrease in the amplitude of the compound muscle action potentials during repeated stimulations (decrement), without showing overt symptoms of muscle weakness. Treatment with three daily doses of 10 mg/kg IgG4Δhinge-637 significantly reduced the IgG1-637-induced increase in jitter, blockings and decrement. Together, these results represent proof-of principle data for therapy of acetylcholine receptor-myasthenia gravis with a monovalent antibody format that blocks binding of pathogenic autoantibodies.
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30
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Gene Polymorphisms for Both Auto-antigen and Immune-Modulating Proteins Are Associated with the Susceptibility of Autoimmune Myasthenia Gravis. Mol Neurobiol 2016; 54:4771-4780. [DOI: 10.1007/s12035-016-0024-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/01/2016] [Indexed: 01/07/2023]
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Melzer N, Ruck T, Fuhr P, Gold R, Hohlfeld R, Marx A, Melms A, Tackenberg B, Schalke B, Schneider-Gold C, Zimprich F, Meuth SG, Wiendl H. Clinical features, pathogenesis, and treatment of myasthenia gravis: a supplement to the Guidelines of the German Neurological Society. J Neurol 2016; 263:1473-94. [PMID: 26886206 PMCID: PMC4971048 DOI: 10.1007/s00415-016-8045-z] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 01/20/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune antibody-mediated disorder of neuromuscular synaptic transmission. The clinical hallmark of MG consists of fluctuating fatigability and weakness affecting ocular, bulbar and (proximal) limb skeletal muscle groups. MG may either occur as an autoimmune disease with distinct immunogenetic characteristics or as a paraneoplastic syndrome associated with tumors of the thymus. Impairment of central thymic and peripheral self-tolerance mechanisms in both cases is thought to favor an autoimmune CD4(+) T cell-mediated B cell activation and synthesis of pathogenic high-affinity autoantibodies of either the IgG1 and 3 or IgG4 subclass. These autoantibodies bind to the nicotinic acetylcholine receptor (AchR) itself, or muscle-specific tyrosine-kinase (MuSK), lipoprotein receptor-related protein 4 (LRP4) and agrin involved in clustering of AchRs within the postsynaptic membrane and structural maintenance of the neuromuscular synapse. This results in disturbance of neuromuscular transmission and thus clinical manifestation of the disease. Emphasizing evidence from clinical trials, we provide an updated overview on immunopathogenesis, and derived current and future treatment strategies for MG divided into: (a) symptomatic treatments facilitating neuromuscular transmission, (b) antibody-depleting treatments, and
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Affiliation(s)
- Nico Melzer
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Tobias Ruck
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Peter Fuhr
- Department of Neurology, University of Basel, Basel, Switzerland
| | - Ralf Gold
- Department of Neurology, University of Bochum, Bochum, Germany
| | - Reinhard Hohlfeld
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
| | - Arthur Melms
- Department of Neurology, University of Erlangen, Erlangen, Germany
| | - Björn Tackenberg
- Department of Neurology, University of Marburg, Marburg, Germany
| | - Berthold Schalke
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | | | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Sven G. Meuth
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Heinz Wiendl
- Department of Neurology, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
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Huijbers MG, Lipka AF, Plomp JJ, Niks EH, van der Maarel SM, Verschuuren JJ. Pathogenic immune mechanisms at the neuromuscular synapse: the role of specific antibody-binding epitopes in myasthenia gravis. J Intern Med 2014; 275:12-26. [PMID: 24215230 DOI: 10.1111/joim.12163] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Autoantibodies against three different postsynaptic antigens and one presynaptic antigen at the neuromuscular junction are known to cause myasthenic syndromes. The mechanisms by which these antibodies cause muscle weakness vary from antigenic modulation and complement-mediated membrane damage to inhibition of endogenous ligand binding and blocking of essential protein-protein interactions. These mechanisms are related to the autoantibody titre, specific epitopes on the target proteins and IgG autoantibody subclass. We here review the role of specific autoantibody-binding epitopes in myasthenia gravis, their possible relevance to the pathophysiology of the disease and potential implications of epitope mapping knowledge for new therapeutic strategies.
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Affiliation(s)
- M 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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Huang CS, Li WY, Lee PC, Kao KP, Chou TY, Wu MH, Hsu HS, Wu YC, Hsu WH, Huang BS. Analysis of outcomes following surgical treatment of thymolipomatous myasthenia gravis: comparison with thymomatous and non-thymomatous myasthenia gravis. Interact Cardiovasc Thorac Surg 2013; 18:475-81. [PMID: 24366316 DOI: 10.1093/icvts/ivt531] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Although significant improvement in myasthenic symptoms has been reported following the removal of thymolipomas, information on surgical outcomes among patients with thymolipomatous myasthenia gravis (MG) is limited. METHODS This was a retrospective review of patients who underwent extended thymectomy for treatment of MG. RESULTS From 1995 to 2010, 267 patients with MG underwent extended thymectomy, including 104 with thymomatous MG, 151 with non-thymomatous MG and 12 (4.4%) with thymolipoma. The mean duration of myasthenic symptoms before surgery was greatest in the thymolipomatous group (P < 0.001). The lowest mean age (36.1 years old, P < 0.001) and the lowest preoperative serum anti-acetylcholine receptor antibody titre (P = 0.015) occurred in the non-thymomatous group. More thymic and adipose tissue was removed from the thymolipomatous group compared with the non-thymomatous group (P < 0.001). Regarding surgical outcomes, the rate of stable remission was higher in the non-thymomatous (42.3%) and thymolipomatous (41.7%) groups compared with the thymomatous group (28.8%, P = 0.029). No instances of postoperative exacerbation of MG or tumour recurrence were noted during the postoperative follow-up of patients treated for thymolipoma. CONCLUSIONS Our results suggest that patients with myasthenia thymolipomatous have surgical outcomes similar to those of patients with non-thymomatous MG and have a mean age at the time of surgery similar to that of patients with thymomatous MG.
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Affiliation(s)
- Chien-Sheng Huang
- Division of Thoracic Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
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35
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36
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Verschuuren JJ, Huijbers MG, Plomp JJ, Niks EH, Molenaar PC, Martinez-Martinez P, Gomez AM, De Baets MH, Losen M. Pathophysiology of myasthenia gravis with antibodies to the acetylcholine receptor, muscle-specific kinase and low-density lipoprotein receptor-related protein 4. Autoimmun Rev 2013; 12:918-23. [DOI: 10.1016/j.autrev.2013.03.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 01/13/2023]
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Huang GZ, Lo YL. Correlation between acetylcholine receptor antibody levels and thymic pathology in myasthenia gravis: a review. J Clin Neuromuscul Dis 2013; 14:209-217. [PMID: 23703018 DOI: 10.1097/cnd.0b013e31828a0090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Myasthenia gravis is the most common chronic autoimmune neuromuscular disease. Anti-acetylcholine receptor (AChR) antibodies are found in at least 80% of patients with generalized myasthenia and have been implicated in disease pathogenesis. Thymic abnormalities are frequently found in seropositive patients, and the thymus is thought to be involved in generation of autoimmunity. This article reviews existing literature on the role of AChR antibodies in the pathogenesis of myasthenia gravis, and the correlation between AChR antibody titers and thymic pathology. Most studies found that highest titers are seen in thymic hyperplasia, followed by intermediate titers in thymoma, and lowest titers in atrophic or normal thymus. One publication found no difference between titers in thymoma and normal thymus.
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Affiliation(s)
- G Z Huang
- Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
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38
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Nakata R, Motomura M, Masuda T, Shiraishi H, Tokuda M, Fukuda T, Ando T, Yoshimura T, Tsujihata M, Kawakami A. Thymus histology and concomitant autoimmune diseases in Japanese patients with muscle-specific receptor tyrosine kinase-antibody-positive myasthenia gravis. Eur J Neurol 2013; 20:1272-6. [PMID: 23679930 DOI: 10.1111/ene.12169] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 03/11/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND PURPOSE The differences in the characteristics of thymus histology, coexisting autoimmune diseases and related autoantibodies between anti-muscle-specific receptor tyrosine kinase (MuSK)-antibody (Ab)-positive myasthenia gravis (MG) patients, and anti-acetylcholine receptor (AChR)-Ab-positive MG patients are not clearly defined. METHODS The types of thymus histology, coexisting autoimmune diseases and associated Abs in 83 MuSK-Ab-positive patients nationwide were investigated and were compared with those in AChR-Ab-positive patients followed at our institute (n = 83). As for the autoantibodies associated with thymoma, titin Abs were measured. RESULTS Thymoma was not present in any of the MuSK-Ab-positive patients but presented in 21 patients (25.3%) amongst the AChR-Ab-positive patients. Titin Abs were absent in MuSK-Ab-positive patients but positive in 25 (30.1%) of the AChR-Ab-positive patients. Concomitant autoimmune diseases were present in eight MuSK-Ab-positive patients (9.6%) amongst whom Hashimoto's thyroiditis and rheumatoid arthritis predominated, whereas 22 AChR-Ab-positive patients (26.5%) had one or more concomitant autoimmune diseases of which Graves' disease predominated. CONCLUSIONS Differences in frequency of thymoma and thymic hyperplasia, coexisting autoimmune diseases and autoantibody positivity between MuSK-Ab-positive and AChR-Ab-positive MG were indicated, suggesting that, in contrast with AChR-Ab-positive MG, thymus does not seem to be involved in the pathogenic mechanisms of MuSK-Ab-positive MG.
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Affiliation(s)
- R Nakata
- Department of Clinical Neuroscience and Neurology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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