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De Bleecker JL, Remiche G, Alonso-Jiménez A, Van Parys V, Bissay V, Delstanche S, Claeys KG. Recommendations for the management of myasthenia gravis in Belgium. Acta Neurol Belg 2024; 124:1371-1383. [PMID: 38649556 PMCID: PMC11266451 DOI: 10.1007/s13760-024-02552-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 03/31/2024] [Indexed: 04/25/2024]
Abstract
International guidelines on the treatment of myasthenia gravis (MG) have been published but are not tailored to the Belgian situation. This publication presents recommendations from a group of Belgian MG experts for the practical management of MG in Belgium. It includes recommendations for treatment of adult patients with generalized myasthenia gravis (gMG) or ocular myasthenia gravis (oMG). Depending on the MG-related antibody a treatment sequence is suggested with therapies that can be added on if the treatment goal is not achieved. Selection of treatments was based on the level of evidence of efficacy, registration and reimbursement status in Belgium, common daily practice and the personal views and experiences of the authors. The paper reflects the situation in February 2024. In addition to the treatment considerations, other relevant aspects in the management of MG are addressed, including comorbidities, drugs aggravating disease symptoms, pregnancy, and vaccination. As many new treatments might potentially come to market, a realistic future perspective on the impact of these treatments on clinical practice is given. In conclusion, these recommendations intend to be a guide for neurologists treating patients with MG in Belgium.
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Affiliation(s)
- Jan L De Bleecker
- Department of Neurology, University Hospital Ghent and AZ Sint-Lucas, Ghent, Belgium.
| | - Gauthier Remiche
- Centre de Référence Neuromusculaire, Department of Neurology, Hôpital Universitaire de Bruxelles (HUB)-Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alicia Alonso-Jiménez
- Department of Neurology, Faculty of Medicine and Health Sciences, Antwerp University Hospital, Translational Neurosciences, UAntwerpen, Antwerp, Belgium
| | - Vinciane Van Parys
- Department of Neurology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain (UCL), Brussels, Belgium
| | - Véronique Bissay
- Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, NEUR Research Group and Department of Neurology, Brussels, Belgium
| | | | - Kristl G Claeys
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
- Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, KULeuven, and Leuven Brain Institute (LBI), Leuven, Belgium
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Ma C, Liu D, Wang B, Yang Y, Zhu R. Advancements and prospects of novel biologicals for myasthenia gravis: toward personalized treatment based on autoantibody specificities. Front Pharmacol 2024; 15:1370411. [PMID: 38881870 PMCID: PMC11177092 DOI: 10.3389/fphar.2024.1370411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 05/06/2024] [Indexed: 06/18/2024] Open
Abstract
Myasthenia gravis (MG) is an antibody-mediated autoimmune disease with a prevalence of 150-250 cases per million individuals. Autoantibodies include long-lived antibodies against the acetylcholine receptor (AChR), mainly of the IgG1 subclass, and IgG4, produced almost exclusively by short-lived plasmablasts, which are prevalent in muscle-specific tyrosine kinase (MuSK) myasthenia gravis. Numerous investigations have demonstrated that MG patients receiving conventional medication today still do not possess satisfactory symptom control, indicating a substantial disease burden. Subsequently, based on the type of the autoantibody and the pathogenesis, we synthesized the published material to date and reached a conclusion regarding the literature related to personalized targeted therapy for MG. Novel agents for AChR MG have shown their efficacy in clinical research, such as complement inhibitors, FcRn receptor antagonists, and B-cell activating factor (BAFF) inhibitors. Rituximab, a representative drug of anti-CD20 therapy, has demonstrated benefits in treatment of MuSK MG patients. Due to the existence of low-affinity antibodies or unidentified antibodies that are inaccessible by existing methods, the treatment for seronegative MG remains complicated; thus, special testing and therapy considerations are necessary. It may be advantageous to initiate the application of novel biologicals at an early stage of the disease. Currently, therapies can also be combined and individualized according to different types of antibodies. With such a wide range of drugs, how to tailor treatment strategies to patients with various conditions and find the most suitable solution for each MG profile are our necessary and urgent aims.
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Affiliation(s)
- Chi Ma
- Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Dan Liu
- Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Benqiao Wang
- Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yingying Yang
- Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Ruixia Zhu
- Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China
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Kim S, Eun M, Lee J, Seok HY. Rethinking the diagnosis of double-seronegative myasthenia gravis. Eur J Neurol 2024; 31:e16151. [PMID: 37975787 PMCID: PMC11235797 DOI: 10.1111/ene.16151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Affiliation(s)
- Sohyeon Kim
- Department of Neurology, Dongsan HospitalKeimyung University School of MedicineDaeguKorea
| | - Mi‐Yeon Eun
- Department of Neurology, School of MedicineKyungpook National University, Kyungpook National University Chilgok HospitalDaeguKorea
| | - Jae‐Joon Lee
- Department of Neurology, Dongsan HospitalKeimyung University School of MedicineDaeguKorea
| | - Hung Youl Seok
- Department of Neurology, Dongsan HospitalKeimyung University School of MedicineDaeguKorea
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Li HY, Xia M, Song M, Xie Y, Wang Q, Yue YX, Li HF. Rs1800629 polymorphism in TNF-alpha is associated with the susceptibility and initial short-term glucocorticoids efficacy in myasthenia gravis patients. J Neuroimmunol 2024; 387:578269. [PMID: 38150890 DOI: 10.1016/j.jneuroim.2023.578269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/30/2023] [Accepted: 12/17/2023] [Indexed: 12/29/2023]
Abstract
Tumor necrosis factor-alpha (TNF-α) is a potent pro-inflammatory agent involved in various autoimmune and inflammatory diseases including myasthenia gravis (MG). In this study, we enrolled 409 adult MG patients and 487 healthy individuals to investigate the association between TNF-α polymorphism and MG. We found the rs1800629 A allele frequency was significantly higher in the MG group than in the control group. Subgroup analysis revealed that the A allele frequencies were significantly higher in the early-onset subgroup, non-thymoma subgroup, ocular-onset subgroup, and mild severity subgroup than in the control group. To minimize the interactions between clinical features, we used a comprehensive classification and found that the rs1800629 A allele frequency was significantly higher in the non-thymoma AChR-Ab negative subgroup than in the control group. In the analysis of initial short-term glucocorticoids (GC) efficacy in the treatment-naive patients, the rs1800629 A allele frequency was significantly higher in the unresponsive subgroup than in the responsive group and the control group. Logistic regression demonstrated the rs1800629 genotypes in the dominant model and disease duration prior to GC treatment independently contributed to initial short-term GC efficacy. In conclusion, our study revealed that in Chinese adult MG patients, rs1800629 polymorphism in TNF-α was associated with the susceptibility of MG and might indicate the initial short-term GC efficacy.
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Affiliation(s)
- Hong-Yan Li
- Department of Neurology, Qilu Hospital of Shandong University, 107 Wenhua West Road, Jinan 250012, China
| | - Meng Xia
- School Hospital, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Min Song
- Department of Neurology, Qilu Hospital (Qingdao) of Shandong University, 758 Hefei Road, Qingdao 266035, China
| | - Yanchen Xie
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, 95 Yongan Road, Xicheng District, Beijing 100050, China
| | - Qi Wang
- Department of Neurology, Affiliated Hospital of Qingdao University, 16 Jiangsu Road, Qingdao 266003, China
| | - Yao-Xian Yue
- Department of Neurology, Qilu Hospital of Shandong University, 107 Wenhua West Road, Jinan 250012, China.
| | - Hai-Feng Li
- Department of Neurology, Qilu Hospital of Shandong University, 107 Wenhua West Road, Jinan 250012, China.
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Liu J, Ma J, Hong S, Jiang L, Li T. Pediatric myasthenia gravis with a combination of AChR and RyR is associated with an earlier onset and lower CSR rate: A cohort study in southwest China. Eur J Paediatr Neurol 2023; 47:1-5. [PMID: 37639776 DOI: 10.1016/j.ejpn.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 08/09/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
BACKGROUND The clinical manifestations and prognosis of myasthenia gravis are related to antibodies, and children are affected differently than adults. The presence of ryanodine receptor and titin antibodies in adults indicates late onset and severe disease related to thymoma, but their role in children is rarely reported. METHODS This study collected a cohort of children according to inclusion and exclusion criteria, consisting of antibody-negative, AChR-positive, and AChR with or without titin and RyR antibodies. The differences among groups in general conditions, clinical manifestation, treatment and prognosis were compared. RESULTS In total, 171 patients were included: 33 patients (19.30%) were antibody-negative, 84 patients (49.12%) were positve for AChR antibody, 22 patients (12.87%) were positve for AChR and RyR antibodies, 5 patients (2.92%) were positve for AChR and Titin antibodies, and 27 patients (15.79%) were positve for AChR, RyR and Titin antibodies. The median onset age of all the patients was 57.8 (9-177) months, and patients with AChR and RyR antibodies (p = 0.02) and AChR, RyR and Titin antibodies (p = 0.0006) had a younger onset age than patients with AChR antibodies. The rate of generalized MG and MG-ADL before treatment in the AChR-, RyR- and Titin antibody-positive groups was distinctly higher than that in the AChR antibody-positive group (p = 0.038, p = 0.0325). The rate of IVIG use in the AChR-, RyR- and Titin antibody-positive groups (p = 0.0388) was higher than that in the AChR antibody-positive group. The rate of immunosuppressant use in the AChR and RyR antibody-positive group (p = 0.0415) and in the AChR, RyR and Titin antibody-positive group (p = 0.0006) was higher than that in the AChR antibody-positive group. Plasmapheresis was performed in 1 case in the AChR-, RyR- and Titin antibody-positive groups. The CSR rate in the AChR and RyR antibody-positive group (p = 0.0423) and in the AChR, RyR and Titin antibody-positive group (p = 0.0152) was significantly lower than that in the AChR antibody-positive group. Gender, ptosis severity, and CSR time were not significantly different between groups. CONCLUSIONS We summarized one of the largest cohorts of pediatric MG patients and compared the clinical phenotype of patients with antibody-negative, AChR-positive, and AChR with or without titin and RyR antibodies. The results showed that patients with AChR and RyR antibodies had a younger onset age, a higher immunosuppressant use rate and a lower CSR rate.
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Affiliation(s)
- Jie Liu
- Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Jiannan Ma
- Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Siqi Hong
- Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Li Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Tianyi Li
- Department of Neurology, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China.
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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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Vinciguerra C, Bevilacqua L, Lupica A, Ginanneschi F, Piscosquito G, Rini N, Rossi A, Barone P, Brighina F, Di Stefano V. Diagnosis and Management of Seronegative Myasthenia Gravis: Lights and Shadows. Brain Sci 2023; 13:1286. [PMID: 37759888 PMCID: PMC10526522 DOI: 10.3390/brainsci13091286] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Myasthenia gravis (MG) is an antibody-mediated neuromuscular disease affecting the neuromuscular junction. In most cases, autoantibodies can be detected in the sera of MG patients, thus aiding in diagnosis and allowing for early screening. However, there is a small proportion of patients who have no detectable auto-antibodies, a condition termed "seronegative MG" (SnMG). Several factors contribute to this, including laboratory test inaccuracies, decreased antibody production, immunosuppressive therapy, immunodeficiencies, antigen depletion, and immune-senescence. The diagnosis of SnMG is more challenging and is based on clinical features and neurophysiological tests. The early identification of these patients is needed in order to ensure early treatment and prevent complications. This narrative review aims to examine the latest updates on SnMG, defining the clinical characteristics of affected patients, diagnostic methods, management, and therapeutic scenarios.
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Affiliation(s)
- Claudia Vinciguerra
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Liliana Bevilacqua
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Antonino Lupica
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Federica Ginanneschi
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (F.G.)
| | - Giuseppe Piscosquito
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Nicasio Rini
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Alessandro Rossi
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (F.G.)
| | - Paolo Barone
- Neurology Unit, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84131 Salerno, Italy; (C.V.)
| | - Filippo Brighina
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
| | - Vincenzo Di Stefano
- Neurology Unit, Department of Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), University of Palermo, 90127 Palermo, Italy (V.D.S.)
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Stergiou C, Williams R, Fleming JR, Zouvelou V, Ninou E, Andreetta F, Rinaldi E, Simoncini O, Mantegazza R, Bogomolovas J, Tzartos J, Labeit S, Mayans O, Tzartos S. Immunological and Structural Characterization of Titin Main Immunogenic Region; I110 Domain Is the Target of Titin Antibodies in Myasthenia Gravis. Biomedicines 2023; 11:biomedicines11020449. [PMID: 36830985 PMCID: PMC9952892 DOI: 10.3390/biomedicines11020449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction (NJ) of skeletal muscles. The major MG autoantigen is nicotinic acetylcholine receptor. Other autoantigens at the NJ include MuSK, LRP4 and agrin. Autoantibodies to the intra-sarcomeric striated muscle-specific gigantic protein titin, although not directed to the NJ, are invaluable biomarkers for thymoma and MG disease severity. Thymus and thymoma are critical in MG mechanisms and management. Titin autoantibodies bind to a 30 KDa titin segment, the main immunogenic region (MIR), consisting of an Ig-FnIII-FnIII 3-domain tandem, termed I109-I111. In this work, we further resolved the localization of titin epitope(s) to facilitate the development of more specific anti-titin diagnostics. For this, we expressed protein samples corresponding to 8 MIR and non-MIR titin fragments and tested 77 anti-titin sera for antibody binding using ELISA, competition experiments and Western blots. All anti-MIR antibodies were bound exclusively to the central MIR domain, I110, and to its containing titin segments. Most antibodies were bound also to SDS-denatured I110 on Western blots, suggesting that their epitope(s) are non-conformational. No significant difference was observed between thymoma and non-thymoma patients or between early- and late-onset MG. In addition, atomic 3D-structures of the MIR and its subcomponents were elucidated using X-ray crystallography. These immunological and structural data will allow further studies into the atomic determinants underlying titin-based autoimmunity, improved diagnostics and how to eventually treat titin autoimmunity associated co-morbidities.
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Affiliation(s)
| | - Rhys Williams
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Vasiliki Zouvelou
- 1st Neurology Department, Eginition Hospital, National and Kapodistrian University of Athens, 157 72 Athens, Greece
| | | | - Francesca Andreetta
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Elena Rinaldi
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Ornella Simoncini
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Renato Mantegazza
- Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Julius Bogomolovas
- School of Medicine, University of California, La Jolla, San Diego, CA 92093, USA
| | - John Tzartos
- School of Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, 124 62 Athens, Greece
| | - Siegfried Labeit
- DZHK Partner Site Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany
- Myomedix GmbH, 69151 Neckargemuend, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, 115 23 Athens, Greece
- Hellenic Pasteur Institute, 115 21 Athens, Greece
- Department of Pharmacy, University of Patras, 265 00 Patras, Greece
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Abstract
INTRODUCTION Myasthenia gravis (MG) is an autoimmune disease where muscle antibodies form against the acetylcholine receptor (AChR), MuSK, or LRP4 at the neuromuscular junction leading to weakness. Patients worry about consequences for pregnancy, giving birth, nursing, and child outcome. AREAS COVERED This review lists the pharmacological treatments for MG in the reproductive age and gives recommendations. Consequences for pregnancy, giving birth, breastfeeding, and child outcome are discussed. EXPERT OPINION Pyridostigmine, corticosteroids in low doses, and azathioprine are regarded as safe during pregnancy and should be continued. Mycophenolate mofetil, methotrexate, and cyclophosphamide should not be used in reproductive age. Rituximab should not be given during pregnancy. Other monoclonal IgG antibodies such as eculizumab and efgartigimod should be given only when regarded strictly necessary to avoid long-term and severe incapacity. Intravenous and subcutaneous immunoglobulin and plasma exchange are safe treatments during pregnancy and are recommended for exacerbations with moderate or severe generalized weakness. Most MG women have spontaneous vaginal deliveries. Indications for Cesarean section are obstetrical and similar to non-MG women. Neonatal myasthenia manifests as a transient weakness caused by the mother's IgG muscle antibodies and affects 10% of the babies. MG women should be supported in their wish to have children.
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Affiliation(s)
- Nils Erik Gilhus
- Department of Neurology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
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Chung HY, Kim MJ, Kim SW, Oh J, Shin HY. Development and Application of a Cell-Based Assay for LRP4 Antibody Associated With Myasthenia Gravis. J Clin Neurol 2023; 19:60-66. [PMID: 36606647 PMCID: PMC9833872 DOI: 10.3988/jcn.2023.19.1.60] [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: 05/20/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Among patients with double-seronegative myasthenia gravis (dSN-MG) who do not have detectable antibodies against acetylcholine receptor or muscle-specific tyrosine kinase, autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4-Ab) have been detected recently. The purpose of this study was to develop an in-house cell-based assay (CBA) to detect LRP4-Ab and to apply it to samples from patients with MG. METHODS The complementary DNA of LRP4 fused into a vector plasmid containing GFP was transfected into human embryonic kidney 293 (HEK293) cells. LRP4 expression in the transfected HEK293 cells was assessed using the reverse-transcription polymerase chain reaction (RT-PCR), Western blotting, and immunocytochemistry. The CBA included 252 sera collected from 202 patients with MG and 38 with other neuromuscular diseases, and 12 healthy controls. The transfected HEK293 cells were incubated using sera and antihuman immunoglobulin G antibodies conjugated with Alexa Fluor 594. The presence of LRP4-Ab was determined based on the fluorescence intensity and the localization in fluorescence microscopy. RESULTS The expressions of the mRNA and protein of LRP4 in the transfected HEK293 cells were confirmed using RT-PCR and Western blotting, respectively. Immunocytochemistry indicated LPR4 expression on the cell membrane. Among 202 patients with MG including 53 with dSN-MG, LRP4-Ab were positive in 3 patients who were all double seronegative. LRP4-Ab were not detected in the patients with other neuromuscular diseases or the healthy controls. CONCLUSIONS A CBA for detecting LRP4-Ab associated with MG has been developed, and was used to find LRP4-Ab in the sera of patients with MG.
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Affiliation(s)
- Hye Yoon Chung
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Min Ju Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea.,Graduate Program of Nano Science and Technology, Yonsei University, Seoul, Korea
| | - Seung Woo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Jeeyoung Oh
- Department of Neurology, Konkuk University Medical Center, School of Medicine, Konkuk University, Seoul, Korea
| | - Ha Young Shin
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
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Abstract
Myasthenia gravis is an autoimmune disorder caused by antibodies against elements in the postsynaptic membrane at the neuromuscular junction, which leads to muscle weakness. Congenital myasthenic syndromes are rare and caused by mutations affecting pre- or postsynaptic function at the neuromuscular synapse and resulting in muscle weakness. MG has a prevalence of 150-250 and an annual incidence of 8-10 individuals per million. The majority has disease onset after age 50 years. Juvenile MG with onset in early childhood is more common in East Asia. MG is subgrouped according to type of pathogenic autoantibodies, age of onset, thymus pathology, and generalization of muscle weakness. More than 80% have antibodies against the acetylcholine receptor. The remaining have antibodies against MuSK, LRP4, or postsynaptic membrane antigens not yet identified. A thymoma is present in 10% of MG patients, and more than one-third of thymoma patients develop MG as a paraneoplastic condition. Immunosuppressive drug therapy, thymectomy, and symptomatic drug therapy with acetylcholine esterase inhibitors represent cornerstones in the treatment. The prognosis is good, with the majority of patients having mild or moderate symptoms only. Most congenital myasthenic syndromes are due to dysfunction in the postsynaptic membrane. Symptom debut is in early life. Symptomatic drug treatment has sometimes a positive effect.
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Affiliation(s)
- Nils Erik Gilhus
- Department of Neurology, Haukeland University Hospital and Department of Clinical Medicine, University of Bergen, Bergen, Norway.
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12
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Lenti MV, Rossi CM, Melazzini F, Gastaldi M, Bugatti S, Rotondi M, Bianchi PI, Gentile A, Chiovato L, Montecucco C, Corazza GR, Di Sabatino A. Seronegative autoimmune diseases: A challenging diagnosis. Autoimmun Rev 2022; 21:103143. [PMID: 35840037 DOI: 10.1016/j.autrev.2022.103143] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 07/10/2022] [Indexed: 12/19/2022]
Abstract
Autoimmune diseases (AID) are increasingly prevalent conditions which comprise more than 100 distinct clinical entities that are responsible for a great disease burden worldwide. The early recognition of these diseases is key for preventing their complications and for tailoring proper management. In most cases, autoantibodies, regardless of their potential pathogenetic role, can be detected in the serum of patients with AID, helping clinicians in making a definitive diagnosis and allowing screening strategies for early -and sometimes pre-clinical- diagnosis. Despite their undoubted crucial role, in a minority of cases, patients with AID may not show any autoantibody, a condition that is referred to as seronegative AID. Suboptimal accuracy of the available laboratory tests, antibody absorption, immunosuppressive therapy, immunodeficiencies, antigen exhaustion, and immunosenescence are the main possible determinants of seronegative AID. Indeed, in seronegative AID, the diagnosis is more challenging and must rely on clinical features and on other available tests, often including histopathological evaluation and radiological diagnostic tests. In this review, we critically dissect, in a narrative fashion, the possible causes of seronegativity, as well as the diagnostic and management implications, in several AID including autoimmune gastritis, celiac disease, autoimmune liver disease, rheumatoid arthritis, autoimmune encephalitis, myasthenia gravis, Sjögren's syndrome, antiphospholipid syndrome, and autoimmune thyroid diseases.
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Affiliation(s)
- Marco Vincenzo Lenti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Carlo Maria Rossi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Federica Melazzini
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Matteo Gastaldi
- Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
| | - Serena Bugatti
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Mario Rotondi
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Paola Ilaria Bianchi
- Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonella Gentile
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Luca Chiovato
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Unit of Internal Medicine and Endocrinology, Laboratory for Endocrine Disruptors, Pavia, Italy
| | - Carlomaurizio Montecucco
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Unit of Rheumatology, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Gino Roberto Corazza
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy
| | - Antonio Di Sabatino
- Department of Internal Medicine and Medical Therapeutics, University of Pavia, Pavia, Italy; Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, Pavia, Italy.
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13
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Aguirre F, Fernández RN, Arrejoría RM, Manin A, Cores VE, Sivori M, Villa AM. Peak expiratory flow and the single-breath count test as markers of respiratory function in patients with myasthenia gravis. NEUROLOGÍA (ENGLISH EDITION) 2022:S2173-5808(22)00076-1. [PMID: 35842128 DOI: 10.1016/j.nrleng.2020.09.006] [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: 04/28/2020] [Accepted: 09/19/2020] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratory muscles. Considering the severity of respiratory involvement in MG, routine evaluation of respiratory function is essential. The aim of this study was to identify a useful clinical marker of respiratory involvement in patients with MG. METHODS We performed an observational study of patients with MG. All cases were evaluated with the single-breath count test, peak expiratory flow (PEF), a modified Medical Research Council dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). RESULTS The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified as grade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were found between single-breath count test scores and FVC values (r = 0.57, P = .000), and between PEF and FVC values (r = 0.76, P = .000). Severity of dyspnoea according to the mMRC scale showed a negative correlation with FVC values (r = -0.31, P = .03). PEF also showed a significant correlation with MEP (r = 0.51, P = .002). CONCLUSIONS PEF, the single-breath count test, and the mMRC scale are useful measures for evaluating respiratory function in patients with MG.
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Affiliation(s)
- F Aguirre
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.
| | - R N Fernández
- Unidad Neumotisiología, Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - R M Arrejoría
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - A Manin
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - V E Cores
- Hospital Interzonal General de Agudos (HIGA) Eva Perón, CONICET, Buenos Aires, Argentina
| | - M Sivori
- Unidad Neumotisiología, Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - A M Villa
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI), Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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14
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Shao K, Yue YX, Zhao LM, Hao HJ, Ding XJ, Jiang P, Yan CZ, Li HF. Optimization of the cut-offs in acetylcholine receptor antibodies and diagnostic performance in myasthenia gravis patients. Clin Chim Acta 2022; 533:122-130. [PMID: 35750085 DOI: 10.1016/j.cca.2022.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 11/19/2022]
Abstract
OBJECTIVE This study aims to establish an optimization procedure to define the cut-offs of quantitative assays for acetylcholine receptor antibody (AChRAb), evaluate their diagnostic performance in myasthenia gravis (MG), and explore the association with clinical features. METHODS Samples from a representative cohort of 77 MG patients, 80 healthy controls (HC) and 80 other autoimmune diseases (OAD) patients were tested using competitive inhibition ELISA and RIA. Raw values (OD and cpm) and processed values (inhibition rate, binding rate and concentration) were used to define the cut-offs with statistical methods, a rough method, and receiver operating characteristic (ROC) curve. Optimal cut-offs were selected by comparing false positive rates in HC and OAD individuals. The diagnostic performance was evaluated in whole MG cohort and subgroups. Agreement between ELISA and RIA for AChRAb positivity were examined with Kappa test and McNemar test. Clinical association with AChRAb was explored by comparison among subgroups and with Spearman rank correlation. RESULTS The optimal cut-offs for AChRAb positivity were determined as OD≤1.79 for ELISA and cpm≥1234.12 for RIA, which derived from statistical method and performed better than those derived from ROC curves. The sensitivity and specificity were 74.03%, 100% for ELISA, and 74.03%, 99.37% for RIA. There was good agreement between ELISA and RIA for AChRAb positivity in whole cohort and subgroups (weighted к ≥0.71, p<0.01; McNemar test, p>0.05). Levels of AChRAb were different in MG subgroups (p<0.01). Correlation between Quantitative Myasthenia Gravis scores and AChRAb levels was moderate for ELISA and RIA (rs=-0.60 and 0.57, p<0.01). CONCLUSION The raw testing values of ELISA and RIA were found as optimal quantitative measures of AChRAb levels. There are good agreements on diagnostic performance between two assays. Quantitative values are more informative than positivity in association with clinical features.
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Affiliation(s)
- Kai Shao
- Department of Central Laboratory and Mitochondrial Medicine Laboratory, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, China.
| | - Yao-Xian Yue
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
| | - Li-Ming Zhao
- Department of Nuclear Medicine, Linyi People's Hospital, Linyi, China.
| | - Hong-Jun Hao
- Laboratory of Neuroimmunology, Peking University First Hospital, Beijing, China.
| | - Xiao-Jun Ding
- Department of Neurology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, China.
| | - Ping Jiang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.
| | - Chuan-Zhu Yan
- Department of Central Laboratory and Mitochondrial Medicine Laboratory, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, China; Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
| | - Hai-Feng Li
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China; Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.
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15
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Michail M, Zouvelou V, Belimezi M, Haroniti A, Zouridakis M, Zisimopoulou P. Analysis of nAChR Autoantibodies Against Extracellular Epitopes in MG Patients. Front Neurol 2022; 13:858998. [PMID: 35418927 PMCID: PMC8995881 DOI: 10.3389/fneur.2022.858998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/28/2022] [Indexed: 01/12/2023] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disorder caused by autoantibodies targeting components of the postsynaptic membrane of the neuromuscular junction (NMJ), leading to neuromuscular transmission deficiency. In the vast majority of patients, these autoantibodies target the nicotinic acetylcholine receptor (nAChR), a heteropentameric ion channel anchored to the postsynaptic membrane of the NMJ. Autoantibodies in patients with MG may target all the subunits of the receptor at both their extracellular and intracellular regions. Here, we combine immunoadsorption with a cell-based assay to examine the specificity of the patients' autoantibodies against the extracellular part of the nAChR. Our results reveal that these autoantibodies can be divided into distinct groups, based on their target, with probably different impacts on disease severity. Although our findings are based on a small sample group of patients, they strongly support that additional analysis of the specificity of the autoantibodies of patients with MG could serve as a valuable tool for the clinicians' decision on the treatment strategy to be followed.
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Affiliation(s)
- Maria Michail
- Laboratory of Molecular Neurobiology and Immunology, Hellenic Pasteur Institute, Athens, Greece.,Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Vasiliki Zouvelou
- Department of Neurology, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Belimezi
- Diagnostic Department, Hellenic Pasteur Institute, Athens, Greece
| | - Anna Haroniti
- Laboratory of Molecular Neurobiology and Immunology, Hellenic Pasteur Institute, Athens, Greece
| | - Marios Zouridakis
- Laboratory of Molecular Neurobiology and Immunology, Hellenic Pasteur Institute, Athens, Greece
| | - Paraskevi Zisimopoulou
- Laboratory of Molecular Neurobiology and Immunology, Hellenic Pasteur Institute, Athens, Greece
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16
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Huijbers MG, Marx A, Plomp JJ, Le Panse R, Phillips WD. Advances in the understanding of disease mechanisms of autoimmune neuromuscular junction disorders. Lancet Neurol 2022; 21:163-175. [DOI: 10.1016/s1474-4422(21)00357-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/15/2021] [Accepted: 10/06/2021] [Indexed: 01/19/2023]
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17
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Song J, Yang J, Jing S, Yan C, Huan X, Chen S, Zhong H, Lu J, Xi J, Luo L, Chen X, Wang Z, Zhao C, Chu M, Luo S. Berberine attenuates experimental autoimmune myasthenia gravis via rebalancing the T cell subsets. J Neuroimmunol 2022; 362:577787. [PMID: 34923373 DOI: 10.1016/j.jneuroim.2021.577787] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 01/18/2023]
Abstract
Myasthenia Gravis (MG) is a T cell-driven, autoantibody-mediated disease. Here we show that oral Berberine (BBR) ameliorated clinical symptoms of experimental autoimmune myasthenia gravis(EAMG) rat model via decreasing the frequencies of Th1, Th17, Th1/17 cell subsets. JAK-STAT pathway was highlighted by transcriptomic analysis with EAMG mononuclear cells (MNCs). Surface plasmon resonance identified ligand binding interaction between BBR and JAK2, and electrostatic interaction was proposed by molecular dynamic simulation. Reduced phosphorylated JAK1/2/3 and STAT1/3 in MNCs from BBR-fed EAMG rats were demonstrated. These results suggest that BBR might improve EAMG by rebalancing T cell subsets through targeting JAK-STAT pathway.
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Affiliation(s)
- Jie Song
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Jie Yang
- Department of Neurology, Wuhan No.1 Hospital, Wuhan, Hubei 430020, China
| | - Sisi Jing
- Department of Neurology, Jing'an District Center Hospital of Shanghai, Shanghai 200040, China
| | - Chong Yan
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Xiao Huan
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Sheng Chen
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Huahua Zhong
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Jun Lu
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Jianying Xi
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Lijun Luo
- Department of Neurology, Wuhan No.1 Hospital, Wuhan, Hubei 430020, China
| | - Xi Chen
- Department of Immunology, School of Basic Medical Sciences, Peking University. NHC Key Laboratory of Medical Immunology (Peking University), Beijing 100191, China
| | - Ziyuan Wang
- Department of Immunology, School of Basic Medical Sciences, Peking University. NHC Key Laboratory of Medical Immunology (Peking University), Beijing 100191, China
| | - Chongbo Zhao
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China
| | - Ming Chu
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China; Department of Immunology, School of Basic Medical Sciences, Peking University. NHC Key Laboratory of Medical Immunology (Peking University), Beijing 100191, China.
| | - Sushan Luo
- Department of Neurology, Huashan hospital Fudan University, Shanghai 200040, China; National Center for Neurological Disorders, Shanghai 200040, China.
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18
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Cai Y, Han L, Zhu D, Peng J, Li J, Ding J, Luo J, Hong R, Wang K, Wan W, Xie C, Zhou X, Zhang Y, Hao Y, Guan Y. A Stable Cell Line Expressing Clustered AChR: A Novel Cell-Based Assay for Anti-AChR Antibody Detection in Myasthenia Gravis. Front Immunol 2021; 12:666046. [PMID: 34305897 PMCID: PMC8297518 DOI: 10.3389/fimmu.2021.666046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/28/2021] [Indexed: 12/13/2022] Open
Abstract
Cell-based assays (CBAs) and radioimmunoprecipitation assay (RIPA) are the most sensitive methods for identifying anti-acetylcholine receptor (AChR) antibody in myasthenia gravis (MG). But CBAs are limited in clinical practice by transient transfection. We established a stable cell line (KL525) expressing clustered AChR by infecting HEK 293T cells with dual lentiviral vectors expressing the genes encoding the human AChR α1, β1, δ, ϵ and the clustering protein rapsyn. We verified the stable expression of human clustered AChR by immunofluorescence, immunoblotting, and real-time PCR. Fluorescence-activated cell sorting (FACS) was used to detect anti-AChR antibodies in 103 MG patients and 58 healthy individuals. The positive results of MG patients reported by the KL525 was 80.6% (83/103), 29.1% higher than the 51.4% (53/103) of RIPA. 58 healthy individuals tested by both the KL525 CBA and RIPA were all negative. In summary, the stable expression of clustered AChR in our cell line makes it highly sensitive and advantageous for broad clinical application in CBAs.
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Affiliation(s)
- Yu Cai
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lu Han
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Desheng Zhu
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Peng
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianping Li
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Ding
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jiaying Luo
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ronghua Hong
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Kan Wang
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wenbin Wan
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Chong Xie
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiajun Zhou
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Zhang
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yong Hao
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yangtai Guan
- Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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19
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Creary LE, Gangavarapu S, Caillier SJ, Cavalcante P, Frangiamore R, Lie BA, Bengtsson M, Harbo HF, Brauner S, Hollenbach JA, Oksenberg JR, Bernasconi P, Maniaol AH, Hammarström L, Mantegazza R, Fernández-Viña MA. Next-Generation Sequencing Identifies Extended HLA Class I and II Haplotypes Associated With Early-Onset and Late-Onset Myasthenia Gravis in Italian, Norwegian, and Swedish Populations. Front Immunol 2021; 12:667336. [PMID: 34163474 PMCID: PMC8215161 DOI: 10.3389/fimmu.2021.667336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/27/2021] [Indexed: 11/13/2022] Open
Abstract
Genetic susceptibility to myasthenia gravis (MG) associates with specific HLA alleles and haplotypes at the class I and II regions in various populations. Previous studies have only examined alleles at a limited number of HLA loci that defined only broad serotypes or alleles defined at the protein sequence level. Consequently, genetic variants in noncoding and untranslated HLA gene segments have not been fully explored but could also be important determinants for MG. To gain further insight into the role of HLA in MG, we applied next-generation sequencing to analyze sequence variation at eleven HLA genes in early-onset (EO) and late-onset (LO) non-thymomatous MG patients positive for the acetylcholine receptor (AChR) antibodies and ethnically matched controls from Italy, Norway, and Sweden. For all three populations, alleles and haplotype blocks present on the ancestral haplotype AH8.1 were associated with risk in AChR-EOMG patients. HLA-B*08:01:01:01 was the dominant risk allele in Italians (OR = 3.28, P = 1.83E-05), Norwegians (OR = 3.52, P = 4.41E-16), and in Swedes HLA-B*08:01 was the primary risk allele (OR = 4.24, P <2.2E-16). Protective alleles and haplotype blocks were identified on the HLA-DRB7, and HLA-DRB13.1 class II haplotypes in Italians and Norwegians, whereas in Swedes HLA-DRB7 exhibited the main protective effect. For AChR-LOMG patients, the HLA-DRB15.1 haplotype and associated alleles were significantly associated with susceptibility in all groups. The HLA-DR13-HLA-DR-HLA-DQ haplotype was associated with protection in all AChR-LOMG groups. This study has confirmed and extended previous findings that the immunogenetic predisposition profiles for EOMG and LOMG are distinct. In addition, the results are consistent with a role for non-coding HLA genetic variants in the pathogenesis of MG.
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Affiliation(s)
- Lisa E Creary
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA, United States.,Histocompatibility, Immunogenetics and Disease Profiling Laboratory, Stanford Blood Center, Palo Alto, CA, United States
| | - Sridevi Gangavarapu
- Histocompatibility, Immunogenetics and Disease Profiling Laboratory, Stanford Blood Center, Palo Alto, CA, United States
| | - Stacy J Caillier
- Department of Neurology, School of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Paola Cavalcante
- Neurology IV Unit Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Rita Frangiamore
- Neurology IV Unit Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Benedicte A Lie
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Department of Medical Genetics, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Mats Bengtsson
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory, Uppsala University and University Hospital, Uppsala, Sweden
| | - Hanne Flinstad Harbo
- Department of Neurology, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Susanna Brauner
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jill A Hollenbach
- Department of Neurology, School of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Jorge R Oksenberg
- Department of Neurology, School of Medicine, University of California San Francisco, San Francisco, CA, United States
| | - Pia Bernasconi
- Neurology IV Unit Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | | | - Lennart Hammarström
- The Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Renato Mantegazza
- Neurology IV Unit Neuroimmunology and Neuromuscular Diseases, Fondazione I.R.C.C.S Istituto Neurologico Carlo Besta (INCB), Milan, Italy.,Department of Clinical Research and Innovation, Fondazione I.R.C.C.S Istituto Neurologico Carlo Besta (INCB), Milan, Italy
| | - Marcelo A Fernández-Viña
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA, United States.,Histocompatibility, Immunogenetics and Disease Profiling Laboratory, Stanford Blood Center, Palo Alto, CA, United States
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20
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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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21
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Han JL, Yue YX, Gao X, Xie YC, Hao HJ, Li HY, Yu XL, Li J, Duan RS, Li HF. Vitamin D Receptor Polymorphism and Myasthenia Gravis in Chinese Han Population. Front Neurol 2021; 12:604052. [PMID: 33633666 PMCID: PMC7900549 DOI: 10.3389/fneur.2021.604052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 01/05/2021] [Indexed: 12/31/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease in which antibodies bind to acetylcholine receptors (AChR) or other functional molecules in the postsynaptic membrane at the neuromuscular junction. Vitamin D (VD) has a number of pluripotent effects, which include immune-regulation and bone metabolism. The immunomodulatory actions of 1,25(OH)2D3 are mediated by its binding to a vitamin D receptor (VDR). In the study, we undertook a case-control study to explore the association between VDR gene polymorphism and the susceptibility and severity of MG patients. Four hundred and eighty MG patients and 487 healthy controls were included and gene polymorphisms of VDR were determined with improved multiplex ligation detection reaction technique and SNPscanTM technique. MG patients were classified into subgroups by essential clinical features and by a comprehensive classification. The frequencies of alleles and genotypes were compared between the MG group and the control group, between each MG subgroup and the control group, and between each pair of MG subgroups. There were no significant differences in frequencies of alleles and genotypes between MG patients and healthy controls, between MG subgroups and healthy controls, or between each pair of MG subgroups in the analysis of subgroups classified by essential clinical features (onset age, gender, thymoma, AChRAb positivity, onset involvement) and the maximal severity (modified Oosterhuis score). In the analysis of subgroups with a comprehensive classification, the frequencies of alleles and genotypes in rs731236 showed significant differences between adult non-thymoma AChRAb negative MG subgroup and the control group, as well as the adult non-thymoma AChRAb positive MG group. In the Chinese Han population, rs731236 was found to be possibly associated with adult non-thymoma AChRAb negative MG patients, although this needs further confirmation.
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Affiliation(s)
- Ji-Lan Han
- Department of Neurology, Shandong Provincial Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Neurology, Weifang People's Hospital, Weifang, China
| | - Yao-Xian Yue
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xiang Gao
- Department of Allergy, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yan-Chen Xie
- Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hong-Jun Hao
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Hong-Yan Li
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xiao-Long Yu
- Department of Neurology, Affiliated Qingdao Central Hospital, Qingdao University, Qingdao, China
| | - Jie Li
- Department of Neurology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Rui-Sheng Duan
- Department of Neurology, Shandong Provincial Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hai-Feng Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
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22
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Aguirre F, Fernández RN, Arrejoría RM, Manin A, Cores VE, Sivori M, Villa AM. Peak expiratory flow and the single-breath counting test as markers of respiratory function in patients with myasthenia gravis. Neurologia 2020; 38:S0213-4853(20)30432-1. [PMID: 33317968 DOI: 10.1016/j.nrl.2020.09.007] [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: 04/28/2020] [Revised: 09/08/2020] [Accepted: 09/19/2020] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION Myasthenia gravis (MG) is an antibody-mediated autoimmune disease characterised by fluctuating, fatigable muscle weakness, frequently involving bulbar and respiratory muscles. Considering the severity of respiratory involvement in MG, routine evaluation of respiratory function is essential. The aim of this study was to identify a useful clinical marker of respiratory involvement in patients with MG. METHODS We performed an observational study of patients with MG. All cases were evaluated with the single-breath counting test, peak expiratory flow (PEF), a modified Medical Research Council dyspnoea scale (mMRC), and a neck strength assessment. The results of these parameters were correlated with forced vital capacity (FVC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP). RESULTS The study included 45 patients with MG: 2 patients classified as grade I on the Myasthenia Gravis Foundation of America classification at the time of evaluation, 35 classified as grade II, 7 classified as grade III, and one classified as grade IV. Positive correlations were found between single-breath counting test scores and FVC values (r = 0.57, p = .000), and between PEF and FVC values (r = 0.76, p = .000). Severity of dyspnoea according to the mMRC scale showed a negative correlation with FVC values (r = -0.31, p = .03). PEF also showed a significant correlation with MEP (r = 0.51, p = .002). CONCLUSIONS PEF, the single-breath counting test, and the mMRC scale are useful measures for evaluating respiratory function in patients with MG.
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Affiliation(s)
- F Aguirre
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina. Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.
| | - R N Fernández
- Unidad Neumotisiología, Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - R M Arrejoría
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - A Manin
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina. Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - V E Cores
- Hospital Interzonal General de Agudos (HIGA) Eva Perón. CONICET, Buenos Aires, Argentina
| | - M Sivori
- Unidad Neumotisiología, Hospital José María Ramos Mejía, Buenos Aires, Argentina
| | - A M Villa
- Sección de Enfermedades Neuromusculares y Neurofisiología, División Neurología. Hospital José María Ramos Mejía, Buenos Aires, Argentina; Centro Argentino de Neuroinmunología (CADENI). Facultad de Medicina. Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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23
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Frykman H, Kumar P, Oger J. Immunopathology of Autoimmune Myasthenia Gravis: Implications for Improved Testing Algorithms and Treatment Strategies. Front Neurol 2020; 11:596621. [PMID: 33362698 PMCID: PMC7755715 DOI: 10.3389/fneur.2020.596621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is a heterogeneous condition, characterized by autoantibodies (Abs) that target functionally important structures within neuromuscular junctions (NMJ), thus affecting nerve-to-muscle transmission. MG patients are more often now subgrouped based on the profile of serum autoantibodies, which segregate with clinical presentation, immunopathology, and their response to therapies. The serological testing plays an essential role in confirming MG diagnosis and guiding disease management, although a small percentage of MG patients remain negative for antibodies. With the advancements in new highly effective pathophysiologically-specific immunotherapeutic options, it has become increasingly important to identify the specific Abs responsible for the pathogenicity in individual MG patients. There are several new assays and protocols being developed for the improved detection of Abs in MG patients. This review focuses on the divergent immunopathological mechanisms in MG, and discusses their relevance to improved diagnostic and treatment. We propose a comprehensive "reflex testing," algorithm for the presence of MG autoantibodies, and foresee that in the near future, the convenience and specificity of novel assays will permit the clinicians to consider them into routine systematic testing, thus stimulating laboratories to make these tests available. Moreover, adopting treatment driven testing algorithms will be crucial to identify subgroups of patients potentially benefiting from novel immunotherapies for MG.
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Affiliation(s)
- Hans Frykman
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
| | - Pankaj Kumar
- BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
| | - Joel Oger
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,BC Neuroimmunology Lab, University of British Columbia, Vancouver, BC, Canada
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24
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Lazaridis K, Tzartos SJ. Myasthenia Gravis: Autoantibody Specificities and Their Role in MG Management. Front Neurol 2020; 11:596981. [PMID: 33329350 PMCID: PMC7734299 DOI: 10.3389/fneur.2020.596981] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 10/30/2020] [Indexed: 12/11/2022] Open
Abstract
Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction, characterized by skeletal muscle weakness and fatigability. It is caused by autoantibodies targeting proteins of the neuromuscular junction; ~85% of MG patients have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 5% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). In the remaining about 10% of patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG). Since serological tests are relatively easy and non-invasive for disease diagnosis, the improvement of methods for the detection of known autoantibodies or the discovery of novel autoantibody specificities to diminish SN-MG and to facilitate differential diagnosis of similar diseases, is crucial. Radioimmunoprecipitation assays (RIPA) are the staple for MG antibody detection, but over the past years, using cell-based assays (CBAs) or improved highly sensitive RIPAs, it has been possible to detect autoantibodies in previously SN-MG patients. This led to the identification of more patients with antibodies to the classical antigens AChR and MuSK and to the third MG autoantigen, the low-density lipoprotein receptor-related protein 4 (LRP4), while antibodies against other extracellular or intracellular targets, such as agrin, Kv1.4 potassium channels, collagen Q, titin, the ryanodine receptor and cortactin have been found in some MG patients. Since the autoantigen targeted determines in part the clinical manifestations, prognosis and response to treatment, serological tests are not only indispensable for initial diagnosis, but also for monitoring treatment efficacy. Importantly, knowing the autoantibody profile of MG patients could allow for more efficient personalized therapeutic approaches. Significant progress has been made over the past years toward the development of antigen-specific therapies, targeting only the specific immune cells or autoantibodies involved in the autoimmune response. In this review, we will present the progress made toward the development of novel sensitive autoantibody detection assays, the identification of new MG autoantigens, and the implications for improved antigen-specific therapeutics. These advancements increase our understanding of MG pathology and improve patient quality of life by providing faster, more accurate diagnosis and better disease management.
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Affiliation(s)
| | - Socrates J Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece.,Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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25
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Vitalo A, Buckley G, Londoño L. Therapeutic plasma exchange as adjunct therapy in 3 dogs with myasthenia gravis and myasthenia-like syndrome. J Vet Emerg Crit Care (San Antonio) 2020; 31:106-111. [PMID: 33217167 DOI: 10.1111/vec.13022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/01/2019] [Accepted: 04/08/2019] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To describe the use of therapeutic membrane-based plasma exchange (TPE) for treatment of clinical signs associated with suspected acquired myasthenia gravis (MG) in 3 dogs. CASE SERIES SUMMARY Three dogs presented with clinical signs consistent with acquired MG. All 3 dogs were medically managed prior to being treated with TPE. Two of the 3 dogs had increased acetylcholine receptor antibody titers that decreased after TPE. One dog diagnosed with primary MG became clinically normal after 2 sessions of TPE and continued to do well with medical management several months later. The second dog was diagnosed with a suspect thymoma, and TPE was performed as a bridge to surgery, with marked improvement of clinical signs after TPE. The dog was ultimately diagnosed with a thymic carcinoma. The third dog had a positive acetylcholine antibody titer and was ultimately diagnosed with hemangiosarcoma (spleen and liver) and invasive mediastinal thymoma. This dog developed severe pneumonia, was ventilator dependent, and died of multiple organ dysfunction. No immediate complications were observed secondary to TPE. All 3 dogs were concurrently treated with either immunosuppressive agents, anticholinesterase drugs, or both. NEW OR UNIQUE INFORMATION PROVIDED The use of TPE in dogs with MG appears to be well tolerated and safe. It may be a reasonable adjunct therapy to acetylcholinesterase drugs in cases that are not responding to medical management alone. Therapeutic plasma exchange might also be considered preoperatively to prevent postoperative complications in dogs with severe MG, although further studies should be performed.
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Affiliation(s)
- Amber Vitalo
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Gareth Buckley
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Leonel Londoño
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
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26
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Yan C, Zhao R, Song J, Feng X, Xi J, Luo S, Zhong H, Zhou S, Li W, Zhao C. Comparison of anti-acetylcholine receptor profiles between Chinese cases of adult- and juvenile-onset myasthenia gravis using cell-based assays. J Neuroimmunol 2020; 349:577403. [PMID: 32992216 DOI: 10.1016/j.jneuroim.2020.577403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/29/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Juvenile-onset myasthenia gravis (JOMG) is a unique clinical subtype in China, featured by a higher prevalence of ocular myasthenia gravis (OMG), higher seronegativity of acetylcholine receptor (AChR) antibodies, and better prognosis than that in adult-onset myasthenia gravis (AOMG). We previously identified low-affinity AChR antibodies in Chinese JOMG patients using cell-based assays (CBAs), indicating a predominantly AChR antibody-positive profile. Here, we further screened AChR antibodies in both Chinese AOMG and JOMG patients by CBAs. MATERIALS AND METHODS We recruited patients with MG who had not received prednisone or immunosuppressive therapies between June 2015 and June 2019, and divided them into AOMG and JOMG subgroups according to their ages at the time of recruitment. Clinical information and blood samples were collected. Serum AChR antibodies were detected by CBAs in HEK293T cells expressing clustered adult and fetal AChRs, as well as by enzyme-linked immunosorbent assays (ELISAs). Differences in AChR antibody profiles between AOMG and JOMG subgroups were determined. RESULTS A total of 239 patients with MG were enrolled in the present study, including 121 AOMG and 118 JOMG patients. Based on ELISAs, 74.4% of AOMG (90/121) and 59.3% of JOMG (70/118) patients were anti-AChR positive (p = 0.02). However, CBAs yielded equal anti-AChR positivities (p = 0.64), as indicated by 80.2% of AOMG patients (97/121) and 77.1% of JOMG patients (91/118). Furthermore, among AOMG patients, 67.8% (82/121) were positive for both adult and fetal AChR antibodies, 5.8% (7/121) were positive for only adult AChR antibodies, and 6.6% (8/121) were positive for only fetal AChR antibodies, while these rates were 50.8% (60/118), 21.2% (25/118), and 5.1% (6/118), respectively, in JOMG cohorts (p < 0.01). Twenty-nine AOMG patients and 10 JOMG patients underwent IgG subclassification of AChR antibodies, which were all confirmed to be predominantly IgG1. CONCLUSIONS The positive rates of AChR antibodies did not differ between Chinese AOMG and JOMG patients, as revealed by CBAs. Furthermore, the screened AChR antibodies were predominantly IgG1 in both AOMG and JOMG patients.
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Affiliation(s)
- Chong Yan
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Rui Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jie Song
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xuelin Feng
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong 510080, China
| | - Jianying Xi
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Sushan Luo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Huahua Zhong
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Shuizhen Zhou
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 200040, China
| | - Wenhui Li
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 200040, China.
| | - Chongbo Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China; Department of Neurology, Jing'an District Center Hospital of Shanghai, Fudan University, Shanghai 200040, China.
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27
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Rivner MH, Quarles BM, Pan JX, Yu Z, Howard JF, Corse A, Dimachkie MM, Jackson C, Vu T, Small G, Lisak RP, Belsh J, Lee I, Nowak RJ, Baute V, Scelsa S, Fernandes JA, Simmons Z, Swenson A, Barohn R, Sanka RB, Gooch C, Ubogu E, Caress J, Pasnoor M, Xu H, Mei L. Clinical features of LRP4/agrin-antibody-positive myasthenia gravis: A multicenter study. Muscle Nerve 2020; 62:333-343. [PMID: 32483837 PMCID: PMC7496236 DOI: 10.1002/mus.26985] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/16/2020] [Accepted: 05/18/2020] [Indexed: 12/13/2022]
Abstract
Introduction Our aim in this study was to identify the prevalence and clinical characteristics of LRP4/agrin‐antibody–positive double‐seronegative myasthenia gravis (DNMG). Methods DNMG patients at 16 sites in the United States were tested for LRP4 and agrin antibodies, and the clinical data were collected. Results Of 181 DNMG patients, 27 (14.9%) were positive for either low‐density lipoprotein receptor–related protein 4 (LRP4) or agrin antibodies. Twenty‐three DNMG patients (12.7%) were positive for both antibodies. More antibody‐positive patients presented with generalized symptoms (69%) compared with antibody‐negative patients (43%) (P ≤ .02). Antibody‐positive patients’ maximum classification on the Myasthenia Gravis Foundation of America (MGFA) scale was significantly higher than that for antibody‐negative patients (P ≤ .005). Seventy percent of antibody‐positive patients were classified as MGFA class III, IV, or V compared with 39% of antibody‐negative patients. Most LRP4‐ and agrin‐antibody–positive patients (24 of 27, 89%) developed generalized myathenia gravis (MG), but with standard MG treatment 81.5% (22 of 27) improved to MGFA class I or II during a mean follow‐up of 11 years. Discussion Antibody‐positive patients had more severe clinical disease than antibody‐negative patients. Most DNMG patients responded to standard therapy regardless of antibody status.
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Affiliation(s)
| | | | - Jin-Xiu Pan
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
| | - Zheng Yu
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
| | - James F Howard
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Andrea Corse
- Department of Neurology, The Johns Hopkins University, Baltimore, Maryland
| | | | - Carlayne Jackson
- Department of Neurology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Tuan Vu
- Department of Neurology, University of South Florida, Tampa, Florida
| | - George Small
- Department of Neurology, Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - Robert P Lisak
- Department of Neurology, Wayne State University, Detroit, Michigan
| | - Jerry Belsh
- Department of Neurology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Ikjae Lee
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Richard J Nowak
- Department of Neurology, Yale University, New Haven, Connecticut
| | - Vanessa Baute
- Department of Neurology, Wake Forest University, Winston-Salem, North Carolina
| | - Stephen Scelsa
- Department of Neurology, Mount Sinai-Beth Israel Hospital, New York, New York
| | - J Americo Fernandes
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska
| | - Zachary Simmons
- Department of Neurology, Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Andrea Swenson
- Department of Neurology, University of Iowa, Iowa City, Iowa
| | - Richard Barohn
- Department of Neurology, University of Kansas, Kansas City, Kansas
| | - R Bhavaraju Sanka
- Department of Neurology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Clifton Gooch
- Department of Neurology, University of South Florida, Tampa, Florida
| | - Eroboghene Ubogu
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - James Caress
- Department of Neurology, Wake Forest University, Winston-Salem, North Carolina
| | - Mamatha Pasnoor
- Department of Neurology, University of Kansas, Kansas City, Kansas
| | - Hongyan Xu
- Department of Population Health Sciences, Augusta University, Augusta, Georgia
| | - Lin Mei
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
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28
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Çebi M, Durmus H, Aysal F, Özkan B, Gül GE, Çakar A, Hocaoglu M, Mercan M, Yentür SP, Tütüncü M, Yayla V, Akan O, Dogan Ö, Parman Y, Saruhan-Direskeneli G. CD4 + T Cells of Myasthenia Gravis Patients Are Characterized by Increased IL-21, IL-4, and IL-17A Productions and Higher Presence of PD-1 and ICOS. Front Immunol 2020; 11:809. [PMID: 32508812 PMCID: PMC7248174 DOI: 10.3389/fimmu.2020.00809] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/08/2020] [Indexed: 12/19/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease mediated by autoantibodies predominantly against the acetylcholine receptor (AChR). Specific T cell subsets are required for long-term antibody responses, and cytokines secreted mainly from CD4+ T cells regulate B cell antibody production. The aim of this study was to assess the differences in the cytokine expressions of CD4+ T cells in MG patients with AChR antibodies (AChR-MG) and the effect of immunosuppressive (IS) therapy on cytokine activity and to test these findings also in MG patients without detectable antibodies (SN-MG). Clinically diagnosed AChR-MG and SN-MG patients were included. The AChR-MG patients were grouped as IS-positive and -negative and compared with age- and sex-matched healthy controls. Peripheral blood mononuclear cells were used for ex vivo intracellular cytokine production, and subsets of CD4+ T cells and circulating follicular helper T (cTfh) cells were detected phenotypically by the expression of the chemokine and the costimulatory receptors. Thymocytes obtained from patients who had thymectomy were also analyzed. IL-21, IL-4, IL-10, and IL-17A productions in CD4+ T cells were increased in AChR-MG compared to those in healthy controls. IS treatment enhanced IL-10 and reduced IFN-γ production in AChR-MG patients compared to those in IS-negative patients. Increased IL-21 and IL-4 productions were also demonstrated in SN-MG patients. Among CD4+ T cells, Th17 cells were increased in both disease subgroups. Treatment induced higher proportions of Th2 cells in AChR-MG patients. Both CXCR5+ and CXCR5− CD4+ T cells expressed higher programmed cell death protein 1 (PD-1) and inducible costimulatory (ICOS) in AChR-MG and SN-MG groups, mostly irrespective of the treatment. Based on chemokine receptors on CXCR5+PD-1+ in CD4+ T (cTfh) cells, in AChR-MG patients without treatment, the proportions of Tfh17 cells were higher than those in the treated group, whereas the Tfh1 cells were decreased compared with those in the controls. The relevance of CXCR5 and PD-1 in the pathogenesis of AChR-MG was also suggested by the increased presence of these molecules on mature CD4 single-positive thymocytes from the thymic samples. The study provides further evidence for the importance of IL-21, IL-17A, IL-4, and IL-10 in AChR-MG. Disease-related CD4+T cells are identified mainly as PD-1+ or ICOS+ with or without CXCR5, resembling cTfh cells in the circulation or probably in the thymus. AChR-MG and SN-MG seem to have some similar characteristics. IS treatment has distinctive effects on cytokine expression.
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Affiliation(s)
- Merve Çebi
- Department of Physiology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Hacer Durmus
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Fikret Aysal
- Department of Neurology, Medipol University, Istanbul, Turkey
| | - Berker Özkan
- Department of Thoracic Surgery, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | | | - Arman Çakar
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Mehmet Hocaoglu
- Department of Physiology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Metin Mercan
- Bakirköy Sadi Konuk State Hospital, Istanbul, Turkey
| | - Sibel P Yentür
- Department of Physiology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Melih Tütüncü
- Department of Neurology, Cerrahpaşa Medical Faculty, Istanbul University Cerrahpaşa, Istanbul, Turkey
| | - Vildan Yayla
- Bakirköy Sadi Konuk State Hospital, Istanbul, Turkey
| | - Onur Akan
- Okmeydani State Hospital, Istanbul, Turkey
| | - Öner Dogan
- Department of Pathology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Yeşim Parman
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
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29
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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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A novel MuSK cell-based myasthenia gravis diagnostic assay. J Neuroimmunol 2019; 337:577076. [PMID: 31655425 DOI: 10.1016/j.jneuroim.2019.577076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/19/2019] [Accepted: 09/27/2019] [Indexed: 10/25/2022]
Abstract
To improve the clinical diagnosis of neural autoimmune diseases, we developed an in-house muscle-specific kinase (MuSK) antibody cell-based assay (CBA) and compared its performance with RIA, ELISA, and other CBAs. Sera from patients with myasthenia gravis (MG) and other autoimmune diseases were analyzed. We found 46 (18.3%) MuSK-CBA Ab positive cases among 251 AChR-Ab negative cases [patients] and 4 (0.6%) MuSK-CBA Ab positive cases [among] the 624 AChR-Ab positive samples. Comparing these with available clinic assays, our highly specific CBA method is more sensitive than commercial ELISA and IFA(indirect immunofluorescence assay).
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Abstract
This article discusses antibodies associated with immune-mediated myasthenia gravis and the pathologic action of these antibodies at the neuromuscular junctions of skeletal muscle. To explain how these antibodies act, we consider the physiology of neuromuscular transmission with emphasis on 4 features: the structure of the neuromuscular junction; the roles of postsynaptic acetylcholine receptors and voltage-gated Na+ channels and in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber that triggers muscle contraction; the safety factor for neuromuscular transmission; and how the safety factor is reduced in different forms of autoimmune myasthenia gravis.
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Affiliation(s)
- Robert L Ruff
- Department of Neurology, Case Western University School of Medicine, The Metro Health System, 2500 Metro Health Drive, Cleveland, OH 44109, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Robert P Lisak
- Department of Neurology, Wayne State University School of Medicine, 8D University Health Center, 4201 St Antoine, Detroit, MI 48201, USA; Department of Biochemistry, Microbiology and Immunology, Wayne State University, Detroit, MI, USA.
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Li M, Han J, Zhang Y, Lv J, Zhang J, Zhao X, Ren L, Fang H, Yang J, Zhang Y, Cui X, Zhang Q, Li Q, Du Y, Gao F. Clinical analysis of Chinese anti-low-density-lipoprotein-receptor-associated protein 4 antibodies in patients with myasthenia gravis. Eur J Neurol 2019; 26:1296-e84. [PMID: 31050101 DOI: 10.1111/ene.13979] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/23/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND PURPOSE Low-density-lipoprotein-receptor-associated protein 4 (LRP4) autoantibodies have recently been detected in myasthenia gravis (MG), but little is known about the clinical characteristics associated with this serological type. In this study, the clinical features of Chinese patients with anti-LRP4 antibody-positive MG were characterized. METHODS A total of 2172 MG serum samples were collected from patients in various parts of China. An enzyme-linked immunosorbent assay was used to detect acetylcholine receptor (AChR) antibody and titin antibody, and cell-based assays were used to detect muscle-specific kinase antibody and LRP4 antibody. Clinical data for patients with MG were collected from different provinces in China. RESULTS In total, 16 (0.8%) patients with LRP4-MG were found amongst 2172 total patients, including three patients with AChR/LRP4-MG. Additionally, 13 (2.9%) patients with LRP4-MG were found amongst 455 patients with double seronegative MG. The ratio of males to females for these 13 patients was 1:1.6, and 53.8% patients were children. A total of 91.7% of cases exhibited initial ocular involvement, and 58.3% of cases exhibited simple eye muscle involvement. Responses to acetylcholinesterase inhibitors and prednisone were observed. CONCLUSION The expanded sample confirmed that the positive rate of LRP4 antibodies in China is lower than that in western countries. Our results highlighted the differences between LRP4-MG and other antibody groups. Children and female patients with LRP4-MG have a higher prevalence, often involving the ocular muscles and limb muscles. The clinical symptoms are mild, and satisfactory responses to treatment are often achieved.
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Affiliation(s)
- M Li
- Department of Neurology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - J Han
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Y Zhang
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - J Lv
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - J Zhang
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - X Zhao
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - L Ren
- Department of Neurology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - H Fang
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - J Yang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of TCM, Zhengzhou, China
| | - Y Zhang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of TCM, Zhengzhou, China
| | - X Cui
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Q Zhang
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Q Li
- Department of Immunology and Microbiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - Y Du
- Department of Immunology and Microbiology, Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - F Gao
- Department of Neuroimmunology, Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
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Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies against the acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or other AChR-related proteins in the postsynaptic muscle membrane. Localized or general muscle weakness is the predominant symptom and is induced by the antibodies. Patients are grouped according to the presence of antibodies, symptoms, age at onset and thymus pathology. Diagnosis is straightforward in most patients with typical symptoms and a positive antibody test, although a detailed clinical and neurophysiological examination is important in antibody-negative patients. MG therapy should be ambitious and aim for clinical remission or only mild symptoms with near-normal function and quality of life. Treatment should be based on MG subgroup and includes symptomatic treatment using acetylcholinesterase inhibitors, thymectomy and immunotherapy. Intravenous immunoglobulin and plasma exchange are fast-acting treatments used for disease exacerbations, and intensive care is necessary during exacerbations with respiratory failure. Comorbidity is frequent, particularly in elderly patients. Active physical training should be encouraged.
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Nagappa M, Mahadevan A, Gangadhar Y, Patil SA, Bokolia S, Bindu PS, Sinha S, Taly AB. Autoantibodies in acquired myasthenia gravis: Clinical phenotype and immunological correlation. Acta Neurol Scand 2019; 139:428-437. [PMID: 30693486 DOI: 10.1111/ane.13071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/25/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Data on antibody profile in myasthenia gravis (MG) from India are limited. OBJECTIVES To investigate antibody profile in patients with MG and their clinical correlates. PATIENTS AND METHODS Patients of MG (n = 85, M:F::1.1:1, mean age: 39.29 ± 17.3 years, mean symptom duration: 72.94 ± 91.8 months) were evaluated for clinical features, MG foundation of America (MGFA) score, response to treatment, and outcome at last follow-up. Antibodies to acetylcholine receptor (AChR), muscle-specific kinase (MUSK), titin and ryanodine receptor (RYR) were analysed using ELISA. RESULTS Based on the regional distribution of weakness, the cohort could be categorized as: generalized: 60, ocular: 16 and oculo-bulbar: 9. Sixty patients were followed up for a mean duration of 26.74 ± 13.8 months. Outcome at last follow-up was as follows: remission-22, no remission-33 and dead-5. AChR and MUSK antibodies were detected in 58 and 8 patients, respectively. Frequency of generalized MG, worse MGFA score during the disease course and thymomatous histology significantly correlated with presence of AChR-antibodies, though outcome at last follow-up was comparable between AChR-antibody positive and negative groups. Patients with MUSK antibodies had oculo-bulbar or generalized MG and frequent respiratory crisis, but majority improved or remitted with treatment. Titin antibodies were detected in 31.8% and RYR antibodies in 32.9%. Their presence did not correlate with age at onset of MG, severity or presence of thymoma. CONCLUSION This report highlights the spectrum of antibodies in MG in an Indian cohort. AChR-antibody positivity correlated with clinical severity. Outcome was good in majority of MUSK antibody-positive MG. The role of other antibodies, complementary vs epiphenomenon, remains open.
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Affiliation(s)
- Madhu Nagappa
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Anita Mahadevan
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Yashwanth Gangadhar
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Department of Neuropathology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Shripad A. Patil
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Suresh Bokolia
- Department of Neuromicrobiology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Parayil S. Bindu
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Sanjib Sinha
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Arun B. Taly
- Department of Neurology National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
- Neuromuscular Laboratory (NML) Neurobiology Research Centre (NBRC) National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
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Abstract
PURPOSE OF REVIEW The current article reviews the recent advances in the field of myasthenia gravis, which span from autoantibody profiling and pathogenic mechanisms to therapy innovation. The overview is highlighting specifically the data and the needs of targeted treatments in the light of precision medicine in myasthenia gravis. RECENT FINDINGS Novel data published recently further increased our knowledge on myasthenia gravis. The use of cell-based assays has greatly improved autoantibody detection in myasthenia gravis patients, and the mechanisms of action of these antibodies have been described. The role of Toll-like receptor activation in the generation of thymic alterations and anti-acetylcholine receptor autosensitization has been further investigated implementing our understanding on the relationships between innate immunity and autoimmunity. Additional studies have been focused on the alterations of T-cell/B-cell regulatory mechanisms in thymus and peripheral blood of myasthenia gravis patients. microRNAs and genetic factors are also emerging as key biomarkers in myasthenia gravis pathogenesis and prediction of drug efficacy in individual patients. SUMMARY The recent immunological and pathological findings in myasthenia gravis promise to improve myasthenia gravis treatment, via the development of more precise and personalized therapies.
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Schapira AHV. Progress in neurology 2017-2018. Eur J Neurol 2018; 25:1389-1397. [DOI: 10.1111/ene.13846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. H. V. Schapira
- Department of Clinical and Movement Neurosciences; UCL Queen Square Institute of Neurology; London UK
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Gilhus NE, Hong Y. Maternal myasthenia gravis represents a risk for the child through autoantibody transfer, immunosuppressive therapy and genetic influence. Eur J Neurol 2018; 25:1402-1409. [PMID: 30133097 DOI: 10.1111/ene.13788] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/17/2018] [Indexed: 12/16/2022]
Abstract
Females with myasthenia gravis (MG) worry about their disease having negative consequences for their children. Autoimmune disease mechanisms, treatment and heredity could all have an impact on the child. This is a subject review where Web of Science was searched for relevant keywords and combinations. Controlled and prospective studies were included, and also results from selected and unselected patient cohorts, guidelines, consensus papers and reviews. Neonatal MG with temporary muscle weakness occurs in 10% of newborn babies where the mother has MG, due to transplacental transfer of antibodies against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or lipoprotein receptor-related protein 4 (LRP4). Arthrogryposis and fetal AChR inactivation syndrome with contractures and permanent myopathy are rare events caused by mother's antibodies against fetal type AChR. The MG drugs pyridostigmine, prednisolone and azathioprine are regarded as safe during pregnancy and breastfeeding. Methotrexate, mycophenolate mofetil and cyclophosphamide are teratogenic. Mother's MG implies at least a 10-fold increased risk for MG and other autoimmune diseases in the child. MG females should receive specific information about pregnancy and giving birth. First-line MG treatments should usually be continued during pregnancy. Intravenous immunoglobulin and plasma exchange represent safe treatments for exacerbations. Neonatal MG risk means that MG women should give birth at hospitals experienced in neonatal intensive care. Neonatal MG needs supportive care, rarely also acetylcholine esterase inhibition or intravenous immunoglobulin. Women with MG should be supported in their wish to have children.
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Affiliation(s)
- N E Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Y Hong
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
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Trakas N, Tzartos SJ. Immunostick ELISA for rapid and easy diagnosis of myasthenia gravis. J Immunol Methods 2018; 460:107-112. [DOI: 10.1016/j.jim.2018.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/14/2018] [Accepted: 06/28/2018] [Indexed: 01/20/2023]
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Galassi G, Mazzoli M, Ariatti A, Kaleci S, Valzania F, Nichelli PF. Antibody profile may predict outcome in ocular myasthenia gravis. Acta Neurol Belg 2018; 118:435-443. [PMID: 29858757 DOI: 10.1007/s13760-018-0943-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/15/2018] [Indexed: 02/04/2023]
Abstract
An unsolved issue remains whether there are clinical and immunological features to predict in a single patient the risk of conversion from ocular Myasthenia Gravis (OMG) to generalized disease (GMG) as 50-60% of patients may progress within 1-2 years since onset. Anti-acetylcholine receptor antibodies (AChR Abs) are found in up to 50% of OMG patients; muscle-specific tyrosine kinase antibodies (MuSK-Abs) are present in about 70% of the whole seronegative (SN), who usually develop a severe disease with bulbar involvement. We surveyed a cohort of 175 OMG patients with purely ocular symptoms and we compare the outcome of patients with antibodies to AChR or to MuSK with those seronegative for both Abs (DSN). All patients had purely ocular signs for at least 24 months. Gender, age at onset, time to generalization or to worsening in quantitative ocular QMG scores, electrophysiological results were analyzed. Males were 58.9%, females 41.1%. Patients with late onset of symptoms after 50 years (LOMG) were 78.3%. We assayed anti-MuSK-Abs in 4.7%, anti-AChR Abs in 38.5%; 57.3% were defined DSN. Thirty-seven patients (21.1%) progressed to GMG during the observational time: 23 were females, 62% of the whole group of the generalized subjects, 75% of MuSK-positive OMG converted to GMG versus the 26.2% of AChR positive and 13.7% of DSN. Statistical analysis showed that gender and presence of antibodies either to AChR or to MuSK were independent predictors of worse outcome; the DSN subjects had lower risk of conversion to GMG.
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Affiliation(s)
- Giuliana Galassi
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy.
| | - Marco Mazzoli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Alessandra Ariatti
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
| | - Shaniko Kaleci
- Department of Diagnostic Clinical Medicine and Public Health, University of Modena, Modena, Italy
| | - Franco Valzania
- Department of Neurology, Arcispedale S. Maria Nuova, Reggio Emilia, Italy
| | - Paolo F Nichelli
- Department of Biomedical, Metabolic and Neural Sciences, University Hospital, Modena, Italy
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40
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Wang J, Xiao Y, Zhang K, Luo B, Shen C. Introducing Autoimmunity at the Synapse by a Novel Animal Model of Experimental Autoimmune Myasthenia Gravis. Neuroscience 2018; 374:264-270. [PMID: 29421431 DOI: 10.1016/j.neuroscience.2018.01.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/22/2017] [Accepted: 01/18/2018] [Indexed: 12/13/2022]
Abstract
The neuromuscular junction (NMJ) is a peripheral synapse between motor neurons and skeletal muscle fibers that controls muscle contraction. The NMJ is the target of various disorders including myasthenia gravis (MG), an autoimmune disease in which auto-antibodies (auto-Abs) attack the synapse, and thus cause muscle weakness in patients. There are multiple auto-Abs in the MG patient sera, but not all the Abs are proven to be pathogenic, which increases the difficulties in clinical diagnoses and treatments. To establish the causative roles of auto-Abs in MG pathogenesis, the experimental autoimmune MG (EAMG) induced by the active immunization of auto-antigens (auto-Ags) or the passive transfer of auto-Abs is required. These models simulate many features of the human disease. To date, there are three kinds of EAMG models reported, of which AChR-EAMG and MuSK-EAMG are well characterized, while the recent LRP4-EAMG is much less studied. Here, we report a current summary of LRP4-EAMG and its pathogenic mechanisms. The features of LRP4-EAMG are more similar to those of AChR-EAMG, indicating a similar clinical treatment for LRP4- and AChR-positive MG patients, compared to MuSK-positive MG patients.
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Affiliation(s)
- Jianwen Wang
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China
| | - Yatao Xiao
- The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China
| | - Kejing Zhang
- The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China
| | - Benyan Luo
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
| | - Chengyong Shen
- The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China.
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41
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Vincent A, Huda S, Cao M, Cetin H, Koneczny I, Rodriguez Cruz PM, Jacobson L, Viegas S, Jacob S, Woodhall M, Nagaishi A, Maniaol A, Damato V, Leite MI, Cossins J, Webster R, Palace J, Beeson D. Serological and experimental studies in different forms of myasthenia gravis. Ann N Y Acad Sci 2018; 1413:143-153. [PMID: 29377162 DOI: 10.1111/nyas.13592] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 12/11/2022]
Abstract
Antibodies to the acetylcholine receptor (AChR) have been recognized for over 40 years and have been important in the diagnosis of myasthenia gravis (MG), and its recognition in patients of different ages and thymic pathologies. The 10-20% of patients who do not have AChR antibodies are now known to comprise different subgroups, the most commonly reported of which is patients with antibodies to muscle-specific kinase (MuSK). The use of cell-based assays has extended the repertoire of antibody tests to clustered AChRs, low-density lipoprotein receptor-related protein 4, and agrin. Autoantibodies against intracellular targets, namely cortactin, titin, and ryanodine receptor (the latter two being associated with the presence of thymoma), may also be helpful as biomarkers in some patients. IgG4 MuSK antibodies are clearly pathogenic, but the coexisting IgG1, IgG2, and IgG3 antibodies, collectively, have effects that question the dominance of IgG4 as the sole pathologic factor in MuSK MG. After a brief historical review, we define the different subgroups and summarize the antibody characteristics. Experiments to demonstrate the in vitro and in vivo pathogenic roles of MuSK antibodies are discussed.
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Affiliation(s)
- Angela Vincent
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Saif Huda
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Michelangelo Cao
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Hakan Cetin
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Inga Koneczny
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Pedro M Rodriguez Cruz
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Leslie Jacobson
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Stuart Viegas
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Saiju Jacob
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Mark Woodhall
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Akiko Nagaishi
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Angelina Maniaol
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Valentina Damato
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - M Isabel Leite
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Judith Cossins
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Richard Webster
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Jacqueline Palace
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - David Beeson
- Neuroimmunology Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
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42
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Yan M, Xing GL, Xiong WC, Mei L. Agrin and LRP4 antibodies as new biomarkers of myasthenia gravis. Ann N Y Acad Sci 2018; 1413:126-135. [PMID: 29377176 DOI: 10.1111/nyas.13573] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/08/2017] [Accepted: 11/11/2017] [Indexed: 12/13/2022]
Abstract
Myasthenia gravis (MG) is a common disorder that affects the neuromuscular junction. It is caused by antibodies against acetylcholine receptor and muscle-specific tyrosine kinase; however, some MG patients do not have antibodies against either of the proteins. Recent studies have revealed antibodies against agrin and its receptor LRP4-both critical for neuromuscular junction formation and maintenance-in MG patients from various populations. Results from experimental autoimmune MG animal models indicate that anti-LRP4 antibodies are causal to MG. Clinical studies have begun to reveal the significance of the new biomarkers. With their identification, MG appears to be a complex disease entity that can be classified into different subtypes with different etiology, each with unique symptoms. Future systematic studies of large cohorts of well-diagnosed MG patients are needed to determine whether each subtype of patients would respond to different therapeutic strategies. Results should contribute to the goal of precision medicine for MG patients. Anti-agrin and anti-LRP4 antibodies are also detectable in some patients with amyotrophic lateral sclerosis or Lou Gehrig's disease; however, whether they are a cause or response to the disorder remains unclear.
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Affiliation(s)
- Min Yan
- Institute of Life Science, Nanchang University, Nanchang, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, China.,Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Guang-Lin Xing
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Wen-Cheng Xiong
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Louis Stokes Cleveland VAMC, Cleveland, Ohio
| | - Lin Mei
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Louis Stokes Cleveland VAMC, Cleveland, Ohio
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Induction of Anti-agrin Antibodies Causes Myasthenia Gravis in Mice. Neuroscience 2018; 373:113-121. [PMID: 29339325 DOI: 10.1016/j.neuroscience.2018.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 12/27/2017] [Accepted: 01/05/2018] [Indexed: 11/21/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction (NMJ). Most cases of MG are caused by autoantibodies against the acetylcholine receptor (AChR), muscle-specific kinase (MuSK) and low-density lipoprotein receptor-related protein 4 (LRP4). Recent studies have identified anti-agrin antibodies in MG patients lacking these three antibodies (i.e., triple negative MG). Agrin is a basal lamina protein that has two isoforms. Neural agrin (N-agrin) binds to LRP4 to activate MuSK to induce AChR clusters and is thus critical for NMJ formation. We demonstrate that mice immunized with N-agrin showed MG-associated symptoms including muscle weakness, fragmented and distorted NMJs. These effects were not observed in mice injected with muscle agrin (M-agrin), an isoform that is inactive in inducing AChR clusters. Treatment with anti-N-agrin, but not anti-M-agrin, antibodies reduced agrin-induced AChR clusters in muscle cells. Together, these observations suggest that agrin antibodies may be play a role in MG pathogenesis.
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Zieda A, Ravina K, Glazere I, Pelcere L, Naudina MS, Liepina L, Kamsa I, Kurjane N, Woodhall M, Jacobson L, Leite MI, Tandon K, Kenina V. A nationwide epidemiological study of myasthenia gravis in Latvia. Eur J Neurol 2018; 25:519-526. [DOI: 10.1111/ene.13535] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 11/27/2017] [Indexed: 01/22/2023]
Affiliation(s)
- A. Zieda
- Department of General Medicine Glasgow Royal Infirmary Glasgow UK
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
| | - K. Ravina
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
- Department of Neurosurgery Stanford University Stanford CA USA
| | - I. Glazere
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
| | - L. Pelcere
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
| | - M. S. Naudina
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
| | - L. Liepina
- Department of Neurology Riga East Clinical University Hospital Riga Latvia
| | - I. Kamsa
- Department of Neurology Pauls Stradins Clinical University Hospital Riga Latvia
| | - N. Kurjane
- Centre of Clinical Immunology Pauls Stradins Clinical University Hospital Riga Latvia
| | - M. Woodhall
- Nuffield Department of Clinical Neurosciences University of Oxford Oxford UK
| | - L. Jacobson
- Nuffield Department of Clinical Neurosciences University of Oxford Oxford UK
| | - M. I. Leite
- Nuffield Department of Clinical Neurosciences University of Oxford Oxford UK
| | - K. Tandon
- Nuffield Department of Clinical Neurosciences University of Oxford Oxford UK
| | - V. Kenina
- Department of Neurology Riga East Clinical University Hospital Riga Latvia
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Autoantibodies to Low-Density Lipoprotein Receptor-Related Protein 4 in Double Seronegative Myasthenia Gravis: A Systematic Review. Can J Neurol Sci 2017; 45:62-67. [DOI: 10.1017/cjn.2017.253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractBackground: Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junction in which a clinical diagnosis may be confirmed with serological testing. The most common autoantibodies used to support a diagnosis of MG are anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies. In cases in which both of these autoantibodies are negative (termed double-seronegative [dSNMG]), other autoantibodies such as low-density lipoprotein receptor-related protein 4 (LRP4) may be used to aid in diagnosis. Methods: We have undertaken a systematic literature review to identify studies that have assessed the frequency of anti-LRP4 antibodies in dSNMG patients and the characteristics of anti-LRP4+ dSNMG patients (epidemiology, clinical features, electromyographic findings, or management). PubMed, EMBASE, Medline, and Scopus were searched on January 14, 2017, using the medical subject headings “myasthenia gravis” and “low-density lipoprotein receptor-related protein 4” or “LRP4.” Results: The initial search identified 367 articles. Fourteen publications met the inclusion criteria. There were ten cross-sectional research studies, three were case series, and one was a case report. The majority of studies were limited by small sample sizes of LRP4+ dSNMG. There has been a wide range of frequencies of anti-LRP4 antibodies detected in different MG patient populations, some involving different laboratory techniques. Conclusions: LRP4+ dSNMG is more likely than LRP4– dSNMG to have a younger onset of disease and occur in females. LRP4+ dSNMG most often is mild in severity and often involves isolated ocular weakness. It typically responds well to pyridostigmine or prednisone.
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Yi JS, Guptill JT, Stathopoulos P, Nowak RJ, O'Connor KC. B cells in the pathophysiology of myasthenia gravis. Muscle Nerve 2017; 57:172-184. [PMID: 28940642 DOI: 10.1002/mus.25973] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2017] [Indexed: 12/21/2022]
Abstract
Myasthenia gravis (MG) is an archetypal autoimmune disease. The pathology is characterized by autoantibodies to the acetylcholine receptor (AChR) in most patients or to muscle-specific tyrosine kinase (MuSK) in others and to a growing number of other postsynaptic proteins in smaller subsets. A decrease in the number of functional AChRs or functional interruption of the AChR within the muscle end plate of the neuromuscular junction is caused by pathogenic autoantibodies. Although the molecular immunology underpinning the pathology is well understood, much remains to be learned about the cellular immunology contributing to the production of autoantibodies. This Review documents research concerning the immunopathology of MG, bringing together evidence principally from human studies with an emphasis on the role of adaptive immunity and B cells in particular. Proposed mechanisms for autoimmunity, which take into account that different types of MG may incorporate divergent immunopathology, are offered. Muscle Nerve 57: 172-184, 2018.
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Affiliation(s)
- John S Yi
- Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Jeffrey T Guptill
- Department of Neurology, Neuromuscular Section, Duke University Medical Center, Durham, North Carolina, USA
| | - Panos Stathopoulos
- Department of Neurology, Yale School of Medicine, Room 353J, 300 George Street, New Haven, Connecticut, 06511, USA
| | - Richard J Nowak
- Department of Neurology, Yale School of Medicine, Room 353J, 300 George Street, New Haven, Connecticut, 06511, USA
| | - Kevin C O'Connor
- Department of Neurology, Yale School of Medicine, Room 353J, 300 George Street, New Haven, Connecticut, 06511, USA
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