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Li X, Xu Y, Si JX, Gu F, Ma YY. Role of Agrin in tissue repair and regeneration: From mechanisms to therapeutic opportunities (Review). Int J Mol Med 2024; 54:98. [PMID: 39301653 PMCID: PMC11410309 DOI: 10.3892/ijmm.2024.5422] [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: 03/05/2024] [Accepted: 08/01/2024] [Indexed: 09/22/2024] Open
Abstract
Tissue regeneration is a complex process that involves the recruitment of various types of cells for healing after injury; it is mediated by numerous precise interactions. However, the identification of effective targets for improving tissue regeneration remains a challenge. As an extracellular matrix protein, Agrin plays a critical role in neuromuscular junction formation. Furthermore, recent studies have revealed the role of Agrin in regulating tissue proliferation and regeneration, which contributes to the repair process of injured tissues. An in‑depth understanding of the role of Agrin will therefore be of value. Given that repair and regeneration processes occur in various parts of the human body, the present systematic review focuses on the role of Agrin in typical tissue and highlights the potential signaling pathways that are involved in Agrin‑induced repair and regeneration. This review offers important insight into novel strategies for the future clinical applications of Agrin‑based therapies, which may represent a feasible treatment option for patients who require organ replacement or repair.
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Affiliation(s)
- Xiang Li
- Center for Plastic and Reconstructive Surgery, Department of Plastic and Reconstructive Surgery, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
- Key Laboratory of Gastroenterology of Zhejiang Province, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Yuan Xu
- Department of Gastrointestinal Surgery, Ningbo Medical Center Lihuili Hospital, Ningbo, Zhejiang 315048, P.R. China
| | - Jing-Xing Si
- Center for Plastic and Reconstructive Surgery, Department of Plastic and Reconstructive Surgery, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Fang Gu
- Department of Paediatrics, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
| | - Ying-Yu Ma
- Center for Plastic and Reconstructive Surgery, Department of Plastic and Reconstructive Surgery, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
- Key Laboratory of Gastroenterology of Zhejiang Province, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, P.R. China
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2
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Bouwman HB, Guchelaar HJ. The efficacy and safety of eculizumab in patients and the role of C5 polymorphisms. Drug Discov Today 2024; 29:104134. [PMID: 39111540 DOI: 10.1016/j.drudis.2024.104134] [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: 03/14/2024] [Revised: 07/11/2024] [Accepted: 07/31/2024] [Indexed: 08/13/2024]
Abstract
Eculizumab is an orphan drug with indications for extremely rare autoimmune disorders. It is primarily prescribed for use in patients with paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome; but is also highly effective in the treatment of myasthenia gravis, among others. By binding to the C5 protein in the complement system, eculizumab effectively inhibits cellular hemolysis and autoimmune reactions. Despite this effective treatment, some patients reported no improvement in symptoms. Genetic sequencing revealed three distinct C5 mutations in the non-responders and these polymorphisms appeared to be most prevalent among Japanese, Korean and African populations. Here, we present an overview of the current and potential future applications of eculizumab, as well as the disadvantages of eculizumab treatment in patients with C5 polymorphisms.
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Affiliation(s)
| | - Henk-Jan Guchelaar
- Clinical Pharmacy and Toxicology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, the Netherlands.
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3
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El-Wahsh S, Fraser C, Vucic S, Reddel S. Neuromuscular junction disorders: mimics and chameleons. Pract Neurol 2024:pn-2024-004148. [PMID: 39174301 DOI: 10.1136/pn-2024-004148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2024] [Indexed: 08/24/2024]
Abstract
Neuromuscular junction (NMJ) disorders represent a heterogenous group of acquired and congenital disorders that present in variable and distinctive ways. The diagnosis is typically reached through a combination of clinical, serological, pharmacological and electrophysiological evaluation. While the diagnosis can be fairly straightforward in some cases, the overlap with other neurological disorders can make diagnosis challenging, particularly in pure ocular presentations and in seronegative patients. The over-reliance on serological tests and electrophysiological evaluation in isolation can lead to misdiagnosis. In this article, we provide an overview of the NMJ disorders, discuss red flags for the key differential diagnoses (mimics) and report the atypical ways in which NMJ disorders may present (chameleons).
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Affiliation(s)
- Shadi El-Wahsh
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
| | - Clare Fraser
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Steve Vucic
- Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
| | - Stephen Reddel
- Neurology Department, Concord Hospital, Concord, New South Wales, Australia
- Brain and Mind Centre, The University of Sydney, Camperdown, New South Wales, Australia
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4
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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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Nelke C, Schmid S, Kleefeld F, Schroeter CB, Goebel HH, Hoffmann S, Preuße C, Kölbel H, Meuth SG, Ruck T, Stenzel W. Complement and MHC patterns can provide the diagnostic framework for inflammatory neuromuscular diseases. Acta Neuropathol 2024; 147:15. [PMID: 38214778 PMCID: PMC10786976 DOI: 10.1007/s00401-023-02669-8] [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: 08/29/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024]
Abstract
Histopathological analysis stands as the gold standard for the identification and differentiation of inflammatory neuromuscular diseases. These disorders continue to constitute a diagnostic challenge due to their clinical heterogeneity, rarity and overlapping features. To establish standardized protocols for the diagnosis of inflammatory neuromuscular diseases, the development of cost-effective and widely applicable tools is crucial, especially in settings constrained by limited resources. The focus of this review is to emphasize the diagnostic value of major histocompatibility complex (MHC) and complement patterns in the immunohistochemical analysis of these diseases. We explore the immunological background of MHC and complement signatures that characterize inflammatory features, with a specific focus on idiopathic inflammatory myopathies. With this approach, we aim to provide a diagnostic algorithm that may improve and simplify the diagnostic workup based on a limited panel of stainings. Our approach acknowledges the current limitations in the field of inflammatory neuromuscular diseases, particularly the scarcity of large-scale, prospective studies that validate the diagnostic potential of these markers. Further efforts are needed to establish a consensus on the diagnostic protocol to effectively distinguish these diseases.
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Affiliation(s)
- Christopher Nelke
- Department of Neurology, Medical Faculty, Heinrich Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Simone Schmid
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany
| | - Felix Kleefeld
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany
| | - Christina B Schroeter
- Department of Neurology, Medical Faculty, Heinrich Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Hans-Hilmar Goebel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany
| | - Sarah Hoffmann
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany
| | - Corinna Preuße
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany
- Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Augustenburger Platz 1, 13353, Berlin, Germany
| | - Heike Kölbel
- Department of Neuropaediatrics, Klinik für Kinderheilkunde I, Universitätsklinikum Essen, Essen, Germany
| | - Sven G Meuth
- Department of Neurology, Medical Faculty, Heinrich Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Duesseldorf, Moorenstr. 5, 40225, Duesseldorf, Germany
| | - Werner Stenzel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health (BIH), Charitéplatz 1, 10117, Berlin, Germany.
- Leibniz Science Campus Chronic Inflammation, Berlin, Germany.
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6
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Tannemaat MR, Huijbers MG, Verschuuren JJGM. Myasthenia gravis-Pathophysiology, diagnosis, and treatment. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:283-305. [PMID: 38494283 DOI: 10.1016/b978-0-12-823912-4.00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.
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Affiliation(s)
- Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Rodrigues PRDVP, Kay CSK, Ducci RDP, Utiumi MAT, Fustes OJH, Werneck LC, Lorenzoni PJ, Scola RH. Triple-seronegative myasthenia gravis: clinical and epidemiological characteristics. ARQUIVOS DE NEURO-PSIQUIATRIA 2024; 82:1-7. [PMID: 38316426 PMCID: PMC10843919 DOI: 10.1055/s-0044-1779052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/04/2023] [Indexed: 02/07/2024]
Abstract
BACKGROUND Myasthenia gravis (MG) is an autoimmune disease usually caused by antibodies against the acetylcholine receptor (AChR-Abs), muscle-specific tyrosine kinase (MuSK-Abs), or low-density lipoprotein receptor-related protein 4 (LRP4-Abs). However, there are MG patients who do not have these antibodies and are thus said to have triple-seronegative (triple-SN) MG. OBJECTIVE This study aims to describe the frequency and clinical and epidemiological characteristics of patients with triple-SN MG. METHODS This was a retrospective cross-sectional study carried out through the analysis of medical records. Descriptive and analytical statistical analysis was performed comparing subgroups of myasthenic patients, classified according to serological profile. RESULTS The sample population consisted of 93 MG patients: 85 were positive for antibodies, 80 (86%) with AChR-Abs, 5 (5.4%) with MuSK-Abs, and no MG patients with LRP4-Abs. Eight patients (8.6%) had triple-SN MG; they had a median age at disease onset of 30 years (21-45). Their most common initial symptoms were ptosis, diplopia, and generalized weakness. Most patients presented with mild symptoms at their last visit, reflecting a median MG composite scale score of 4 (0-6), and 75% of patients had an adequate response to treatment. CONCLUSION Our study showed a low frequency of triple-SN MG in Brazilian MG patients. Triple-SN MG was predominant in females, who presented with ptosis, diplopia, and generalized weakness, and most patients had an adequate response to immunosuppressive treatment. There was no significant difference between triple-SN MG and the other subgroups.
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Affiliation(s)
- Paula Raquel do Vale Pascoal Rodrigues
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
- Universidade Federal do Paraná, Programa de Pós-Graduação em Medicina Interna, Curitiba PR, Brazil.
| | - Cláudia Suemi Kamoi Kay
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
| | - Renata Dal-Pra Ducci
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
| | | | - Otto Jesus Hernandez Fustes
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
| | - Lineu Cesar Werneck
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
- Universidade Federal do Paraná, Programa de Pós-Graduação em Medicina Interna, Curitiba PR, Brazil.
| | - Paulo José Lorenzoni
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
| | - Rosana Herminia Scola
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil.
- Universidade Federal do Paraná, Programa de Pós-Graduação em Medicina Interna, Curitiba PR, Brazil.
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Tian Y, Shen Q, Peng S, Meng L, Fang R, Xiong A, Li S, Yang Y, Chang W, Ni J, Zhu W. Mapping current trends and hotspots in myasthenia gravis from 2003 to 2022: a bibliometric analysis. Front Neurol 2023; 14:1320344. [PMID: 38213833 PMCID: PMC10782526 DOI: 10.3389/fneur.2023.1320344] [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: 10/12/2023] [Accepted: 12/15/2023] [Indexed: 01/13/2024] Open
Abstract
Introduction Research on myasthenia gravis (MG) has undergone rapid development in recent years. This article aimed to elucidate the characteristics of MG publications over the past 20 years and analyze emerging trends using bibliometric methods. Methods Information on MG articles was obtained from the Web of Science Core Collection and stored in Excel for quantitative analyses. Bibliometric analyses were performed using CiteSpace and VOSviewer to visualize publications according to countries/regions, institutions, journals, and authors. Results A total of 3,610 publications were included in the analysis. The USA had the highest number of publications (NP) and H-index. Among the institutions, the University of Oxford had the highest NP, followed by the University of Toronto and Duke University. Close cooperation was observed among countries and institutions. The most productive author was Renato Mantegazza, followed by Jan J. Verschuuren, and Amelia Evoli. Muscle & Nerve published the most articles on MG, followed by the Journal of Neuroimmunology and Neuromuscular Disorders. The keyword with the highest strength is "neuromuscular transmission," followed by "safety" and "rituximab." Co-citation analysis includes 103 publications cited at least 65 times, categorized into four clusters. Additionally, 123 keywords cited more than 40 times were analyzed and divided into five clusters. Conclusion This bibliometric analysis shows the framework of research over the past 20 years by mapping the scholarly contributions of various countries or regions, institutions, journals, and authors in MG. The analysis also explores future trends and prospective directions, emphasizing individualized treatment based on subtypes, novel immunotherapeutic approaches, and thymectomy.
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Affiliation(s)
- Yukun Tian
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Qiqi Shen
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Siyang Peng
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Linghao Meng
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ruiying Fang
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Anni Xiong
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shaohong Li
- Treatment Center of Traditional Chinese Medicine Bo’ai Hospital, China Rehabilitation Research Center, Beijing, China
| | - Yajing Yang
- Department of Traditional Chinese Medicine, Yuyuantan Community Health Center, Beijing, China
| | - Weiqian Chang
- Department of Acupuncture, Guang’anmen Hospital, Chinese Academy of Traditional Chinese Medicine Ji’nan Hospital (Ji’nan Hospital of Traditional Chinese Medicine), Jinan, Shandong, China
| | - Jinxia Ni
- Department of Acupuncture, Dongzhimen Hospital of Beijing University of Traditional Chinese Medicine, Beijing, China
| | - Wenzeng Zhu
- Department of Acupuncture, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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Hayashi M. Pathophysiology of Childhood-Onset Myasthenia: Abnormalities of Neuromuscular Junction and Autoimmunity and Its Background. PATHOPHYSIOLOGY 2023; 30:599-617. [PMID: 38133144 PMCID: PMC10747330 DOI: 10.3390/pathophysiology30040043] [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: 10/28/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
The pathophysiology of myasthenia gravis (MG) has been largely elucidated over the past half century, and treatment methods have advanced. However, the number of cases of childhood-onset MG is smaller than that of adult MG, and the treatment of childhood-onset MG has continued to be based on research in the adult field. Research on pathophysiology and treatment methods that account for the unique growth and development of children is now desired. According to an epidemiological survey conducted by the Ministry of Health, Labour and Welfare of Japan, the number of patients with MG by age of onset in Japan is high in early childhood. In recent years, MG has been reported from many countries around the world, but the pattern of the number of patients by age of onset differs between East Asia and Western Europe, confirming that the Japanese pattern is common in East Asia. Furthermore, there are racial differences in autoimmune MG and congenital myasthenic syndromes according to immunogenetic background, and their pathophysiology and relationships are gradually becoming clear. In addition, treatment options are also recognized in different regions of the world. In this review article, I will present recent findings focusing on the differences in pathophysiology.
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Affiliation(s)
- Masatoshi Hayashi
- Department of Pediatrics, Uwajima City Hospital, Uwajima 798-8510, Japan
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10
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Kouyoumdjian JA, Estephan EDP. Electrophysiological evaluation of the neuromuscular junction: a brief review. ARQUIVOS DE NEURO-PSIQUIATRIA 2023; 81:1040-1052. [PMID: 38157872 PMCID: PMC10756823 DOI: 10.1055/s-0043-1777749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/17/2023] [Indexed: 01/03/2024]
Abstract
The nerve terminal and muscle membrane compose the neuromuscular junction. After opening the voltage-gated calcium channels, action potentials from the motor axons provoke a cascade for the acetylcholine release from synaptic vesicles to the synaptic cleft, where it binds to its receptor at the muscle membrane for depolarization. Low amplitude compound muscle action potential typically presents in presynaptic disorders, increasing by more than 100% after a 10-second effort in the Lambert-Eaton myasthenic syndrome and less in botulism. Needle electromyography may show myopathic motor unit action potentials and morphological instability ("jiggle") due to impulse blocking. Low-frequency repetitive nerve stimulation (RNS) is helpful in postsynaptic disorders, such as myasthenia gravis and most congenital myasthenic syndromes, where the number of functioning acetylcholine receptors is reduced. Low-frequency RNS with a decrement >10% is abnormal when comparing the 4th to the first compound muscle action potential amplitude. High-frequency RNS is helpful in presynaptic disorders like Lambert-Eaton myasthenic syndrome, botulism, and some rare congenital myasthenic syndromes. The high-frequency RNS releases more calcium, increasing the acetylcholine with a compound muscle action potential increment. Concentric needle records apparent single-fiber action potentials (spikes). A voluntary activation measures the jitter between spikes from two endplates. An electrical activation measures the jitter of one spike (one endplate). The jitter is the most sensitive test for detecting a neuromuscular junction dysfunction. Most neuromuscular junction disorders are responsive to treatment.
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Affiliation(s)
- João Aris Kouyoumdjian
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
| | - Eduardo de Paula Estephan
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
- Universidade de São Paulo, Departamento de Neurologia, São Paulo SP, Brazil.
- Faculdade de Medicina Santa Marcelina, São Paulo SP, Brazil.
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11
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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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12
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Almodovar JL, Mehrabyan A. Disease-Based Prognostication: Myasthenia Gravis. Semin Neurol 2023; 43:799-806. [PMID: 37751854 DOI: 10.1055/s-0043-1775791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Myasthenia gravis (MG) is an acquired autoimmune neuromuscular junction transmission disorder that clinically presents as fluctuating or persistent weakness in various skeletal muscle groups. Neuroprognostication in MG begins with some basic observations on the natural history of the disease and known treatment outcomes. Our objective is to provide a framework that can assist a clinician who encounters the MG patient for the first time and attempts to prognosticate probable outcomes in individual patients. In this review article, we explore clinical type, age of onset, antibody status, severity of disease, thymus pathology, autoimmune, and other comorbidities as prognostic factors in MG.
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Affiliation(s)
- Jorge L Almodovar
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Anahit Mehrabyan
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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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: 8] [Impact Index Per Article: 8.0] [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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Bhandari V, Bril V. FcRN receptor antagonists in the management of myasthenia gravis. Front Neurol 2023; 14:1229112. [PMID: 37602255 PMCID: PMC10439012 DOI: 10.3389/fneur.2023.1229112] [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: 05/25/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disorder characterized by autoantibodies specifically directed against proteins located within the postsynaptic membrane of the neuromuscular junction. These pathogenic autoantibodies can be reduced by therapies such as plasma exchange, IVIG infusions and other immunosuppressive agents. However, there are significant side effects associated with most of these therapies. Since there is a better understanding of the molecular structure and the biological properties of the neonatal Fc receptors (FcRn), it possesses an attractive profile in treating myasthenia gravis. FcRn receptors prevent the catabolism of IgG by impeding their lysosomal degradation and facilitating their extracellular release at physiological pH, consequently extending the IgG half-life. Thus, the catabolism of IgG can be enhanced by blocking the FcRn, leading to outcomes similar to those achieved through plasma exchange with no significant safety concerns. The available studies suggest that FcRn holds promise as a versatile therapeutic intervention, capable of delivering beneficial outcomes in patients with distinct characteristics and varying degrees of MG severity. Efgartigimod is already approved for the treatment of generalized MG, rozanolixizumab is under review by health authorities, and phase 3 trials of nipocalimab and batoclimab are underway. Here, we will review the available data on FcRn therapeutic agents in the management of MG.
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Affiliation(s)
| | - Vera Bril
- Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Toronto General Hospital, University Health Network, University of Toronto, Toronto, ON, Canada
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Gambino CM, Agnello L, Ciaccio AM, Scazzone C, Vidali M, Di Stefano V, Milano S, Brighina F, Candore G, Lo Sasso B, Ciaccio M. Detection of Antibodies against the Acetylcholine Receptor in Patients with Myasthenia Gravis: A Comparison of Two Enzyme Immunoassays and a Fixed Cell-Based Assay. J Clin Med 2023; 12:4781. [PMID: 37510896 PMCID: PMC10381261 DOI: 10.3390/jcm12144781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/28/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The detection of serum anti-acetylcholine receptor (AChR) antibodies is currently an important tool for diagnosing myasthenia gravis (MG) since they are present in about 85% of MG patients. Many serological tests are now available. Nevertheless, results from these tests can be different in some patients. The aim of this study is to compare the sensitivity of a commercially available fixed cell-based assay (F-CBA) to that of enzyme-linked immunosorbent assay (ELISA) kits for anti-AChR detection in patients with a diagnosis of MG. Overall, 143 patients with a confirmed MG diagnosis were included in the study. The detection and measurement of serum anti-AChR antibodies were performed by three analytical methods, namely, a competitive ELISA (cELISA), an indirect ELISA (iELISA), and an F-CBA, according to the manufacturers' instructions. Anti-AChR antibody titers were positive in 94/143 (66%) using the cELISA, in 75/143 (52%) using the iELISA and in 61/143 (43%) using the F-CBA (adult and/or fetal). Method agreement, evaluated by concordant pairs and Cohen's kappa, was as follows: cELISA-iELISA: 110/143 (77%), k = 0.53 (95%CI 0.40-0.66); cELISA-F-CBA: 108/143 (76%), k = 0.53 (95%CI 0.41-0.66); iELISA-F-CBA: 121/143 (85%), k = 0.70 (95%CI 0.57-0.80). Our findings show that the cELISA has better analytical performance than the iELISA and F-CBA. However, the iELISA and F-CBA show the highest concordance.
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Affiliation(s)
- Caterina Maria Gambino
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
- Department of Laboratory Medicine, University Hospital "P. Giaccone", 90127 Palermo, Italy
| | - Luisa Agnello
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
| | - Anna Maria Ciaccio
- Department of Health Promotion, Maternal and Infant Care, Internal Medicine and Medical Specialties "G. D'Alessandro", University of Palermo, 90127 Palermo, Italy
| | - Concetta Scazzone
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
| | - Matteo Vidali
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Vincenzo Di Stefano
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Unit of Neurology, University of Palermo, 90127 Palermo, Italy
| | - Salvatore Milano
- Department of Laboratory Medicine, University Hospital "P. Giaccone", 90127 Palermo, Italy
| | - Filippo Brighina
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Unit of Neurology, University of Palermo, 90127 Palermo, Italy
| | - Giuseppina Candore
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
- Department of Laboratory Medicine, University Hospital "P. Giaccone", 90127 Palermo, Italy
| | - Bruna Lo Sasso
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
- Department of Laboratory Medicine, University Hospital "P. Giaccone", 90127 Palermo, Italy
| | - Marcello Ciaccio
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, Institute of Clinical Biochemistry, Clinical Molecular Medicine and Clinical Laboratory Medicine, University of Palermo, 90127 Palermo, Italy
- Department of Laboratory Medicine, University Hospital "P. Giaccone", 90127 Palermo, Italy
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Younger DS. Critical illness-associated weakness and related motor disorders. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:707-777. [PMID: 37562893 DOI: 10.1016/b978-0-323-98818-6.00031-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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Younger DS. On the path to evidence-based therapy in neuromuscular disorders. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:315-358. [PMID: 37562877 DOI: 10.1016/b978-0-323-98818-6.00007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Neuromuscular disorders encompass a diverse group of acquired and genetic diseases characterized by loss of motor functionality. Although cure is the goal, many therapeutic strategies have been envisioned and are being studied in randomized clinical trials and entered clinical practice. As in all scientific endeavors, the successful clinical translation depends on the quality and translatability of preclinical findings and on the predictive value and feasibility of the clinical models. This chapter focuses on five exemplary diseases: childhood spinal muscular atrophy (SMA), Charcot-Marie-Tooth (CMT) disorders, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), acquired autoimmune myasthenia gravis (MG), and Duchenne muscular dystrophy (DMD), to illustrate the progress made on the path to evidenced-based therapy.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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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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Hehir MK, Li Y. Diagnosis and Management of Myasthenia Gravis. Continuum (Minneap Minn) 2022; 28:1615-1642. [PMID: 36537972 DOI: 10.1212/con.0000000000001161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This article reviews updated diagnostic procedures and currently available treatment modalities for myasthenia gravis (MG). RECENT FINDINGS Patients with MG can be classified based on antibody status and their clinical presentation; treatment responses may differ based on disease subtypes. Improved diagnostic methods and recognition of new antigenic targets such as lipoprotein-related protein 4 have led to improved diagnostic efficiencies. Corticosteroids remain the first-line immunotherapy, but there is a trend toward minimizing their use at high doses and for long durations. Oral immunosuppressants such as mycophenolate mofetil, azathioprine, and tacrolimus remain useful. An international, multicenter randomized trial comparing thymectomy plus prednisone with prednisone alone demonstrated that thymectomy improves clinical outcomes in selected patients with nonthymomatous MG. Eculizumab, efgartigimod, and ravulizumab have recently been approved by the US Food and Drug Administration (FDA) for adult patients with generalized MG who are acetylcholine receptor-antibody positive. These drugs take advantage of novel mechanisms of action and expand treatment options for patients with MG. Data on rituximab suggest that it can be a good option, especially for patients with MG who are positive for antibodies against muscle-specific tyrosine kinase (MuSK). The number of clinical trials and drugs in development for MG is steadily increasing. SUMMARY The diagnosis of MG can generally be made from the patient's history, a neurologic examination, and laboratory and electrodiagnostic testing. Carefully selected treatment improves outcomes in MG. Additional treatment options for MG will likely be available in the near future.
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Abstract
PURPOSE OF REVIEW This review summarizes recent insights into the immunopathogenesis of autoimmune myasthenia gravis (MG). Mechanistic understanding is presented according to MG disease subtypes and by leveraging the knowledge gained through the use of immunomodulating biological therapeutics. RECENT FINDINGS The past two years of research on MG have led to a more accurate definition of the mechanisms through which muscle-specific tyrosine kinase (MuSK) autoantibodies induce pathology. Novel insights have also emerged from the collection of stronger evidence on the pathogenic capacity of low-density lipoprotein receptor-related protein 4 autoantibodies. Clinical observations have revealed a new MG phenotype triggered by cancer immunotherapy, but the underlying immunobiology remains undetermined. From a therapeutic perspective, MG patients can now benefit from a wider spectrum of treatment options. Such therapies have uncovered profound differences in clinical responses between and within the acetylcholine receptor and MuSK MG subtypes. Diverse mechanisms of immunopathology between the two subtypes, as well as qualitative nuances in the autoantibody repertoire of each patient, likely underpin the variability in therapeutic outcomes. Although predictive biomarkers of clinical response are lacking, these observations have ignited the development of assays that might assist clinicians in the choice of specific therapeutic strategies. SUMMARY Recent advances in the understanding of autoantibody functionalities are bringing neuroimmunologists closer to a more detailed appreciation of the mechanisms that govern MG pathology. Future investigations on the immunological heterogeneity among MG patients will be key to developing effective, individually tailored therapies.
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Affiliation(s)
- Gianvito Masi
- Department of Neurology, Yale School of Medicine, New Haven, CT 06511 USA
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06511 USA
| | - Kevin C. O’Connor
- Department of Neurology, Yale School of Medicine, New Haven, CT 06511 USA
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06511 USA
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Racke MK, Batish SD, Lisak RP, Barohn RJ. LRP4 antibody testing in myasthenia gravis. J Neuroimmunol 2022; 371:577949. [PMID: 35973344 DOI: 10.1016/j.jneuroim.2022.577949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 10/15/2022]
Affiliation(s)
- Michael K Racke
- Quest Diagnostics, 500 Plaza Drive, Secaucus, NJ 07094, USA.
| | | | - Robert P Lisak
- Department of Neurology, Wayne State University and Detroit Medical Center, Detroit, MI, USA
| | - Richard J Barohn
- Department of Neurology, School of Medicine, University of Missouri, Columbia, MO, USA
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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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Chen Y, Tao X, Wang Y, Xu S, Yang Y, Han J, Qiu F. Clinical Characteristics and Prognosis of Anti-AChR Positive Myasthenia Gravis Combined With Anti-LRP4 or Anti-Titin Antibody. Front Neurol 2022; 13:873599. [PMID: 35614931 PMCID: PMC9124862 DOI: 10.3389/fneur.2022.873599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/06/2022] [Indexed: 11/29/2022] Open
Abstract
Objective This study aimed to summarize the clinical characteristics and prognosis of patients with anti- acetylcholine receptor (AChR) positive myasthenia gravis (MG) with a combination of anti-LRP4 or Titin antibodies. Methods A total of 188 patients with generalized MG before immunotherapy were retrospectively collected and then divided into three groups: single anti-AChR positive-MG (AChR-MG, 101 cases), anti-AChR combined with anti-low-density lipoprotein receptor-related protein four-positive MG (AChR+LRP4-MG, 29 cases), and anti-AChR combined with anti-Titin-positive MG (AChR+Titin-MG, 58 cases). Clinical manifestations, therapeutic responses to immunotherapy, and follow-up information were analyzed. Results Of the 188 seropositive MG patients, 29 (15.4%) were positive for both AChR and LRP4 antibodies, and 58 (30.9%) were positive for both AChR and Titin antibodies. The mean disease onset ages in the three groups were 47.41 ± 7.0, 49.81 ± 9.2, and 48.11 ± 6.5 years, respectively. AChR+LRP4-MG showed female predominance (27.6% were males and 72.4% were females), with mild overall clinical symptoms. The AChR+Titin-MG group showed shorter times for conversion to generalized MG (5.14 ± 0.0 months) than the AChR-MG group (11.69 ± 0.0 months) and the AChR+LRP4-MG group (13.08 ± 0.5 months; P < 0.001 in both cases). Furthermore, AChR+Titin-MG group had increased bulbar dysfunction, higher incidences of thymoma (32.8 vs. 19.8% and 3.4%, P=0.035), more severe quantitative MG scores, as assessed by both QMG scores [15.5 (11.75–22.5) vs. 13 (8–19), P = 0.005; and 9 (6–14) P < 0.001], and MG-ADL scores [10 (8–13) vs. 8 (5–13), P = 0.018; and 6 (4–8), P < 0.001]. Treatment for AChR+Titin-MG was largely dependent on corticosteroids and immunosuppressive agents (56.7 vs. 19.2% and 16.7%, p = 0.028). The rates of achieving s(MMS) or better within 2 years following immunotherapy in the three groups were 51.5, 62.1, and 51.7%, respectively (P = 0.581). Conclusion Clinical symptoms of anti-AChR positive MG combined with Titin antibody were more severe and progressed faster than those in the AChR + LRP4 and AChR groups. Regardless of antibody status, all patients responded well to immunotherapy and had relatively good prognoses.
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Affiliation(s)
- Yuping Chen
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
| | - Xiaoyong Tao
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
| | - Yan Wang
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
| | - Shengjie Xu
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
| | - Yanhua Yang
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
| | - Jinming Han
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Jinming Han
| | - Feng Qiu
- Senior Department of Neurology, The First Medical Center of PLA General Hospital, Beijing, China
- *Correspondence: Feng Qiu
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LRP4-IgG service line testing in seronegative myasthenia gravis and controls. J Neuroimmunol 2022; 368:577895. [DOI: 10.1016/j.jneuroim.2022.577895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/25/2022] [Accepted: 05/14/2022] [Indexed: 11/13/2022]
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Veltsista D, Kefalopoulou Z, Tzartos J, Chroni E. Autoantibody profile in myasthenia gravis patients with a refractory phase. Muscle Nerve 2022; 65:607-611. [PMID: 35195920 DOI: 10.1002/mus.27521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION A subgroup of myasthenia gravis (MG) patients fails to respond adequately to recommended treatments, a condition referred to as refractory MG. During the refractory phase patients experience persistent debilitating symptoms with potential life-threatening events or inability to reduce immunosuppressant dosages and minimize long-term toxicities. METHODS We conducted a retrospective single-centre study of 113 MG patients to investigate the autoantibody profile and clinical characteristics of refractory MG patients, compared to non-refractory patients, based on predefined criteria. RESULTS Fifteen patients (13.3%) were classified as refractory. Double seronegative MG (DSNMG), without detectable nicotinic acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies, was identified in 6 refractory patients, significantly higher than those with non-refractory MG (40% vs 16.3%, p=0.031). None of the refractory patients had MuSK antibodies. Patients in the refractory group more frequently had an earlier disease onset, thymic pathology and thymectomy (all p-values ≤0.03). DISCUSSION In this study, patients with refractory MG were more likely than those with non-refractory MG to be DSN; and refractory DSNMG patients had worse MGFA classes in their recent visit compared to anti-AChR positive refractory patients. Refractory DSNMG patients may represent a distinct group that requires more individualized and targeted treatment approaches. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Dimitra Veltsista
- Neuromuscular Center, Department of Neurology, University of Patras, Rio, Patras, Greece
| | - Zinovia Kefalopoulou
- Neuromuscular Center, Department of Neurology, University of Patras, Rio, Patras, Greece
| | - John Tzartos
- 2nd Department of Neurology, School of Medicine, National and Kapodistrian University of Athens, "Attikon" University Hospital, Rimini 1, Chaidari, Athens, Greece.,Tzartos NeuroDiagnostics, Eslin street 3, 115 23, Athens, Greece
| | - Elisabeth Chroni
- Neuromuscular Center, Department of Neurology, University of Patras, Rio, Patras, Greece
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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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Wang S, Yang H, Guo R, Wang L, Zhang Y, Lv J, Zhao X, Zhang J, Fang H, Zhang Q, Zhang Y, Yang J, Cui X, Gao P, Chang T, Gao F. Antibodies to Full-Length Agrin Protein in Chinese Patients With Myasthenia Gravis. Front Immunol 2021; 12:753247. [PMID: 34956185 PMCID: PMC8692888 DOI: 10.3389/fimmu.2021.753247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
This study aimed to establish a cell-based assay (CBA) for the detection of agrin antibodies (Agrin-Ab) to explore the clinical features of agrin antibody-positive Chinese patients with myasthenia gravis (Agrin-MG). We developed a CBA based on the human full-length agrin protein expressed in HEK293T cells for the reliable and efficient detection of Agrin-Ab. Clinical data and serum samples were collected from 1948 MG patients in 26 provinces in China. The demographic and clinical features of Agrin-MG patients were compared with those of other MG patient subsets. Eighteen Agrin-MG cases were identified from 1948 MG patients. Nine patients were Agrin-Ab positive, and nine were AChR-Ab and Agrin-Ab double-positive (Agrin/AChR-MG). Eleven (61.11%) patients were males older than 40 years of age. The initial symptom in 13 (81.25%) cases was ocular weakness. Occasionally, the initial symptom was limb-girdle weakness (two cases) or bulbar muscle weakness (one case). Agrin-MG patients demonstrated slight improvement following treatment with either acetylcholinesterase inhibitor or prednisone; however, the combination of the two drugs could effectively relieve MG symptoms. In China, Agrin-MG demonstrated seropositivity rates of 0.92%. These patients were commonly middle-aged or elderly men. The patients usually presented weakness in the ocular, bulbar, and limb muscles, which may be combined with thymoma. These patients have more severe diseases, although the combination of pyridostigmine and prednisone was usually effective in relieving symptoms.
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Affiliation(s)
- Shumin Wang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Haonan Yang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,BGI College, Zhengzhou University, Zhengzhou, China
| | - Rongjing Guo
- Department of Neurology, Tangdu Hospital, The Air Force Medical University, Xi'an, China
| | - Lulu Wang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China.,Department of Neurology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yingna Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jie Lv
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Xue Zhao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Jing Zhang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Hua Fang
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Qingyong Zhang
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yunke Zhang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of Traditional Chinese Medicine (TCM), Zhengzhou, China
| | - Junhong Yang
- Department of Encephalopathy, First Affiliated Hospital of Henan University of Traditional Chinese Medicine (TCM), Zhengzhou, China
| | - Xinzheng Cui
- Myasthenia Gravis Comprehensive Diagnosis and Treatment Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Peiyang Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Ting Chang
- Department of Neurology, Tangdu Hospital, The Air Force Medical University, Xi'an, China
| | - Feng Gao
- Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
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Moodley K, Bill PLA, Patel VB. A Comparison of Clinical, Electro-Diagnostic, Laboratory, and Treatment Outcome Differences in a Cohort of HIV-Infected and HIV-Uninfected Patients With Myasthenia Gravis. Front Neurol 2021; 12:738813. [PMID: 34721269 PMCID: PMC8553930 DOI: 10.3389/fneur.2021.738813] [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: 07/09/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
There is limited literature comparing the clinical parameters and treatment outcomes in HIV-infected and HIV-uninfected myasthenia gravis (MG) patients. The aim of the study was to investigate the clinical differences and treatment outcomes in the two categories of patients, particularly the safe use of immunosuppressive therapy in immunocompromised patients. The study was a retrospective analysis of medical records of MG patients from the neuromuscular unit at Inkosi Albert Luthuli Central Hospital in Kwa-Zulu Natal between 2003 and 2019. One hundred and seventy-eight (178) patients fulfilled the clinical criteria for MG. Twenty-four (13.4%) were HIV-infected and 154 (86.5%) were HIV-uninfected. There were 116 (65%) females, median 45 years, (IQR 40–62), 90 (50.5%) black African, 66 (37%) Indian, 20 (11.2%) white, and 2 (1.1%) of mixed ancestry. In the HIV-infected cohort, 20 (87%) had generalized MG, 12 (50%) bulbar, and 14 (60.9%) respiratory onset MG, 12 (50%) presented with MG Foundation of America (MGFA) class five diseases at diagnosis, six (25%) presented with MG crisis during the 5-year follow-up. Thirteen (54%) of the HIV-infected group required rescue therapy using (plasma exchange or IV immunoglobulin) combined with pulse cyclophosphamide compared with 17 (11%) in the HIV-uninfected cohort, respectively. At 5 years, 8 (33%) of the HIV-infected group remained refractory to treatment compared with 10 (6.5%) HIV-uninfected cohort, respectively. No adverse events were documented in HIV-infected patients receiving combination rescue therapy (PLEX or IVIG combined with IV cyclophosphamide). In conclusion HIV-infected MG patients are more likely to require combination rescue therapy with PE/IVIG and IV cyclophosphamide compared with those who were HIV-uninfected. No side effects were documented in the HIV-infected group receiving the above therapy.
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Affiliation(s)
- Kaminie Moodley
- Department of Neurology, University of KwaZulu-Natal, Durban, South Africa
| | - Pierre L A Bill
- Department of Neurology, University of KwaZulu-Natal, Durban, South Africa
| | - Vinod B Patel
- Department of Neurology, University of KwaZulu-Natal, Durban, South Africa
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Yu Z, Zhang M, Jing H, Chen P, Cao R, Pan J, Luo B, Yu Y, Quarles BM, Xiong W, Rivner MH, Mei L. Characterization of LRP4/Agrin Antibodies From a Patient With Myasthenia Gravis. Neurology 2021; 97:e975-e987. [PMID: 34233932 PMCID: PMC8448554 DOI: 10.1212/wnl.0000000000012463] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/22/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVE To determine whether human anti-LRP4/agrin antibodies are pathogenic in mice and to investigate underpinning pathogenic mechanisms. METHODS Immunoglobulin (Ig) was purified from a patient with myasthenia gravis (MG) with anti-LRP4/agrin antibodies and transferred to mice. Mice were characterized for body weight, muscle strength, twitch and tetanic force, neuromuscular junction (NMJ) functions including compound muscle action potential (CMAP) and endplate potentials, and NMJ structure. Effects of the antibodies on agrin-elicited muscle-specific tyrosine kinase (MuSK) activation and AChR clustering were studied and the epitopes of these antibodies were identified. RESULTS Patient Ig-injected mice had MG symptoms, including weight loss and muscle weakness. Decreased CMAPs, reduced twitch and tetanus force, compromised neuromuscular transmission, and NMJ fragmentation and distortion were detected in patient Ig-injected mice. Patient Ig inhibited agrin-elicited MuSK activation and AChR clustering. The patient Ig recognized the β3 domain of LRP4 and the C-terminus of agrin and reduced agrin-enhanced LRP4-MuSK interaction. DISCUSSION Anti-LRP4/agrin antibodies in the patient with MG is pathogenic. It impairs the NMJ by interrupting agrin-dependent LRP4-MuSK interaction.
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Affiliation(s)
- Zheng Yu
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Meiying Zhang
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Hongyang Jing
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Peng Chen
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Rangjuan Cao
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Jinxiu Pan
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Bin Luo
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Yue Yu
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Brandy M Quarles
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Wencheng Xiong
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH
| | - Michael H Rivner
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH.
| | - Lin Mei
- From the Department of Neurosciences (Z.Y., M.Z., H.J., P.C., R.C., J.P., B.L., W.X., L.M.), School of Medicine, Case Western Reserve University, Cleveland; Beachwood High School (Y.Y.), OH; Department of Neurology (B.M.Q., M.H.R.), Augusta University, GA; and Louis Stokes Cleveland Veterans Affairs Medical Center (W.X., L.M.), OH.
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Topaloudi A, Zagoriti Z, Flint AC, Martinez MB, Yang Z, Tsetsos F, Christou YP, Lagoumintzis G, Yannaki E, Zamba-Papanicolaou E, Tzartos J, Tsekmekidou X, Kotsa K, Maltezos E, Papanas N, Papazoglou D, Passadakis P, Roumeliotis A, Roumeliotis S, Theodoridis M, Thodis E, Panagoutsos S, Yovos J, Stamatoyannopoulos J, Poulas K, Kleopa K, Tzartos S, Georgitsi M, Paschou P. Myasthenia gravis genome-wide association study implicates AGRN as a risk locus. J Med Genet 2021; 59:801-809. [PMID: 34400559 DOI: 10.1136/jmedgenet-2021-107953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/20/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND Myasthenia gravis (MG) is a rare autoimmune disorder affecting the neuromuscular junction (NMJ). Here, we investigate the genetic architecture of MG via a genome-wide association study (GWAS) of the largest MG data set analysed to date. METHODS We performed GWAS meta-analysis integrating three different data sets (total of 1401 cases and 3508 controls). We carried out human leucocyte antigen (HLA) fine-mapping, gene-based and tissue enrichment analyses and investigated genetic correlation with 13 other autoimmune disorders as well as pleiotropy across MG and correlated disorders. RESULTS We confirmed the previously reported MG association with TNFRSF11A (rs4369774; p=1.09×10-13, OR=1.4). Furthermore, gene-based analysis revealed AGRN as a novel MG susceptibility gene. HLA fine-mapping pointed to two independent MG loci: HLA-DRB1 and HLA-B. MG onset-specific analysis reveals differences in the genetic architecture of early-onset MG (EOMG) versus late-onset MG (LOMG). Furthermore, we find MG to be genetically correlated with type 1 diabetes (T1D), rheumatoid arthritis (RA), late-onset vitiligo and autoimmune thyroid disease (ATD). Cross-disorder meta-analysis reveals multiple risk loci that appear pleiotropic across MG and correlated disorders. DISCUSSION Our gene-based analysis identifies AGRN as a novel MG susceptibility gene, implicating for the first time a locus encoding a protein (agrin) that is directly relevant to NMJ activation. Mutations in AGRN have been found to underlie congenital myasthenic syndrome. Our results are also consistent with previous studies highlighting the role of HLA and TNFRSF11A in MG aetiology and the different risk genes in EOMG versus LOMG. Finally, we uncover the genetic correlation of MG with T1D, RA, ATD and late-onset vitiligo, pointing to shared underlying genetic mechanisms.
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Affiliation(s)
- Apostolia Topaloudi
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Zoi Zagoriti
- Department of Pharmacy, University of Patras, Rio, Greece
| | - Alyssa Camille Flint
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | | | - Zhiyu Yang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Fotis Tsetsos
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupoli, Greece
| | | | | | - Evangelia Yannaki
- Department of Hematology, George Papanicolaou Hospital, Thessaloniki, Greece
| | - Eleni Zamba-Papanicolaou
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Department of Neuroepidemiology and Centre for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | | | - Xanthippi Tsekmekidou
- Division of Endocrinology and Metabolism-Diabetes Center, 1st Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Kalliopi Kotsa
- Division of Endocrinology and Metabolism-Diabetes Center, 1st Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Efstratios Maltezos
- Diabetes Center, 2nd Department of Internal Medicine, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Nikolaos Papanas
- Diabetes Center, 2nd Department of Internal Medicine, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Dimitrios Papazoglou
- Diabetes Center, 2nd Department of Internal Medicine, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Ploumis Passadakis
- Department of Nephrology, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Athanasios Roumeliotis
- Division of Nephrology and Hypertension, 1st Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Stefanos Roumeliotis
- Division of Nephrology and Hypertension, 1st Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Marios Theodoridis
- Department of Nephrology, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Elias Thodis
- Department of Nephrology, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - Stylianos Panagoutsos
- Department of Nephrology, Alexandroupolis University General Hospital, Democritus University of Thrace, Alexandroupoli, Greece
| | - John Yovos
- Division of Endocrinology and Metabolism-Diabetes Center, 1st Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - John Stamatoyannopoulos
- Departments of Medicine and Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Kleopas Kleopa
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus.,Department of Neuroscience and Centre for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Socrates Tzartos
- Department of Pharmacy, University of Patras, Rio, Greece.,Hellenic Pasteur Institute, Athens, Greece
| | - Marianthi Georgitsi
- 1st Laboratory of Medical Biology-Genetics, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Peristera Paschou
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
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31
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Wang JY, Roehrl MW, Roehrl VB, Roehrl MH. A Master Autoantigen-ome Links Alternative Splicing, Female Predilection, and COVID-19 to Autoimmune Diseases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.07.30.454526. [PMID: 34373855 PMCID: PMC8351778 DOI: 10.1101/2021.07.30.454526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic and debilitating autoimmune sequelae pose a grave concern for the post-COVID-19 pandemic era. Based on our discovery that the glycosaminoglycan dermatan sulfate (DS) displays peculiar affinity to apoptotic cells and autoantigens (autoAgs) and that DS-autoAg complexes cooperatively stimulate autoreactive B1 cell responses, we compiled a database of 751 candidate autoAgs from six human cell types. At least 657 of these have been found to be affected by SARS-CoV-2 infection based on currently available multi-omic COVID data, and at least 400 are confirmed targets of autoantibodies in a wide array of autoimmune diseases and cancer. The autoantigen-ome is significantly associated with various processes in viral infections, such as translation, protein processing, and vesicle transport. Interestingly, the coding genes of autoAgs predominantly contain multiple exons with many possible alternative splicing variants, short transcripts, and short UTR lengths. These observations and the finding that numerous autoAgs involved in RNA-splicing showed altered expression in viral infections suggest that viruses exploit alternative splicing to reprogram host cell machinery to ensure viral replication and survival. While each cell type gives rise to a unique pool of autoAgs, 39 common autoAgs associated with cell stress and apoptosis were identified from all six cell types, with several being known markers of systemic autoimmune diseases. In particular, the common autoAg UBA1 that catalyzes the first step in ubiquitination is encoded by an X-chromosome escape gene. Given its essential function in apoptotic cell clearance and that X-inactivation escape tends to increase with aging, UBA1 dysfunction can therefore predispose aging women to autoimmune disorders. In summary, we propose a model of how viral infections lead to extensive molecular alterations and host cell death, autoimmune responses facilitated by autoAg-DS complexes, and ultimately autoimmune diseases. Overall, this master autoantigen-ome provides a molecular guide for investigating the myriad of autoimmune sequalae to COVID-19 and clues to the rare but reported adverse effects of the currently available COVID vaccines.
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Affiliation(s)
| | | | | | - Michael H. Roehrl
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, USA
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32
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Lee I, Sanders D. Rethinking the utility of acetylcholine receptor antibody titer as a pharmacodynamic biomarker for myasthenia gravis. Muscle Nerve 2021; 64:385-387. [PMID: 34287983 DOI: 10.1002/mus.27381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/09/2021] [Accepted: 07/18/2021] [Indexed: 11/06/2022]
Affiliation(s)
- Ikjae Lee
- The Neurological Institute of New York, Columbia University, New York, New York, USA
| | - Donald Sanders
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, USA
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33
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Lisak RP. Antibodies to LRP4 and Agrin Are Pathogenic in Myasthenia Gravis: At the Junction Where It Happens. Neurology 2021; 97:463-464. [PMID: 34233934 DOI: 10.1212/wnl.0000000000012471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Robert P Lisak
- From the Wayne State University School of Medicine, Detroit, MI.
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34
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Evoli A, Spagni G, Monte G, Damato V. Heterogeneity in myasthenia gravis: considerations for disease management. Expert Rev Clin Immunol 2021; 17:761-771. [PMID: 34043932 DOI: 10.1080/1744666x.2021.1936500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: Myasthenia gravis is a rare disease of the neuromuscular junction and a prototype of B cell-driven immunopathology. Pathogenic antibodies target post-synaptic transmembrane proteins, most commonly the nicotinic acetylcholine receptor and the muscle-specific tyrosine kinase, inducing end-plate alterations and neuromuscular transmission impairment. Several clinical subtypes are distinct on the basis of associated antibodies, age at symptom onset, thymus pathology, genetic factors, and weakness distribution. These subtypes have distinct pathogenesis that can account for different responses to treatment. Conventional therapy is based on the use of symptomatic agents, steroids, immunosuppressants and thymectomy. Of late, biologics have emerged as effective therapeutic options.Areas covered: In this review, we will discuss the management of myasthenia gravis in relation to its phenotypic and biological heterogeneity, in the light of recent advances in the disease immunopathology, new diagnostic tools, and results of clinical trialsExpert opinion: Clinical management is shaped on serological subtype, and patient age at onset, lifestyle and comorbidities, balancing therapeutic needs and safety. Although reliable biomarkers predictive of clinical and biologic outcome are still lacking, recent developments promise a more effective and safe treatment. Disease subtyping according to serological testing and immunopathology is crucial to the appropriateness of clinical management.
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Affiliation(s)
- Amelia Evoli
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy.,Unità Operativa Complessa di Neurologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - Gregorio Spagni
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Gabriele Monte
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
| | - Valentina Damato
- Dipartimento di Neuroscienze, Università Cattolica Del Sacro Cuore, Rome, Italy
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Myasthenia Gravis: Epidemiology, Pathophysiology and Clinical Manifestations. J Clin Med 2021; 10:jcm10112235. [PMID: 34064035 PMCID: PMC8196750 DOI: 10.3390/jcm10112235] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/17/2021] [Accepted: 05/17/2021] [Indexed: 12/12/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune neurological disorder characterized by defective transmission at the neuromuscular junction. The incidence of the disease is 4.1 to 30 cases per million person-years, and the prevalence rate ranges from 150 to 200 cases per million. MG is considered a classic example of antibody-mediated autoimmune disease. Most patients with MG have autoantibodies against the acetylcholine receptors (AChRs). Less commonly identified autoantibodies include those targeted to muscle-specific kinase (MuSK), low-density lipoprotein receptor-related protein 4 (Lrp4), and agrin. These autoantibodies disrupt cholinergic transmission between nerve terminals and muscle fibers by causing downregulation, destruction, functional blocking of AChRs, or disrupting the clustering of AChRs in the postsynaptic membrane. The core clinical manifestation of MG is fatigable muscle weakness, which may affect ocular, bulbar, respiratory and limb muscles. Clinical manifestations vary according to the type of autoantibody, and whether a thymoma is present.
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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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Doppler K, Hemprich A, Haarmann A, Brecht I, Franke M, Kröger S, Villmann C, Sommer C. Autoantibodies to cortactin and agrin in sera of patients with myasthenia gravis. J Neuroimmunol 2021; 356:577588. [PMID: 33962172 DOI: 10.1016/j.jneuroim.2021.577588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/13/2021] [Accepted: 04/22/2021] [Indexed: 12/13/2022]
Abstract
Autoantibodies against agrin and cortactin have been described in patients with myasthenia gravis. To further validate and characterize these autoantibodies, sera and/or plasma exchange material of 135 patients with myasthenia gravis were screened for anti-agrin or anti-cortactin autoantibodies. Autoantibodies against cortactin were detected in three patients and two controls and could be confirmed by cell-based assays using cortactin-transfected human embryonic kidney cells in both controls and one patient, but were not detectable in follow-up sera of the three patients. We did not detect any autoantibodies against agrin. The clinical phenotype of anti-cortactin-positive patients varied, arguing against a relevant pathogenic role.
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Affiliation(s)
- Kathrin Doppler
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany.
| | - Antonia Hemprich
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany.
| | - Axel Haarmann
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany.
| | - Isabel Brecht
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | - Maximilian Franke
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany.
| | - Stephan Kröger
- Ludwig-Maximilians-Universität München, Department of Physiological Genomics, BioMedical Center, Großhaderner Str. 9, 82152 Planegg-Martinsried, Germany.
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany.
| | - Claudia Sommer
- University Hospital Würzburg, Department of Neurology, Josef-Schneider-Str. 11, 97080 Würzburg, Germany.
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Wang JY, Zhang W, Roehrl MW, Roehrl VB, Roehrl MH. An autoantigen profile of human A549 lung cells reveals viral and host etiologic molecular attributes of autoimmunity in COVID-19. J Autoimmun 2021; 120:102644. [PMID: 33971585 PMCID: PMC8075847 DOI: 10.1016/j.jaut.2021.102644] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 04/08/2021] [Indexed: 12/13/2022]
Abstract
We aim to establish a comprehensive COVID-19 autoantigen atlas in order to understand autoimmune diseases caused by SARS-CoV-2 infection. Based on the unique affinity between dermatan sulfate and autoantigens, we identified 348 proteins from human lung A549 cells, of which 198 are known targets of autoantibodies. Comparison with current COVID data identified 291 proteins that are altered at protein or transcript level in SARS-CoV-2 infection, with 191 being known autoantigens. These known and putative autoantigens are significantly associated with viral replication and trafficking processes, including gene expression, ribonucleoprotein biogenesis, mRNA metabolism, translation, vesicle and vesicle-mediated transport, and apoptosis. They are also associated with cytoskeleton, platelet degranulation, IL-12 signaling, and smooth muscle contraction. Host proteins that interact with and that are perturbed by viral proteins are a major source of autoantigens. Orf3 induces the largest number of protein alterations, Orf9 affects the mitochondrial ribosome, and they and E, M, N, and Nsp proteins affect protein localization to membrane, immune responses, and apoptosis. Phosphorylation and ubiquitination alterations by viral infection define major molecular changes in autoantigen origination. This study provides a large list of autoantigens as well as new targets for future investigation, e.g., UBA1, UCHL1, USP7, CDK11A, PRKDC, PLD3, PSAT1, RAB1A, SLC2A1, platelet activating factor acetylhydrolase, and mitochondrial ribosomal proteins. This study illustrates how viral infection can modify host cellular proteins extensively, yield diverse autoantigens, and trigger a myriad of autoimmune sequelae. Our work provides a rich resource for studies into “long COVID” and related autoimmune sequelae.
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Affiliation(s)
| | - Wei Zhang
- Department of Gastroenterology, Affiliated Hospital of Guizhou Medical University, Guizhou, China
| | | | | | - Michael H Roehrl
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, USA.
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Abstract
Discovery and characterization of serologic biomarkers has revolutionized the diagnostic framework of systemic and paraneoplastic autoimmune neuro-ophthalmic diseases. Expanding recognition of the multiple ocular and visual manifestations of these conditions highlights the important role of the referring provider in identifying potential cases. Increasing ease of access to serologic testing also enables these practitioners to initiate the diagnostic work-up in suspected cases. We aimed to provide an update on the current knowledge surrounding and use of relevant autoimmune biomarkers by correlating specific clinical neuro-ophthalmic manifestations with autoantibody biomarkers. The utility of select biomarkers for myasthenia gravis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein-IgG-associated disorder, opsoclonus-myoclonus syndrome, anti-collapsin-response mediator protein-5 optic neuropathy, and glial fibrillary acidic protein-IgG-associated disease are discussed with particular focus on the clinical contexts in which to consider testing.
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Affiliation(s)
- Devon A Cohen
- Department of Ophthalmology, Harvard Medical School, Boston.,Department of Ophthalmology, Massachusetts Eye and Ear, Boston
| | - Ryan Gise
- Department of Ophthalmology, Harvard Medical School, Boston.,Department of Ophthalmology, Massachusetts Eye and Ear, Boston.,Department of Ophthalmology, Boston Children's Hospital, Boston
| | - Eric D Gaier
- Department of Ophthalmology, Harvard Medical School, Boston.,Department of Ophthalmology, Massachusetts Eye and Ear, Boston.,Department of Ophthalmology, Boston Children's Hospital, Boston.,Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge
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40
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Abstract
ABSTRACT This update covers recommendations for myasthenia gravis (MG) in patients with coronavirus 2019 disease as well as reports of the clinical features of patients with MG and coronavirus 2019. Updated advisory committee recommendations for the use of thymectomy in generalized MG are also provided. Other MG topics include lipoprotein receptor-4 and agrin antibody associations, factors influencing conversion of ocular to generalized MG, the use of rituximab for more recent onset disease, immunoglobulins for maintenance therapy, and fatigue and depression.
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Affiliation(s)
- David Lacomis
- Departments of Neurology and Pathology (Neuropathology), University of Pittsburgh School of Medicine, Pittsburgh, PA; and
| | - Gil I Wolfe
- Department of Neurology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences/SUNY, Buffalo, NY
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41
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Wang JY, Zhang W, Roehrl MW, Roehrl VB, Roehrl MH. An Autoantigen Profile of Human A549 Lung Cells Reveals Viral and Host Etiologic Molecular Attributes of Autoimmunity in COVID-19. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.02.21.432171. [PMID: 33655248 PMCID: PMC7924268 DOI: 10.1101/2021.02.21.432171] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We aim to establish a comprehensive COVID-19 autoantigen atlas in order to understand autoimmune diseases caused by SARS-CoV-2 infection. Based on the unique affinity between dermatan sulfate and autoantigens, we identified 348 proteins from human lung A549 cells, of which 198 are known targets of autoantibodies. Comparison with current COVID data identified 291 proteins that are altered at protein or transcript level in SARS-CoV-2 infection, with 191 being known autoantigens. These known and putative autoantigens are significantly associated with viral replication and trafficking processes, including gene expression, ribonucleoprotein biogenesis, mRNA metabolism, translation, vesicle and vesicle-mediated transport, and apoptosis. They are also associated with cytoskeleton, platelet degranulation, IL-12 signaling, and smooth muscle contraction. Host proteins that interact with and that are perturbed by viral proteins are a major source of autoantigens. Orf3 induces the largest number of protein alterations, Orf9 affects the mitochondrial ribosome, and they and E, M, N, and Nsp proteins affect protein localization to membrane, immune responses, and apoptosis. Phosphorylation and ubiquitination alterations by viral infection define major molecular changes in autoantigen origination. This study provides a large list of autoantigens as well as new targets for future investigation, e.g., UBA1, UCHL1, USP7, CDK11A, PRKDC, PLD3, PSAT1, RAB1A, SLC2A1, platelet activating factor acetylhydrolase, and mitochondrial ribosomal proteins. This study illustrates how viral infection can modify host cellular proteins extensively, yield diverse autoantigens, and trigger a myriad of autoimmune sequelae.
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Affiliation(s)
| | - Wei Zhang
- Department of Gastroenterology, Affiliated Hospital of Guizhou Medical University, Guizhou, China
| | | | | | - Michael H. Roehrl
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, USA
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, USA
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42
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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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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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