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Abstract
PURPOSE OF REVIEW This article provides an update on the most recent advances in diagnostic procedures and therapeutic approaches for myasthenia gravis, spanning from autoantibody and neuroelectrophysiological tests as diagnostic tools, to innovative and promising treatments based on biological drugs. RECENT FINDINGS Novel studies performed by cell-based assays (CBAs) indicate an improvement in the chance of identifying serum autoantibodies in myasthenic patients. Clinical trials on the use of biological drugs were recently concluded, providing important data on safety and efficacy of eculizumab, efgartigimod and amifampridine phosphate: the first, a complement blocker, showed long-term safety and efficacy in acetylcholine receptor (AChR)-positive myasthenic patients with refractory generalized disease; the second, the neonatal Fc receptor blocker, was well tolerated and clinically effective in both AChR-specific and muscle-specific kinase receptor (MuSK)-positive patients; the third, a blocker of presynaptic potassium channels, was found to be well tolerated and effective in MuSK-positive patients. SUMMARY CBAs can lead to a significant reduction of seronegative patients, improving myasthenia gravis diagnostic process. New biological drugs offer innovative approaches to treat myasthenic patients with generalized disease, promising to change the paradigm of treatment and to significantly enhance therapeutic success within a precision medicine framework.
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102
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Yang H, Liu D, Hong X, Sun H, Zheng Y, Yang B, Wang W. Effectiveness and safety of thymectomy plus prednisone compares with prednisone monotherapy for the treatment of non-thymomatous Myasthenia Gravis: Protocol for a systematic review. Medicine (Baltimore) 2020; 99:e20832. [PMID: 32569233 PMCID: PMC7310738 DOI: 10.1097/md.0000000000020832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The pathogenesis of myasthenia gravis (MG) has strong connection with thymic abnormalities. Thymic hyperplasia or thymoma can be found with most patients. Thymectomy is currently one of the regular treatment in clinic, which is, however, still controversial for non-thymomatous MG. This research will assess the effectiveness and safety of thymectomy plus prednisone compared to prednisone monotherapy for the treatment of non-thymomatous MG systematically. METHODS According to eligibility and ineligibility criteria, 8 databases, including PubMed, EMBASE, the Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan-fang Database, Chinese Biomedical Literature Database (CBM), China Science and Technology Journal Database (CSTJ), will be searched to gather the up-to-standard articles from September 2000 to September 2025. Inclusion criteria are as follows: randomized controlled trials of thymectomy plus prednisone for the treatment of non-thymomatous MG. The quantitative myasthenia gravis score (QMG) and the dose of prednisone required will be accepted as the main outcomes. Data synthesis, subgroup analysis, sensitivity analysis, and meta-regression analysis will be conducted using RevMan 5.3 software. We will use Egger or Begg test to evaluate symmetry on a funnel plot which is made to assess reporting bias, and use trial sequential analysis (TSA) to exclude the probability of false positives. RESULTS This systematic review will measure the QMG and the dose of prednisone required, the myasthenia gravis activities of daily living scale scores (MG-ADL), treatment-associated complications, incidence of myasthenic crisis and other aspects to comprehensively assess the clinical benefits of thymectomy plus prednisone for MG patients without thymoma. CONCLUSION The conclusion of this study will achieve convincing evidence to evaluate the effectiveness and safety of thymectomy plus prednisone for the treatment of non-thymomatous MG. PROSPERO REGISTRATION NUMBER CRD 42020167735.
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Affiliation(s)
- Huili Yang
- The Second Clinical Medical College of Guangzhou University of Chinese Medicine
- Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine
- Department of Graduate School, Guangzhou University of Chinese Medicine
| | - Dandan Liu
- Department of Graduate School, Guangzhou University of Chinese Medicine
- General Hospital of Southern Theater Command of PLA, Guangzhou
| | - Xinxin Hong
- The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen
| | - Haonan Sun
- Traditional Chinese Medicine Hospital, Xinjiang Medical University, Urumqi, China
| | - Yu Zheng
- The Second Clinical Medical College of Guangzhou University of Chinese Medicine
- Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine
| | - Biying Yang
- The Second Clinical Medical College of Guangzhou University of Chinese Medicine
- Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine
| | - Wanshun Wang
- Department of Graduate School, Guangzhou University of Chinese Medicine
- General Hospital of Southern Theater Command of PLA, Guangzhou
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103
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Nguyen T, Phan CL, Supsupin E, Sheikh K. Therapeutic and Diagnostic Challenges in Myasthenia Gravis. Neurol Clin 2020; 38:577-590. [PMID: 32703470 DOI: 10.1016/j.ncl.2020.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
"Myasthenia gravis (MG) is the most common autoimmune neuromuscular disorder. This article highlights several cases that the practicing neurologist may encounter in the treatment of MG. Diagnostic uncertainty continues to be an issue in patients who are seronegative to the 2 most common antibodies, acetylcholine receptor and muscle-specific tyrosine kinase (MuSK). Specific populations of patients with MG including MuSK MG, thymomatous MG, refractory MG, and pregnant women also require special consideration. This article reviews specific cases and an update on current management."
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Affiliation(s)
- Thy Nguyen
- Department of Neurology, McGovern Medical School, University of Texas Houston Health Science Center, 6431 Fannin Street, MSE R 462, Houston, TX 77030, USA.
| | - Cecile L Phan
- 7-125 Clinical Sciences Building, 2J2.00 WC Mackenzie Health Sciences Centre, 8440 112 St. NW, Edmonton, Alberta, T6G 2R7 Canada
| | - Emilio Supsupin
- Department of Diagnostic and Interventional Imaging, 6431 Fannin St. 2.103 MSMB, Houston, Texas 77030, USA
| | - Kazim Sheikh
- Department of Neurology, McGovern Medical School, University of Texas Houston Health Science Center, 6431 Fannin street, MSE R454 Houston, TX 77030, USA
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104
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McPherson T, Aban I, Duda PW, Farzaneh-Far R, Wolfe GI, Kaminski HJ, Cutter G, Lee I. Correlation of Quantitative Myasthenia Gravis and Myasthenia Gravis Activities of Daily Living scales in the MGTX study. Muscle Nerve 2020; 62:261-266. [PMID: 32369631 PMCID: PMC7496446 DOI: 10.1002/mus.26910] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/23/2020] [Accepted: 04/29/2020] [Indexed: 01/19/2023]
Abstract
Introduction Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Activities of Daily Living (MG‐ADL) scales were compared using the data from the Thymectomy Trial in Non‐Thymomatous Myasthenia Gravis Patients Receiving Prednisone Therapy (MGTX) study. Methods Correlation between QMG and MG‐ADL raw and change‐from‐baseline scores was calculated every 3 months for 60 months based on treatment groups and minimal manifestation status (MMS). Results QMG and MG‐ADL change‐from‐baseline scores correlated significantly, with increasing strength of correlation over time, in both treatment groups. QMG and MG‐ADL raw scores correlated significantly in both treatment groups, with increasing correlation only in the prednisone‐alone group. Correlation between raw scores was weaker in patients who were in MMS, demonstrating a “floor effect” on the MG‐ADL scale. Raw QMG scores could be modeled assuming a normal distribution, whereas raw MG‐ADL scores could not be modeled this way. Discussion The floor effect and skewed distribution of the MG‐ADL measure should be taken into account in the design of myasthenia gravis clinical trials.
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Affiliation(s)
- Tarrant McPherson
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Inmaculada Aban
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | - Gil I Wolfe
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo/State University of New York, Buffalo, New York
| | - Henry J Kaminski
- Department of Neurology, School of Medicine and Health Sciences, George Washington University, Washington, DC
| | - Gary Cutter
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ikjae Lee
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
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105
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Habib AA, Ahmadi Jazi G, Mozaffar T. Update on immune-mediated therapies for myasthenia gravis. Muscle Nerve 2020; 62:579-592. [PMID: 32462710 DOI: 10.1002/mus.26919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/04/2020] [Accepted: 05/07/2020] [Indexed: 11/05/2022]
Abstract
With the exception of thymectomy, immune modulatory treatment strategies and clinical trials in myasthenia gravis over the past 50 y were mainly borrowed from experience in other nonneurologic autoimmune disorders. The current experimental therapy paradigm has significantly changed such that treatments directed against the pathological mechanisms specific to myasthenia gravis are being tested, in some cases as the initial disease indication. Key advances have been made in three areas: (i) the expanded role and long-term benefits of thymectomy, (ii) complement inhibition to prevent antibody-mediated postsynaptic membrane damage, and (iii) neonatal Fc receptor (FcRn) inhibition as in vivo apheresis, removing pathogenic antibodies. Herein, we discuss these advances and the potential for these newer therapies to significantly influence the current treatment paradigms. While these therapies provide exciting new options with rapid efficacy, there are anticipated challenges to their use, especially in terms of a dramatic increase in cost of care for some patients with myasthenia gravis.
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Affiliation(s)
- Ali Aamer Habib
- Department of Neurology, University of California, Irvine, California
| | | | - Tahseen Mozaffar
- Department of Neurology, University of California, Irvine, California.,Department of Orthopedic Surgery, University of California, Irvine, California.,Departments of Pathology and Laboratory Medicine, University of California, Irvine, California
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106
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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107
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Fichtner ML, Jiang R, Bourke A, Nowak RJ, O'Connor KC. Autoimmune Pathology in Myasthenia Gravis Disease Subtypes Is Governed by Divergent Mechanisms of Immunopathology. Front Immunol 2020; 11:776. [PMID: 32547535 PMCID: PMC7274207 DOI: 10.3389/fimmu.2020.00776] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.
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Affiliation(s)
- Miriam L Fichtner
- Department of Neurology, School of Medicine, Yale University, New Haven, CT, United States.,Department of Immunobiology, School of Medicine, Yale University, New Haven, CT, United States
| | - Ruoyi Jiang
- Department of Immunobiology, School of Medicine, Yale University, New Haven, CT, United States
| | - Aoibh Bourke
- Trinity Hall, University of Cambridge, Cambridge, United Kingdom
| | - Richard J Nowak
- Department of Neurology, School of Medicine, Yale University, New Haven, CT, United States
| | - Kevin C O'Connor
- Department of Neurology, School of Medicine, Yale University, New Haven, CT, United States.,Department of Immunobiology, School of Medicine, Yale University, New Haven, CT, United States
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108
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Rashid MH, Yasir HKM, Piracha MU, Salman U, Yousaf H. Review Analysis on Thymectomy vs Conservative Medical Management in Myasthenia Gravis. Cureus 2020; 12:e7425. [PMID: 32337145 PMCID: PMC7182154 DOI: 10.7759/cureus.7425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 03/26/2020] [Indexed: 11/05/2022] Open
Abstract
Myasthenia gravis (MG) is an acquired, rare autoimmune disease that occurs due to autoantibodies blocking neuromuscular transmission. Its pathophysiology involves production of antibodies against the nicotinic acetylcholine receptors. Patients with negative anti-acetylcholine receptors (AChR) antibodies results are recognized as seronegative myasthenia gravis. In this review we tried to compare surgical and medical management of MG with each other to find out which is more effective. Different clinical trials and retrospective cohorts comparing these two parameters statistically were searched and studied. Remission rates in both medical and surgical management were compared. We found out that rates of remission were better in post thymectomy patients than patients on various medical treatment options including corticosteroids, immunosuppressants, intravenous immunoglobulins and acetylcholinesterase inhibitors alone. Hence thymectomy is studied to be the superior treatment option than other conservative medical management options alone.
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Affiliation(s)
- Muhammad Humayoun Rashid
- Neurology, Bakhtawar Amin Medical and Dental College, Multan, PAK
- Internal Medicine, Nishtar Medical University and Hospital, Multan, PAK
| | | | | | - Umer Salman
- Internal Medicine, City Hospital, Multan, PAK
| | - Hamza Yousaf
- Internal Medicine, Nishtar Medical University and Hospital, Multan, PAK
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109
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Gronseth GS, Barohn R, Narayanaswami P. Practice advisory: Thymectomy for myasthenia gravis (practice parameter update): Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology 2020; 94:705-709. [PMID: 32213645 DOI: 10.1212/wnl.0000000000009294] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/05/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To review updated evidence regarding the effectiveness of thymectomy for treating patients with myasthenia gravis (MG). METHODS The practice advisory panel performed a systematic review and developed practice recommendations using methods developed by the American Academy of Neurology. RESULTS One Class I study of patients younger than 65 years with nonthymomatous acetylcholine receptor antibody-positive (AChR ab+) generalized MG demonstrated better clinical outcomes in patients treated with oral prednisone and undergoing thymectomy compared with patients treated with prednisone alone, including an increased probability of attaining minimal manifestation status (no symptoms or functional limitations). CONCLUSION For patients with nonthymomatous AChR ab+ generalized MG, treatment with thymectomy plus prednisone is probably more effective than treatment with prednisone alone for increasing the chance of attaining minimal manifestation status (risk difference at 36 months, 20%; 95% confidence interval, 1.6%-37%; moderate confidence in the evidence). RECOMMENDATIONS Clinicians should discuss thymectomy treatment with patients with AChR ab+ generalized MG (Level B). Clinicians should counsel patients with AChR ab+ generalized MG considering minimally invasive thymectomy techniques that it is uncertain whether the benefit attained by extended transsternal thymectomy will also be attained by minimally invasive approaches (Level B).
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Affiliation(s)
- Gary S Gronseth
- From the Department of Neurology (G.S.G., R.B.), University of Kansas Medical Center, Kansas City; and Department of Neurology (P.N.), Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA
| | - Richard Barohn
- From the Department of Neurology (G.S.G., R.B.), University of Kansas Medical Center, Kansas City; and Department of Neurology (P.N.), Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA
| | - Pushpa Narayanaswami
- From the Department of Neurology (G.S.G., R.B.), University of Kansas Medical Center, Kansas City; and Department of Neurology (P.N.), Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA
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110
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Bortone F, Scandiffio L, Marcuzzo S, Bonanno S, Frangiamore R, Motta T, Antozzi C, Mantegazza R, Cavalcante P, Bernasconi P. miR-146a in Myasthenia Gravis Thymus Bridges Innate Immunity With Autoimmunity and Is Linked to Therapeutic Effects of Corticosteroids. Front Immunol 2020; 11:142. [PMID: 32210951 PMCID: PMC7075812 DOI: 10.3389/fimmu.2020.00142] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/20/2020] [Indexed: 12/17/2022] Open
Abstract
Toll-like receptor (TLR)-mediated innate immune responses are critically involved in the pathogenesis of myasthenia gravis (MG), an autoimmune disorder affecting neuromuscular junction mainly mediated by antiacetylcholine receptor antibodies. Considerable evidence indicate that uncontrolled TLR activation and chronic inflammation significantly contribute to hyperplastic changes and germinal center (GC) formation in the MG thymus, ultimately leading to autoantibody production and autoimmunity. miR-146a is a key modulator of innate immunity, whose dysregulation has been associated with autoimmune diseases. It acts as inhibitor of TLR pathways, mainly by targeting the nuclear factor kappa B (NF-κB) signaling transducers, interleukin 1 receptor associated kinase 1 (IRAK1) and tumor necrosis factor (TNF) receptor associated factor 6 (TRAF6); miR-146a is also able to target c-REL, inducible T-cell costimulator (ICOS), and Fas cell surface death receptor (FAS), known to regulate B-cell function and GC response. Herein, we investigated the miR-146a contribution to the intrathymic MG pathogenesis. By real-time PCR, we found that miR-146a expression was significantly downregulated in hyperplastic MG compared to control thymuses; contrariwise, IRAK1, TRAF6, c-REL, and ICOS messenger RNA (mRNA) levels were upregulated and negatively correlated with miR-146a levels. Microdissection experiments revealed that miR-146a deficiency in hyperplastic MG thymuses was not due to GCs, but restricted to the GC-surrounding medulla, characterized by IRAK1 overexpression. We also showed higher c-REL and ICOS mRNA levels, and lower FAS mRNA levels, in GCs than in the remaining medulla, according to the contribution of these molecules in GC formation. By double immunofluorescence, an increased proportion of IRAK1-expressing dendritic cells and macrophages was found in hyperplastic MG compared to control thymuses, along with GC immunoreactivity for c-REL. Interestingly, in corticosteroid-treated MG patients intrathymic miR-146a and mRNA target levels were comparable to those of controls, suggesting that immunosuppressive therapy may restore the microRNA (miRNA) levels. Indeed, an effect of prednisone on miR-146a expression was demonstrated in vitro on peripheral blood cells. Serum miR-146a levels were lower in MG patients compared to controls, indicating dysregulation of the circulating miRNA. Our overall findings strongly suggest that defective miR-146a expression could contribute to persistent TLR activation, lack of inflammation resolution, and hyperplastic changes in MG thymuses, thus linking TLR-mediated innate immunity to B-cell-mediated autoimmunity. Furthermore, they unraveled a new mechanism of action of corticosteroids in inducing control of autoimmunity in MG via miR-146a.
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Affiliation(s)
- Federica Bortone
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Letizia Scandiffio
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefania Marcuzzo
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silvia Bonanno
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Rita Frangiamore
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Teresio Motta
- Department of Pathological Anatomy, ASST-Bergamo Est Ospedale Bolognini Seriate, Bergamo, Italy
| | - Carlo Antozzi
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Renato Mantegazza
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Paola Cavalcante
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Pia Bernasconi
- Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
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111
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Singh N, Goyal V. Thymectomy in Non-Thymomatous Myasthenia Gravis: Does An RCT Solve The 75-Year-Old Controversy? Ann Indian Acad Neurol 2020; 23:10-12. [PMID: 32055115 PMCID: PMC7001447 DOI: 10.4103/aian.aian_162_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 03/25/2019] [Accepted: 05/05/2019] [Indexed: 11/11/2022] Open
Abstract
The role of thymectomy in thymomatous myasthenia gravis (MG) is unambiguous. However, its role in non-thymomatous MG (NTMG) remains debatable. The evidence till date is not robust. In this short review, we try to see the pros and cons of thymectomy in NTMG and critically appraise the evidence available till date.
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Affiliation(s)
- Nishita Singh
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - Vinay Goyal
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
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242nd ENMC International Workshop: Diagnosis and management of juvenile myasthenia gravis Hoofddorp, the Netherlands, 1-3 March 2019. Neuromuscul Disord 2020; 30:254-264. [PMID: 32173249 DOI: 10.1016/j.nmd.2020.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/03/2020] [Indexed: 12/13/2022]
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113
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Abstract
Many neuromuscular disorders preexist or occur during pregnancy. In some cases, pregnancy unmasks a latent hereditary disorder. Most available information is based on case reports or series or retrospective clinical experience or patient surveys. Of special interest are pregnancy-induced changes in disease course or severity and likelihood for baseline recovery of function postpartum. Labor and delivery present special challenges in many conditions that affect skeletal but not smooth (uterine) muscle; so labor complications must be anticipated. Anesthesia for cesarean section surgery requires special precautions in many disorders. The types of conditions reviewed are broad and include examples of autoimmune, hereditary, and compressive/mechanical processes. Disorders include carpal tunnel syndrome and other focal neuropathies, Bell palsy, myasthenia gravis, and other neuromuscular junction disorders, acute and chronic inflammatory neuropathy, hereditary and acquired muscle diseases, spinal muscular atrophy, amyotrophic lateral sclerosis, channelopathies, autonomic neuropathy, and dysautonomia. Many commonly used therapies have fetal animal but no proven human toxicity concerns, complicating treatment and risk decisions. Weaning off effective therapeutic agents or preemptive aggressive treatment or surgery prior to planned pregnancy is an option in some conditions.
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Affiliation(s)
- Louis H. Weimer
- Correspondence to: Louis H. Weimer, M.D., Neurological Institute of New York, 710 W. 168th Street, New York, NY 10032, United States. Tel: + 1-212-305-1516, Fax: + 1-212-305-4268
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114
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Maintenance immunosuppression in myasthenia gravis, an update. J Neurol Sci 2019; 410:116648. [PMID: 31901719 DOI: 10.1016/j.jns.2019.116648] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/25/2019] [Accepted: 12/24/2019] [Indexed: 01/08/2023]
Abstract
Therapies for myasthenia gravis (MG) include symptomatic and immunosuppressive/immunomodulatory treatment. Options for immunosuppression include corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, tacrolimus, methotrexate, rituximab, cyclophosphamide, eculizumab, intravenous immunoglobulin, subcutaneous immunoglobulin, plasmapheresis, and thymectomy. The practical aspects of long-term immunosuppressive therapy in MG are critically reviewed in this article. Application of one or more of these specific therapies is guided based on known efficacy, adverse effect profile, particular disease subtype and severity, and patient co-morbidities.
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115
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Vecchio D, Ramdas S, Munot P, Pitt M, Beeson D, Knight R, Rodríguez Cruz P, Vincent A, Jayawant S, DeVile C, Buckley C, Hilton-Jones D, Robb S, Palace J. Paediatric myasthenia gravis: Prognostic factors for drug free remission. Neuromuscul Disord 2019; 30:120-127. [PMID: 32001147 DOI: 10.1016/j.nmd.2019.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 11/04/2019] [Accepted: 11/18/2019] [Indexed: 11/15/2022]
Abstract
Our aim was to identify clinical outcomes, serological features and possible prognostic indicators of paediatric myasthenia gravis (MG). We collected 74 MG patients with disease onset before the age of 16 years (73% pre-pubertal onset defined as ≤10 years), seen regularly at two UK specialist centres, over a period of 11 years. The cohort was multi-ethnic, with a high number of non-Caucasians (52%). Ocular presentation was seen in 38 (51%) and only 8 (21%) of these generalised. Fifty-two (70%) patients had antibodies to the acetylcholine receptor (AChR) measured by radioimmunoprecipitation, 10 (14%) had antibodies only to clustered AChRs detected by a cell based assay, 3 (4%) had muscle-specific kinase and one (1%) low-density lipoprotein receptor-related protein 4 antibody. Only 8 (11%) had no detectable antibodies. Seventeen patients attained drug free remission (Kaplan Meyer survival curve estimates 25% by 7 years). Several factors were associated with a higher likelihood of free remission: onset age ≤10 years, Asian and Caucasian races, lack of AChR antibodies on RIA, and normal repetitive nerve stimulation at diagnosis. However, in a multifactorial regression analysis, the antibody status was the only significant predictor for drug free remission, with 60% of patients with antibodies only to clustered AChR achieving this outcome. Complete drug free remission is not uncommon in paediatric MG and several factors appear to influence this outcome with antibody status being the most important. These factors can be easily evaluated at diagnosis, and may help to determine whose patients are likely to require more intensive treatments.
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Affiliation(s)
- Domizia Vecchio
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom; University of Piemonte Orientale, Novara 28100, Italy.
| | - Sithara Ramdas
- Department of Paediatric Neurology, Oxford Radcliffe Hospitals NHS Trust, Oxford OX3 9DU, United Kingdom
| | - Pinki Munot
- Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital, London WC1N 1EH, United Kingdom
| | - Matthew Pitt
- Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS foundation Trust, London WC1N 3JH, United Kingdom
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Ravi Knight
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Pedro Rodríguez Cruz
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Angela Vincent
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Sandeep Jayawant
- Department of Paediatric Neurology, Oxford Radcliffe Hospitals NHS Trust, Oxford OX3 9DU, United Kingdom
| | - Catherine DeVile
- Department of Paediatric Neurology, Great Ormond Street Hospital, London WC1N 1EH, United Kingdom
| | - Camilla Buckley
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - David Hilton-Jones
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
| | - Stephanie Robb
- Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital, London WC1N 1EH, United Kingdom
| | - Jackie Palace
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom
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116
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Li F, Li Z, Takahashi R, Ioannis A, Ismail M, Meisel A, Rueckert JC. Robotic-Extended Rethymectomy for Refractory Myasthenia Gravis: A Case Series. Semin Thorac Cardiovasc Surg 2019; 32:593-602. [PMID: 31682904 DOI: 10.1053/j.semtcvs.2019.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 10/25/2019] [Indexed: 11/11/2022]
Abstract
To assess the safety and efficacy of robotic-extended rethymectomy in selected refractory myasthenia gravis (MG) patients with suspected residual thymic tissue. Robotic-extended rethymectomy was performed in 6 MG patients with seropositive acetylcholine receptors (AChR) antibody who had undergone a previous thymectomy (1 cervicotomy, 2 video-assisted thoracoscopic surgeries, and 3 sternotomies). The median observation time before robotic rethymectomy was 108 (24-171) months. The main outcomes were perioperative morbidity, mortality, conversion to open surgery, and clinical outcomes according to the Myasthenia Gravis Foundation of America Post-Intervention Status (MGFA-PIS). Before rethymectomy, all patients required immunosuppressants and 5 patients (83.3%) required intravenous immune globulin and/or plasma exchange to control the symptoms. The median specimen weight was 24.5 (14-144) g after rethymectomy, and residual thymic tissue was found in 5 patients (83.3%). No conversion to open surgery or perioperative morbidity and mortality was observed. With a median follow-up time of 46.5 (13-155) months, 3 patients (50%) achieved "improved" and 3 (50%) were "unchanged" according to the MGFA-PIS. Compared with preoperative use, the median daily dose of corticosteroids statistically decreased (25 [7.5-60] vs 0 [0-5] mg, P = 0.002) without significant change in azathioprine use (100 [0-200] vs 50 [0-150] mg, P = 0.360). AChR antibody positive MG patients with a treatment refractory long-term course after thymectomy might have remaining thymic tissue with the 2 commonly associated thymus pathologies, thymoma, and follicular hyperplasia. Robotic-extended rethymectomy might be considered as a safe and beneficial treatment option in these patients.
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Affiliation(s)
- Feng Li
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Zhongmin Li
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Reona Takahashi
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | | | - Mahmoud Ismail
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Andreas Meisel
- Department of Neurology Berlin, Charité University Hospital Berlin, Berlin, Germany
| | - Jens-C Rueckert
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany.
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117
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Akaishi T, Motomura M, Aoki M, Utsugisawa K. MGTX extension study longitudinally favors early thymectomy in non-thymomatous young-adult patients with AChR antibody-positive myasthenia gravis. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:S208. [PMID: 31656787 DOI: 10.21037/atm.2019.06.65] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Tetsuya Akaishi
- Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan.,Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Japan
| | - Masakatsu Motomura
- Medical Engineering Course, Department of Engineering, Faculty of Engineering, Nagasaki Institute of Applied Science, Nagasaki, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan
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118
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Abstract
Myasthenia gravis (MG) is an autoimmune disorder caused by antibodies against acetylcholine receptors (AChR) or other structural proteins of the neuromuscular junction. This diminishes cholinergic transmission, thus leading to exercise-induced fatigue and sometimes manifest muscle weakness, including the bulbar and ocular musculature. Whereas ocular MG is as a rule initially symptomatically treated with acetylcholine esterase inhibitors, generalized MG requires long-term immunosuppression. The thymus plays a particular role in the pathophysiology of AChR antibody-positive MG, which can also manifest as a paraneoplastic disorder in the context of a thymoma. This article reviews the basic and advanced treatment options of the different disease subtypes including plasma exchange and immunoglobulins for treatment in a myasthenic crisis. Recently, clinical approval of eculizumab, a complement inhibitor, enriched the pharmacological armamentarium for AChR antibody-positive MG patients not appropriately responding to immunosuppression alone.
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119
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Li F, Tao Y, Bauer G, Elsner A, Li Z, Swierzy M, Englisch J, Meisel A, Ismail M, Rückert JC. Unraveling the role of ectopic thymic tissue in patients undergoing thymectomy for myasthenia gravis. J Thorac Dis 2019; 11:4039-4048. [PMID: 31656680 DOI: 10.21037/jtd.2019.08.109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Extended thymectomy has been considered the goal of surgery for myasthenia gravis (MG) mainly due to the existence of ectopic thymic tissue. Recently, ectopic thymic tissue has attracted increasing attention in patients with MG following thymectomy. However, the specific role of ectopic thymic tissue in patients with MG is still under debate. A systematic search of the literature was performed on PubMed and Medline according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISM) statement. Studies evaluating the rate of ectopic thymic tissue in patients with MG with or without thymoma were included. Extraction was performed for all eligible studies and the rate of ectopic thymic tissue at common locations was calculated. Eighteen out of fifty-nine studies were eligible for inclusion, of which ten studies reported the common locations of ectopic thymic tissue in mediastinal fat. Of these ten studies, the presence of ectopic thymic tissue was investigated in different anatomical locations in 882 patients, of whom, 509 patients (58%) have at least one positive location with the most common ones being anterior mediastinal fat, pericardiophrenic angles, aortopulmonary window, cervical region (pretracheal fat) and lateral to phrenic nerves. On the other hand, nine studies analyzed the influence of the presence of ectopic thymic tissue on the clinical outcomes of MG patients. Of these, six found that the presence of ectopic thymic tissue in MG patients is a significant predictor of poor outcome after thymectomy, however, the other three did not find a significance. Altogether, ectopic thymic tissue is likely to present in more than a half of patients undergoing thymectomy for MG. Besides, MG patients who have ectopic thymic tissue after thymectomy do not seem to have as good outcome as those who have not.
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Affiliation(s)
- Feng Li
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Ya Tao
- Department of Obstetrics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Gero Bauer
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Aron Elsner
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Zhongmin Li
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Marc Swierzy
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Julianna Englisch
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Andreas Meisel
- Department of Neurology Berlin, Charité University Hospital Berlin, Berlin, Germany
| | - Mahmoud Ismail
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
| | - Jens-C Rückert
- Department of Surgery, Competence Center of Thoracic Surgery, Charité University Hospital Berlin, Berlin, Germany
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120
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Huang K, Luo YB, Yang H. Autoimmune Channelopathies at Neuromuscular Junction. Front Neurol 2019; 10:516. [PMID: 31156543 PMCID: PMC6533877 DOI: 10.3389/fneur.2019.00516] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/30/2019] [Indexed: 12/22/2022] Open
Abstract
The neuromuscular junction, also called myoneural junction, is a site of chemical communication between a nerve fiber and a muscle cell. There are many types of channels at neuromuscular junction that play indispensable roles in neuromuscular signal transmission, such as voltage-gated calcium channels and voltage-gated potassium channels on presynaptic membrane, and acetylcholine receptors on post-synaptic membrane. Over the last two decades, our understanding of the role that autoantibodies play in neuromuscular junction disorders has been greatly improved. Antibodies against these channels cause a heterogeneous group of diseases, such as Lambert-Eaton syndrome, Isaacs' syndrome and myasthenia gravis. Lambert-Eaton syndrome is characterized by late onset of fatigue, skeletal muscle weakness, and autonomic symptoms. Patients with Isaacs' syndrome demonstrate muscle cramps and fasciculation. Myasthenia gravis is the most common autoimmune neuromuscular junction channelopathy characterized by fluctuation of muscle weakness. All these disorders have a high risk of tumor. Although these channelopathies share some common features, they differ for clinical features, antibodies profile, neurophysiological features, and treatments. The purpose of this review is to give a comprehensive insight on recent advances in autoimmune channelopathies at the neuromuscular junction.
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Affiliation(s)
- Kun Huang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China.,Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yue-Bei Luo
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Huan Yang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
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121
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Berrih-Aknin S, Le Panse R. Thymectomy in myasthenia gravis: when, why, and how? Lancet Neurol 2019; 18:225-226. [DOI: 10.1016/s1474-4422(18)30467-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 01/08/2023]
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