A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis

Background: Myasthenia gravis (MG) is an autoimmune disorder of unknown etiology in most patients, in which autoantibodies target components of neuromuscular junctions and impair nerve to muscle transmission.Objective: To provide a synthesis of the evidence examining infectious agents associated wit...

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Main Authors: Victoria Leopardi, Yu-Mei Chang, Andrew Pham, Jie Luo, Oliver A. Garden
Format: Article
Language:English
Published: Frontiers Media S.A. 2021-06-01
Series:Frontiers in Neurology
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fneur.2021.618021/full
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author Victoria Leopardi
Yu-Mei Chang
Andrew Pham
Jie Luo
Oliver A. Garden
author_facet Victoria Leopardi
Yu-Mei Chang
Andrew Pham
Jie Luo
Oliver A. Garden
author_sort Victoria Leopardi
collection DOAJ
description Background: Myasthenia gravis (MG) is an autoimmune disorder of unknown etiology in most patients, in which autoantibodies target components of neuromuscular junctions and impair nerve to muscle transmission.Objective: To provide a synthesis of the evidence examining infectious agents associated with the onset of MG.Hypothesis: We hypothesized that microbes play a pathogenic role in the initiation of MG. For clinical cases, the onset of clinical signs is used as a proxy for the true onset of autoimmunity.Methods: We searched PubMed and Web of Science. Papers captured through database searching (n = 827) were assessed, yielding a total of 42 publications meeting the inclusion and exclusion criteria. An additional 6 papers were retrieved from the reference lists of relevant articles. For each pathogen, an integrated metric of evidence (IME) value, from minus 8 to plus 8, was computed based on study design, quality of data, confidence of infectious disease diagnosis, likelihood of a causal link between the pathogen and MG, confidence of MG diagnosis, and the number of infected patients. Negative IME values corresponded to studies providing evidence against a role for microbes as triggers of MG.Results: One hundred and sixty-nine myasthenic patients infected with 21 different pathogens were documented. Epstein-Barr virus (median = 4.71), human papillomavirus (median = 4.35), and poliovirus (median = 4.29) demonstrated the highest IME values. The total median IME was 2.63 (mean = 2.53; range −3.79–5.25), suggesting a general lack of evidence for a causal link.Conclusions: There was a notable absence of mechanistic studies designed to answer this question directly. The question of the pathogenic contribution of microbes to MG remains open.
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spelling doaj.art-0787f14e503449729dc658cd7d402c282022-12-21T18:42:50ZengFrontiers Media S.A.Frontiers in Neurology1664-22952021-06-011210.3389/fneur.2021.618021618021A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia GravisVictoria Leopardi0Yu-Mei Chang1Andrew Pham2Jie Luo3Oliver A. Garden4Garden and Luo Immune Regulation Laboratory, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United StatesResearch Support Office, Royal Veterinary College, University of London, London, United KingdomGarden and Luo Immune Regulation Laboratory, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United StatesGarden and Luo Immune Regulation Laboratory, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United StatesGarden and Luo Immune Regulation Laboratory, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United StatesBackground: Myasthenia gravis (MG) is an autoimmune disorder of unknown etiology in most patients, in which autoantibodies target components of neuromuscular junctions and impair nerve to muscle transmission.Objective: To provide a synthesis of the evidence examining infectious agents associated with the onset of MG.Hypothesis: We hypothesized that microbes play a pathogenic role in the initiation of MG. For clinical cases, the onset of clinical signs is used as a proxy for the true onset of autoimmunity.Methods: We searched PubMed and Web of Science. Papers captured through database searching (n = 827) were assessed, yielding a total of 42 publications meeting the inclusion and exclusion criteria. An additional 6 papers were retrieved from the reference lists of relevant articles. For each pathogen, an integrated metric of evidence (IME) value, from minus 8 to plus 8, was computed based on study design, quality of data, confidence of infectious disease diagnosis, likelihood of a causal link between the pathogen and MG, confidence of MG diagnosis, and the number of infected patients. Negative IME values corresponded to studies providing evidence against a role for microbes as triggers of MG.Results: One hundred and sixty-nine myasthenic patients infected with 21 different pathogens were documented. Epstein-Barr virus (median = 4.71), human papillomavirus (median = 4.35), and poliovirus (median = 4.29) demonstrated the highest IME values. The total median IME was 2.63 (mean = 2.53; range −3.79–5.25), suggesting a general lack of evidence for a causal link.Conclusions: There was a notable absence of mechanistic studies designed to answer this question directly. The question of the pathogenic contribution of microbes to MG remains open.https://www.frontiersin.org/articles/10.3389/fneur.2021.618021/fullmyasthenia gravisautoimmunityinfectionvirusetiology
spellingShingle Victoria Leopardi
Yu-Mei Chang
Andrew Pham
Jie Luo
Oliver A. Garden
A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
Frontiers in Neurology
myasthenia gravis
autoimmunity
infection
virus
etiology
title A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
title_full A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
title_fullStr A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
title_full_unstemmed A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
title_short A Systematic Review of the Potential Implication of Infectious Agents in Myasthenia Gravis
title_sort systematic review of the potential implication of infectious agents in myasthenia gravis
topic myasthenia gravis
autoimmunity
infection
virus
etiology
url https://www.frontiersin.org/articles/10.3389/fneur.2021.618021/full
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