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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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Yan C, Zhao R, Song J, Feng X, Xi J, Luo S, Zhong H, Zhou S, Li W, Zhao C. Comparison of anti-acetylcholine receptor profiles between Chinese cases of adult- and juvenile-onset myasthenia gravis using cell-based assays. J Neuroimmunol 2020; 349:577403. [PMID: 32992216 DOI: 10.1016/j.jneuroim.2020.577403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/29/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Juvenile-onset myasthenia gravis (JOMG) is a unique clinical subtype in China, featured by a higher prevalence of ocular myasthenia gravis (OMG), higher seronegativity of acetylcholine receptor (AChR) antibodies, and better prognosis than that in adult-onset myasthenia gravis (AOMG). We previously identified low-affinity AChR antibodies in Chinese JOMG patients using cell-based assays (CBAs), indicating a predominantly AChR antibody-positive profile. Here, we further screened AChR antibodies in both Chinese AOMG and JOMG patients by CBAs. MATERIALS AND METHODS We recruited patients with MG who had not received prednisone or immunosuppressive therapies between June 2015 and June 2019, and divided them into AOMG and JOMG subgroups according to their ages at the time of recruitment. Clinical information and blood samples were collected. Serum AChR antibodies were detected by CBAs in HEK293T cells expressing clustered adult and fetal AChRs, as well as by enzyme-linked immunosorbent assays (ELISAs). Differences in AChR antibody profiles between AOMG and JOMG subgroups were determined. RESULTS A total of 239 patients with MG were enrolled in the present study, including 121 AOMG and 118 JOMG patients. Based on ELISAs, 74.4% of AOMG (90/121) and 59.3% of JOMG (70/118) patients were anti-AChR positive (p = 0.02). However, CBAs yielded equal anti-AChR positivities (p = 0.64), as indicated by 80.2% of AOMG patients (97/121) and 77.1% of JOMG patients (91/118). Furthermore, among AOMG patients, 67.8% (82/121) were positive for both adult and fetal AChR antibodies, 5.8% (7/121) were positive for only adult AChR antibodies, and 6.6% (8/121) were positive for only fetal AChR antibodies, while these rates were 50.8% (60/118), 21.2% (25/118), and 5.1% (6/118), respectively, in JOMG cohorts (p < 0.01). Twenty-nine AOMG patients and 10 JOMG patients underwent IgG subclassification of AChR antibodies, which were all confirmed to be predominantly IgG1. CONCLUSIONS The positive rates of AChR antibodies did not differ between Chinese AOMG and JOMG patients, as revealed by CBAs. Furthermore, the screened AChR antibodies were predominantly IgG1 in both AOMG and JOMG patients.
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Affiliation(s)
- Chong Yan
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Rui Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jie Song
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xuelin Feng
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangdong 510080, China
| | - Jianying Xi
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Sushan Luo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Huahua Zhong
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Shuizhen Zhou
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 200040, China
| | - Wenhui Li
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 200040, China.
| | - Chongbo Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China; Department of Neurology, Jing'an District Center Hospital of Shanghai, Fudan University, Shanghai 200040, China.
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Susukida T, Aoki S, Shirayanagi T, Yamada Y, Kuwahara S, Ito K. HLA transgenic mice: application in reproducing idiosyncratic drug toxicity. Drug Metab Rev 2020; 52:540-567. [PMID: 32847422 DOI: 10.1080/03602532.2020.1800725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Various types of transgenic mice carrying either class I or II human leukocyte antigen (HLA) molecules are readily available, and reports describing their use in a variety of studies have been published for more than 30 years. Examples of their use include the discovery of HLA-specific antigens against viral infection as well as the reproduction of HLA-mediated autoimmune diseases for the development of therapeutic strategies. Recently, HLA transgenic mice have been used to reproduce HLA-mediated idiosyncratic drug toxicity (IDT), a rare and unpredictable adverse drug reaction that can result in death. For example, abacavir-induced IDT has successfully been reproduced in HLA-B*57:01 transgenic mice. Several reports using HLA transgenic mice for IDT have proven the utility of this concept for the evaluation of IDT using various HLA allele combinations and drugs. It has become apparent that such models may be a valuable tool to investigate the mechanisms underlying HLA-mediated IDT. This review summarizes the latest findings in the area of HLA transgenic mouse models and discusses the current challenges that must be overcome to maximize the potential of this unique animal model.
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Affiliation(s)
- Takeshi Susukida
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.,Laboratory of Cancer Biology and Immunology, Section of Host Defenses, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Shigeki Aoki
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Tomohiro Shirayanagi
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Yushiro Yamada
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Saki Kuwahara
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Kousei Ito
- Laboratory of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
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Zhong H, Zhao C, Luo S. HLA in myasthenia gravis: From superficial correlation to underlying mechanism. Autoimmun Rev 2019; 18:102349. [DOI: 10.1016/j.autrev.2019.102349] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 03/01/2019] [Indexed: 12/26/2022]
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Feng X, Li W, Song J, Liu X, Gu Y, Yan C, Wu H, Xi J, Zhou S, Zhao C. HLA typing using next-generation sequencing for Chinese juvenile- and adult-onset myasthenia gravis patients. J Clin Neurosci 2018; 59:179-184. [PMID: 30595166 DOI: 10.1016/j.jocn.2018.10.077] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 09/27/2018] [Accepted: 10/14/2018] [Indexed: 11/15/2022]
Abstract
To compare HLA typing between juvenile- and adult-onset myasthenia gravis (MG), we enrolled 101 children (age ≤12 years) and 168 adults (age ≥20 years) with MG. We excluded patients with histories of thymoma, thyroid disease, or other autoimmune disease. We selected 41 seronegative juvenile-onset patients with ocular symptoms only, and 41 seropositive adult-onset patients with generalized symptoms. We used next-generation sequencing for typing and analysis of HLA genes (Loci: A, B, C, DPA1, DPB1, DQA1, DQB1 and DRB1). Haplotypes HLA-A∗02:07:01-B∗46:01:01-C∗01:02:01-DQA1∗01:01:01-DQB1∗03:03:02-DRB1∗09:01:02, HLA-A∗11:01:01, HLA-A∗24:02:01, and HLA-DPA1∗02:02:02 were found to be related to juvenile-onset MG and HLA-A∗01:01:01, HLA-A∗02:03:01, HLA-C∗03:04:01, and HLA-DQB1∗06:02:01 to adult-onset MG. Therefore, our findings suggested that HLA typing might determine the heterogeneity between AChR-Ab negative juvenile-onset and AChR-Ab positive adult-onset Chinese MG patients.
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Affiliation(s)
- Xuelin Feng
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, China
| | - Wenhui Li
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China
| | - Jie Song
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, China
| | - Xiaoni Liu
- Institute of Neurology, Fudan University, Shanghai, China
| | - Yuehua Gu
- Institute of Neurology, Fudan University, Shanghai, China
| | - Chong Yan
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, China
| | - Hui Wu
- Department of Neurology, Jing'an District Centre Hospital of Shanghai, China
| | - Jianying Xi
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, China
| | - Shuizhen Zhou
- Department of Neurology, Children's Hospital of Fudan University, Shanghai, China.
| | - Chongbo Zhao
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, China; Department of Neurology, Jing'an District Centre Hospital of Shanghai, China.
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Heterogeneity of auto-antibodies against nAChR in myasthenic serum and their pathogenic roles in experimental autoimmune myasthenia gravis. J Neuroimmunol 2018; 320:64-75. [PMID: 29759142 DOI: 10.1016/j.jneuroim.2018.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 11/20/2022]
Abstract
Many myasthenia gravis (MG) patients have auto-antibodies against the nicotinic acetylcholine receptor (nAChR), and monoclonal antibodies against the main immunogenic region (MIR) of nAChR can induce experimental autoimmune MG (EAMG). We investigated whether Fab fragment of MIR antibody (Fab35) could block the pathogenicity of polyclonal antibodies. Fab35 partially inhibited nAChR downmodulation, blocked EAMG serum-induced binding of polyclonal antibodies and complement deposition in vitro. Moreover, Fab35 did not ameliorate the EAMG serum-induced EAMG phenotype in rats. These results suggested that the EAMG serum possessed several different pathogenic antibodies that might be sufficient to induce the EAMG phenotype.
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Wu X, Tüzün E. Are linear AChR epitopes the real culprit in ocular myasthenia gravis? Med Hypotheses 2017; 99:26-28. [DOI: 10.1016/j.mehy.2016.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 11/23/2016] [Indexed: 10/20/2022]
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