重症肌无力患者低频重复神经电刺激的特点

目的研究重症肌无力(myasthenia gravis,MG)患者低频重复神经电刺激(repetitive nerve stimulation,RNS)的特点。方法回顾性分析1995-2010年作者医院住院的275例MG患者的低频RNS检查资料。结果 275例患者中RNS检查结果异常216例,异常率为78.55%。其中Ⅰ型RNS异常率最低(48.91%),且与其他临床分型异常率之间存在统计学差异(P<0.05)。刺激腋神经RNS异常率最高(58.68%),面神经次之(56.18%),尺神经最低(18.88%)。在眼轮匝肌和三角肌进行记录时所测得的RNS异常率高于在小指展肌所测(P<0.01)。结论 MG患者RNS异常率与临床分型及检测部位有关。Ⅰ型患者RNS异常率低于其余各分型,于近端肌肉记录时所测的RNS异常率明显高于在远端肌肉所测。     

Statins can induce myasthenia gravis

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statins, are commonly prescribed for prevention of cardiovascular morbidity. A rare side effect of statin medication is the induction of autoimmune illnesses, including myasthenia gravis (myasthenia). Here we present two patients with seropositive myasthenia that developed 4 weeks after initiation of atorvastatin, increasing the total reported patients to seven. Reviewing recent literature we highlight the connections between statins, auto-immunity and myasthenia. Statins may favour T-cell phenotypes that reduce cell-mediated immunity but could increase antibody-mediated humoral immunity.     

Myasthenia gravis after allogeneic bone marrow transplantation treated with mycophenolate mofetil monitored by peripheral blood OX40+ CD4+ T cells

A patient who developed myasthenia gravis (MG) 25 months after allogeneic bone marrow transplant was immunologically analyzed. OX40+CD4+ T cells in the peripheral blood prominently increased one month before the onset of MG. CD4/CD8 ratios, usually abnormally inverted in patients with chronic graft-vs.-host disease (cGVHD), showed pseudonormalization during the course of MG. We succeeded in uneventful rapid tapering of prednisolone (PSL) using mycophenolate mofetil (MMF). Monitoring of OX40+CD4+ T cells supported the tapering of PSL and MMF as a marker of cGVHD activity. This case suggested the utility of MMF and monitoring of OX40+CD4+ T cells in the management of cGVHD-associated autoimmune diseases.     

External treatment of traditional Chinese medicine for myasthenia gravis: A protocol for systematic review and meta-analysis

Background:Myasthenia gravis (MG) is an archetypal autoimmune disorder. The conventional treatments for this disease are drugs, plasma exchange, surgical, and so on. However, this disease is difficult to cure. A mass of studies revealed that the external treatment of traditional Chinese medicine (TCM) for MG is a safe and economical approach. The present study conducted a meta-analysis to compare TCM external treatment combined with modern medicine with modern medicine for MG, in order to determine which TCM external treatment intervention has the best relative efficacy, safety, and provide the best evidence for clinical practice.Methods:PubMed, Cochrane Library, EMBASE, Web of Science, Springer, China National Knowledge Infrastructure (CNKI), Wan-fang database, VIP Chinese Science and Technique Journals Database, the Chinese Bio Medical Database (CBM), and Baidu Scholar were searched. The time of publication was limited from inception to February 28, 2021. Two reviewers independently searched for the selected articles and extract the data. The RevMan V.5.3 statistical software (Cochrane Collaboration) and Stata V.16.0 software were used to conduct the meta-analysis.Results:The results of the systematic review and meta-analysis will be published in a peer-reviewed journal.Conclusion:The present study provides a protocol that can be used in the systematic review and meta-analysis, with the intent to inform professionals on the external treatment of TCM for MG. These would lead to investigations on the use of the most external treatment of TCM for MG.Trial registration number:INPLASY202110083     

Efficacy and safety of Buzhong Yiqi decoction combined with western medicine in the treatment of myasthenia gravis: A protocol for systematic review and meta-analysis

Background:Myasthenia gravis is a common autoimmune disease in clinic. Although there are various ways and drugs for the treatment of myasthenia gravis in Western medicine, there are still a variety of adverse reactions. Studies have shown that Buzhong Yiqi decoction combined with Western medicine has a certain efficacy in the treatment of myasthenia gravis, but there is a lack of evidence-based medicine. The research carried out in this scheme is to systematically evaluate the efficacy and safety of Buzhong Yiqi decoction combined with Western medicine in the treatment of myasthenia gravis, and to provide reliable evidence for guiding clinical practice.Methods:English databases (the Cochrane Library, PubMed, Web of Science, Embase) and Chinese databases (China Biomedical Database, China Science and Technology Journal Database, China National Knowledge Infrastructure, Wanfang) will be searched by computer. In addition, Baidu Academic and Chinese Clinical Trial Registration Center will be searched manually. A randomized controlled clinical trial of Buzhong Yiqi decoction combined with Western medicine in the treatment of myasthenia gravis will be conducted from the establishment of the database to December 2020. The 2 researchers independently carry out data extraction and literature quality evaluation on the quality of the included study, and meta-analysis of the included literature will be carried out by using RevMan 5.3 software.Results:This study will evaluate the efficacy and safety of Buzhong Yiqi decoction combined with Western medicine in the treatment of myasthenia gravis by Quantitive MGscore, the number of Tregs cells and the content of anti-acetylcholine receptor antibody (AchR-Ab).Conclusion:This study will provide reliable evidence-based evidence for the clinical application of Buzhong Yiqi decoction combined with Western medicine in the treatment of myasthenia gravis.Ethics and dissemination:Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.OSF Registration number:DOI 10.17605/OSF.IO/MXUPK.     

Postoperative survival for patients with thymoma complicating myasthenia gravis—preliminary retrospective results of the ChART database

Background

It is so far not clear that how myasthenia gravis (MG) affected the prognosis of thymoma patients. The aim of this assay is to compare the postoperative survival between patients with thymoma only and those with both thymoma and MG.

Methods

The Chinese Alliance for Research in Thymomas (ChART) registry recruited patients with thymoma from 18 centers over the country on an intention to treat basis from 1992 to 2012. Two groups were formed according to whether the patient complicated MG. Demographic and clinical data were reviewed, patients were followed and their survival status were analyzed.

Results

There were 1,850 patients included in this study, including 421 with and 1,429 without MG. Complete thymectomy were done in 91.2% patients in MG group and 71.0% in non-MG group (P<0.05). There were more percentage of patients with the histology of thymoma AB, B1, or B2 (P<0.05) in MG group, and more percentage of patients with MG were in Masaoka stage I and II. The 5- and 10-year overall survival (OS) rates were both higher in MG group (93% vs. 88%; 83% vs. 81%, P=0.034) respectively. The survival rate was significantly higher in patients with MG when the Masaoka staging was 3/4 (P=0.003). Among patients with advanced stage thymoma (stage 3, 4a, 4b), the constituent ratios of 3, 4a, 4b were similar between MG and non-MG group. Histologically, however, there were significantly more proportion of AB/B1/B2/B3 in the MG group while there were more C in the non-MG group (P=0.000). Univariate analyses for all patients showed that MG, WHO classification, Masaoka stage, surgical approach, chemotherapy and radiotherapy and resectability were significant factors, and multivariate analysis showed WHO classification, Masaoka stage, and resectability were strong independent prognostic indicators.

Conclusions

Although MG is not an independent prognostic factor, the survival of patients with thymoma was superior when MG was present, especially in late Masaoka stage patients. Possible reasons included early diagnosis of the tumor, better histologic types, an overall higher R0 resection and less recurrence.     

重症肌无力患者胸腺自身免疫相关基因表达的研究

目的探讨MG患者和正常对照者的胸腺组织炎症反应与自身免疫性疾病相关基因的表达情况。方法取MG患者（MG组）和正常对照者（对照组）的胸腺组织标本，提取总RNA，反转录合成cDNA后，体外转录合成生物素标记的cRNA与基因芯片进行杂交，通过化学发光法检测基因表达，比较两组胸腺组织基因表达的差异。结果MG组与对照组比较，有61条基因存在显著性差异，其中表达上调33条，下调28条，这些基因包括炎症相关趋化因子基因、细胞因子及其受体基因、与细胞因子产生与代谢有关的基因、细胞因子及其受体相互作用相关的基因、炎症反应相关基因以及体液免疫相关基因等。结论芯片筛选MG患者胸腺自身免疫相关基因表达与正常对照组存在显著差异。     

Antibody effector mechanisms in myasthenia gravis—Pathogenesis at the neuromuscular junction

Myasthenia gravis (MG) is an autoimmune disorder caused by autoantibodies that are either directed to the muscle nicotinic acetylcholine receptor (AChR) or to the muscle-specific tyrosine kinase (MuSK). These autoantibodies define two distinct subforms of the disease—AChR-MG and MuSK-MG. Both AChR and MuSK are expressed on the postsynaptic membrane of the neuromuscular junction (NMJ), which is a highly specialized region of the muscle dedicated to receive and process signals from the motor nerve. Autoantibody binding to proteins of the postsynaptic membrane leads to impaired neuromuscular transmission and muscle weakness. Pro-inflammatory antibodies of the human IgG1 and IgG3 subclass modulate the AChR, cause complement activation, and attract lymphocytes; together acting to decrease levels of the AChR and AChR-associated proteins and to reduce postsynaptic folding. In patients with anti-MuSK antibodies, there is no evidence of loss of junctional folds and no apparent loss of AChR density. Anti-MuSK antibodies are predominantly of the IgG4 isotype, which functionally differs from other IgG subclasses in its anti-inflammatory activity. Moreover, IgG4 undergoes a posttranslational modification termed Fab arm exchange that prevents cross-linking of antigens. These findings suggest that MuSK-MG may be different in etiological and pathological mechanisms from AChR-MG. The effector functions of IgG subclasses on synapse structure and function are discussed in this review.     

The auto-antigen repertoire in myasthenia gravis

Myasthenia Gravis (MG) is an antibody-mediated autoimmune disorder affecting the postsynaptic membrane of the neuromuscular junction (NMJ). MG is characterized by an impaired signal transmission between the motor neuron and the skeletal muscle cell, caused by auto-antibodies directed against NMJ proteins. The auto-antibodies target the nicotinic acetylcholine receptor (nAChR) in about 90% of MG patients. In approximately 5% of MG patients, the muscle specific kinase (MuSK) is the auto-antigen. In the remaining 5% of MG patients, however, antibodies against the nAChR or MuSK are not detectable (idiopathic MG, iMG). Although only the anti-nAChR and anti-MuSK auto-antibodies have been demonstrated to be pathogenic, several other antibodies recognizing self-antigens can also be found in MG patients. Various auto-antibodies associated with thymic abnormalities have been reported, as well as many non-MG-specific auto-antibodies. However, their contribution to the cause, pathology and severity of the disease is still poorly understood. Here, we comprehensively review the reported auto-antibodies in MG patients and discuss their role in the pathology of this autoimmune disease.     

In vitro characterization of an acetylcholine receptor–transferrin fusion protein for the treatment of myasthenia gravis

SHG2210, a fusion protein containing the N-terminus of human nicotinic acetylcholine receptor α (AchR-α; aa1-210) and human transferrin (TF), was characterized as a potential therapeutic for myasthenia gravis (MG) caused predominately by α subunit autoantibodies. SHG2210 was shown to be able to bind to α subunit autoantibodies and the TF receptor (TFR). SHG2210 and SHG2210–anti-AchR antibody complex are internalized through TFR-mediated endocytosis. The SHG2210 and SHG2210–anti-AchR antibody complex is present in Lamp1-positive lysosomal compartments after internalization; however, neither SHG2210 nor SHG2210–antibody complex is present in Rab11-positive recycling endosomes. SHG2210 bound to α subunit of AChR autoantibodies may be cleared by the lysosome, resulting in short cellular half-life relative to SHG2210. SHG2210 is shown to have a protective effect on antigenic modulation of the AChR induced by serum from select patients with MG, suggesting that a fusion protein approach may be an effective therapeutic for treating MG.