重症肌无力的免疫学研究进展

重症肌无力是抗乙酰胆碱受体抗体介导的、细胞免疫依赖性、补体参与的神经肌肉接头处的自身免疫病，其发病本质就是针对乙酰胆碱受体的免疫应答异常。辅助性T细胞、细胞因子及胸腺在重症肌无力的发病机制中起重要作用，肌细胞亦主动地参与了重症肌无力的发病过程。重症肌无力的免疫启动目前多倾向于交叉反应学说。     

重症肌无力患者记忆的初步研究

重症肌无力患者记忆的初步研究王文敏弓少霞王荪王毅昆明医学院第一附属医院神经内科目前认为重症肌无力（ｍｙａｓｔｈｅｎｉａｇｒａｖｉｓ，ＭＳ）是一种因体内产生的抗乙酰胆碱受体（ａｎｔｉ－ＡＣｈ－Ｒ）抗体作用于神经肌肉接头的运动终板，从而导致神经肌肉接头处...     

重症肌无力致病性自身抗体的人工构建

目的 构建一株具有致病性的人抗乙酰胆碱受体（AchR）自身抗体，用于诱导猴实验性自身免疫性重症肌无力（EAMG）模型。方法 将分离自重症肌无力（MG）患者胸腺的抗AchR抗体的抗原结合片段（Fab637）克隆至含有免疫球蛋白（IgG1）基因的载体pIgG1，构建能在哺乳类细胞表达完整IgG1类抗AchR抗体（IgG1-637）的重组表达载体（pIgG1-637），将pIgG1-637转染CHO-k1细胞系，筛选出稳定表达IgG1-637的细胞株扩大培养。将纯化的IgG1-637注射5只恒河猴，通过检查猴肌肉收缩强度和复合肌肉运动电位（CMAP），判定猴EAMG发病情况，从而鉴定IgG1-637的致病性。结果 20μmol／L MSX（L-methionine sulfoxmine）选择的CHO-k1细胞表达最高水平的抗体IgG1-637，表达产量为17．4μg/ml。3只猴（分别接受1．7、1．7和5．0mg／kg的注射剂量）在注射IgG1-637后1周内出现肌肉收缩无力临床症状，并表现出CMAP减弱现象。结论 由Fab637构建的完整的IgG1-637是一株致病性抗AchR抗体，可在猴诱导出EAMG。     

重症肌无力的免疫学研究进展

重症肌无力是抗乙酰胆碱受体抗体介导的、细胞免疫依赖性、补体参与的神经肌肉接头处的自身免疫病,其发病本质就是针对乙酰胆碱受体的免疫应答异常.辅助性T细胞、细胞因子及胸腺在重症肌无力的发病机制中起重要作用,肌细胞亦主动地参与了重症肌无力的发病过程.重症肌无力的免疫启动目前多倾向于交叉反应学说.     

丙种球蛋白与血浆置换治疗重症肌无力的疗效比较

目的比较血浆置换与丙种球蛋白两种方法治疗重症肌无力（MG）的临床疗效。方法回顾性分析29例MG患者的临床资料,其中16例（A组）进行丙种球蛋白治疗,13例（B组）进行血浆置换治疗,ELISA法检测29例MG患者治疗前后血清乙酰胆碱受体抗体（AchRAb）变化情况,采用临床绝对和相对评分法评价治疗1周后疗效。结果ELISA法检测结果表明两种治疗方法均能使MG患者血浆AchRAb水平明显下调,丙种球蛋白组治疗后AchRAb水平下调至（0.71±0.25）nmol/L,有效率为87.5%;血浆置换组AchRAb水平下调至（0.67±0.27）nmol/L,有效率为92.3%,均有统计学意义（P〈0.01）,但两种治疗方法之间尚无明显差异（P〉0.01）。结论丙种球蛋白与血浆置换治疗重症肌无力疗效确切,两者之间无明显差异性。     

重症肌无力患者AchR-Ab、Titin-Ab的检测及其临床意义

目的 对重症肌无力患者血清乙酰胆碱受体抗体(AchR-Ab)、连接素抗体(Titin-Ab)进行检测,探讨其临床意义,为临床提供诊断、治疗的依据.方法 选取本院2013年1月至2014年12月收治的重症肌无力患者80例.依据胸部CT检查结果将患者分为伴胸腺瘤(MGT)组与不伴胸腺瘤(NTMG)组.测定各组患者外周血AchR-Ab与Titin-Ab的含量并统计阳性例数,探讨其用于诊断重症肌无力的价值及意义.结果 MG组AchR-Ab与Titin-Ab阳性率明显高于HC组,MGT组AchR-Ab与Titin-Ab阳性率明显高于NTMG组,全身型(Ⅱ～Ⅳ型)AchR-Ab与Titin-Ab阳性率明显高于眼睑型(Ⅰ型)组,差异具有统计学意义(P＜0.05).结论 AChR抗体作为临床使用最广泛的重症肌无力患者检测指标具有一定价值,Titin抗体是应用于重症肌无力患者合并胸腺瘤时敏感而特异的血清学指标,在重症肌无力患者中开展血清Titin抗体的测定对于胸腺瘤的诊断及判断预后具有重要的临床指导意义.     

树突状细胞亚群与重症肌无力

重症肌无力(MG)是一种依赖T细胞的抗体介导的以神经肌肉接头处传递障碍为特征的自身免疫性疾病,与机体免疫调节失衡有关.树突状细胞(DC)是目前功能最强的抗原递呈细胞(APC),在调节机体免疫反应中起着重要作用.不同表型的DC在自身免疫性疾病中的作用不同,它们通过不同的途径参与MG的发病.DC分泌的细胞凶子在MG发病机制巾也起着重要作用.细胞因子干预诱导的耐受性DC在治疗MG中取得了巨大进步,有望成为治疗MG的一种新方法.     

重症肌无力患者乙酰胆碱酯酶抗体的测定

纯化人脑组织中的乙酰胆碱酯酶为抗原包被免疫板，建立血清中乙酰胆碱酯酶抗体测定的ＥＬＩＳＡ法。探讨了检测方法的特异性和可重复性，并对３组样本进行了测定。证明此方法特异、灵敏、可重复。提示对下肌无力的研究可能提供１个新的实验检测指标。     

重症肌无力患者肌肉AChR亚单位基因的表达

目的：探讨重症肌无力（MG）患者眼外肌易于受累的机制。方法：采用RT-PCR对正常人眼外肌、其他骨骼肌群（8例）以及MG患者肋间肌（10例）AChRα、β、γ、ε、δ亚单位mRNA的表达进行分析，同时采用ELISA方法检测83例MG患者血清AChR抗体对不同骨骼肌群AChR的反应。结果：①正常人眼外肌与其他骨骼肌一样均可见AChRα、β、γ、ε、δ亚单位mRNA的表达；②全身型MG患者肌肉AChRα P3A^＋／β—actin较正常对照组高（P=O．028）；③眼肌型、全身型MG抗成人腓肠肌AChR抗体显著高于抗胎儿肌肉AChR抗体（P=0．001，0．016）。结论：MG患者眼外肌易受累机制可能与眼外肌AChR亚单位mRNA表达水平及眼外肌的内在易感性有关。     

诱导实验性自身免疫性重症肌无力耐受性的机制初步探讨

目的:探讨鼻腔耐受和Wistar大鼠对实验性自身免疫性重症肌无力(EAMG)耐受的机制。方法:TdR掺入和酶联免疫斑点法。结果:免疫后第3、5、7周EAMG大鼠月国窝和腹股沟淋巴结(PILN)中乙酰胆碱受体(AChR)特异的淋巴细胞增生反应(LPR)刺激指数比鼻腔耐受大鼠高,第7周比Wistar大鼠高(P＜0.05)。免疫后第5、7周EAMG大鼠PILN中AChR反应性γ干扰素分泌细胞数比鼻腔耐受大鼠和Wistar大鼠高(P＜0.05)。结论:EAMG发生时淋巴细胞对AChR的免疫应答增强,分泌IFN-γ的Th1样细胞增多。EAMG耐受时,淋巴细胞对AChR的免疫应答降低,分泌IFN-γ的Th1样细胞受抑制。     

重症肌无力的免疫修饰治疗

重症肌无力是一种主要由乙酰胆碱受体抗体介导累及神经-肌肉接头的自身免疫疾病.免疫修饰治疗可明显减少重症肌无力患者病死率并提升社会生活质量,但可用免疫抑制剂品种多样且均有剂量相关性的不良反应.目前国内外研究者对符合重症肌无力的免疫抑制剂选取、具体使用方法等问题尚无确切定论,因此有必要对重症肌无力常用免疫修饰治疗的临床应用进行综述,为临床医师在重症肌无力个体化免疫修饰治疗方面提供参考.     

Antigen-specific therapy of experimental myasthenia gravis with acetylcholine receptor-gelonin conjugates in vivo

Rats suffering from experimental autoimmune myasthenia gravis (EAMG) induced by previous immunization with foreign acetylcholine receptor (AChR) were treated with AChR-toxin conjugates using the plant toxin gelonin. This led to a marked improvement of clinical symptoms as well as a significant increase in functional AChR compared to untreated rats with EAMG as determined 6 to 10 weeks later. No therapeutic effect was observed after treatment with gelonin or AChR alone. The immune response to irrelevant control antigens was not altered by this treatment.     

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.     

鼻黏膜耐受对实验性重症肌无力大鼠胸腺细胞凋亡的影响

目的探讨鼻黏膜耐受处理对实验性自身免疫性重症肌无力(EAMG)大鼠胸腺细胞凋亡及Caspase-3表达的影响。方法将实验大鼠随机分为正常对照组、EAMG组和耐受组,将EAMG组及耐受组大鼠采用Rα97-116肽段多点皮下注射法制备成EAMG大鼠模型后,再将耐受组大鼠经鼻腔滴注Rα97-116(V108A)行免疫耐受处理,10d后评估疗效(临床症状、体质量、抗体滴度等),并采用TUNEL法计数对照组、EAMG组及耐受组大鼠胸腺细胞的凋亡程度,用免疫组化法检测3组大鼠胸腺淋巴细胞内Caspase-3的表达,并分析其阳性细胞染色强度。结果 EAMG组大鼠胸腺细胞的凋亡数较对照组显著减少,鼻黏膜耐受处理能明显促进EAMG大鼠胸腺细胞的凋亡,并改善EAMG大鼠的肌无力症状,增加其体重及降低AchR抗体滴度。EAMG组胸腺中Caspase-3阳性细胞表达较对照组明显下调,耐受组其表达则明显增加,3组之间有显著的统计学意义(F=58.26,P0.01)。结论 Rα97-116(V108A)鼻黏膜耐受能明显减轻EAMG大鼠肌无力症状,缓解胸腺细胞凋亡异常。     

重症肌无力治疗性单价IgG抗体基因的构建

目的:构建一株对重症肌无力(MG)具有特异性免疫治疗作用的单价IgG类抗体基因.方法:应用定点突变技术,将致病性抗乙酰胆碱受体(AChR)抗体IgG637的重(H)链第322位氨基酸进行K322A突变,获得的突变型抗体IgG637/K322A基因再进行H链互补决定区3(CDR3)缺失突变,获得突变型抗体IgG637/K322A/CDR3ΔPLKP基因.经转化大肠杆菌XL1-Blue进行增殖后,转染哺乳类细胞CHO-k1进行表达,表达产物经ELIAS检测与补体C3的结合活性,经RIA检测与特异性抗原人AChR的结合活性.突变抗体H链再经杵(T366Y)臼(Y407T)突变,以利于异源H链的配对.结果:突变型抗体IgG637/K322A丧失了与补体C3结合的能力,突变型抗体IgG637/K322A/CDR3ΔPLKP丧失了与人AChR结合的能力.测序证实已经获得了预想的杵臼突变序列.结论:已经成功的制备了无补体激活能力的单价IgG类抗AChR抗体基因.     

Diagnostic and clinical classification of autoimmune myasthenia gravis

Myasthenia gravis is characterized by muscle weakness and abnormal fatigability. It is an autoimmune disease caused by the presence of antibodies against components of the muscle membrane localized at the neuromuscular junction. In most cases, the autoantibodies are against the acetylcholine receptor (AChR). Recently, other targets have been described such as the MuSK protein (muscle-specific kinase) or the LRP4 (lipoprotein related protein 4). Myasthenia gravis can be classified according to the profile of the autoantibodies, the location of the affected muscles (ocular versus generalized), the age of onset of symptoms and thymic abnormalities.The disease generally begins with ocular symptoms (ptosis and/or diplopia) and extends to other muscles in 80% of cases. Other features that characterize MG include the following: variability, effort induced worsening, successive periods of exacerbation during the course of the disease, severity dependent on respiratory and swallowing impairment (if rapid worsening occurs, a myasthenic crisis is suspected), and an association with thymoma in 20% of patients and with other autoimmune diseases such as hyperthyroidism and Hashimoto's disease. The diagnosis is based on the clinical features, the benefit of the cholinesterase inhibitors, the detection of specific autoantibodies (anti-AChR, anti-MuSK or anti-LRP4), and significant decrement evidenced by electrophysiological tests.In this review, we briefly describe the history and epidemiology of the disease and the diagnostic and clinical classification. The neonatal form of myasthenia is explained, and finally we discuss the main difficulties of diagnosis.     

Insights in the autoimmunity of myasthenia gravis

Myasthenia gravis is a prototype anti-receptor autoimmune disease. Antibodies against proteins at the neuromuscular junction cause a defect in the signal transmission from nerve terminal to the damaged postsynaptic membrane. This issue of Autoimmunity reviews the mechanisms that lead to the destruction of the neuromuscular junction and the role of the thymus in myasthenia gravis and its animal models. In addition, this issue explores recent advances in diagnosis and treatment of this disease.     

Plasma-separation in myasthenia gravis: A new method of rapid plasma exchange

Summary A patient with myasthenic crisis was successfully treated with a new method of plasma exchange using a hollow-fiber filter connected to a standard dialysis pump. The filter allows PE to be performed at more clinical centers and probably at lower costs than current methods applying blood cell separators.Supported by a grant from the Deutsche Forschungsgemeinschaft Bonn-Bad Godesberg (To 61/3)