Evoli Amelia
Neuroscience Department, Catholic University, Roma, Italy.
Acta Neurol Scand Suppl. 2006;183:8-11. doi: 10.1111/j.1600-0404.2006.00606.x.
Autoimmune disorders of neuromuscular transmission are caused by antibodies (abs) directed against membrane proteins at the motor end-plate. Myasthenia gravis (MG) is due, in most cases, to abs against the nicotinic acetylcholine receptor (AChR). Anti-AChR-positive MG actually includes different disease entities: weakness can be confined to extrinsic ocular muscles or can be generalized; patients with generalized MG (G-MG) can be subdivided on the basis of age of onset, HLA association and thymic pathology. About 15% of G-MG patients are anti-AChR-negative; in a proportion of these cases serum abs against the muscle- specific kinase (MuSK) are found. Anti-MuSK-positive MG is characterized by predominant involvement of bulbar muscles and very low frequency of thymic pathology. The Lambert-Eaton myasthenic syndrome (LEMS) is caused by abs against voltage-gated calcium channels at nerve terminal. LEMS is characterized by muscle weakness and autonomic disturbances and it is paraneoplastic in over 50% of the cases. In neuromyotonia and cramp-fasciculation syndrome, that are thought to be due to anti-voltage-gated potassium channel abs, signs of peripheral nerve hyperexcitability can be associated with CNS features.
自身免疫性神经肌肉传递障碍由针对运动终板膜蛋白的抗体引起。重症肌无力（MG）在大多数情况下是由于针对烟碱型乙酰胆碱受体（AChR）的抗体所致。抗AChR阳性的MG实际上包括不同的疾病实体：肌无力可局限于眼外肌或为全身性；全身性MG（G-MG）患者可根据发病年龄、HLA相关性和胸腺病理进行细分。约15%的G-MG患者抗AChR阴性；在这些病例中，一部分患者血清中可检测到针对肌肉特异性激酶（MuSK）的抗体。抗MuSK阳性的MG以延髓肌受累为主且胸腺病理发生率极低为特征。兰伯特-伊顿肌无力综合征（LEMS）由针对神经末梢电压门控钙通道的抗体引起。LEMS的特征是肌无力和自主神经功能紊乱，超过50%的病例为副肿瘤性。在被认为由抗电压门控钾通道抗体引起的神经性肌强直和肌束震颤综合征中，周围神经兴奋性增高的体征可伴有中枢神经系统特征。
