Myasthenia gravis (MG) is an autoimmune disease amyotrophic lateral sclerosis, 3 with polymyositis, and 2 with Lambert-Eaton syndrome) were used for con-of the neuromuscular junction caused by circulating antibodies to acetylcholine receptor (AChR). In addi-trol; none had antihuman AChR antibodies. tion, MG patients, particularly those with thymoma, also show presence of striational antibodies (StrAb)
Preparation of Antigen. The preparation of striawhich are reactive with various myofibrillary protional antigen from skeletal muscle was previously teins. 1,[7][8][9]16,17 Neither the mechanism stimulating their described. 16 The antigen was obtained from ampuproduction nor the basis for their association with tated human skeletal muscle. The RyR antigen for MG and thymoma is known. The present study underimmunoblots was prepared from rabbit skeletal mustook to define the antigenic specificities of StrAb cle as previously described with some modificain MG patients with or without thymoma. Particular tions. 4,14 The pellets were quickly frozen using liquid attention was focused on antibodies directed against nitrogen and stored at Ϫ70ЊC until use. the ryanodine receptor (RyR), which are frequently seen in MG patients with thymoma. 7,8 Enzyme Immunoassay for Detection of StrAb. Details were previously described. 3 For each serum dilu-