Coexistence of Myasthenia Gravis and Systemic Lupus Erythematosus

중증 근무력증과 전신성 홍반성 낭창의 동반 발생

Background: Myasthenia gravis (MG) and systemic lupus erythematosus (SLE) are well recognized to coexist and have some similarities in immunologic, clinical and serologic findings. Despite several reports of the association with autoantibodies and thymectomy in these disorders, the pathomechanism of coexistence remains to be elucidated. Objective: We aimed to investigate the relationship of MG and SLE through overall features of patients with both disorders;: clinical, laboratory, and electrophysiological findings. Materials and Methods: We reviewed the medical records of 6 consecutive patients with MG and SLE (2 men, 4 women, ages 17-51, mean 30.5 years, Seoul National University Hospital, from 1998 to 2005). Results: Three patients who developed SLE first, had ocular type of MG and 2 were children showing much severe and recurrent SLE features and only 1 patient had thymic hyperplasia. The other 3 developed MG first and they were generalized type and none underwent thymectomy. In addition, the development of MG or SLE was not coincident with remission or improvement of another disorder. Conclusion: The coexistence of SLE and MG may support the hypothesis of two different antibody populations modulated by thymus in the opposite extremesThis report suggests that the systemic and extensive autoimmune response in preceding MG or SLE may effect the development of the other disorder followed, while. the coexistence of two disorders cannot be explained by the hypothesis of two different antibody populations modulated by thymus in the opposite extremes The role of thymectomy and the theorectical subsequent effect on the development of SLE have been debated with controversy. However, SLE occurred without thymectomy in MG and these disorders did not develop in the quiescent period of another disorder. Therefore, the other pathomechanism for the coexistence of MG and SLE should be elucidated.