2026 年 43 巻 1 号 p. 38-43
Idiopathic inflammatory myopathies are a group of muscle diseases in which muscle fibers are damaged by immunological mechanisms. Advances in muscle pathology and the discovery of numerous myositis–specific autoantibodies have led to their classification into many distinct clinical subtypes : polymyositis, dermatomyositis, immune–mediated necrotizing myopathy, anti–synthetase syndrome, inclusion body myositis. Treatment strategies require careful assessment of muscle strength, systemic inflammatory findings, muscle pathology, muscle imaging, and complications. Glucocorticoids are administered as first–line therapy, while immunosuppressants and intravenous immunoglobulin play a crucial role as second–line treatments. Furthermore, numerous molecularly targeted drugs are currently under development. Presently, treatment strategies for refractory cases remain unestablished, necessitating further development of therapeutic approaches.