[A case of anti-Th/To antibody-positive systemic sclerosis with muscle symptoms and interstitial pneumonia].

A 62-year-old Japanese man with swollen fingers and walking difficulty due to myalgia and muscle weakness in proximal limb muscles was admitted to our hospital. Serum creatine kinase was remarkably increased (7,380 U/l) and rapidly progressing interstitial pneumonia developed. Muscle biopsy showed necrotic and regenerating fibers without mononuclear infiltration and fibrosis. Anti-Th/To antibodies were detected in the serum, and anti-Th/To antibody-positive systemic sclerosis was diagnosed. Anti-Th/To antibody-positive sclerosis-associated myopathy has not yet been reported in the literature. The present case suggests that anti-Th/To antibody-positive systemic sclerosis can be accompanied by immune-mediated necrotizing myopathy and be effectively treated with immunotherapy comprising corticosteroids, tacrolimus and immunoglobulin.