A Case of Polymyositis associated with Hepatitis B infection

Polymyositis(PM) is one of idiopathic inflammatory myopathy, characterized by proximal muscle weakness, myalgia and muscle enzyme elevation. Currently the main pathogenesis is well documented, the cell-mediated immunity. We experienced a case of polymyositis associated with hepatitis, developed after hepatitis B virus(HBV) infection. This virus-induced autoimmunity seems to result from the cross-reactivity between muscle protein and B-viral antigen, so called antigenic mimicry. This relation of PM and HBV is more significant in Korea because of the epidemicity of HBV infection.