Overlap syndrome of polymyositis and progressive systemic sclerosis associated with interferon therapy for chronic hepatitis C

Interferon (IFN)-α therapy may induce, reveal, or exacerbate various autoimmune-related disorders. We describe a 48-year-old female patient who developed muscle weakness during IFN-α therapy given for hepatitis C virus-associated chronic active hepatitis. This symptom diminished slightly after discontinuation of the therapy, but she then began to complain of Raynaud's phenomenon, swelling of bilateral dorsal hands and dysphagia. Accompanied by an elevation of serum antinuclear antibody, the subsequent development of polymyositis (PM) and progressive systemic sclerosis was considered to have been induced by the IFN-α.