Virus-like structures in muscle in chronic polymyositis

Summary Electron microscopic examination of a biopsy of skeletal muscle from a young girl with chronic polymyositis revealed the presence of sarcoplasmic and perinuclear inclusions.A large number of virus-like particles was demonstrated at the surface of muscle cells and in extracellular space. On the basis of the microscopic appearance it is suggested that the virus particles belong to one of the members of the paramyxovirus group.These studies are part of a research project supported by NIH Bethesda Md (U.S.A.) under agreement No. 05-002-1.