The etiology of collagen diseases has long interested the world of science. Various theories, including that of autoimmunity, have been proposed. Since 1969 numerous authors have reported the finding of virus-like structures resembling a noncapsulated myxovirus in the tissues of patients with collagen diseases. Gyorkey and his colleagues1,2 called attention to myxovirus-like structures in human collagen diseases, including systemic lupus erythematosus. Others3-10 have reported the finding of a virus resembling nucleoprotein strands, epithelial inclusions, or myxovirus-like viral structures in patients with lupus erythematosus, Sjögren's syndrome, and other collagen diseases.
The most recent report comes from the M. D. Anderson Hospital and Tumor Institute in Houston. Grausz et al11 found cytoplasmic filamentous structures resembling unenveloped nucleocapsids of paramyxovirus or related virus types in vascular endothelial cells of the kidney, skin, and circulating leukocytes from 52 patients with systemic lupus erythematosus, in four patients with systemic sclerosis, in the