A morphologic study on the occurrence and distribution of structures resembling viral nucleocapsids in collagen diseases

Abstract

Cytoplasmic filamentous structures resembling unenveloped nucleocapsids of paramyxo- or related viruses were found in vascular endothelial cells of the kidney and skin and in circulating leukocytes from patients with systemic lupus erythematosus (SLE) (fifty-two cases) and systemic sclerosis (four cases). These structures also occurred in the synovium in rheumatoid arthritis (four cases), in the vascular endothelial cells of the glomeruli in Sjögren's syndrome (three cases) and in the muscle cells in polymyositis (three cases). The structures were most abundant in systemic lupus erythematosus. It is proposed that the presence of these structures in large numbers suggests the diagnosis of systemic lupus erythematosus. These structures were absent in patients with procainamideinduced lupus syndrome and in eighty-three patients with kidney diseases other than those of the connective (collagen) tissues. These structures were also absent in nineteen patients without kidney disease or collagen disease. Occasionally, similar structures were found in one patient who received a renal transplant and in two patients with sickle cell disease; in these cases the extreme rarity of the structures was conspicuous. Morphologic studies suggest that the structures undergo developmental phases comparable to those of myxoviruses. The pathogenesis of collagen diseases is compatible with the etiologic role of a defective virus.