Virus-like particles in paraspinal muscle in scoliosis.

Biopsy material from the skeletal muscle (paraxials) of 21 patients with scoliosis was examined by light and electron microscopy. Virus-like particles, 17 nm in diameter with a crystalline structure, were identified in the skeletal muscle fibres of four patients. Associated changes in the sarcoplasm included swelling of mitochondria, presence of lipid droplets, and vesicular structures. Serological studies and culture for virus isolation gave negative results. An excess of lipid (predominantly in type 1 fibres) was noted in the skeletal muscle of several other cases. The significance of these findings is obscure, but the morphology of the paraxial muscles of patients with scoliosis and controls is currently being investigated in greater detail.