HTLV-1 and polymyositis in Jamaica.

IgG antibodies to human T-cell lymphotropic virus (HTLV-1) were found in 11 of 13 (85%) Jamaican patients with idiopathic adult polymyositis. The association was first observed in 7 patients with polymyositis who were included in a control group of 100 patients with neurological and neuromuscular diseases in a serological investigation of the prevalence of HTLV-1 antibody in patients with tropical spastic paraparesis. All 7 patients with polymyositis were positive for the antibody by an enzyme-linked immunosorbent assay, confirmed by western blot. Because of this striking association a further 6 patients with polymyositis were identified and tested, 4 of whom were also seropositive for HTLV-1 antibody.