HTLV-1 associated polymyositis in Jamaica.

The clinical, laboratory and epidemiological characteristics of 38 adult Jamaican patients with polymyositis were evaluated. Twenty-four patients (63%) were human T-lymphotropic virus 1 (HTLV-1) seropositive and 14 patients (37%) were HTLV-1 seronegative. Polymyositis runs a more protracted course in seropositive patients who had more frequent hospital admissions and a significantly longer duration of symptoms prior to presentation. Joint swelling, chest pain and dyspnoea were more frequent complaints among the seronegative patients. There was no significant difference between the two serological groups in muscle enzyme levels, antinuclear antibody positivity or frequency of Jo-1 antibodies. HTLV-1 infection may define a subgroup of polymyositis patients with a more insidious presentation and poorer response to corticosteroid therapy.