Three-year prospective study of HTLV-III/LAV infection in homosexual men.

170 symptom-free homosexual men were recruited in London in 1982-83 and 133 were evaluable in 1983-85. Of the 33 who were seropositive to HTLV-III/LAV at entry, 4 (12%) progressed to AIDS, 16 (48%) progressed to persistent generalised lymphadenopathy (PGL), and 13 (40%) remained symptom-free. A further 15 men seroconverted during the study (7% per annum), of whom 8 progressed to PGL. Serial estimations of T lymphocyte subsets showed progressive reduction in T4 numbers in the seropositive groups, but these indices also varied widely in the seronegative group. Counts of T4 and T8 cells or T4/T8 ratio at entry were not of prognostic value. Seronegative subjects were as likely as seropositives to have abnormal immunological tests. Serial measurement of T lymphocyte subsets seems to be of little prognostic or clinical value in the monitoring of populations infected with the HTLV-III/LAV virus. The strongest association with prognosis was an episode of sexually transmitted disease in the six months before entry to the study. This supports the hypothesis that intercurrent infection may be an important co-factor in the acquisition of HTLV-III/LAV infection, and in subsequent disease progression.