Human T-lymphotropic virus type III in high-risk, antibody-negative homosexual men.

A cohort of 215 asymptomatic homosexually active men from a Boston community health center are being prospectively followed to assess the natural history of the human T-lymphotropic virus type III (HTLV-III) infection. To determine if certain asymptomatic persons who are HTLV-III antibody negative may be viremic, an algorithm was developed that defined high-risk characteristics (a sexual partner with the acquired immunodeficiency syndrome [AIDS]; more than 100 homosexual partners; or leukopenia, lymphopenia, neutropenia, or thrombocytopenia). Of 33 asymptomatic homosexual men who did not have antibody to HTLV-III and whose cases have not been previously reported, 2 had HTLV-III recovered from their lymphocytes. Clinical, behavioral, and hematologic data from seronegative persons did not distinguish between those with negative or positive viral cultures. Asymptomatic carriage of HTLV-III in high-risk seronegative persons underscores the need to base preventive educational strategies and behavioral modification on the assessment of risk factors and not solely on the results of HTLV-III antibody screening.