Normal T cell subsets in homosexual men living in a community without endemic AIDS.

The cause of the abnormal T lymphocyte subsets reported in healthy homosexual men is not known. Frequent sexually transmitted infections including human T cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) are possible causes. To determine if the T lymphocyte subsets were abnormal in this population in an area without endemic acquired immune deficiency syndrome (AIDS), T lymphocyte subsets of 52 homosexual men in Rochester, New York, were enumerated, and evidence of infections known to cause these abnormalities was sought. Unlike the findings in previous reports, relative numbers of T helper and T suppressor cells and helper/suppressor T cell ratios were normal. Prevalence of cytomegalovirus infection (86 percent) was similar to that found in analogous populations, but only 9 percent had seropositive results for HTLV-III/LAV. Men with serologic evidence of nonprimary cytomegalovirus disease had lower helper/suppressor T cell ratios (1.5 +/- 0.2 versus 2.2 +/- 0.2; p less than 0.01). Hence, despite frequent infections with cytomegalovirus and other sexually transmitted pathogens, T cell subsets are normal in homosexual men in an area without endemic AIDS. Therefore, HTLV-III/LAV is primarily responsible for the T cell abnormalities observed elsewhere.