Sexually transmitted diseases, T cell subsets, and sexual practices in homosexual men attending an STD clinic.

Sixty three homosexually active men and 42 heterosexual men answered questionnaires regarding aspects of their social life and sexual practices. Assessment of past sexually transmitted disease showed the homosexual group to have had a significantly greater incidence of syphilis, gonorrhoea, perianal warts, and cytomegalovirus infections. T cell subset counts were carried out, and results for 60 of the homosexual men and 39 of the heterosexual men showed that the homosexuals had a significantly greater mean T cell suppressor cell count (p = 0.0019). The mean T helper cell count was not significantly different between the two groups, but it was significantly more (p = 0.033) in the more promiscuous homosexuals (who had more than 20 sexual partners a year) than in the heterosexuals. No relation was found between T cell subset counts and evidence of past cytomegalovirus infection. The practice of passive anal intercourse, oroanal sex, and swallowing semen during oral sex did not appear to influence T cell subset counts in the homosexuals.