Associations of age, immunosuppression, and AIDS among homosexual men in the Tricontinental Seroconverter Study.

To characterize the associations of age, immunosuppression, and AIDS outcomes, we evaluated serial measures of CD4+ lymphocytes from 376 homosexual men with documented dates of HIV-1 seroconversion registered in the Tricontinental Seroconverter Study. Using regression models and adjusting for variation within individuals, we found no association between age and the number of CD4+ lymphocytes at seroconversion or with CD4+ lymphocyte decline after seroconversion. Men who developed opportunistic infections had fewer CD4+ lymphocytes at the time of diagnosis compared with men who developed AIDS-defining Kaposi's sarcoma. Older age was significantly associated with higher numbers of CD4+ lymphocytes in individuals diagnosed with AIDS-defining Kaposi's sarcoma but was not significant for individuals with opportunistic infections. Because older age shortens the latency period of Kaposi's sarcoma and does not affect the CD4+ lymphocyte loss, it results in higher CD4+ lymphocytes at the time of diagnosis. These findings suggest distinct biologic mechanisms for various AIDS manifestations, which is important for clinical decision making and health care planning.