Thirty-seven men (36 homosexual or bisexual and one heterosexual) with epidemic Kaposi's sarcoma and underlying HIV infection were followed up over a period of up to 32 months. Fourteen patients (38%) died, with a median survival time of 7.2 months after the diagnosis of AIDS. Seventeen patients (46%) presented with one or more opportunistic infections, mostly Pneumocystis carinii pneumonia. Eighteen patients (49%) had lymphadenopathy syndrome according to the definition of the CDC. Using the Laubenstein-classification of Kaposi's sarcoma, all patients either remained stable or deteriorated, improvement was never observed. Absolute T4 lymphocyte counts and the T4/T8 ratio were not related to the disease stage. With the onset of B symptoms (systemic symptoms), however, the absolute T4 numbers and the T4/T8 ratio markedly decreased. Delayed type hypersensitivity also showed no relationship to the clinical stages of Kaposi's sarcoma. Thus, the clinical progression of Kaposi's sarcoma lesions seems to be largely independent of the immunological parameters investigated. However, the onset of B symptoms was observed to be related to changes in immune status.