Incidence of Kaposi's sarcoma in a cohort of homosexual men infected with the human immunodeficiency virus type 1. The Multicenter AIDS Cohort Study Group.

Longitudinal data on 2,125 participants in the Multicenter AIDS Cohort Study (MACS) with documented antibodies to the human immunodeficiency virus type 1 (HIV-1) were used to examine the incidence of acquired immune deficiency syndrome (AIDS)-related Kaposi's sarcoma (KS) over time and to determine if sexual practices and hematologic variables prior to diagnosis differed for participants who develop KS vs. non-KS AIDS (NKS). In the first 4 years of the study, 84 seropositive men were observed to develop KS and 307 presented with an AIDS diagnosis other than KS. A systematic trend in the incidence of KS over time was not apparent in this population. The number of anal-receptive intercourse partners prior to diagnosis declined in a similar fashion for both AIDS groups. Although the number of partners with whom the men performed rimming decreased prior to diagnosis for both AIDS groups, a greater proportion of the KS AIDS group had performed this activity with multiple partners than had the non-KS AIDS group. Furthermore, history of oral gonorrhea was significantly (p = 0.027) more prevalent in the KS group. In addition, the KS AIDS group had lower cytomegalovirus antibody levels prior to diagnosis and higher levels of total immunoglobulin G. The groups did not differ with respect to baseline hematological measures, temporal trends in helper and suppressor T cells, or hepatitis B surface antigen or antibody. Given this profile of factors associated with the occurrence of KS, an infectious agent, in addition to HIV-1, is plausible as a proposed cofactor in the development of KS.