Interaction of Human Immunodeficiency Virus Type 1 and Human Herpesvirus Type 8 Infections on the Incidence of Kaposi's Sarcoma [Jacobson LP, et al. JID 2000; 181: 1940]: This is a report from the Multicenter AIDS Cohort Study (MACS) to determine the risk of Kaposi's sarcoma in relationship to the time of acquisition of HIV and HHV-8 infections. Stored sera that was collected longitudinally from 400 gay men with known dates of HIV-1 seroconversion were tested for HHV-8 antibody. The time from HHV-8 seroconversion to clinical KS was compared for 69 men who developed HHV-8 infection after HIV to 182 men who were seropositive for HHV-8 before HIV-1 infection. The former group, those with HHV-8 seroconversion after HIV-1 infection, had an increased rate of KS with a risk ratio of 2.6. Other risk factors associated with the development of KS were a more rapid decline in CD4 cell counts and high HIV-1 RNA plasma levels.
Comment: This is an extraordinary study that illustrates the advantage of a cohort with longitudinally collected samples over a sustained period. The findings in this review include the following:

• Most of the patients, 73%, acquired HHV-8 before HIV-1 infection.
• There are several behavioral risk factors for acquiring HHV-8 including large numbers of sex partners, multiple sexually transmitted diseases and recreational drug use. None of these were risk factors for progression to KS.
• HHV-8 appears to be similar to other herpesviruses such as CMV, EBV and HSV: They all remain latent in the immune-competent host and then cause severe disease reflecting viral reactivation or primary infection when there is immunosuppression.
• Among the 400 men who participated, 37% were HHV-8 seropositive at baseline, and 102 (40%) became infected with HHV-8 during a follow-up period of approximately 10 years. This shows the high rate of HHV-8 infection in this population.
• Of the 251 patients with HHV-8, 42 (17%) developed KS.
• The median CD4 cell count was 120/mm³ at the time of KS.
• The high rate of HHV-8 infection and the low rate of KS in the absence of immunosuppression indicates that persons with HHV-8 infection do not need to be monitored unless they have a condition that will compromise cell-mediated immunity such as HIV-1.
• The association of immunosuppression with the development of KS indicates that the risk of KS should be reduced with immune reconstitution, and this has been shown [AIDS 1998; 12: F45; JAIDS 1999; 21: S34]. posted 8/3/2000