Risk factors for human Herpesvirus 8 infection and AIDS‐associated Kaposi's sarcoma among men who have sex with men in a European multicentre study

We aimed to identify risk factors for Kaposi's sarcoma (KS) among HIV‐positive patients and behaviors associated with human Herpesvirus 8 (HHV‐8) infection, as well as to assess KS incidence and mortality rates longitudinally. To fulfill the first objective, a European case‐control study was designed in the early 1990s (each KS case was matched to 2 controls with another AIDS indicative disease). After the discovery of HHV‐8, serology testing enabled us to assess risk factors for KS development among HHV‐8 and HIV‐1 coinfected men who have sex with men (MSM), as well as risk factors for HHV‐8 infection. HHV‐8 seroprevalence was determined using a latent immunofluorescence assay. Relevant information was obtained by means of a questionnaire and medical charts review. Assessment of risk factors for KS development and HHV‐8 infection was performed using conditional and unconditional logistic regression models, respectively. A low CD4 count was the only significant risk factor for KS. HHV‐8 infection was most strongly linked to the number of life‐time sex partners, and multiple body fluids such as saliva and semen are quite likely involved in sexual transmission. Longitudinal follow up showed a significant protective role for highly‐active antiretroviral therapy (HAART) both on KS development and mortality of KS patients. Although more conclusive data from cohort studies are needed to better define specific transmission mechanisms for HHV‐8, our results contribute to explain why KS incidence is higher among MSM, and the decreasing KS incidence trend observed in countries with universal access to HAART. © 2006 Wiley‐Liss, Inc.