Kaposi's sarcoma in transplant and HIV-infected patients: An epidemiologic study in Italy and France

Background. A follow-up study was conducted in Italy and in France to compare the epidemiology of Kaposi's sarcoma (KS) between human immunodeficiency virus (HIV)-infected people and transplant recipients. Methods. In all, 8,074 HIV-positive individuals (6,072 from France and 2,002 HIV-seroconverters from Italy) and 2,705 Italian transplant recipients (1,844 kidney transplants, 702 heart transplants, and 159 liver transplants) were followed-up between 1970 and 2004. Standardized incidence ratios (SIRs) and 95% confidence intervals (Cls) were computed to estimate the risk of KS, as compared to sex- and age-matched Italian and French populations. Incidence rate ratios (IRRs) were used to identify risk factors for KS. Results. A 451-fold higher SIR for KS was recorded in HIV-infected subjects and a 128-fold higher SIR was seen in transplant recipients. Significantly increased KS risks were observed in HIV-infected homosexual men (IRR=9.7 in France and IRR=6.7 in Italy vs. intravenous drug users), and in transplant recipients born in southern Italy (IRR=5.2 vs. those born in northern Italy). HIV-infected patients with high CD4+ cell counts and those treated with antiretroviral therapies had reduced KS risks. In relation to duration of immunosuppression, KS occurred earlier in transplant patients than in HIV-seroconverters. Conclusions. This comparison highlighted that the risk of KS was higher among HIV-infected individuals than in transplant recipients, and that different co-factors are likely to influence the risk of KS. Moreover, the early KS occurrence in transplant recipients could be associated with different patterns of progressive impairment of the immune function.