Infection with human herpesvirus type 8 and Kaposi's sarcoma in Sardinia

Background: A cross-sectional study was conducted in the provinces of Sassari (northern Sardinia, covered by a population-based cancer registry), and of Cagliari (southern Sardinia) to estimate the prevalence of infection with human herpesvirus type 8 (HHV8) and the incidence of classic Kaposi's sarcoma (KS) among HHV8-infected individuals. Patients and Methods: Sera from 297 hospitalized persons potentially at risk of developing classic KS (i.e., those aged 50 years or older) were tested for antibodies against HHV8. HHV8 seroprevalence rates (with 95% confidence intervals - CI) and yearly incidence rates (IR/100,000) of KS were calculated according to age and sex. Results: Of tested individuals, 32.0% had antibodies against HHV8 in Sassari and 30.0% in Cagliari. Estimated IR of KS among HHV8-positive persons and KS:HHV8 ratio were two times higher in Sassari (1:3,891) than in Cagliari (1:8,114), and higher in men (1:2,846 in Sassari; 1:5,483 in Cagliari) as compared to women (1:6,827 in Sassari; 1:12,489 in Cagliari). Conclusions: Although the overall prevalence of HHV8 seemed similar in Sassari and in Cagliari, the risk of KS was higher in Sassari, suggesting that different cofactor(s), or different distribution of the same cofactor(s) between the two provinces of Sardinia, might have played a role in KS development.