Prevalence of Toscana and Sicilian Phlebovirus Antibodies in Classic Kaposi Sarcoma Case Patients and Control Subjects in Sicily

To assess whether arthropod bites promote Kaposi sarcoma (KS), we determined the seroprevalence of Sicilian (SFSV) and Toscana (TOSV) phlebovirus antibodies in 30 patients with classic KS and 100 controls in Sicily. Nine (6.9%) subjects, all controls, were positive for SFSV, whereas 41 (31.5%) were positive for TOSV. Seroprevalence with immunoglobulin (Ig) M or IgG against either virus was significantly higher in controls (43% vs 13.3% in case patients; P < .01). Adjusted for age, IgG seroprevalence was significantly lower in KS patients compared to controls (adjusted odds ratio, 0.22; 95% confidence interval, .07—. 72). Low phlebovirus seroprevalence in patients with KS may reflect incapacity to produce robust, persistent antibody responses, and suggests that arthropod bites do not promote KS.