HTLV-III and HTLV-I infection in populations at risk in the Veneto region of Italy.

A seroepidemiological survey has been carried out in the Veneto region to determine the prevalence of HTLV-III and HTLV-I antibodies in subjects at risk for development of AIDS and related conditions. Serum samples were tested by ELISA and, for confirmation, by radioimmunoassay (Western blot), using disrupted virus as antigen. The results show that 22 out of 112 hemophiliacs had antibodies against HTLV-III; however disaggregation of data resulted in 22.6 and 77.8% positivity for patients with severe forms of hemophilia A and B, respectively. Two patients with hemophilia A and two with hemophilia B were positive for antibodies to HTLV-I. The prevalence of HTLV-III antibodies in the homosexual and intravenous drug abuser groups was 52 and 33% respectively. No positive cases for antibodies to HTLV-I were found in homosexuals, while 4.3% seropositivity to HTLV-I was observed in drug abusers. Among patients suffering from various pathologic conditions not strictly AIDS related, only 1 with generalized non-Hodgkin lymphoma was positive for HTLV-I antibodies. In a further group of patients with clinical diagnosis of LAS and AIDS, antibodies to HTLV-III were found in 90 and 100% respectively, while seropositivity for HTLV-I was observed only in 6.4% of LAS patients. The implications of these findings are discussed, particularly in view of the potential oncogenic effect possessed by HTLV-I.