Anti-LAV/HTLV-III antibodies in groups of individuals at high risk for infection in Italy.

We have studied anti-LAV/HTLV-III antibody prevalence in individuals at high risk for infection, such as intravenous drug addicts, hemophiliacs and homosexual men. Among intravenous drug addicts, LAV/HTLV-III infection was first recognized in 1981 and positive serum reactions for anti-LAV/HTLV-III antibody rose in successive years to 53%. Anti-LAV/HTLV-III antibody prevalence was 13.5% in the group of homosexual men, while in hemophiliacs treated with commercial concentrates it was 37% in 1984 and had increased to 45% in 1985. There was a significant correlation between antibody status and concentrate consumption in these patients. Results of studies of anti-LAV/HTLV-III antibody patterns with the Western blot technique suggest that antibodies against core proteins (mainly p25 and p18) and the envelope protein gp40 are always present in asymptomatic individuals and in patients with the lymphadenopathy syndrome, but usually not in patients with full-blown AIDS. These last patients have typical positive reactions only against the envelope proteins gp110 and gp40.