Prevalence of HTLV-III/LAV antibodies in Italian asymptomatic hemophiliacs given commercial concentrates of factors VIII and IX.

The prevalence of HTLV-III/LAV antibodies was evaluated in 222 Italian asymptomatic hemophiliacs treated exclusively with commercial factor concentrates made with American plasma. An increase of HTLV-III/LAV seropositivity from 1983 to 1985 was evident. This was independent of the type of hemophilia (A or B) but directly correlated to the amount of concentrate administered in the previous year. Immunological data (T4 and T8 lymphocyte subsets) were evaluated in relation to seropositivity to HTLV-III/LAV. The presence of antibodies was found to be significantly associated with a low T4/T8 ratio and to a reduced T4 subpopulation, whereas increased levels of T8 lymphocytes correlated weakly with seropositivity. Data from 47 hemophiliacs tested both in 1984 and 1985 showed that 100% of those negative in 1984 and highly transfused in the previous year seroconverted up to 1985, whereas 33% of those not highly transfused did so.