HTLV-III: the etiologic agent of AIDS

A retrovirus belonging to the family of human T-cell leukemia/lymphoma virus (HTLV) was isolated from several patients with acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC) and asymptomatic homosexual males at increased risk of developing AIDS. This new virus was designated HTLV-III. A serological screening procedure incorporating an enzyme-linked immunosorbent assay (ELISA) and a radioimmunoassay using a Western blot technique was developed employing disrupted HTLV-III as the antigen source. These assays identified serum antibodies to HTLV-III antigens in almost all patients with AIDS, greater than 90% patients with ARC and about 40% of homosexual males at risk for developing AIDS. In a study of transfusion associated AIDS (TA-AIDS) all 19 of the TA-AIDS cases had antibodies to HTLV-III. Similarly 31 of 35 high risk donors who donated to cases of TA-AIDS had antibodies to HTLV-III. All four of the antibody negative high risk donors donated to cases that received blood from at least one other high risk donor. In contrast only 2 of 255 other donors were antibody positive. The data clearly indicate that TA-AIDS cases developed the disease as a result of transmission of HTLV-III through contaminated blood and that HTLV-III is the primary etiologic agent of AIDS.