Transfusion-associated acquired immunodeficiency syndrome. Evidence for persistent infection in blood donors.

To investigate whether infection with human T-cell lymphotropic virus/lymphadenopathy-associated virus (HTLV-III/LAV) may be persistent in asymptomatic persons and to correlate infection with seropositivity, we performed virologic and serologic studies in 25 of 30 persons who were identified as being at high risk for the acquired immunodeficiency syndrome (AIDS) and who had donated blood to patients who later contracted transfusion-associated AIDS. High-risk donors were those who belonged to a high-risk population, had AIDS or a closely related condition, or had a low ratio of helper to suppressor T lymphocytes. We performed similar studies in 6 of the 24 patients with AIDS who had received donations from this group. HTLV-III/LAV was isolated from 22 of the 25 donors, between 12 and 52 months (mean, 28) after they had donated blood, and from all 6 recipients, between 14 and 37 months (mean, 26) after they had received blood. Of the 22 virus-positive donors, 2 have contracted AIDS, 5 have generalized lymphadenopathy, and 15 (68 per cent) remain asymptomatic. Antibodies to HTLV-III/LAV were detectable by the enzyme-linked immunosorbent assay in serum samples obtained from each person at the time the virus was isolated. We conclude that infection with HTLV-III/LAV may be persistent and asymptomatic for years. This demonstration that viremic patients may be asymptomatic supports the use of serologic screening of donated blood to supplement current procedures for the prevention of transfusion-associated AIDS.