HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE-1 TAX AMONG AMERICAN BLOOD-DONORS

In the United States, all blood used for transfusion is tested for the presence of antibodies to the structural components of the human T-ce ll lymphotropic viruses types 1 and 2 (HTLV-1 and -2). Based on such s erologic tests, the prevalence of HTLV-1 infection is estimated to ran ge from 0.016 to 0.1%. As a consequence of studies of patients with my cosis fungoides and some of their healthy relatives who are antibody n egative but were found to carry the tax sequence of HTLV-1 in their ly mphocytes and who had antibodies to the p40(tax) protein, a study was undertaken to determine the prevalence of the ''tax-only'' state in 25 0 healthy blood donors and other volunteers. Using PCR and Southern an alysis for cell lysates and using Western blotting for plasmas, 8.6% o f the blood donors proved to be tax sequence positive and antibody pos itive. Sequence analysis of specimens from 22 individuals proved that 20 of the sequences were homologous with that of HTLV-1 while 2 resemb led the HTLV-2 sequence. The latter were obtained from volunteers of I ndian origin. The possible clinical significance of the tax-only carri er state is discussed.