Relatedness by nucleic acid hybridization of new isolates of human T-cell leukemia-lymphoma virus (HTLV) and demonstration of provirus in uncultured leukemic blood cells.

Human T-cell leukemia-lymphoma virus (HTLV) has now been isolated from many different patients with cutaneous T-cell lymphoma and leukemia, as judged by detection of media reverse transcriptase and virus particles and of antigenic determinants related to those of viral structural proteins p24 and p19. Molecular hybridization experiments with HTLV cDNA to viral mRNA or proviral DNA to ascertain the relatedness of four of these new isolates to the first HTLV isolate have been used. By these assays, three appear virtually indistinguishable from the original isolate, HTLV-I(CR), the second U.S. isolate (HTLV-I[MB]), and the Japanese ATLV isolates. Proviral sequences indistinguishable from those of HTLV-I(CR) were also detected in uncultured leukemic blood leukocytes from a patient of Japanese origin with adult T-cell leukemia. These viral isolates thus form a closely related virus group, HTLV-I. In contrast, however, RNA and DNA from one cell line derived from a patient with a T-cell variant of hairy cell leukemia, which expresses media reverse transcriptase and antigenic determinants related to but distinguishable from HTLV p24, did not hybridize substantially with HTLV cDNA. This latter virus appears to represent a second type of HTLV (HTLV-II), related to but substantially different from HTLV-I.