B - Lymphocytic Hairy Cells Contain no HTLV - H DNA Sequences

T HE HUMAN lymphotropic virus HTLV-II has been isolated from two patients with a variant T-cell form of hairy cell leukemia (HCL).”2 However, HCL is seen predominantly as a malignancy of B-cell lineage. Some suggestive evidence for HTLV-II in connection with HCL comes from the observation of cell-surface Tac antigen, which is correlated with T cells and selected T-cell malignancies, in B lymphocytic cells.3 In adult T-cell leukemias, the expression of cell-surface Tac antigen is strongly correlated with the presence of human T-cell leukemia virus type-I (HTLV-I).4 Furthermore, both HTLV-I and II are capable of infecting and transforming normal T lymphocytes in vitro.57 HTLVII, whose host range has not been fully established, also infects B-cells in vitro.5 These observations led us to ask directly whether HTLV-II is associated with the predominant B-cell form of HCL.