Immunological distinction of adult T cell leukaemia from T cell acute lymphoblastic leukaemia.

The antigenic properties of leukaemic cells from five patients with adult T cell leukaemia were studied with rabbit anti-MOLT-4 and anti-human thymocyte antisera using indirect membrane immunofluorescent staining. The E rosette-positive, surface immunoglobulin (sIg) negative leukaemic cells from these patients gave a positive reaction with the appropriately absorbed antisera, which reacted specifically with thymocytes, cells from T cell acute lymphoblastic leukaemia (T-ALL) and T-ALL-derived lymphoblastoid cell lines (T-LCLs) and normal peripheral blood T cells. Nevertheless, the antisera further absorbed with fresh normal peripheral blood lymphocytes (FN-PBL) lost almost all the reactivities with the leukaemic cells as well as with normal peripheral blood T cells but still retained the reactivities with thymocytes, T-LCLs and T-ALL cells. The results suggest that adult T cell leukaemia cells possess a peripheral blood T cell antigen but not a thymocyte-specific antigen.