In vitro function of a T-cell chronic lymphocytic leukemia with suppressor cell phenotype.

Surface membrane studies of cells from a patient with T-cell chronic lymphocytic leukemia (T-CLL) showed that they had an OKT3+, OKT4-, OKT8+ phenotype which is consistent with the phenotype of normal circulating peripheral blood suppressor/cytotoxic T-lymphocytes. The cells were HLA-DR+, anti-Tac-, SmIg- and E rosette+. Parallel studies in vitro showed that the T-CLL cells had a marked suppressive effect on both the mixed lymphocyte culture (MLC) proliferative response and the activation of cytotoxic T-lymphocytes. The T-CLL cells failed to respond or stimulate in MLC and were not directly cytotoxic to allogeneic peripheral blood lymphocyte targets. Both the suppression of the MLC and the cytotoxic responses depended on the presence of the T-CLL cells and not T-CLL culture supernatants. The T-CLL cells did not suppress the production of polyclonal antibody and did not produce interleukin-2 to levels above normal control lymphocytes.