Phytohemagglutinin or pokeweed mitogen induction of in vitro colony formation by T-cells from patients with chronic lymphocytic leukemia.

The colony-forming capacity of peripheral blood T-cells isolated from B-cell chronic lymphocytic leukemia patients was studied and compared with that of peripheral blood T-cells isolated from 2 groups of normal controls (young and aged healthy donors). Upon stimulation with phytohemagglutinin or pokeweed mitogen. T-cells from both the patients and the controls developed into colonies but only in the presence of the appropriate conditioned media. When the responses of the 3 groups were compared, no statistically significant differences were detected. However, the number of patients who failed to respond to phytohemagglutinin was larger than that of normal controls. Studies on a selected group of patients demonstrated that such unresponsiveness was unrelated to the presence of suppressor cells or to inadequate conditions used for stimulation in culture. Rather, this unresponsiveness may be connected with an intrinsic T-cell defect present in certain B-cell chronic lymphocytic leukemia patients.