Impaired T-cell transformation in chronic lymphocytic leukemia (CLL): Demonstration of a blastogenesis inhibitory factor.

A noncytotoxic serum factor was found in CLL serum which interfered with the response of normal lymphocytes to phytohemagglutinin (PHA) and pokeweed mitogen (PWM). This factor was not produced by B-lymphocytes during short-term culture. This factor may contribute to the impaired lymphocyte responsiveness in CLL. In five of six patients, T-lymphocytes which were purified by passage over nylon wool columns exhibited an impaired response to both PHA and PWM, suggesting that a dilutional effect alone does not fully explain the impaired lymphocyte transformation in CLL.