Phenotypic and functional changes in chronic lymphocytic leukemia.

The study was carried out in 170 patients with chronic lymphocytic leukemia (CLL) at the onset, grouped according to RAI staging system, and in 20 controls. Using the rosette tests (E4 degrees, E 29 degrees, EAC and M) different lymphocytic subpopulations were detected. Their functional competence was studied by in vitro response to mitogens (PHA, PWM) and to an antigen (PPD). As it is well known the mean values of these parameters in CLL were found significantly reduced as compared to controls. But when compared according to the five clinical stages in CLL, two main aspects were observed. (a) stage 0 of the disease differs from the other clinical stages by the significantly low mean values of the parameters characteristic of the B cell line namely EAC rosetting and the in vitro response to PPD and PWM. Stage 0 of the disease is closer to the normal values; (b) the response of the PWM-stimulated T-dependent B cells decreases gradually and significantly with the clinical course of the disease and hence with the advance of clinical stages. The functional contribution of the various lymphocytic populations in this test is discussed as well as their possible implication in the pathogenesis of the disease.