Lack of effector cell function in chronic lymphocytic leukemia, a B-cell malignancy, and the Sézary syndrome, a T-cell malignancy

In vitro reactivity of peripheral blood lymphocytes was examined from 13 patients with CLL and four patients with the Sézary syndrome. Lymphocyte proliferative responses to nonspecific mitogenic stimuli were generally depressed compared to normal controls. In vitro proliferative responses to specific antigenic stimuli were even more depressed. Lymphocyte effector functions which were independent of cellular division were also profoundly abnormal. Peripheral blood lymphocytes from both Sézary patients and CLL patients were incapable of mediating significant cytotoxicity toward 51Cr-labeled CRBC targets in either an antibody-dependent cellular cytotoxicity or a mitogen-induced cellular cytotoxicity model of nonspecific cytotoxicity. Similarly, cells from these patients were unable to produce normal quantities of lymphocyte-derived chemotactic factor when activated with either nonspecific mitogens or specific antigens. Thus malignant T cells and malignant B cells are incapable of performing many in vitro functions subserved by a broad range of normal lymphocytes.