Immunoregulatory abnormalities in chronic lymphocytic leukemia. I. Correlations of immunoregulatory subpopulations with stage of disease.

Previous studies have demonstrated multiple immunologic abnormalities in Chronic Lymphocytic Leukemia (CLL). We, therefore, investigated the relationship of immunoregulatory mononuclear cell subpopulations and disease activity in inactive and active CLL. The absolute number of T cells is increased in both groups compared to controls and a significant increase (p less than 0.001) in the number of monocytes was found in active patients. When the number of Fc gamma bearing T cells was compared to the number of B cells, active patients revealed a 993% decrease and inactive patients a 93% decrease compared to controls. Inactive patients also revealed increased proliferation when stimulated (PHA) after 48 hours in media alone compared to fresh cells. The active group revealed no increase in preincubated (PHA) stimulated cultures. As this suggested the possibility of immunoregulatory differences, suppressor cells were studied. Con A induced suppressor cells decreased proliferation of PHA stimulated cultures in inactive and control groups but had no effect in active patients. Isolated fresh autochthonous T cells (1:1) decreased PHA-induced proliferation 86% in the inactive group, 50% in the control group but had no effect in active patients. Pre-incubation (48 hr) followed by T cell separation revealed decreased Fc gamma T cells and abrogation of this suppressive effect in both inactive and control groups. Finally, isolated adherent cells decreased PHA stimulation by 86% in active patients but had insignificant effects on preincubated PHA stimulated cultures in the other groups. These data suggest that inactive CLL is characterized by a population of T suppressor cells that are more active than similar numbers of this population in control cultures. This population is short-lived and correlated with the Fc gamma bearing T cell population. This population appears inactive or non-functional in active CLL where adherent suppressor cells are increased.