Decreased natural killer cell activity versus normal natural killer cell markers in mononuclear cells from patients with smouldering leukemia.

Peripheral blood (PB) and bone marrow mononuclear cells from 23 patients with smouldering leukemia were analyzed for natural killer (NK) cell activity and various surface cell markers. Significantly reduced NK activity was detected in the patients' PB compared with the activity in the healthy controls (p less than 0.0005). A similar difference in NK cell activity between the 2 groups was also observed in bone marrow mononuclear cells (p = 0.005). In contrast, no significant differences in cells positive for the NK cell markers Leu-7 and Leu-11b were found between patients and controls, either in PB or in bone marrow. The patients' PB and bone marrow mononuclear cells had, however, a reduced percentage and absolute number of Leu 3a+ and T8+ cells. Patients with smouldering leukemia have immunological derangements which may make them predisposed for the later development of florid leukemia.