Normal antibody-dependent killer cell function in patients with chronic lymphocytic leukemia.

Unfractionated mononuclear peripheral blood leukocytes (PBL) and nylon wool-nonadherent (B-cell-depleted and T- and null-cell enriched) cells from normal control individuals and untreated patients with chronic lymphocytic leukemia (CLL) were tested for killer cell function in an antibody-dependent cell-mediated cytotoxicity assay. Killer cell activity was present in unfractionated cells from normal individuals and was enriched after removal of adherent cells. Target cell killing by unfractionated mononuclear cells from CLL patients was deficient in 5 of 6 patients tested, but after removal of adherent cells it was approximately equal to that of normal nonadherent cells. Our results indicate that the apparent deficit of killer cells in unfractionated PBL from some CLL patients is due to dilution of killer cells and not to an intrinsic defect in the function of these cells, the presence of suppressor cells in the adherent population, or suppression of killer cell function by serum factors.