INTERLEUKIN-12 AUGMENTS NATURAL-KILLER-CELL MEDIATED CYTOTOXICITY IN HAIRY-CELL LEUKEMIA

Interleukin 12 (IL12, NKSF-natural killer stimulatory factor) was foun d to stimulate natural killer (NK) cell activity of hairy cell leukemi a (HCL) patients. Two patients not responding to IL12 stimulation were also resistant to interferon alpha (IFN alpha)-mediated augmentation of NK activity. IL12 also enhanced slightly the interleukin 2 (IL2)-in duced cytotoxicity of HCL patients, while IFN alpha reduced the stimul atory effect of IL2. These data suggest that interleukin 12 has NK mod ulatory properties in HCL leukemia patients, which may be different fr om those of IFN alpha.