INVITRO EFFECT OF 2 RELATED FORMS OF INTERFERONS (BETA AND ALPHA) ON NK ACTIVITY OF PATIENTS WITH HAIRY-CELL LEUKEMIA

The in vitro effect of beta- and alpha-IFN on NK activity has been evaluated in 10 patients with Hairy Cell Leukemia (HCL), selected from a larger group on the ground of peripheral blood neoplastic cell infiltration. In 5 patients (group A) more than 85% hairy cells were found, while in the others (group B) a lower infiltration (< 15%) was present. In the first group the baseline NK activity and NK active cells number were undetectable and neither beta- nor alpha-IFN had any enhancing effect. Conversely, in group B patients NK activity was measurable, despite an equally reduced NK active cell amount, only beta-IFN had a statistically significant enhancing effect. We suggest that this discrepancy in NK modulation by beta- and alpha-IFN, in HCL patients, may be ascribed to the differing affinity for type I IFN receptor and/or to postreceptorial activity.