Effect of recombinant interferons on hairy cell leukemia progenitors

The effects of recombinant interferons (rIFNs) on colony formation by progenitor cells from the peripheral blood of patients with hairy cell leukemia (HCL) were examined. Results showed that both rIFN-alpha and -beta inhibited HCL colony formation in a dose-dependent manner, with the inhibitory effect of rIFN-alpha being similar in degree with that of rIFN-beta. The inhibitory effect of rIFN-gamma, however, was not uniform; of four patients, inhibition was observed in cells from two patients, but no effect was found in the cells of the other two. These results indicate that rIFN-alpha and -beta could be effective in the treatment of HCL, whereas rIFN-gamma may be of limited efficacy.