ABOLITION OF SUPPRESSIVE EFFECT OF ACUTE MYELOID-LEUKEMIA CELLS ON NORMAL GRANULOCYTE-MACROPHAGE COLONY FORMATION INDUCED BY INTERLEUKIN-5 ASSOCIATED WITH EOSINOPHILIC CELL INDUCTION

The effects of recombinant interleukin-5 (rIL-5) on leukemic blasts ob tained from 22 acute myeloid leukemia (AML) patients were investigated . Recombinant IL-5 stimulated leukemic colony formation in the leukemi c blasts of 50% of the patients (11/22), and in 7 of these 11 cell cul tures leukemic eosinophilic colonies were induced. Eosinophilic cell i nduction was associated with cellular proliferation, that is, colony o r cluster formation, Leukemic blasts cultured with rIL-5 and forming e osinophilic colonies no longer suppressed normal granulocyte-macrophag e colony formation, suggesting that functional differentiation of thes e leukemic blasts took place. Induction of this type of functional dif ferentiation of leukemic blasts may be of clinical value in promoting normal hematopoiesis.