Differentiation of human leukemic cells in primary culture-The effect of retinoic acid and harringtonine on acute and chronic myelogsnous leukemic cells

The effect of retinoic acid （RA） and antileukemic drug Harringtonine （Harr） on acute onlymphoid and chronic myeloid leukemic （CML） cells was investigated. RA 10^-6M and Harr 0.01, 0.003, 0.001μg/ml) could induce partial Mscells to differentiate into monocyte-macrophage cells nd romote CML cells to differentiate along the granulocyte pathway. RA and Harr-exposed leukemic cells howed morphological, histochemical and functional characteristics of granulocytes and macrophages, educed in NBT, stained positive for naphthol AS-D chlorqacetate esterase and （τ-naphthol acetate esterase α-NAE）, with corresponding changes of morphology. We also observed that Harr-inducing leukemic cell ifferentiation was accompanied by cytotoxic effect which paralleled with the concentration of Harr. These esults provide some useful data for clinic therapeutic use of RA and Harr.