| Abstract: | The effects of glucocorticoid on the differentiation of myeloid leukemia cells were examined. Dexamethasone at 10(-6)M or 10(-7)M revealed marked effects not only on leukemic blasts' survival but also on its' differentiation in vitro. In 10 of 17 cases of myeloid leukemia, the obvious morphological and functional differentiation induction effects were observed in vitro. The direction of differentiation were differed in leukemia cell lineage and in cases. Granulocytic differentiation in M2 cells, mono-macrophage differentiation in M5 cells and either granulocytic or monocytic differentiation in M4 cells were induced. A AML (M2), it's leukemia cells were induced into granulocytic pathway by dexamethasone in vitro, was treated with prednisolone (40 mg per day).Ara-C (15 mg per day). The increase in peripheral leukocyte count and the decrease in immature cells were observed simultaneously. The peripheral leukocytes mainly consisted of intermediate forms of granulocytes and Pelger-Hu?t like neutrophils probably originated from leukemia cells. After that course, abnormal clone was eliminated from bone marrow. A AMoL, it's leukemia cells were induced into macrophage like cells completely by dexamethasone in vitro, was treated with prednisolone (30 mg per day) and complete remission was obtained without passing through a hematological nadir. It is indicated that anti-tumor effects of glucocorticoid on myeloid leukemia cells are closely related to it's differentiation inducing effect and glucocorticoid can be used as the drug intending for the differentiation induction therapy of acute myeloid leukemia. |
