Studies on CFU-mix of 47 patients with leukemia and myelodysplastic syndrome.

By limiting dilution assay, CFU-Mix of 47 cases of untreated leukemia, myelodysplastic syndrome and 30 cases of normal adults were studied. It is suggested that most cases of acute nonlymphocytic leukemia, like chronic myelogenous leukemia (CML) and myelodysplastic syndrome should have defect in pluripotent hemopoietic stem cell. The CFU-Mix of acute myelogenous leukemia (AML) and CML were obviously lower than that of normal adults (p less than 0.001). By light microscopy, scanning and transmission electron microscopy, it was confirmed that the CFU-Mix colonies, of leukemic patients were chiefly composed of leukemic cells. Their incorporating rate of 3H-TdR was high in the early stage of culture, but that of 55 + 59Fe was low in the whole course. This phenomenon was quite different from that of the normal adults in that the CFU-Mix of the patients showed distinctive proliferation and differentiation into the leukemic progenitor cells.