Effects of recombinant human G-CSF and GM-CSF on primary human leukemic cells

The effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on primary human leukemic cells were studied. Phagocyte-depleted mononuclear cells containing more than 88% blasts were obtained from peripheral blood of 11 AML and 2 ALL patients and from bone marrow aspirates from 2 ALL patients. The leukemic cells were incubated with these CSF in suspension cultures or in methylcellulose cultures. In suspension cultures, the spontaneous proliferation was observed in 1 M4 patient. RhG-CSF stimulated the leukemic cell proliferation in 5 AML, cases and rhGM-CSF that in 4 AML cases. In methylcellulose cultures, spontaneous colony formation occurred in 3 M4 patients. RhG-CSF and rhGM-CSF stimulated the leukemic colony formation in 8 AML cases. The CSFs had an additive effect in both cultures. Neither CSF induced O2- production or phagocytic activity. From these results, we concluded that both CSFs stimulated the proliferation of leukemic cells without inducing differentiation.