In Vitro Growth Kinetics of Myeloid Progenitor Cells of Myelodysplastic Patients in Response to Granulocyte-Macrophage Colony-Stimulating Factor and Interleukin-3

The myelodysplastic syndrome (MDS) is a clonal disorder of the hemopoietic stem cell resulting in multilineage cytopenias in vivo. In vitro a reduced myeloid and erythroid colony formation is observed [1, 2]. The reduced colony formation may be due to functional abnormalities of the progenitor cells such as an altered response to hemopoietic growth factors. Current investigations suggest that stimulation with certain colony-stimulating factors is only effective in early G1 [3]. This would imply that variations in the resting time of progenitor cells would influence the responsiveness of these cells for hemopoietic growth factors. In order to obtain more insight into this problem, we determined the colony formation kinetics of myeloid progenitor cells of MDS patients in response to rhGM-CSF, rhIl-3, and GCT- CM.