Human serum-dependent survival of GM-CFCs in vitro from patients with chronic granulocytic leukemia

Bone marrow (BM) cells from 15 patients with chronic granulocytic leukemia (CGL) and 12 normal donors were placed in liquid culture for 4–7 days in the presence of fetal calf serum (FCS) or human AB serum. BM cells were plated in agar for GM-CFC growth at day 0, day 4, day 7 of culture, in the presence of human placenta conditioned medium (HPCM). The recovery of GM-CFCs on day 4 in FCS was 86 ± 18 and 15 ± 18% from normal or CGL BM cells respectively (p = 0.005). The recovery of GM-CFCs on day 4 in human AB serum was comparable for normal (66 ± 48%) and CGL (69 ± 32%) BM cells. Similar results were obtained on day 7 of culture. Cytochemical staining of agar plates showed a sharp drop of macrophage colonies in CGL BM cells kept in FCS cultures on day 4–7, when compared to both normal BM cells and baseline colonies. These data suggest that the survival in liquid culture of GM-CFCs from patients with CGL is dependent on a factor present in human and not in fetal calf serum. This is not the case for normal GM-CFCs.