Survival of granulocytic progenitors in the nonadherent and adherent compartments of human long-term marrow cultures

We have studied the survival of granulocytic and monocytic progenitor cells (CFU-GM) in human liquid marrow cultures. CFU-GM were present in the nonadherent cell population for a mean of 12 weeks without recharging. Histochemical analysis of agar gels revealed that most day-7 colonies were of neutrophilic type (CFU-N), whereas the majority of day-14 colonies were of mixed neutrophilic-macrophagic type (CFU-NM) for the first four weeks of culture and became predominantly of macrophagic type (CFU-M) thereafter. Eosinophilic colonies (CFU-Eo) declined after week 2 of culture. We have documented that CFU-GM were present in the adherent layer of these cultures, and that the CFU-GM in the nonadherent compartment arise from the adherent layer. In addition, we have compared the pre-CFU-GM survival in the adherent and nonadherent populations and determined that these progenitors were rapidly depleted from both compartments though their survival at the end of week 1 was better in the adherent than in the nonadherent layer.