The myeloid progenitor cell: a parallel study of subpopulations in human marrow and peripheral blood.

Ten persons who had no evident hematologic disorder or previous history of chemotherapy or irradiation were studied. Parallel in vitro agar cultures from marrow and peripheral blood were grown, colonies and clusters were scored and examined morphologically after 7 and 14 days of incubation. Mean marrow myeloid progenitor cell (CFUc) incidences after 7 and 14 days were 76 +/- 55.4 S.D. and 37.3 +/- 22.0 S.D. per 10(5)ficoll-hypaque interface cells respectively. Most of the colonies on day 7 were neutrophilic (median 86%). Eosinophil colonies made up only a minority (0%-2%) of the total number of colonies. By day 14 a decrease in neutrophil colonies (median 6%) and a rise in eosinophil colonies (median 37%) was observed. Most of the colonies on day 14 were mixed neutrophil-macrophage colonies (median 55%). Parallel studies from blood revealed no colony growth on day 7 except on one occasion. The mean cluster incidence was 1.1 +/- 0.9 S.D. per 10(5) mononuclear cells. Most of these colonies were identified as eosinophilic (median 83%). The relative incidence of various subpopulations of myeloid progenitor cells in marrow and blood is different. Cluster transplantation from peripheral blood cultures strongly suggests the possibility for separate eosinophil progenitor cells. However a possibility of a rare occurrence of bipotent neutrophil-eosinophil colony forming cell can not be completely excluded.