In vitro differentiation of myeloid progenitor cells in patients with eosinophilia

Colony-forming cells of the granulocytic/macrophage ( CFCGM ) and eosinophilic ( CFCEo ) series were grown from bone marrow and/or peripheral blood of 20 patients with persistent eosinophilia mainly due to helminthic diseases and of 17 patients without eosinophilia. The semi-solid culture technique of haemopoietic cells was applied using different sources of colony-stimulating factor (CSF). After 14 d of incubation the number of CFCs as well as their differentiation into the CFCGM and CFCEo was evaluated. The total median CFC count in the bone marrow differed significantly between the patient and the control group. No difference of the total colony count was observed when culturing peripheral-blood lymphocytes of patients or controls. 47% Luxol-fast-blue positive colonies were identified in the peripheral blood cultures from patients with eosinophilia as compared with 56% from controls using human placenta-conditioned medium as source of CSF. In contrast, bone-marrow cultures showed a significantly lower proportion of CFCEo (14% v. 18% resp.). No difference could be observed with regard to the source of stimulus. Thus, the discrepancy of the peripheral-blood and bone-marrow eosinophilia and of the in vitro culture findings may indicate that the commitment of granulocytic progenitor cells into the eosinophilic series is unaffected by a defined stress, such as helminthic diseases or is not measurable in the culture dish.