Granulocyte-macrophage colony stimulating factor expands the circulating haemopoietic progenitor cell compartment in man.

The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on bone-marrow and peripheral-blood progenitor cells was investigated in a three-phase study in 13 patients with sarcoma. In the first phase patients were given GM-CSF alone. In phase II, which started a week after completion of phase I, patients received a course of cytotoxic chemotherapy, then a course of GM-CSF. Phase III consisted only of cytotoxic chemotherapy. GM-CSF (phase I) alone produced an 18-fold increase in peripheral blood granulocyte-macrophage colony-forming units (CFU-GM) and an 8-fold increase in erythroid burst-forming units (BFU-E) in the peripheral blood. GM-CSF had no effect on bone-marrow CFU-GM and BFU-E in the group as a whole. Three patients were investigated after phases II and III. GM-CSF increased the absolute number of peripheral blood CFU-GM by approximately 60-fold compared with the pretreatment baseline. These effects of GM-CSF may be of clinical importance with regard to facilitating the harvest of peripheral blood progenitor cells for autotransplantation.