[Expansion of peripheral blood progenitors by recombinant human granulocyte colony-stimulating factor]

The levels of peripheral progenitor cells was measured serially after cancer chemotherapy in 4 patients with non-Hodgkin's lymphoma and one patient with rhabdomyosarcoma who received recombinant human granulocyte colony-stimulating factor (rG-CSF). This study was composed of two independent phases: in the first phase, patients received a course of cytotoxic chemotherapy only, and in the second phase, they received the same chemotherapy followed by subcutaneous injection of rG-CSF (2 micrograms/kg/day) for 10-14 days. In the control phase, the levels of granulocyte-macrophage colony-forming units (CFU-GM) and erythroid burst-forming units (BFU-E) per milliliter increased during the early recovery phase, but rG-CSF treatment increased the number of CFU-GM 3 to 18-folds, and the number of BFU-E increased 1.3 to 4.6-folds. An overshoot in the blood progenitor levels occurred at the day 8-10 of rG-CSF administration. And then, the peak of neutrophil count followed 3-5 days later. After the discontinuation of rG-CSF, the number of blood CFU-GM and BFU-E fell rapidly. This results suggest that in vivo expansion of circulating hemopoietic progenitors can be achieved by the administration of rG-CSF, and this approach might be clinically applicable to cancer patients who are a candidate of peripheral blood stem cell autotransplantation.