Mobilization of human hematopoietic progenitors. Untransplanted and engrafted animals (at 6-8 weeks post-transplantation) were treated with various regimens to mobilize hematopoietic cells. In each case, the left hand panel shows the percentage of human cells in the BM, whereas the right hand panel shows the number of human progenitor cells per femur and per mL of peripheral blood. Bars indicate mean ± SEM. (A) Control (n = 4) and treated (n = 5) with a single injection of cyclophosphamide (200 mg/kg) followed by 4 days of hG-CSF (250 μg/kg/d); (B) control (n = 3) and treated (n = 3) with hG-CSF (25 μg/kg/d) for 4 days; (C) control (n = 2) and treated (n = 3) with hG-CSF (250 μg/kg/d for 4 days); (D) control (n = 2) and treated with hG-CSF (25 μg/kg/d) with or without pegylated-hSCF (20 μg/kg/d) for 4 days (both n = 2); and (E) control (n = 3) and treated (n = 4) with hG-CSF (250 μg/kg/d) and pegylated-hSCF (20 μg/kg/d) for 6 days.