Rapid engraftment by peripheral blood progenitor cells mobilized by recombinant human stem cell factor and recombinant human granulocyte colony-stimulating factor in nonhuman primates.
We have previously shown that administration of low-dose recombinant human stem cell factor (rhSCF) plus recombinant human granulocyte colony-stimulating factor (rhG-CSF) to baboons mobilizes greater numbers of progenitor cells in the blood than does administration of rhG-CSF alone. The purpose of the present study was to determine whether marrow repopulating cells are present in the blood of nonhuman primates administered low-dose rhSCF plus rhG-CSF, and if present, whether these cells engraft lethally irradiated recipients as rapidly as blood cells mobilized by treatment with rhG-CSF alone. One group of baboons was administered low-dose rhSCF (25 micrograms/kg/d) plus rhG-CSF (100 micrograms/kg/d) while a second group received rhG-CSF alone (100 micrograms/kg/d). Each animal underwent a single 2-hour leukapheresis occurring the day when the number of progenitor cells per volume of blood was maximal. For baboons administered low-dose rhSCF plus rhG-CSF, the leukapheresis products contained 1.8-fold more mononuclear cells and 14.0-fold more progenitor cells compared to the leukapheresis products from animals treated with rhG-CSF alone. All animals successfully engrafted after transplantation of cryopreserved autologous blood cells. In animals transplanted with low-dose rhSCF plus rhG-CSF mobilized blood cells, we observed a time to a platelet count of > 20,000 was 8 days +/- 0, to a white blood cell count (WBC) of > 1,000 was 11 +/- 1 days, and to an absolute neutrophil count (ANC) of > 500 was 12 +/- 1 days. These results compared with 42 +/- 12, 16 +/- 1, and 24 +/- 4 days to achieve platelets > 20,000, WBC > 1,000, and ANC > 500, respectively, for baboons transplanted with rhG-CSF mobilized blood cells. Animals transplanted with low-dose rhSCF plus rhG-CSF mobilized blood cells had blood counts equivalent to pretransplant values within 3 weeks after transplant. The results suggest that the combination of low-dose rhSCF plus rhG-CSF mobilizes greater numbers of progenitor cells that can be collected by leukapheresis than does rhG-CSF alone, that blood cells mobilized by low-dose rhSCF plus rhG-CSF contain marrow repopulating cells, and finally that using a single 2-hour leukapheresis to collect cells, the blood cells mobilized by low-dose rhSCF plus rhG-CSF engraft lethally irradiated recipients more rapidly than do blood cells mobilized by rhG-CSF alone.
Andrews
R G
RG
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98104.
Briddell
R A
RA
Knitter
G H
GH
Rowley
S D
SD
Appelbaum
F R
FR
McNiece
I K
IK
D000818:Animals; D001772:Blood Cell Count; D006085:Graft Survival; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage / Q000494:pharmacology*; D016298:Hematopoietic Cell Growth Factors / Q000008:administration & dosage / Q000494:pharmacology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007937:Leukapheresis; D007958:Leukocyte Count; D009504:Neutrophils / Q000166:cytology; D010215:Papio; D010976:Platelet Count; D011994:Recombinant Proteins / Q000494:pharmacology; D019089:Stem Cell Factor
D016298:Hematopoietic Cell Growth Factors; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D016179:Granulocyte Colony-Stimulating Factor