POTENTIATION OF GM-CSF OR G-CSF INDUCED MOBILIZATION OF CIRCULATING PROGENITOR CELLS BY PRETREATMENT WITH IL-3 AND HARVEST BY APHERESIS

Recombinant human colony-stimulating factors (CSFs) are increasingly u sed for mobilizing progenitor cells in the peripheral blood (PB). 7 pa tients were treated with GM-CSF or G-CSF at a dose of 5 mu g/kg/d for 5 days and after a treatment free interval received another cycle of t he same cytokine after pretreatment with IL-3. Pretreatment with 5 mu g/kg/d of IL-3 for 7 days did not mobilize by itself but significantly potentiated GM-CSF or G-CSF induced mobilization of PB progenitor cel ls in all 5 patients tested. As compared to the mobilization capacity of GM-CSF or G-CSF alone, 7 day IL-3 pretreatment potentiated maximum values of CFU-GM by 3.7-6.3 fold in patients receiving GM-CSF (n=2) an d by 1.8-3.3 fold in patients receiving G-CSF leading to a 10-23 fold increase in numbers of circulating CFU-GM by the combination IL-3/GM-C SF, and a 26-101 fold increase by IL-3/G-CSF, respectively. Stem cell apheresis in patients treated with IL-3 + G-CSF or GM-CSF yielded enou gh PB-stem cells to ensure complete engraftment after ablative chemoth erapy.