IN-VITRO PRODUCTION OF MEGAKARYOCYTES FROM PIXY321 VERSUS GM-CSF-MOBILIZED PERIPHERAL-BLOOD PROGENITOR CELLS

The generation of megakaryocytes (MK) from cultured peripheral blood p rogenitor cells (PBSC), harvested via apheresis, from 18 female breast cancer patients treated with either PIXY321 or GM-CSF was compared. N onadherent mononuclear cells (MNC) were cultured in liquid suspension with 50 U/ml thrombopoietin (TPO) and 2.5% autologous heparinized plas ma for 12 days, Flow cytometric analysis was used to measure the perce ntage of CB34(+) on day 1 and CD41(+) cells on day 12, The frequency o f CD34(+) cells was greater in GR3-CSF-mobilized samples than in PIXY3 21-mobilized samples, and MK/MNC yields correlated directly with the n umber of CD34(+) cells seeded, PIXY311-mobilized samples produced more MKs per CD34(+) cell than GM-CSF-mobilized samples, Overall, there wa s no significant difference in the MK/MNC yield between PIXY321- and G M-CSF-mobilized samples, Cyclophosphamide (CY) increased the frequency of CD34(+) cells and the corresponding MK/MNC yield for both cytokine s, but had no effect on the MK/CD34(+) yield, Compared to GM-CSF, PIXY 321 mobilization resulted in increased CD34(+) cell commitment to the MK lineage.