OPTIMIZATION OF CONDITIONS FOR EX-VIVO EXPANSION OF CD34(-IV BREAST-CANCER() CELLS FROM PATIENTS WITH STAGE)

Multiple cycles of high-dose chemotherapy can be hematologically suppo rted by repeated administration of peripheral blood progenitors obtain ed after mobilization using cytokine alone or in combination with chem otherapy. We have explored the quality of such cells and their potenti al to undergo ex vivo expansion. Twenty-five leukapheresis samples fro m 19 patients who had received extensive prior chemotherapy for stage IV breast cancer were subjected to CD34(+) cell selection using immuno affinity columns or immunomagnetic bead separation. Cells were culture d in suspension in the presence of c-kit ligand, interleukin-3, interl eukin-6, erythropoietin, and granulocyte colony-stimulating factor. Te n experiments were performed using weekly exchange of media and cytoki nes (Delta assay). Median myeloid and erythroid progenitors expanded 1 5-fold at 7 days (range, 7 to 43), 40-fold at 14 days (range, 18 to 47 0), 46-fold at 21 days (range, 0 to 118), and 21-fold at 28 days (rang e, 0 to 61). In a system using gas-permeable bags without exchange of media or cytokine, median progenitors expanded 13-fold ant 7 days (ran ge, 7 to 36), 14-fold at 10 days (range, 4 to 61), 14-fold at 12 days (range, 3 to 46), and 10-fold at 14 days (range, 1 to 35). Progenitor expansion less than 10-fold occurred in 8% of experiments at day 7, in 17% at day 10, in 43% at day 12 and 50% at day 14. When autologous pl asma, autologous plasma processed (removal of cryoprecipitate, centrif ugation, then filtration), or human serum were substituted for 20% fet al calf serum, the ratio of progenitor expansion at 7 days relative to 20% human serum, and 1% autologous plasma processed was 1.01 (range, 0.62 to 1.33), 0.88 (range, 0.61 to 1.20), and 0.96 (range, 0.55 to 1. 64), respectively. These findings support the feasibility of ex vivo e xpansion in a system free of nonhuman proteins of CD34(+)-derived prog enitors obtained from the peripheral blood of patients who have receiv ed prior chemotherapy. (C) 1994 by The America Society of Hematology.