Fetal cord blood as an alternative source of hematopoietic progenitor cells: Immunophenotype, maternal cell contamination, and ex vivo expansion

The present study was performed to investigate the character of hematopoiet ic progenitor cells in fetal cord blood (CB), Thirty blood samples from fet uses at a median of 24 weeks of gestation (range 19-29) and 30 neonatal CB samples were analyzed for their immunophenotype by three-color flow cytomet ry and examined for the presence of female cells by fluorescence in situ hy bridization (FISH). We tested the effects of different cytokine combination s (rhIL-1 beta, rhIL-3, rhIL-6, rh erythropoietin [rhEPO], rhGM-CSF plus rh SCF, and rhSCF plus rhflt3-ligand) on the differentiation of 100 CD34(+)-en riched neonatal CB cells for up to 21 days, Ex vivo expansion of 32 unselec ted fetal blood samples cells was performed in the presence of rhSCF and rh flt3-ligand. The percentage of CD34(+) cells in fetal blood was significant ly higher compared with neonatal CB (1.24% +/- 0.82% versus 0.33% +/- 0.18% , p = 0.0001) and inversely correlated with the age of gestation. The conta mination of fetal and neonatal CB with maternal cells was low (1.72% +/- 0. 89%, range 1.0%-4.0%). By using rhflt3-ligand we were able to expand commit ted progenitor cells while maintaining cells with stem cell function. The u se of expanded fetal immature progenitors might have implications for in ut ero transplantation and autologous gene therapy.