Red cell depletion of umbilical cord blood (UCB): Comparison between unmanipulated and red cell-depleted UCB by Ficoll-Paque density gradient separation

Stem cells from umbilical cord blood (UCB) represent an alternative source of cells for clinical transplantation. Many issues remain unsolved with regard to their collection, manipulation, and storage. In this study, we attempted to compare the effect of red cell depletion by Ficoll-Paque density gradient separation versus unmanipulated cord blood stem cells postthawing. We found no statistical difference between the two technologies when comparing viability, 98.6 +/- 0.3% versus 99.1 a 0.42% (p = < 0.16); CD34+/CD38+, 1.6 +/- 0.13% versus 1.2 +/- 0.17% (p = < 0.13); HLA DR+/CD34+, 1.8 +/- 0.15% versus 1.9 +/- 0.21% (p = < 0.6); blast colonies, 8.0 +/- 1.5 versus 12.2 +/- 2.1 (p < 0.15); CFU-GEMM colonies, 143.7 +/- 27.9 versus 80.7 (p = < 0.10); CFU-GM colonies, 101.2 +/- 23 versus 173 +/- 23.2 (p = < 0.07). There was a statistical difference in the content of CD34+/CD38+, 1.6 +/- 0.14% versus 1.2 +/- 0.14% (p = < 0.05), and the BFU-E colonies, 96 +/- 29.8 versus 165 +/- 23.9 (p = < 0.03). We conclude that red cell depletion using Ficoll-Paque gradient separation preserves viability of progenitor cells, as evidenced by immunophenotyping and colony assays.