[Residual placental blood and bone marrow as sources of hematopoietic stem cells for allogenic stem cell transplantation. Comparative analysis of hematopoietic potential].

Umbilical cord blood (UCB) contains a high number of hematopoietic progenitor cells, which can be used for a HLA-identical transplantation. To proof the usefulness of this source of stem cells for transplantation we compared the cellular composition of 19 specimen of bone marrow of healthy donors (BM) and 23 of UCB. We determined the cell number, the frequency of CD34+ progenitor cells and the CFU-GM as well as the T- and B-cell-subsets by means of flow cytometry and in vitro culture methods. The T-cell content was higher in UCB than in BM while the B-cell number was lower. The CD34+ progenitor number per ml was 2.9 fold higher in BM than in UCB, but the frequency and the proliferative capacity of the CFU-GM progenitor cells in the CD34+ population was 8.6 fold higher in UCB than in BM. First clinical trials have demonstrated the usefulness of UCB for allogeneic stem cell transplantation in children. It is possible to harvest 80-100 ml UCB per placenta containing 1.2 x 10(9) nucleated cells with 9.7 x 10(5) (4-15 x 10(5)) CFU-GM.