Erythrocyte depletion of human umbilical cord blood using dextran sedimentation.

We report on the results of a study using high molecular weight dextran for depletion of red blood cells (RBCs) from cord blood. Our technique achieved efficient RBC depletion by sedimentation without a significant loss in haemopoietic stem cells. Cord blood units were fractionated for erythrocyte depletion by unit gravity sedimentation in 3 per cent high molecular weight dextran. Dextran sedimentation enabled recovery of more than 80 per cent of the total nucleated cells present and 100 per cent mononuclear cell (MNC) recovery as compared to unfractionated cord blood. A four-fold increase in the colony forming unit-granulocyte macrophage (CFU-GM) number per 2 x 10(5) cells was observed after dextran treatment suggesting that this step also resulted in the enrichment of stem cells.