Purpose : Cord blood, a rich source of hematopoietic stem cell, has been used without RBC depletion in most cases of cord blood transplantation because of loss of stem cells.
Accordingly, ABO blood group incompatibility and toxicity from DMSO infusion have been unavoidable and large scale cord blood banking has been difficult due to large
storage volume of unmanipulated cord blood. 4 simple and effective RBC depletion method was investigated for use in RBC depleted cord blood transplantation and cord blood banking.
Methods : In 20 cases of normal delivery, about 50mL of cord blood was collected.
Two Methods, conventional Ficoll-hypaque centrifugation and 3% gelatin sedimentation (modified Pahwa's method), were used for RBC depletion. Separated cells were mixed with equal volume of cryomedia containing 20% DMSO and frozen in a -80℃ freezer and stored in a -196℃ liquid nitrogen (or 14 clays. After RBC depletion and cryopreservation, viabilityand recoveryof mononuclearcells(MNC),
CD34+ cells, and day 14 CFU-GM were compared between two Methods.
Results: Viability and number of MNC, 34 + cells, and day 14 CFU-GM in unmanipulated cord blood were 99.6±1.0%, 4.8±1.6(×106/mL), 2.5±1.8(×10 4/mL), and 6.1±2.0(×103 /mL), respectively. After RBC depletion, mean recovery of MNC, CD34+ cells, and day 14 CFU-GM were 54.2%, 74.0%, and 36.4% in Ficoll-hypaque centrifugation, and 89.0%, 98,3%, and 98.0% in 3% gelatin sedimentation(P-values 0.0001, 0.0008, and 0.0001, respectively).
After thawing of cryopreserved cells, mean recovery of MNC, CD34+ cells, and day 14 CFU-GM were 47.5%, 56.9%, and 27.3% in Ficoll-hypaque centrifugation, and 66.5%, 92,1%, and 63.9% in 3% gelatin sedimentation(P-values 0.0001, 0.0001, and 0.0001, respectively)
Conclusion : Three percent gelatin sedimentation can be used as a simple and effective method for RBC depleted cord blood transplantation and large scale cord blood banking.

Keywords: Cord blood, 3% Gelatin, RBC depletion