Optimal length of time of cryopreserved umbilical cord blood infusion after thawing

Abstract

ObjectiveDimethyl sulfoxide (DMSO) can damage hematopoietic progenitor cells (HPCs) at room temperature. To minimize the time of contact between DMSO and the thawed umbilical cord blood (UCB), there is an incentive to infuse the UCB as quickly as possible. However, the infusion of cryopreserved UCB also results in side effects. Currently, it is difficult to determine the optimal length of time for cryopreserved UCB infusion, not only to ensure the maximum effect of engraftment but also to reduce the toxicity of the cord blood infusion.MethodsTen units of cord blood were thawed to assess viability, apoptotic events of CD34+ cells and CD45+ cells, and the number of colony-forming units (CFUs) at four time points: 0, 10, 20, and 30 minutes post-thaw (PT). The infusion time, side effects, and the speed of platelet and neutrophil engraftment of the 10 patients were monitored.ResultsWithin 30 minutes, the viability decreased (P < 0.01), the percentage of early apoptotic CD34+ cells and CD45+ cells was unchanged. At time point PT30, the number of CFUs was decreased compared to PT0 (P < 0.05), but it was unchanged within 20 minutes. All the 10 UCB cells engrafted well in patients.ConclusionThis study indicates that post-thawed UCB HPCs are preserved for less than 30 minutes at room temperature; thus, the optimal length of time of cryopreserved cord blood infusion should be no more than 20 minutes after thawing.