Impact of Long-Term Cryopreservation on Single Umbilical Cord Blood Transplantation Outcomes

• Long-term cryopreservation of umbilical cord blood units does not impact engraftment in single umbilical cord blood transplantation.
• Long-term cryopreservation does not impact total nucleated cells recovery, viability, or colony-forming units-granulocyte macrophage of umbilical cord blood units
• Cryopreservation of umbilical cord blood units can safely be performed for up to 10 years.

Umbilical cord blood (UCB) may be collected and cryopreserved for years before use. In vitro and murine models suggest that the duration of storage does not affect UCB progenitor cell performance; however, the impact of UCB age on clinical outcomes has not been definitely defined. This study sought to determine the effect of UCB unit cryopreservation time on hematopoietic potency. We analyzed 288 single UCB units used for transplantation from 1992 to 2013, with unit cryopreservation time ranging from .08 to 11.07 years. UCB unit post-thaw characteristics were examined, including percent recovery of total nucleated cells (TNC). The number of years the UCB unit spent in cryopreservation had no impact on TNC recovery nor UCB unit post-thaw viability. Duration of cryopreservation also had no impact on neutrophil or platelet engraftment in single UCB transplantations. These results show that UCB units can undergo cryopreservation for at least 10 years with no impact on clinical outcomes.