The COVID-19 pandemic has affected the practice of allogeneic hematopoietic stem cell transplantation (AHSCT) at multiple levels including stem cell collection and processing. Prior to the COVID-19 crisis, cryopreservation of allogeneic grafts accounted for less than 2% of the total AHSCT. In the past two years, almost all allogeneic grafts were cryopreserved due to COVID-19 risks and restrictions. Although several groups have reported on the cryopreservation of allogeneic products before the pandemic, the number of studies evaluating the impact of cryopreservation on graft quality and transplant outcome is limited. A systematic review of the data accumulated during the past two years will be presented including the impact of cryopreservation on the viability, safety, and potency of the Cell Therapy products as well as the clinical outcome. In addition, cryopreserving allogeneic grafts beyond the pandemic will be discussed in the context of a typical laboratory setup. That is, strategies for process improvement are warranted to evaluate product quality (i.e., cell enumeration, immunophenotyping) and to maximize efficiency, safety, and resource utilization.
Review the process of cryopreservation of allogeneic hematopoietic stem cell products for transplantation.
Distinguish between the transplantation of fresh versus cryopreserved cellular products and the impact of clinical outcome.
Recognize that to ensure potency, safety and efficient resource utilization, process improvement might be necessary if cryopreservation of allogeneic products continues after the pandemic.