Study Identifies Factors Influencing Variability in Postthaw Product Quality of Donor Stem Cells – Cancer Network

A study published in Blood Advances suggested that although postthaw CD34+ cell recovery and viability of cryopreserved allogeneic hemopoietic progenitor cell (HPC) is typically acceptable, there is a significant risk of poor postthaw product quality, associated with prolonged storage time, higher white cell count, and complex product manipulation precryopreservation.1

Given these findings, researchers suggested that transplant centers should request a higher CD34+ cell dose from donors whose products are to be cryopreserved and that optimization of precryopreservation factors, such as transit time and white cell count, during storage may improve postthaw yield.

“Prior to COVID-19, the donor and transplant systems were well coordinated and effective. Now, with irregular flights and closed borders, travel and transportation are not assured,” lead study author Duncan Purtill, MD, of Fiona Stanley Hospital in Western Australia, said in a press release.2

“Five to 7 days before stem cell transplant, the recipient usually starts chemotherapy to remove all their bone marrow cells,” Purtill continued. “Without a healthy transplant to replace the cells on the same day, they would be left with no functioning bone marrow, which would of course be very high risk and carry a poor prognosis. Life literally depends on the safe arrival and immediate infusion of stem cells.”

Using 305 allogeneic HPC products cryopreserved at 9 laboratories across Australia, researchers sought to understand the postthaw CD34+ cell recovery. Of note, all products were cryopreserved in controlled rate freezers, and CD34+ cell quantitation was performed with single-platform assays.

Median postthaw CD34+ cell recovery was 76% and ranged