Viable CD34+ stem cell content of a cord blood graft: which measurement performed before transplantation is most representative?

Abstract

Viable CD34 cell count of the graft is both accurate and precise when measured on a separate sample frozen together with the cord blood unit. This measurement can be performed by the transplant center to exclude between-laboratory variability.

Dominant unit CD34+ cell dose predicts engraftment after double-unit cord blood transplantation and is influenced by bank practice

“…In addition, the correlation between precryopreservation TNC and postthaw CD34 1 cell count was considerably weaker than that observed between precryopreservation and postthaw CD34 1 cell counts. Moreover, the close correlations we observed between prefreeze and postthaw CD34 1 cell measurements for units from many banks support previous reports that reproducibility within laboratories 35 and between laboratories 36 can be achieved. Further critical novel findings of the 402 unit analysis were that the key determinants of infused viable CD34 1 cell dose (ie, recovery and viability) were associated with information that was available at the time of unit selection and that poor unit quality (low postthaw recovery and viability) relates to variations in bank practices.…”

Evaluation of Quality Parameters for Cord Blood Donations

“…Enumeration of the content of CD34/CD45+ cells in CB in conjunction with viability proved to be specific for and predictive of CFU activity [26]. The applicability of CD34/CD45+ dose for hematological recovery has been reported by Jansen et al [27] for autologous peripheral blood progenitor cell transplantation, and therefore the selection of CB donations for transplantation according to CD34/CD45+ cell content appears to be a reliable parameter for progenitor activity as has been suggested by Solves et al [28].…”

Assessment of cord blood unit characteristics on the day of transplant: comparison with data issued by cord blood banks

“…It is possible that other characteristics such as viable CD34+ cell dose or CFC dose infused may be too low for engraftment to occur despite adequate TNC doses 36 . For example, the TNC content of CB units was shown to correlate poorly with the viable CD34+ cell content 37 . The low number of patients in addition to lack of standardization of specific assays, however, preclude any definitive conclusions.…”

“…Previous studies have shown that testing on a separate vial leads to falsely low results compared to the bag that contains the graft, due to differences in freezing kinetics 38,39 . Recent studies, however, suggest that CB samples from the attached segment of the freezing bag or a separate cryovial can accurately predict the graft content 32,36 , 37 . If validated on a larger scale, these observations from CBBs may provide a rationale for use of test‐thaw samples for accurate CB characterization before release to transplant centers.…”