This partially retrospective study identified CB characteristics such as gestational age and CB volume/cell count correlated with higher quality. For the nonHES validation, CB was analyzed for total nucleated cell (TNC), mononuclear cell (MNC) recovery, hematocrit (HCT) and colony-forming units (CFUs). Viabilities of CD34+ and CD45+ cells were determined by 7-aminoactinomycin D (7-AAD) and AnnexinV (AnnV) staining and compared for 21 mL and 42 mL buffy coat (BC) samples applying the HES/nonHES protocol.
Factors affecting the potency of CB transplants were the gestational age and the volume reduction to a defined BC volume. High initial cell counts and CB volumes correlated negatively with post-processing TNC recovery for lower BC volumes. Post-processing HES and nonHES results were comparable, but nonHES revealed a significantly lower post-thaw recovery of viable CD34+ cells measured by 7-AAD/AnnV (21 mL: 45.4 ± 16.4%; 42 mL: 67.3 ± 14.5%) as compared with HES (21 mL: 72.7 ± 14.4%, P = 0.0164; 42 mL: 83.4 ± 14.7%, P = 0.0203).
Due to the lower post-thaw CD34+ cell viability (AnnV−/7-AAD−) for nonHES samples, the use of HES is recommended, ideally combined with a high BC volume. The post-processing HCT has no statistically significant impact on the post-thaw CD34+ cell viability (AnnV−/7-AAD−).