Collection strategies and cryopreservation of umbilical cord blood

summary The aim of this study was to compare (a) two different umbilical cord blood (UCB) collection methods while the placenta is still in the uterus (in utero), and (b) to evaluate the efficacy of four cryopreservation protocols based on UCB haematopoiestic stem cell (HSC) recovery. We analysed UCB samples collected with our original collection system designed for active Syringe/Flush/Syringe method or by standard in utero method. For comparing different cryopreservation procedures, dimethyl sulphoxide (DMSO) at final concentration of 5 and 10% was used and combined with our own controlled‐rate or uncontrolled‐rate cryopreservation. A total of 99 samples were collected. A significantly higher UCB volume, total nucleated cell and mononuclear cell were seen following the first collection strategy (n= 49; mean ± SD, 103 ± 35·4 mL; 12·34 ± 5·27 × 108; 595 ± 3·47 × 106) vs. the second strategy (n= 50; 86 ± 29·3 mL; 9·87 ± 4·47; 424 ± 2·82 × 106) respectively (P < 0·01). The discard rate was 14% for the first and 36% for the second collection strategy (P < 0·01). It was shown that the most efficient procedure was the controlled‐rate protocol combined with lower (5%) DMSO concentration. Using active Syringe/Flush/Syringe method, we collected UCB with greater volumes and with lower discard rate compared to the standard by gravity technique. The data presented also showed much better recovery of UCB cells when controlled‐rate freezing procedure and 5% DMSO were combined.