Evaluation of umbilical cord blood unit processing efficiency in routine laboratory conditions

Introduction: Umbilical cord blood (UCB) is an alternative stem cell source increasingly used for patients lacking an HLA matched sibling or unrelated donor. For UCB transplantation the total nucleated cells (TNC) and CD34+ cells greatly influence transplant outcome. UCB banks perform a white cell enrichment and red cell depletion prior to cryopreservation in order to decrease the stored product volumes. Various techniques have been evaluated in a restricted number of products; however the efficacy of volume reduction under routine laboratory conditions is lacking. We report on the results of 1280 UCB processed in two banks using the same device and compare them with the manufacturer's qualification reports. Materials and methods: 1280 units were processed between 1994 and 2008, 456 in centre 1 and 856 in centre 2 using a Sepax (r) S-100 device (Biosafe, Eysins, Switzerland) piloted by proprietary software (version 1.17 to 264), according to the manufacturer's instructions. UCB were collected in 5 different maternity wards and processed within 36 hours after collection. TNC and CD34+ counts were performed before and after volume reduction using standardized counting methods. Results: Median volume obtained immediately after processing was 21% of the initial volume (10th/90th percentile 15/29%). Median TNC and CD34+ cell recoveries were 76% (10th/90th percentile 63/86%) and 81% (10th/90th percentile 64/95%) respectively in both sites, whereas the device qualification report proposes 88% and 96% for TNC and CD34+ cell recovery respectively (p