Comparative study of different procedures for the collection and banking of umbilical cord blood.

Different procedures for umbilical cord blood (CB) collection, separation, and cryopreservation were compared to evaluate the feasibility of large-scale CB banking for unrelated transplant. CB collection using an open system was associated with a 12.5% rate of bacterial contamination, whereas this rate fell to 3.3% using a closed collection system. When the umbilical cord was clamped within 30 s after delivery, on 378 occasions it was possible to collect 77 +/- 23 ml of CB without risk to mother or infant. Considering that engraftment can be obtained in recipients of 20 x 10(3) CFU-GM/kg, 86% and 28% of CB samples with a volume larger than 50 ml were found to contain a sufficient number of CFU-GM to engraft patients of 20 and 70 kg, respectively. Both Ficoll and gelatin purification procedures were associated with a recovery of 86-92% of CFU-GM, BFU-E, CFU-GEMM, and HPP-CFC, but the gelatin method appears to be more suitable for large-scale CB banking in vials. After cryopreservation, the recovery of clonogenic progenitors was similar for both CB samples stored as whole blood or as mononuclear cells separated using Ficoll or gelatin. In conclusion, large-scale CB banking seems feasible, and CB cell separation could allow storage of a large number of CB samples in a limited liquid nitrogen space.