Hematopoietic Progenitor Content of Fetal Cord Blood Collected Using Citrate-Phosphate-Dextrose: Influence of Holding Temperature and Delays

Storage of unseparated fetal cord blood collected into citrate-phosphate-dextrose (CPD) for 48 hours has been studied using progenitor cell assays [plasma clot technique with plasma-conditioned medium, erythropoietin (EPO), erythropoietin + IL-3 as growth factors]; collected fetal blood volume was low [61 ± 4 ml, mean ± 95% confidence interval (CI)]. The CFU-GM concentration in total cord blood was 2460 ± 1476 CFU-GM/ml, comparable to normal bone marrow collected into medium RPMI + heparin (2350 ± 1258); 2 of 12 samples contained fewer than 10³ CFU-GM. Storage of unseparated cord blood CFU-GM in CPD was better at 4°C (rapid decrease at day (D) 2 from 15 ± 9 X 10⁴ at D0; 14 ± 11 X 10⁴ at D1 to 6 ± 4 X 10⁴ at (D2) than at 22°C (strong decrease since D1: 5 ± 4 X 10⁴ CFU-GM). The CFU-GEMM content remained steady at 4°C: from 16 ± 16 X 10⁴ at D0 to 18 ± 16 at D2. Cryopreservation and thawing of unfractionated cord blood at D0 did not affect the CFU-FM cloning rates. Whether mature progenitors are more affected than stem cells by storage in CPD remains to be determined.