Storage characteristics of cord blood progenitor cells: Report of a multicenter study by the cellular therapies team of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative

BACKGROUND: Most hematopoietic progenitor cell (HPC) products are infused or processed shortly after collection, but in some cases this may be delayed for up to 48 hours. A number of variables such as temperature and cell concentration are of critical importance for the integrity of HPCs during this time. STUDY DESIGN AND METHODS: We evaluated critical variables using cord blood HPC units that were divided equally and stored at 4°C versus room temperature (RT) for up to 96 hours. Total nucleated cell (TNC) and mononuclear cell (MNC) counts, viable CD34+ cell counts, and CD45+ cell viability as well as colony-forming unit-granulocyte-macrophage (CFU-GM) present over time at each temperature were determined. RESULTS: Overall, the data indicate that with the exception of viable CD34+ cells, there was a significant decrease in each variable measured for 72 to 96 hours and, with the exception of viable CD34+ cells and CFU-GM, the reductions were significantly greater in RT units than 4°C units. There was an increase in viable CD34+ count for units where TNC count was greater than 8.5 × 10⁹/L, compared with units where TNC count was less than 8.5 × 10⁹/L, that was different for each storage temperature. CONCLUSIONS: Cord blood HPC collections maintained at 4°C retained higher TNC counts, MNC counts, and CD45+ cell viability over a 72- to 96-hour storage period.