Optimum Temperature for Maintaining the Viability of CD34+ Cells during Storage and Transport of Fresh Hemopoietic Progenitor Cells.

Background and Aim: The optimum storage and transport of freshly harvested hemopoetic progenitor cells (HPC) in the liquid state is not specified in the JACIE and FACT guidelines. Depending upon transplant centre, there is a range of reported ideal temperatures (1°C to 24°C) for HPC storage and transport but little data exists to justify the recommendations. Due to the limitations of Trypan Blue viability assays and CFU-GM colony assays, we used a no-lyse, CD34 assay (Sartor et al, Bone Marrow Transplantation 2005) to determine the optimum storage and transport temperature for maintaining viability of CD34+ stem cells in freshly harvested HPC.

Method: Samples were aseptically removed from 46 fresh HPC harvests (34 PBSC & 12 BM) and stored at refrigerated temperature (2°– 8°C), room temperature (18°– 24°C) and 37°C, for up to 72 hours. Samples were analysed for viable CD34+ cells/ml at 0, 24, 48 and 72 hours.

Results: The mean viable CD34⁺ yield prior to storage was 7.7x10⁶/kg (range: 0.7 – 30.3). No viable CD34⁺ cells remained after storage at 37°C for 24 hours. The mean % loss of viable CD34⁺ cells at refrigerated and room temperatures can be summarized as follows:

Conclusion: These results demonstrate that the optimum temperature to maintain the viability of CD34⁺ stem cells for up to 72 hours during storage and transport of freshly harvested HPC is 2°– 8°C.