Relative recovery of haematopoietic stem cell products after cryogenic storage of up to 19 years

There is an increasing trend towards long-term frozen storage of haematopoietic stem cells. For such stem cells, harvested from peripheral blood (PB) or BM, it is not known if stem cell viability decreases with time. In this study, 31 separate bags of stem cell product (SCP) stored for 11-19 years (median 15 years) were assessed for total nucleated cell (TNC) count, colony forming unit-granulocyte/macrophage (CFU-GM), CD34(+) cell count and cell viability. The results were compared with the initial results obtained for the products at the time of stem cell harvest, and the percentage recovery of each parameter was plotted against time. Recovery of TNC, CD34(+) cell count and cell viability decreased with time (P = <0.01) but CFU-GM did not. This study shows that SCPs harvested from PB and BM do deteriorate with long-term storage. This could have an impact on rates of engraftment. Bone Marrow Transplantation (2013) 48, 32-35; doi:10.1038/bmt.2012.97; published online 4 June 2012