Effect of nucleated cell count and cryopreservation on engraftment post autologous stem cell transplant.

Using 753 collections from 426 adult haematology patients, we conducted a retrospective, analysis into the effects of overnight storage and nucleated cell counts (NCC) on viable, CD34+ (vCD34+) recovery and engraftment kinetics post autologous stem cell, transplant (ASCT) with peripheral blood stem cells (PBSC). There were significant, differences in vCD34 + recovery ( P < 0.01) after cryopreservation associated with, the fresh NCC of ≥ 300 × 10 6 /mL in products stored overnight, but no association, with time to platelet or neutrophil engraftment post-ASCT was observed for these, products. There was no association of vCD34+ numbers or engraftment kinetics with cryopreserved NCC with either below or greater than the local recommended concentration of 400 × 106 /mL of product. However, there was significant difference in engraftment kinetics in relation to the viable CD34+ dose given at ASCT, in relation to the time to early engraftment and the amount of platelet support given during the engraftment period post-ASCT. We conclude the vCD34+ dose at ASCT is of great importance to early engraftment kinetics and that NCC is an important factor during overnight storage, but not for cryopreservation of PBSC. In light of our findings, we recommend that apheresis products collected in a closed system can safely be stored undiluted overnight.