To freeze or not to freeze peripheral blood stem cells prior to allogeneic transplantation from matched related donors.

Background The standard practice in allogeneic stem cell transplant (alloSCT) is to infuse peripheral blood stem cells (PBSC) the same day or the day after collection once the patient has received conditioning regimen. To obtain and freeze PBSC prior to SCT would be desirable to get a better logistic and to confirm the quality of the product. Unfortunately, studies comparing both approaches are lacking. Aim In this retrospective study, we analyze the impact of using fresh (N: 107) or previously frozen PBSC (N: 224) on overall outcomes among patients consecutively undergoing alloPBSCT from a matched related donor. Results Granulocyte engraftment (>500/mcl × 3 days) was faster in the frozen group (14 vs. 16 days, respectively; P = 0.001), while no significant differences on platelet recovery were observed. Patients receiving frozen PBSC had a higher incidence of global acute graft-versus-host disease (aGVHD) (63 vs. 44%, P < 0.001) mostly involving skin and had an earlier onset (13 vs. 30 days, P < 0.001). Response to first-line treatment with corticoids was similar in both groups. No statistically significant differences were found regarding overall chronic GVHD (58 vs. 66%) nor global survival (44 vs 48%), disease-free survival (39 vs. 33%), non-relapse mortality (24 vs. 16% at 1 year), and relapse rates in the frozen vs. fresh group, respectively. Conclusions Infusion of previously frozen stem cells may achieve similar overall outcomes compared to fresh infusion, allowing to program donor apheresis and transplantation. However, cryopreservation might influence on the different pattern of aGVHD, issue that deserves further studies.