Cryopreservation of allogeneic PBSC from related and unrelated donors is associated with delayed platelet engraftment but has no impact on survival.

Cryopreservation of PBSC for allo-SCT offers potential advantages; however, its impact on engraftment and outcomes remains unclear. A total of 76 allo-SCT performed using cryopreserved PBSC from HLA identical related (n=57) and unrelated donors (n=19) were compared with 123 fresh PBSC allo-SCT. Median neutrophil engraftment was on day 12 for both cryopreserved and fresh PBSC; in multivariate analysis, there was a slight but significant delay in neutrophil engraftment after the median date (hazard ratio (HR)=1.44, P=0.003). Platelet engraftment was significantly delayed in cryopreserved PBSC recipients (median time 19 vs 14 days). In multivariate analysis cryopreservation (HR=1.85, P<0.001), earlier date of transplant and lower CD34+ cell dose were associated with delayed platelet engraftment. Two-year OS and relapse and 1-year TRM rates did not differ significantly. Acute GVHD incidence was comparable, and extensive chronic GVHD at 1 year was higher in cryopreserved PBSC recipients (40.3 vs. 28.3%), but not significantly so (P=0.13). Cryopreservation of related and unrelated donor allogeneic PBSC is safe and effective where its benefits outweigh the risks of delayed platelet engraftment; its impact on chronic GVHD incidence requires further assessment.