Use of nonvolume-reduced (unmanipulated after thawing) umbilical cord blood stem cells for allogeneic transplantation results in safe engraftment.

Volume reduction of umbilical cord blood (UCB) units before infusion is standard in most transplant centers. We examined 26 patients who underwent transplantation from May 1997 to December 2001 with unmanipulated (n=18) or volume-reduced (n=8) UCB units for engraftment. Of 18 unmanipulated UCBT patients, 16 achieved ANC >500/mm(3), a median of 26 days (range, 16-104) post-UCBT; two died before engraftment on days +2 and +14. Of 18 unmanipulated UCBT patients, 10 achieved platelet recovery, a median of 60.5 days (range, 41-144) post-UCBT; eight patients died before platelet recovery +2 to +255 days post-UCBT. These results are similar to several reported studies and our series utilizing volume-reduced UCB units for UCBT. At a median follow-up of 29.5 months, the 100-day and 3-year overall survivals of unmanipulated UCBT were 61.1% (95% CI, 38.6-83.6) and 48.6% (95% CI, 24.8-72.4) and of volume-reduced UCBT were 60% (95% CI, 24.4-95.6) and 22.5% (95% CI, 0-58.7). There was no serious toxicity from UCB infusion using unmanipulated UCB units. We conclude that unmanipulated UCB units may be infused safely into UCBT patients with adequate engraftment and survival.