TRANSPLANTATION AND CELLULAR ENGINEERING Engraftment for CD34 selected stem cell products is not compromised by cryopreservation Ronit Reich-Slotky, 1 Lohith S. Bachegowda, 1,2 Michael Ancharski, 1 Usama Gergis, 3 Koen van Besien, 3 and Melissa M. Cushing 1,4 BACKGROUND: The coinfusion of haploidentical CD341 selected peripheral blood stem cell products with umbilical cord blood (UCB) provides early neutrophil recovery, long-term UCB engraftment, and a lower incidence of graft-versus-host disease; however, this complex transplant presents a scheduling challenge for both the cellular therapy laboratory and the clinical team. Cryopreservation of the haploidentical product can facilitate scheduling, but has been previously shown to be associated with infusion reactions and delayed platelet (PLT) engraftment in allogeneic hematopoietic progenitor cell transplant. STUDY DESIGN AND METHODS: To test whether cryopreservation of the CD341 selected product compromises the graft, we compared neutrophil and PLT engraftment kinetics for patients receiving freshly infused or cryopreserved products. Seventy-two products collected from haploidentical related donors were CD341 selected and infused in a combined transplant with UCB: 32 were cryopreserved before infusion and 40 were infused fresh. RESULTS: No adverse infusion events were reported in either group and there was no difference in neutrophil and PLTengraftment time between fresh and cryopreserved products. CONCLUSION: Cryopreservation of a CD341-selected product can be safely used in a combined transplant with UCB and does not affect engraftment time. U mbilical cord blood (UCB) is increasingly used as a hematopoietic progenitor cell (HPC) graft source in both children and adults who do not have a matched related or unrelated donor. Unfortunately, the low number of progenitor cells in UCB units is associated with slow hematopoietic recovery, which can lead to early morbidity and mortality. 1,2 Trans- plantation of a single UCB unit containing a cell dose of less than 2.5 3 10 7 nucleated cells per kilogram has been associated with poor engraftment, nonrelapse mortality, and poor survival. 3 Hematopoietic recovery in recipients of double UCB remains delayed relative to other donor sources, resulting in higher high nonrelapse mortality mostly due to infections. 4 The coinfusion of haploidenti- cal CD341-selected peripheral blood stem cells (PBSCs) with a single UCB unit provides early neutrophil recovery from the haploidentical product, long-term UCB engraft- ment, and a lower incidence of graft-versus-host disease (GVHD). 5 Engraftment time is comparable to matched- related and matched-unrelated allogeneic donors and is improved compared to double cord blood transplants. 4 The survival outcomes of both haploidentical and ABBREVIATIONS: UCB 5 umbilical cord blood. From the 1 Department of Transfusion Medicine and Cellular Therapy, New York Presbyterian Hospital/Weill Cornell Medical Center; the 2 National Cord Blood Program, New York Blood Center; and the 3 Department of Medicine and the 4 Department of Pathology, Weill Cornell Medical College, New York, New York. Address reprint requests to: Ronit Reich Slotky, PhD, New York Presbyterian/Weill Cornell Medical Center, 525 East 68th Street, Room M-039, New York, NY 10065, e-mail: ros9085@ nyp.org. Received for publication August 4, 2015; revision received October 29, 2015; and accepted November 3, 2015. doi:10.1111/trf.13435 V C 2015 AABB TRANSFUSION 2016;56;893–898 Volume 56, April 2016 TRANSFUSION 893