Outcomes of processing of bone marrow harvests for hematopoietic stem cell transplantation in pediatric patients utilizing a novel red blood cell sedimentation kit

Abstract

BACKGROUND Bone marrow (BM) grafts are often subject to manipulation to minimize infusion volume, to deplete red blood cells (RBCs), to deplete plasma, and/or to achieve optimal concentration of nucleated cells (NCs) for freezing. Here, we report results of processing and infusion of four major ABO‐incompatible BM grafts for allogeneic hematopoietic transplantation in pediatric patients. CASES AND METHODS Patients ranging in age from 5 months to 18 years received hematopoietic stem cell transplantation for benign or malignant indications. Allogeneic BM grafts were processed using PrepaCyte‐CB kits, approved by the Food and Drug Administration for enrichment of mononuclear cells in cord blood units for hematopoietic transplantation. Resulting grafts were dosed and infused using standard institutional protocol. After transplantation patients were evaluated for hematologic recovery. RESULTS The PrepaCyte‐CB processing method achieved on average 97.1% depletion of RBCs and 68.5% volume reduction, with a fairly efficient NC recovery (total NCs, 85.6%; white blood cells, 89.7%; CD34+ cells, 103.3%; and colony‐forming unit cells, 87.5%). No microbial contamination was detectable in any of the processed grafts. Infusions were well tolerated, and all four patients achieved durable hematopoietic engraftment within expected time interval. CONCLUSION Our results suggest that PrepaCyte‐CB is safe and effective for minimal processing of BM grafts. Engraftment outcomes were comparable with other published BM processing methods. In addition, NC recovery achieved using this method appears to exceed that of previously described sedimentation reagents such as hetastarch and Ficoll.

Analysis of outcomes of single‐unit cord blood transplantation with umbilical cord blood units processed with two different red blood cell sedimentation reagents

“…PrepaCyte is a novel red blood cell aggregation reagent that facilitates rapid 1 g sedimentation of RBCs in UCB and Bone Marrow graft 11,20 . The remaining white blood cells are recovered with high efficiency 18,21 . To evaluate the effects of PrepaCyte reagent on UCB unit post‐thaw characteristics and on post‐transplant clinical outcomes, we performed a retrospective analysis of single‐unit cord blood transplants utilizing units processed at SLCBB with either Hetastarch or the PrepaCyte‐CB kit.…”

“…The specific reason for the post‐thaw TNC recovery advantage of PCB is currently unknown. One possibility may be related to relatively high efficiency of the PrepaCyte‐CB in removal of nucleated red blood cells, 18,21 a population of cells included in TNC measurement that is especially susceptible to lysis at thaw. Alternatively, differences in cryopreservation or thaw methodologies used for HCB and PCB could also result in significant impact on final cell yield of UCB products 22,24,25 .…”