Comparison of human umbilical cord blood processing with or without hydroxyethyl starch

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

BACKGROUND

Various processing methodologies are routinely used to reduce volume and red blood cell content of umbilical cord blood (UCB) units collected for hematopoietic stem cell transplantation. There is limited information regarding effects of UCB processing techniques on clinical outcomes.

STUDY DESIGN AND METHODS

Retrospective data analysis compared laboratory and clinical outcomes following single-unit UCB transplantation performed between 1999 and 2015. All UCB units were from St. Louis Cord Blood Bank and all were manually processed with either Hetastarch processed cord blood units (HCB) (n = 661) or PrepaCyte processed cord blood units (PCB) (n = 84). Additional sensitivity analysis focused on units transplanted from 2010 to 2015 and included 105 HCB and 84 PCB.

RESULTS

There were no significant differences in patient characteristics between the two groups. Pre-freeze total nucleated and CD34+ cell counts, cell doses/kg of recipient weight, and total colony-forming units (CFUs) were higher in PCB compared with HCB. Post-thaw, the PCB group had a significantly better total nucleated cell recovery, while there were no significant differences in cell viability, CFU recovery, or CD34+ cell recovery. Primary analysis demonstrated faster neutrophil and platelet engraftment for PCB but no differences in overall survival (OS), whereas sensitivity analysis found no effect of processing method on engraftment, but better OS in the HCB group compared with PCB group.

CONCLUSION

The UCB processing method had no significant impact on engraftment. However, we cannot completely exclude the effect of processing method on OS. Additional studies may be warranted to investigate the potential impact of the PCB processing method on clinical outcomes.

Discarded plasma obtained after cord blood volume reduction as an alternative for fetal calf serum in mesenchymal stromal cells cultures

BACKGROUND

Utilization of the fetal calf serum (FCS) carries a potential health risk and raises growing economic and ethical problems. Umbilical cord blood volume reduction, required for banking, provides clinical-grade umbilical cord blood plasma (UCBP) discarded as a waste. The aim of this study was to test whether serum derived from UCBP could replace FCS for the amplification of mesenchymal stromal cells (MSCs).

STUDY DESIGN AND METHODS

To this end, the amplification of the MSCs and mesenchymal progenitors was estimated in the presence of serum derived from UCBP and its cytokine content was determined by cytometric bead array and enzyme-linked immunosorbent assay techniques. As a comparison, other sources of clinical-grade human serum were tested in parallel: serum derived from solvent/detergent-treated fresh-frozen plasma (S/D-FFP) and from platelet (PLT)-rich and PLT-poor umbilical plasma.

RESULTS

Serum derived from UCBP-supplemented culture sustains identical amplification of MSCs and their progenitors as in the case of FCS addition. Furthermore, the assays reveal the presence in the serum derived from UCBP of cytokines influencing the properties of MSCs (basic fibroblast growth factor, transforming growth factor-β, vascular endothelial growth factor, and interleukin-8) or involved in the development of the myeloid lineage (thrombopoietin, erythropoietin, granulocyte-colony-stimulating factor, and granulocyte-macrophage-colony-stimulating factor). Also, our study indicates important differences between neonatal and adult-derived serum. Poor cytokine content in the S/D-FFP makes a less efficient replacement of FCS comparing to other human blood-derived supplements.

CONCLUSION

Our work shows that the discarded human cord blood plasma from volume reduction is an easily obtainable and greatly available, xeno-free source of serum that is a highly efficient replacement of FCS in sustaining MSC growth.

Nucleated red blood cells as a novel indicator of CD34+ cell content in umbilical cord blood

BACKGROUND

Umbilical cord blood (UCB) has become an important source of transplantable CD34⁺ hematopoietic progenitor cells. Cord blood banks (CBBs) can increase their efficiency by minimizing the processing of UCB units with low CD34⁺ content, which have a lower likelihood of transplant utilization. We sought to identify a readily available preprocessing metric that would correlate with CD34⁺ cell counts, without the cost of additional analysis.

STUDY DESIGN AND METHODS

Data were compiled for 131 UCB units processed at the regional CBB. Preprocessing hematologic metrics, including complete blood count and differential, were compared to postprocessing CD34⁺ cell quantities. The data were divided into six groups of varying preprocessing metrics, then compared for significant differences in postprocessing CD34⁺ cell quantities to develop a screening guidance.

RESULTS

UCB units with nucleated RBC (nRBC) content of 15% or greater were found to have a significant increase in CD34⁺ cell percentage (p < 0.00001) and total CD34⁺ cell content (p < 0.0001). Units with preprocessing total nucleated cell count (TNC) of ≥ 1.50 × 10⁹ with nRBC content of 15% or greater, and for TNC ≥ of 2.00 × 10⁹ with nRBC content less than15%, had a significant increase in CD34⁺ content (p < 0.05 and p < 0.001, respectively). Applied as a screening guideline, these units had an increase in mean CD34⁺ content from 6.24 × 10⁶ to 9.27 × 10⁶ . Units originally in the bottom and top quartiles of CD34⁺ content constitute 5% and 53% of processed units meeting these TNC/nRBC criteria, respectively.

CONCLUSION

These screening criteria utilizing nRBC provides a guideline that public CBBs may use to increase their efficiency by minimizing the processing of UCB units with lower CD34⁺ cell content.

Automated thawing increases recovery of colony-forming units from banked cord blood unit grafts

BACKGROUND

The cell dose infused for cord blood transplantation strongly correlates with outcomes following transplantation. Post thaw recoveries can be improved by washing cord blood units (CBUs) in dextran/albumin. Early methods used a labor-intensive manual process. We have recently developed and validated an automated washing method. We now report our results of a study comparing cellular recoveries achieved after manual and automated wash, as well as the impact on engraftment following allogeneic transplantation.

STUDY DESIGN AND METHODS

CBUs distributed by the Carolinas Cord Blood Bank for clinical use at Duke University after manual or automated wash were included in this report. Precryopreservation total nucleated cell count, total CD34+, colony-forming units, recoveries, and sterility were analyzed by wash method. Patient age, cell dose/weight, diagnosis, conditioning regimen, immunosuppression, and time to neutrophil engraftment were also analyzed.

RESULTS

Manual and automated washed CBUs yielded similar total nucleated cell count and total CD34+ recoveries. Significantly higher colony-forming units recoveries were achieved after automated washing. Patients who received CBUs washed via an automated method experienced earlier neutrophil engraftment.

CONCLUSION

While manual and automated washing achieved similar post thaw cellular recoveries, automated washed CBUs demonstrated higher colony-forming unit recovery, which is an important predictor of potency and engraftment. Furthermore, we demonstrated that automated washing was associated with earlier neutrophil engraftment. Our findings favor the use of an automated wash method over a manual approach.