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BACKGROUND: Clinical transplant outcome with umbilical cord blood (UCB) as source of hematopoietic progenitor cells (HPCs) is, among other factors, determined by the total number of viable nucleated cells and/or CD34+ cells in the unit. Quantitative and qualitative losses by processing and cryopreservation and by thawing and washing before transfusion may occur, however. Another reason for a discrepancy between the number of cells in the unit released by the cord blood bank and found in the transplant center may be technical differences in cell counting methods between the two sites. STUDY DESIGN AND METHODS: With the collaborative group for Biomedical Excellence for Safer Transfusion (BEST), an interlaboratory exercise was conducted among nine sites for thawed UCB variables: total nucleated cells, CD34+ cells, viability, and HPC cultures. Three frozen UCB samples were shipped, with instructions for thawing, counting, and HPC plating. RESULTS: Unexpectedly samples arrived at all nine receiving centers without detectable hematopoietic progenitor colony-forming cells. Nevertheless, wide interlaboratory ranges for viability were obtained. The proportion of viable cells was found higher with manual methods, but all viability assays used in the study overestimated functional progenitor cells. CONCLUSIONS: The results underscore the complexity of evaluation of frozen-thawed cord blood cells and the need for standardization of assessment. [ABSTRACT FROM AUTHOR]

BACKGROUND: A novel filter system was developed for umbilical cord blood (UCB) volume reduction. The aim of this study was to compare the functions of cryopreserved UCB cells processed by the filter and by the hydroxyethyl starch (HES) sedimentation method from the aspect of the graft quality. STUDY DESIGN AND METHODS: UCB specimens were divided into two portions, processed in parallel by the filter or HES, and then cryopreserved in the clinical setting. The thawed UCB specimens containing 1 × 105 CD34+ cells were injected into nonobese diabetic/Shi-SCID mice, and the engraftment capacity in primary and secondary transplants was assessed. The functions of natural killer (NK) cells and monocyte-derived dendritic cells (DCs) were also assayed in vitro. RESULTS: The percentage of recovery of CD34+ cells by both methods was equivalent. In the marrow of the primary transplant recipients, the percentage of hCD45+ cells in the filter group and HES group was 58.2 ± 31.6 and 46.5 ± 28.4 percent, respectively (p = 0.016). The engraftment capacity and multilineage differentiation in the secondary transplantations were equal in both groups. The cytotoxic activity of the NK cells and phagocytosis activity of the DCs from both the groups were similar. CONCLUSION: The filter yielded a desirable percentage of recovery of hematopoietic cells with engraftment ability in the clinical setting. Thus, it is considered that the filter system may be useful for UCB banking for cord blood transplantation. [ABSTRACT FROM AUTHOR]

Background: Volume reduction and removal of RBCs are essential for cost-efficient cord blood (CB) banking. It has previously been shown that a newly developed device, a stem cell-collection filter (SCCF), can reduce the CB volume and remove RBCs efficiently, giving high recovery rates for CD34+ cells, colony-forming cells, and long-term culture-initiating cells with short operation time. The aim of this study was to compare the quality of CB cells separated by SCCF and HES by analyzing repopulation in NOD/SCID mice.Study Design and Methods: A total of 1 x 10(6) or 5 x 10(6) nucleated cells derived from SCCF- or HES-separated, cryopreserved, thawed, and washed CB were transplanted into NOD/SCID mice. Eight weeks after transplantation, bone marrow cells of the recipient mice were examined by flow cytometry and hematopoietic progenitor assay for the engraftment of human cells.Results: Mice given human CB cells, separated by SCCF, showed degrees of engraftment similar to those in mice given HES-separated CB cells. There was no significant difference in the lymphohematopoietic reconstitution pattern in the two groups of mice.Conclusion: SCCF processing does not appear to reduce the number of repopulating cells in NOD/SCID mice or alter the number of HPCs. It is now shown that these cells can be captured by SCCF and removed, and that they will engraft. [ABSTRACT FROM AUTHOR]