Red blood cell depletion with a semiautomated system or hydroxyethyl starch sedimentation for routine cord blood banking: a comparative study

Single laboratory evaluation of umbilical cord blood units processing methodologies for banking

OBJECTIVE

To compare the efficiency of 3 different processing methods (Sepax, AutoXpress [AXP], and manual processing with hydroxyethyl starch [HES] sedimentation) used at Stemlab during a 10-year period.

METHODS

Historical data were compiled and the analytical results obtained for the 3 different methods were compared.

RESULTS

The manual processing (HES) method yielded the highest level of total nucleated cell recovery after processing, and the AXP system yielded the highest CD34+ cell number. The red blood cell reduction was also significantly higher with the HES method. Also, HES showed comparable results to Toticyte technology for umbilical cord blood (UCB) processing.

CONCLUSION

These results show that the HES method is as effective as automated technologies for UCB volume reduction; hence, it is a suitable methodology for private and public UCB banks. The HES method also proved to be superior to Toticyte technology for medical applications, with higher recovery yields of total nucleated cells after thawing and equivalent CD34+ cell recovery and functionality.

Umbilical cord blood quality and quantity: Collection up to transplantation

Umbilical cord blood (UCB) is an attractive source of hematopoietic stem cells for transplantation in some blood disorders. One of the major factors that influence on transplantation fate is cord blood (CB) cell count, in addition to human leukocyte antigen similarity and CD34+ cell number. Here, we review the factors that could effect on quality and quantity of CBUs. Relevant English-language literatures were searched and retrieved from PubMed using the terms: CB, quality, collection, and transplantation. The numbers of total nucleated cells (TNCs) and CD34+ cells are good indicators of CB quality because they have been associated with engraftment; thereby, whatever the TNCs in a CB unit (CBU) are higher, more likely they led to successful engraftment. Many factors influence the quantity and quality of UCB units that collect after delivery. Some parameters are not in our hands, such as maternal and infant factors, and hence, we cannot change these. However, some other factors are in our authority, such as mode of collection, type and amount of anticoagulant, and time and temperature during collection to postthaw CBUs and freeze-and-thaw procedures. By optimizing the CB collection, we can improve the quantity and quality of UCB for storage and increase the likelihood of its use for transplantation.

A comparison of two protocols for optimal red blood cell depletion using Sepax-2 device for ABO-major incompatible transplantation in adults

PURPOSE OF THE STUDY

In ABO-incompatible bone marrow transplantation, an efficient depletion of red blood cells (RBC) within the graft is mandatory to avoid adverse events in transplanted patients. Using non therapeutic products, we evaluated the substitution of the standard density gradient-based separation (DGBS) over Ficoll-Paque with the use of an automated procedure intended for buffy coat only (SmartRedux software) introducing modifications within the settings to achieve a drastic reduction of the initial volume of the product. Both methods were conducted on the Sepax-2 device.

SAMPLES AND METHODS

RBC depletion rates and CD34+ cells recoveries from eight procedures with SmartRedux software using "in-house" settings (method A) were compared to those obtained from four procedures using NeatCell software, an automated DGBS over Ficoll-Paque (method B).

RESULTS

Median erythrocyte depletion of 95,4% (92,7%-99,0%) and 99,8% (99,0%-99,9%) were observed using methods A and B, respectively. Median residual RBC volumes in the final product were 19 mL (4,4 mL-31,2 mL) and 0,7 mL (0,4 mL-4,7 mL), respectively (p = 0,014). CD34+ cells recoveries of 90,9% (62,7%-102,1%) and 78,4% (64,1%-86,2%) were achieved for methods A and B. Median platelet depletion was 16,6% (10%-42,7%) and 89,8% (88,5%-92,4%) using methods A and B, respectively (p = 0,004). Processing duration was shorter using method A (168 ± 29 min) than method B (295 ± 21 min) (p = 0,004).

CONCLUSION

Both methods achieved satisfactory erythrocyte depletion and CD34+ recovery. The use of Sepax-2 device in association with SmartRedux software could be extended to efficiently deplete RBC from large-volume BM in a raw instead of DGBS.

Flow Cytometry and Cell Sorting Using Hematopoietic Progenitor Cells

Flow cytometry is a widely used laser-based technology for rapid analysis of the expression of cell surface antigens and intracellular molecules in various cell types including hematopoietic stem/progenitor cells (HSPCs). Multiparametric analysis of individual cells within a short time frame makes this tool attractive and indispensable in the field of stem cell research. This is accomplished by harnessing the specific light scattering ability of the cell type, which determines its size and internal complexity. In addition, use of fluorescently conjugated antibodies allows the detection of a specific surface or intracellular antigen present at that particular stage. Fluorescent Activated Cell Sorting (FACS) is used to separate a subset of cells from a heterogeneous cell population based on fluorescent labeling. Here we describe the general principles of flow cytometry and detailed methods for the isolation of HSPCs using flow cytometry as a tool.

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

BACKGROUND

Umbilical cord blood (UCB) processing with hydroxyethyl starch (HES) is the most common protocol in the cord blood banks. The quality of UCB volume reduction was guaranteed by minimum manipulation of cord blood samples in the closed system. This study aimed to analyze and compare cell recovery and viability of UCB processed using the Sepax automated system in the presence and absence of HES.

STUDY DESIGN AND METHODS

Thirty UCB bags with a total nucleated cell (TNC) count of more than 2.5 × 109 were divided in two bags with equal volume. HES solution was added to one bag and another was intact. Both bags were processed with the Sepax. To determine cell recovery, viability, and potential of colony-forming cells (CFCs), preprocessing, postprocessing, and thawing samples were analyzed.

RESULTS

The mean TNC recovery after processing and after thaw was significantly better with the HES method (p < 0.01 for the postprocessing step and p < 0.05 for the postthaw step). There were no significant differences to mononucleated cells (MNCs) and CD34+ cell recovery between the two methods after processing and after thaw. TNC and MNC viability was significantly higher without HES after processing and after thaw (p < 0.01). The results of the CFC assay were similar for both methods after processing and after thaw.

CONCLUSION

These results showed that processing of UCB using the Sepax system with the without-HES protocol due to the lower manipulation of samples could be used as an eligible protocol to reduce the volume of UCB.

An update on ABO incompatible hematopoietic progenitor cell transplantation

Hematopoietic progenitor cell (HPC) transplantation has long been established as the optimal treatment for many hematologic malignancies. In the setting of allogenic HLA matched HPC transplantation, greater than 50% of unrelated donors and 30% of related donors demonstrate some degree of ABO incompatibility (ABOi), which is classified in one of three ways: major, minor, or bidirectional. Major ABOi refers to the presence of recipient isoagglutinins against the donor's A and/or B antigen. Minor ABOi occurs when the HPC product contains the isoagglutinins targeting the recipient's A and/or B antigen. Bidirectional refers to the presence of both major and minor ABOi. Major adverse events associated with ABOi HPC transplantation includes acute and delayed hemolysis, pure red cell aplasia, and delayed engraftment. ABOi HPC transplantation poses a unique challenge to the clinical transplantation unit, the HPC processing lab, and the transfusion medicine service. Therefore, it is essential that these services actively communicate with one another to ensure patient safety. This review will attempt to globally address the challenges related to ABOi HPC transplantation, with an increased focus on aspects related to the laboratory and transfusion medicine services.

Factors which can influence the quality related to cell viability of the umbilical cord blood units

Cell viability is an important indicator for the quality of umbilical cord blood (UCB) units that can influence the transplant final outcome. Thus, it is particularly important to identify the factors that may affect the cell quality during the banking process. The present study is a first attempt to correlate the impact of exogenous factors (time from collection to processing, collected UCB volume) and endogenous factors (TNCC--total nucleated cell count, CD34(+)cell count) on cell viability assessed before UCB units cryopreservation within a banking standardized process. Three thousand UCB units collected in 35 ml CPDA containing bags were processed by HES sedimentation within 48 h. TNCC, CD34(+) cell counts and total cell viability were determined after processing. Cell viability of 94.37 ± 4.67%, TNCC of 73.17 ± 36.73 × 10(7) and CD34(+)cell count of 2.61 ± 2.29 × 10(6) was obtained after processing of units with UCB collected volume of 80.23 ± 28.52 ml. A significant negative correlation was found between cell viability and the time from collection to processing (r = -0.7228; P < 0.0001). The cell viability decreasing rate of 20.54%, 15.18% and 3-10% were achieved for units with collected UCB volume <40 ml, (40-80 ml) and >80 ml, to 48 h versus 12 h. There were no differences considering cell viability for the UCB units with similar collected UCB volume that had various CD34(+)cell count or TNCC (P > 0.05). The extension of the time from collection to processing of UCB units can reduce the quality by decreasing cell viability. The cell viability decreasing rate owing to the time influence is determined by the collected UCB volume being inversely proportional to it. Endogenous factors do not affect the cell viability.

The cord blood separation league table: a comparison of the major clinical grade harvesting techniques for cord blood stem cells

BACKGROUND AND OBJECTIVES

Well over 1 million Umbilical Cord Blood units (UCB) have been stored globally in the last 10 years. Already, over 20,000 transplants been performed using UCB for haematopoietic reconstitution alone, now this potential is joined by regenerative medicine. However, more needs to be known about processing of this stem cell source for it to reach full potential.

METHODS AND RESULTS

IN THIS STUDY WE EVALUATED FIVE SEPARATION METHODS: plasma depletion, density gradient, Hetastarch, a novel method known as PrepaCyte-CB and an automated centrifugal machine. Sepax gives the highest recovery of nucleated cells, an average of 78.8% (SD±21.36). When looking at CD34+ haematopoietic stem cells PrepaCyte-CB provided the greatest recovery at 74.47% (SD±8.89). For volume reduction density gradient was the most effective leaving 0.03×10(6) RBC/ml, 8 times more efficient than its nearest competitor PrepaCyte-CB (p<0.05). Finally PrepaCyte-CB processing left samples with the highest clonogenic potential after processing and more significantly after cryopreservation: 9.23 CFU/10(8) cells (SD±2.33), 1.5 fold more effective than its nearest rival Sepax (p<0.05).

CONCLUSIONS

PrepaCyte-CB was the most flexible method; the only processing type unaffected by volume. Results indicate that processing choice is important depending on your final intended use.

Clinical-grade generation of active NK cells from cord blood hematopoietic progenitor cells for immunotherapy using a closed-system culture process

Natural killer (NK) cell-based adoptive immunotherapy is a promising treatment approach for many cancers. However, development of protocols that provide large numbers of functional NK cells produced under GMP conditions are required to facilitate clinical studies. In this study, we translated our cytokine-based culture protocol for ex vivo expansion of NK cells from umbilical cord blood (UCB) hematopoietic stem cells into a fully closed, large-scale, cell culture bioprocess. We optimized enrichment of CD34⁺ cells from cryopreserved UCB units using the CliniMACS system followed by efficient expansion for 14 days in gas-permeable cell culture bags. Thereafter, expanded CD34⁺ UCB cells could be reproducibly amplified and differentiated into CD56⁺CD3⁻ NK cell products using bioreactors with a mean expansion of more than 2,000 fold and a purity of >90%. Moreover, expansion in the bioreactor yielded a clinically relevant dose of NK cells (mean: 2×10⁹ NK cells), which display high expression of activating NK receptors and cytolytic activity against K562. Finally, we established a versatile closed washing procedure resulting in optimal reduction of medium, serum and cytokines used in the cell culture process without changes in phenotype and cytotoxic activity. These results demonstrate that large numbers of UCB stem cell-derived NK cell products for adoptive immunotherapy can be produced in closed, large-scale bioreactors for the use in clinical trials.

Processing of hematopoietic stem cells from peripheral blood before cryopreservation: use of a closed automated system

BACKGROUND

Hematopoietic stem cell transplantation is commonly used to treat several oncohematologic diseases. The autologous hematopoietic progenitor cells collected through apheresis (HPC-A) must be cryopreserved and stored before use in vivo. Cell processing that precedes cryopreservation of HPC-A includes volume reduction aimed at reducing the amount of dimethyl sulfoxide used, as well as storage space.

STUDY DESIGN AND METHODS

The aim of our study was to assess the effectiveness of volume reduction performed with an automated closed system, namely, the Sepax S100 cell separation device (Biosafe SA). A total of 165 procedures were carried out on concentrates collected from 104 adult and pediatric patients. As a control group, 30 HPC-A units processed according to the standard method (i.e., centrifugation at a speed of 850 × g for 10 minutes, followed by manual plasma reduction) were evaluated.

RESULTS

The volume reduction obtained was 59% (range, 20.54%-84.21%; standard deviation [SD], ± 12.19%), going from 236 mL (range, 100-443 mL; SD, ± 80.41 mL) to 97 mL (range, 33.00-263.00 mL; SD, ± 47.41 mL); recovery of nucleated cells was 90% (range, 64.84%-105.93%; SD, ± 8.76%), while that of CD34+ cells was 91% (range, 59.30%-119.37%; SD, ± 13.30%). These values did not differ from those obtained using the standard method. Automated processing required 20 minutes versus 40 minutes of manual processing.

DISCUSSION

Our data demonstrate that volume reduction carried out with the Sepax S100 automated system was particularly effective; cell recovery was excellent and the time spent was short. Moreover, the closed system allows cell processing to be carried out in a contamination-controlled environment, in accordance with good manufacturing practice guidelines.

5% dimethyl sulfoxide (DMSO) and pentastarch improves cryopreservation of cord blood cells over 10% DMSO

BACKGROUND

Cell number and viability are important in cord blood (CB) transplantation. While 10% dimethyl sulfoxide (DMSO) is the standard medium, adding a starch to freezing medium is increasingly utilized as a cytoprotectant for the thawing process. Similar to hetastarch, pentastarch has the advantages of faster renal clearance and less effect on the coagulation system.

STUDY DESIGN AND METHODS

We compared a lower DMSO concentration (5%) containing pentastarch with 10% DMSO and performed cell viability assay, colony-forming units (CFUs), and transplantation of CB cells in NOD/SCID IL2Rγ(null) mice.

RESULTS

CB cells in 5% DMSO/pentastarch had similar CD34+, CD3+, and CD19+ cell percentages after thawing as fresh CB cells. CB cells in 5% DMSO/pentastarch had higher viability (83.3±9.23%) than those frozen in 10% DMSO (75.3±11.0%, p<0.05). We monitored cell viability postthaw every 30 minutes. The mean loss in the first 30 minutes was less in the 5% DMSO/pentastarch group. At the end of 3 hours, the viability decreased by a mean of 7.75% for the 5% DMSO/pentastarch and 17.5% for the 10% DMSO groups. CFUs were similar between the two cryopreserved groups. Frozen CB cells engrafted equally well in IL2Rγ(null) mice compared to fresh CB cells up to 24 weeks, and CB cells frozen in 5% DMSO/pentastarch engrafted better than those in 10% DMSO.

CONCLUSION

Our data indicate that the lower DMSO concentration with pentastarch represents an improvement in the CB cryopreservation process and could have wider clinical application as an alternate freezing medium over 10% DMSO.

Factors affecting mortality following myeloablative cord blood transplantation in adults: a pooled analysis of three international registries

A retrospective analysis was conducted to examine factors affecting early mortality after myeloablative, single-unit cord blood transplantation (CBT) for hematological malignancies in adolescents and adults. Data were collected from the three main CBT registries pooling 514 records of unrelated, single, unmanipulated, first myeloablative allogeneic CBTs conducted in North America or Europe from 1995 to 2005, with an HLA match ≥ 4/6 loci, in patients aged 12-55. Overall 100-day, 180-day and 1-year survival (Kaplan-Meier method) were 56, 46 and 37%, respectively, with no significant heterogeneity across registries. Multivariate analysis showed cell dose < 2.5 × 10⁷/kg (odds ratio (OR) 2.76, P < 0.0001), older age (P = 0.002), advanced disease (P = 0.02), positive CMV sero-status (OR 1.37 P = 0.11), female gender (OR 1.43, P = 0.07) and limited CBT center experience (< 10 records contributed, OR 2.08, P = 0.0003) to be associated with higher 100-day mortality. A multivariate model predictive of 1-year mortality included similar prognostic factors except female gender. Transplant year did not appear as a significant independent predictor. This is the first analysis to pool records from three major CBT registries in the United States and Europe. In spite of some differences in practice patterns, survival was remarkably homogeneous. The resulting model may contribute to better understanding factors affecting CBT outcomes.

Umbilical cord blood processing using Prepacyte-CB increases haematopoietic progenitor cell availability over conventional Hetastarch separation

BACKGROUND

Currently the most frequently used method for umbilical cord blood separation in many hospitals across the UK and the rest of the world, where small-to-medium amounts of samples are processed, is Hetastarch, a mechanical, starch-based method, which causes red cell agglutination by rouleaux formation.

AIM

In this study, a novel method (Prepa-Cyte-CB), in comparison with Hetastarch as part of an FDA-approved clinical study, was evaluated.

MATERIALS AND METHODS

Validation of data included recovery of nucleated and CD34+ cells, red blood cell reduction, colony forming unit potential, flow cytometric analysis and sterility tests.

RESULTS

PrepaCyte-CB, in comparison with Hetastarch offers fast, reliable separation with improved recovery of nucleated cells, 72.03% (+/-8.48 SD) compared to 58.09% (+/-20.06 SD), and CD34+ haematopoietic progenitor cells, 76% (+/-19.54 SD) compared to 64.19% (+/-29.77 SD). PrepaCyte-CB was also 12-fold more efficient in removing red blood cells and haemoglobin (P < 0.001) than Hetastarch.

CONCLUSIONS

These results show that PrepaCyte-CB offers superior separation of UCB when compared to Hetastarch.

A simple filtration system for red blood cell depletion and volume reduction in routine processing of human umbilical cord blood

BACKGROUND AND OBJECTIVES

Currently, stem cells and other progenitor cells are obtained from human umbilical cord blood (HUCB) using a variety of methods that are designed primarily for red blood cell depletion and volume reduction prior to freezing and storage. Some of these methods are very cumbersome and involve several steps that may result in significant cell loss. Therefore, processes that minimize the loss of haematopoietic stem and progenitor cells (HSPC) remains very critical. In the present study, we describe a simple filtration process for achieving both volume reduction and red blood cell depletion in a 'closed sterile system' with significant recovery of viable HSPC.

MATERIALS AND METHODS

About 80-100 ml of HUCB were collected into citrate-phosphate-dextrose-adenine 1 anticoagulant. Each HUCB was divided into 25-70-ml aliquots and then either diluted with isotonic saline or filtered without any prior dilution with an experimental Red Cell Volume Reduction System (RCVRS). The HSPCs were recovered by retrograde rinsing of the filter with an isotonic stem cell recovery solution. The viability, colony forming properties, leucocytes and CD34+ cells recoveries were determined.

RESULTS

The mean volume of the HUCB before processing was reduced from 43.9 +/- 7.9 ml to 11.8 +/- 0.7 ml (n = 55) with red blood cell depletion of 85.2 +/- 3.7%. Diluting the HUCB with isotonic saline prior to processing with RCVRS increased the red blood cell depletion to 91.9 +/- 3.0% (n = 7) without any significant loss in viability or cell recovery. The mean viability of the RCVRS-processed HUCB was not significantly different from the control unprocessed blood (96.60 +/- 1.90 vs. 96.63 +/- 2.12%; P > 0.05). The mean recoveries of the CD34+ and the haematopoietic clonogenic progenitor cells with the filter were 83.9 +/- 26.8 (n = 40) and 99.9 +/- 27.9% (n = 35), respectively.

CONCLUSION

The present results show that the RCVRS provides a simple and easy-to-use process for obtaining red blood cell depletion and volume reduction of HUCB with good cell viability and recoveries.

A new automatic device for routine cord blood banking: critical analysis of different volume reduction methodologies

BACKGROUND AIMS

Volume reduction is the usual process in cord blood banking that has some advantages regarding reducing the storage space and dimethyl sulfoxide (DMSO) quantity in the final product. The volume reduction methodology must guarantee high cell recovery and red blood cell (RBC) depletion by reducing all the umbilical cord blood (UCB) units to a standard volume.

METHODS

We analyzed and compared critically three different volume reduction methods [hydroxyethylstarch (HES), top and bottom with Optipress II and Compomat G4, and AXP] used at the Valencia Cord Blood Bank over 10 years.

RESULTS

The highest significant RBC depletion was achieved with the AXP system (P<0.001), while the top and bottom system with Compomat G4 and an adjusted buffy coat (BC) volume to 41 mL enabled the best total nucleated cell (TNC) recovery (P<0.001). TNC recovery and RBC depletion were similar for AXP and HES with an adjusted volume to 21 mL. In the multivariate analysis, when analyzing all cases, the BC volume set significantly influenced TNC, CD34+ and lymphocyte recoveries and RBC depletion (P<0.001). RBC depletion was significantly influenced by the initial volume and initial RBC content of UCB units (P<0.001).

CONCLUSIONS

AXP is a highly efficient method for RBC depletion, providing the same TNC recovery as HES method with a final volume of 41 mL. AXP has the advantages of being an automatic and functionally closed system that shortens and better standardizes the proceedings. Top and bottom is a closed system that allows better TNC recoveries when the BC volume set is 41 mL.

Ten-year quality control of a semiautomated procedure of cord blood unit volume reduction

BACKGROUND

Volume reduction of cord blood units decreases the cost of cryogenic storage. This study reports the analysis of a 10-year quality control program of a semiautomated cord blood volume reduction procedure.

STUDY DESIGN AND METHODS

Cord blood was collected in a plastic bag containing 29 mL citrate-phosphate-dextrose, centrifuged at 2124 x g for 12 minutes, and processed with a semiautomated device. The procedure was aimed at removing most red blood cells and plasma and concentrating hematopoietic progenitors in the buffy coat (BC), thus reducing the unit volume and saving cryogenic space. Finally, the BC was cryopreserved with an equal volume of 20 percent dimethyl sulfoxide. Total nucleated cells (TNCs) were counted before and after processing in the 4311 units banked from 1998 through 2007, whereas CD34+ cells and colony-forming units-granulocyte-macrophage (CFU-GM) were counted in 420 random units from 2001 through 2007.

RESULTS

Mean postvolume reduction annual recoveries of TNCs, CD34+ cells, and CFU-GM ranged from 82.8 +/- 12.3 (standard deviation) to 91.4 +/- 6.4 percent, from 87.8 +/- 14.1 to 95.2 +/- 23.8 percent, and from 101.5 +/- 51.4 to 117.8 +/- 59.5 percent, respectively. Very strong correlations were found (r > 0.87) between postprocessing versus preprocessing TNCs, CD34+ cells, and CFU-GM; a moderate correlation between initial TNC count and unit's volume (r = 0.51); and no correlation between TNC percentage of recovery in the BC and initial unit's volume. The latter data indicate that most TNCs concentrate in the BC.

CONCLUSIONS

The semiautomated procedure of cord blood unit volume reduction used in this study provides high and stable cellular recoveries during several years of routine cord blood banking.

Influence of volume reduction and cryopreservation methodologies on quality of thawed umbilical cord blood units for transplantation

INTRODUCTION

Although there is considerable variability in methodology among umbilical cord blood banks, their common goal is to achieve optimal product quality for transplantation. Cryopreservation is a critical issue for a long-term maintenance of cord blood viability and colony-forming capacities.

MATERIALS AND METHODS

We designed a prospective study to compare controlled (CRF) vs. non-controlled freezing (URF) of volume-reduced cord blood units. In addition, the influence of hydroxy ethyl starch (HES) on cryopreservation was also assayed. To assess the efficiency of protocols used, cell recoveries were measured and the presence of hematopoietic colony-forming units was quantified.

RESULTS

In the study phase, we observed similar CB haematopoietc recoveries for CRF and URF strategies, except for TNC recovery that was better for HES volume reduced CB units in the URF group. When we analysed the data of routine processed CB units in samples from satellite cryovials, we found better BFU-E, CFU-GM, CFU-GEMM and CFU recoveries for those units processed with HES than without HES, in an URF manner.

CONCLUSIONS

URF of CB units is a cryopreservation procedure that allows similar hematopoietic progenitor recoveries than CRF with programmed devices. However, our study suggests that those banks that cryopreserve CB units in a URF manner should use HES for volume reduction. On the other hand, for CRF cryopreservation methodology volume reduction with and without HES are equally useful.

[Donors selection and retrieval of units in an umbilical cord blood bank]

BACKGROUND AND OBJECTIVE

Umbilical cord blood (UCB) contains hematopoietic stem cells that can be used as an alternative to bone marrow transplantation in certain cases. This study was designed to investigate the influence of obstetric, neonatal and collection factors on the hematopoietic content of UCB donations.

MATERIAL AND METHOD

A total of 391 consecutive maternal-neonatal pairs were evaluated during the prepartum period in the maternity ward at La Fe University Hospital. Maternal, neonatal and collection factors influencing cord blood quality measured as volume, total nucleated cells count, CD34+ cells and colony forming units were analyzed in 2,000 UCB collections.

RESULTS

32.5% of UCB potential donors were excluded, mainly due to obstetrical reasons. Among the collected units, 56% were discarded before cryopreservation, mainly due to low cell counts. In the multivariate analysis, placental weight was a predictor variable for total nucleated cells, CD34+ cells and colony forming units, while the mode of collection influenced the total nucleated cells and CD34+ cell counts.

CONCLUSIONS

The collection of UCB units before placental delivery (using the birth weight as an estimation of the placental weight) could be added to standard cord blood donors criteria in order to improve the bank efficiency.

CD34+ progenitors are reproducibly recovered in thawed umbilical grafts, and positively influence haematopoietic reconstitution after transplantation

Cord blood (CB) units are increasingly used for allogeneic transplantation. Cell dose, a major factor for CB selection, is evaluated before freezing by each CB bank, using various techniques. This may introduce variability and affect the prediction of cell recovery after thawing, or haematopoietic reconstitution. Forty-two children were transplanted at the same institution with unrelated CB units. All units were thawed and evaluated at the same cell therapy facility, using standard procedures. We investigated: (i) factors that affect cell loss after thawing, and (ii) the importance of CD34(+) cell doses. Prefreeze and post-thaw CD34(+) cell doses were statistically correlated, thus suggesting that variability in numeration techniques used by different CB banks does not compromise the biological and clinical value of these figures. CD34(+) cell recovery appeared to be correlated with the absolute number of CD34(+) cells per frozen bag. Infused CD34(+) is the cell dose that better correlates with platelet reconstitution delay; in addition, when using a quartile comparison, haematopoietic recovery appeared to be related with prefreeze and post-thaw CD34(+) cell doses. We conclude that enumeration of CD34(+) cells in CB units is of biological significance, and may help select CB units and identify patients at risk of delayed recovery.

Cord blood volume reduction using an automated system (Sepax) vs. a semi-automated system (Optipress II) and a manual method (hydroxyethyl starch sedimentation) for routine cord blood banking: a comparative study

Background With the development of cord blood banking, solutions have to be found to solve the storage space problem, by reducing the volume of cord blood units (CBU). Methods We compared total nucleated cell (TNC) and CD34(+) cell counts before and after processing with three different CBU volume reduction methods used consecutively in our bank: a manual method based on hydroxyethyl starch sedimentation (HES) (n=447), a top-and-bottom (TB) semi-automated method (n=181) using Optipress II, and the Sepax automated method (n=213). Statistical analysis was done using t-tests, linear regression and Spearman correlation coefficients. Adjusted variables included TNC, CD34(+) cell counts, CD34(+) cell percentage and CB volume before processing. Results TNC recovery was higher with Sepax (80.3+/-7.7%) than with HES (76.8+/-9.1%) and TB (60.7+/-13.5%) (P<0.0001, both). It was higher with HES than with TB (P<0.0001). CD34(+) cell recovery was higher with Sepax (86+/-11.6%) than with HES (81.5+/-12.5%) and TB (82.0+/-17.7%) (P<0.008 and <0.0001, respectively) and results with HES and TB were not significantly different (P=0.7). Interestingly, with Sepax, TNC and CD34(+) cell recoveries were not correlated with pre-processing values (P=0.8 and 0.4, respectively). Discussion In conclusion, the Sepax volume reduction method allows higher TNC and CD34(+) cell recoveries.

Automated separation of cord blood units in top and bottom bags using the Compomat G4

Cord blood (CB) has become a real alternative source of haematopoietic stem cells for bone marrow reconstitution in a variety of malignant disorders. As a response to this increasing activity, CB banks have been developed to guarantee the quality of processed CB units. Volume reduction of CB units maximizes storage space and also has other advantages. The aim of this study was to develop a program for the volume reduction of CB in the Compomat G4 device. We also compared two different top and bottom systems for CB fractionation (Compomat G4 and Optipress II). We empirically designed three different programs for volume reduction of CB with Compomat G4: two for final BC volume of 41 ml (CB1 and CB2) and the other one for buffy coat (BC) volume of 25 ml (CB3). Significantly worse recoveries were achieved for CB processed with program CB3. A RBC depletion of >or=50%, >or=60% and >or=70% were achieved for 67%, 39% and 9% of all units respectively. When comparing Compomat G4 and Optipress II, total nucleated cell recovery was similar for both methods, while lymphocytes recovery was significantly better for Optipress II.