Cord blood banking in London: the first 1000 collections

Ethics and Governance of Stem Cell Banks

This chapter examines the ethical principles and governance frameworks for stem cell banks. Good governance of stem cell banks should balance facilitation of the clinical use of stem cells with the proper respect and protection of stem cell sample providers and stem cell recipients and ensure compliance with national regulatory requirements to foster public trust in the use of stem cell technology. Stem cell banks must develop with regard to the science, the needs of scientists, and the requirements of the public, which will benefit from this science. Given the international reach of this promising research and its clinical application, it is necessary for stem cell bank governance frameworks to be harmonized across jurisdictions.

The effect of maternal and infant factors on cord blood yield

Umbilical cord blood (CB) can be used as an alternative hematopoietic stem cell source for transplantation in hematological malignancy and blood disorders. The success of transplantation is highly related to the levels of total nucleated cell and CD34⁺ cell counts. The evaluation of optimal conditions can decrease the rate of graft rejection due to low cell count and increases the quality of CB units (CBUs) in the blood bank and the success rate of engraftment. To this end, we review the maternal and infant parameters affecting the quality and quantity of CBUs.

Effects of cryopreservation on microbial-contaminated cord blood

BACKGROUND

Cord blood units (CBUs) are associated with significant risk of exposure to microbial contamination during collection and processing; however, the survival of bacteria within a CBU is poorly understood. This study aimed to determine whether contaminating organisms in CBU survive the cryopreservation, frozen storage, and subsequent thawing conditions before infusion.

STUDY DESIGN AND METHODS

A total of 134 CBUs rejected from banking due to known contamination were thawed and rescreened using blood culture bottles (BacT/ALERT, bioMérieux). An additional 61 fresh CBUs were deliberately spiked with a range of microbial organisms and evaluated both before freeze and after thaw.

RESULTS

Microbial contaminants were detected after thaw in 63% of stored contaminated CBUs and 85% of spiked CBUs. Postthaw organism detection in spiked cord blood (CB) was higher in adult culture bottles (80%) than pediatric culture bottles (61%). Twenty percent of spiked organisms, particularly Bacillus subtilis, Escherichia coli, Clostridium sporogenes, and Propionibacterium acnes, were not detected in prefreeze samples but were detectable after thaw.

CONCLUSIONS

This study demonstrates that the majority of contaminating organisms isolated in a prefreeze sample of CB have the ability to survive cryopreservation, frozen storage, and thawing. Further, CBUs reported as microbial free may contain microbial contamination, which could result in transplantation of contaminated CB and be potentially deleterious to a patient.

Factors affecting microbial contamination rate of cord blood collected for transplantation

BACKGROUND

Collection and processing of cord blood (CB) is associated with significant risk of microbial contamination and hence relevant standards mandate microbial screening of the final product. This study aimed to determine the contamination rate and associated risk factors during 14 years of banking at the Sydney Cord Blood Bank.

STUDY DESIGN AND METHODS

CB was collected and processed using a closed system and tested for contamination using blood culture bottles (BacT/ALERT, bioMérieux) incubated for a minimum of 5 days. Four microbial screening methods were used with different combinations of inoculated bottles (adult or pediatric) and associated sample volumes (10 or 1 mL).

RESULTS

Of 13,344 CB units screened, 537 (4.0%) tested positive for contamination, with Bacteroides spp. (20.9%), Staphylococcus spp. (18.6%), and Propionibacterium spp. (13.7%) being the most common isolates. The contamination rate reduced from 10% in 1997 to 1.1% in 2009. Multivariate analysis demonstrated the following variables were independently associated with higher contamination rates: vaginal delivery, collection by obstetric staff, and use of an anaerobic bottle in addition to an aerobic bottle (which facilitated a larger sample inoculation volume than pediatric bottles).

CONCLUSIONS

This study demonstrates that contamination rates of CB collected for transplantation can be substantially reduced by collection after cesarean delivery and utilizing trained CB collection staff. These data also indicate that the common practice of testing using a pediatric (aerobic) bottle with its attendant small volume of the final CB product may be suboptimal for sensitive detection of contaminating anaerobic microbes.

The microbiologic safety of umbilical cord blood transfusion for children with severe anemia in Mombasa, Kenya

BACKGROUND

Severe anemia requiring blood transfusion is common in hospitalized young children in sub-Saharan Africa but blood is often in short supply. Umbilical cord blood may be a useful source of blood if microbiologic safety concerns can be addressed.

STUDY DESIGN AND METHODS

Cord blood, donated on the labor ward at the provincial hospital in Mombasa, was cultured soon after collection (screening culture) and after a period of storage (poststorage culture). Conventional blood transfused to children at the hospital was cultured only at the time of issue (poststorage culture). Maternal sera (cord blood) and conventional blood donations were also screened for transfusion-transmitted infection.

RESULTS

At poststorage culture, the overall contamination rate of cord blood was one-third that of conventional blood (13/449 vs. 38/434; odds ratio [OR], 0.31; 95% confidence interval [CI], 0.15-0.61) and for bacteria of high pathogenic potential it was half that of conventional blood (4/449 vs. 7/434; OR, 0.55; 95% CI, 0.12-2.18). Screening cultures were positive in 50% (2/4) of cord blood packs where an organism of high pathogenic potential was isolated at poststorage culture. Cord blood donors had a lower seroreactivity than conventional donors for human immunodeficiency virus (OR, 0.63; 95% CI, 0.29-1.18), hepatitis B virus (OR, 0.32; 95% CI, 0.16-0.59), and hepatitis C virus (OR, 0.20; 95% CI, 0.24-0.76). For syphilis, initial seroreactivity in cord blood donors was 3.8% compared to 1.8% in conventional blood donors (OR, 2.10; 95% CI, 1.15-3.60) but was 0.5% after retesting.

CONCLUSION

With respect to bacterial contamination and seroreactivity for transfusion-transmitted infection, the safety of cord blood in Mombasa compares favorably with conventional blood. Clinical trials of cord blood transfusion are justified.

Is there a role for autologous/placental red blood cell transfusions in the anemia of prematurity?

Because most extremely preterm infants with birth weight less than 1000 g need red blood cell transfusions, many attempts have been made to collect, process, and store placental blood (ie, umbilical cord blood) for autologous transfusions. Although it is feasible to do this, multiple problems in doing so including insufficient volumes collected, clotting, hemolysis, bacterial contamination, failure to significantly supplant need for allogeneic transfusions, and high costs have led many to question whether, on balance, autologous/placental red blood cell transfusion offers clinically significant benefits.

The meanings of consent to the donation of cord blood stem cells: perspectives from an interview-based study of a public cord blood bank in England

This paper explores the perspectives of women who have agreed that their umbilical cord blood may be collected for a public 'cord blood bank', for use in transplant medicine or research. Drawing on interview data from 27 mothers who agreed to the collection and use of their umbilical cord blood, these choices and the informed consent process are explored. It is shown that the needs of sick children requiring transplants are prominent in narrative accounts of cord blood banking, together with high expectations for future applications of stem cells. Given this dynamic, a concern arises that the complex and multiple uses of tissues and related data might be oversimplified in the consent process. In conclusion, the positive finding of a commitment to mutuality in cord blood banking among these women is underlined, and its implications for the wider debate on cord blood banking are discussed.

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 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.

Freeze-dried somatic cells direct embryonic development after nuclear transfer

The natural capacity of simple organisms to survive in a dehydrated state has long been exploited by man, with lyophylization the method of choice for the long term storage of bacterial and yeast cells. More recently, attempts have been made to apply this procedure to the long term storage of blood cells. However, despite significant progress, practical application in a clinical setting is still some way off. Conversely, to date there are no reports of attempts to lyophilize nucleated somatic cells for possible downstream applications. Here we demonstrate that lyophilised somatic cells stored for 3 years at room temperature are able to direct embryonic development following injection into enucleated oocytes. These remarkable results demonstrate that alternative systems for the long-term storage of cell lines are now possible, and open unprecedented opportunities in the fields of biomedicine and for conservation strategies.

Characterization of mesenchymal stromal cells derived from full-term umbilical cord blood

BACKGROUND

Multipotent mesenchymal stromal cells (MSC) are of interest for their potential to repair bone and cartilage, and also their immunosuppressive properties. Umbilical cord blood (UCB) is reported to contain MSC, and therefore may be a useful source of these cells for clinical applications.

METHODS

We evaluated protocols for isolating MSC from UCB and characterized the surface phenotype, differentiation potential and immunoregulatory properties of the cells obtained.

RESULTS

Ten of 25 UCB units processed yielded MSC-like colonies, with depletion of lineage+ cells providing a higher efficiency. Only two of the cultures could be expanded satisfactorily; the remainder failed to proliferate. One culture generated transformed lines that were grossly aneuploid, had up-regulated TERT transcripts and had lost CD90 expression and the capacity to differentiate. The two propagated UCB-MSC lines were similar to those from bone marrow but were not identical to each other, with differences seen in expression of surface markers and cytoskeletal proteins. Both underwent osteogenesis, but at different rates and to different degrees, while neither generated adipocytes. When added as a third party to a mixed lymphocyte culture, both suppressed proliferation.

DISCUSSION

MSC-like cells can be isolated from UCB, but at low efficiencies, and they exhibit a variety of morphologies, growth rates and differentiation potentials and can transform in culture.

Confirmation of cadaveric blood sample identity by DNA profiling using Short Tandem Repeat (STR) analysis

Blood samples collected from deceased tissue donors for mandatory transfusion microbiology testing may be taken either at the time of tissue donation, or residual samples may be retrieved from hospital laboratories where they were originally used for ante-mortem tests. In the latter case, sample labelling may not conform to the required standard, which stipulates that three independent identifiers be provided. If no alternative adequately labelled sample is available for testing the donated tissues may have to be discarded, which can adversely affect tissue sufficiency. An alternative method to ensure that the blood sample to be tested is from the intended deceased donor is to confirm the identity of the blood sample by Deoxyribonucleic Nucleic Acid (DNA) Short Tandem Repeats (STR) analysis, then comparing the DNA profile with the DNA from the donated tissues. If the two DNA profiles are identical, probability calculations can demonstrate the chance of the two samples of DNA being from the same or different individuals. The authors have used this approach to salvage deceased tissue donations.

A closed system for the clinical banking of umbilical cord blood

Umbilical cord blood (UCB) is a source of hematopoietic progenitor cells and is used as an alternative to the bone marrow or peripheral blood for treatment of several onco-hematological diseases. Because of the limited number of CD34+ hematopoietic stem cells present in UCB units and of the elevated costs of cryopreservation, it is of paramount importance to select the UCB units that are clinically useful before storage and optimize banking efficiency by designing reliable procedures to process and freeze the selected units. Among the different parameters characterizing UCB, nucleated cell (NC) and CD34+ cell content provides useful criteria to select UCB units since clinical data documented that the infused cell load (both NC and CD34+ cells) plays an important role in the successful outcome of transplants. By evaluating volume, CD34+ cell content, NC total amount, and NC density of 117 UCB units, we found a significant association between CD34+ cell content and NC density and total amount, indicating these parameters as useful to decide UCB clinical utility. Furthermore, we set up a fast procedure to process UCB units for storage. A system for NC separation and volume reduction of UCB samples in a dedicated, germ-free, closed circuit was developed, where plasma and red blood cells (RBC) depletion was obtained by sedimentation in the presence of a 3.5% Polygeline solution. By this separation system, both RBC depletion and high NC and CD34+ cell recoveries were achieved in 60 min, and the yield was comparable to the one obtained by other separation methods. Since Polygeline has been clinically used as a plasma expander and no toxic effects on patients were reported, the protocol can be applied in the large-scale banking of UCB.

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

BACKGROUND

The major problem with long-term cord blood (CB) banking is the required storage space. In this sense, many studies have been performed to establish techniques for volume reduction of CB units.

STUDY DESIGN AND METHODS

We compared two different methods for CB volume reduction in both development and routine phases: hydroxyethyl starch (HES) sedimentation and top-and-bottom fractionation with the Optipress II (Baxter Healthcare). Monitoring the total nucleated cell (TNC) count, lymphocytes, CD34+ cells, and colony-forming unit (CFU) content in both preprocess and postprocess CB units assessed the volume reduction process.

RESULTS

The CB units processed in both groups had comparable volume and cells counts before and after volume reduction, except for number of red blood cells (RBCs), which was significantly greater for the Optipress II group. Recoveries of CD34+ and RBC depletion were significantly better for the HES group. For routine processing, TNC and lymphocyte recoveries were significantly better for CB units processed by the Optipress II system. There was, however, significantly less depletion of RBCs for this group. The time required for CB processing with the Optipress II was significantly shorter than the time needed for volume reduction by addition of HES (25+/-5 min vs. 55+/-10 min).

CONCLUSION

The volume reduction method with the Optipress II is a closed time-saving system that allows good cell recoveries. In contrast, the main advantage of the HES method is the higher RBC depletion that influences CFU content. Reducing RBC content must be the object of further improvements for volume reduction using the Optipress II method.

Cord blood hematopoietic progenitor cell concentration and infant sex

BACKGROUND

Characterization of cord blood facilitates understanding of the factors affecting cord blood transplant quality and improvement of transplantation results. Cord blood obtained from male and female infants has not been thoroughly characterized.

STUDY DESIGN AND METHODS

A study was performed to test the hypothesis that the cord blood hematopoietic progenitor cell content-of which the CD34+ cell and colony-forming unit (CFU) concentrations were taken as markers-would not only associate with birth weight but also with sex. The hematopoietic progenitor cell concentrations of 1999 healthy infants (47% female) were analyzed in a cord blood bank setting.

RESULTS

Male infants had significantly higher median CD34+ cell concentrations than female infants (31.8/microL vs. 30.2/microL, respectively; p = 0.03). Although the disparity in absolute concentrations was small, it was 5.3 percent. In CFU subgroup analysis, the median CFU-mixed concentration of male infants (11.1/microL) was higher than in female infants (9.9/microL; p = 0.03). The difference was more pronounced when cumulative frequencies of the CFU-mixed concentrations from cesarean section deliveries were compared. In multivariate linear regression analysis, the positive influence of male sex on the CD34+ cell concentration was significant (p < 0.05). The expected higher median nucleated cell concentration of female compared to male infants (13.9 x 10(9)/L vs. 13.3 x 10(9)/L, respectively; p = 0.0001) was mainly due to the higher neutrophil concentration of female infants (7.1 x 10(9)/L vs. 6.5 x 10(9)/L, respectively, p < 0.0001).

CONCLUSION

Cord blood hematopoietic progenitor cell concentration was higher in male infants, even after correcting for birth weight. Sex may affect the hematopoietic potential of cord blood transplants.

How to improve the search for an unrelated haematopoietic stem cell donor. Faster is better than more!

Many patients do not reach haematopoietic stem cell transplantation. Shortage of unrelated donors (UDs) is still seen as the main cause. However, with a worldwide UD pool containing more than 8 million donors, it is possible that other impediments are becoming more important. We analysed 549 UD searches for Dutch patients, performed between 1987 and 2000, in order to find the reasons for failure or success to reach transplantation. Between 1996 and 2000, 59% of the patients of Northwest European origin received a graft from an UD with a median time span of 4.4 months from the start of the search. In all, 11% of the patients lacked a compatible donor, while 30% became medically unfit for transplantation. This is in contrast to the patients of non-Northwest European origin for whom UD shortage is still the most important impediment; only 32% were transplanted while 50% lacked a compatible donor. We conclude that the shortage of donors is no longer the biggest constraint in unrelated stem cell transplantation for patients of Northwest European origin. It may be more effective to optimize the chance on transplantation by making the search process more efficient.

Qualitative multiplex RT-PCR for simultaneous detection of hepatitis C virus and human immunodeficiency virus in plasma samples

This report describes the development of a one-tube multiplex reverse transcriptase (RT)-PCR assay for the simultaneous detection of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in plasma samples. The assay was evaluated with two panels of HCV- and HIV-1-positive samples, as well as negative plasma specimens. Extraction and amplification of HCV and HIV-1 RNA from plasma samples were performed in a single reaction, and amplified genomes were detected with specific probes. Serial dilutions of the HCV and HIV-1 first World Health Organization International Standards were used to evaluate the sensitivity of the method. Two RNA controls were constructed to determine inter-assay variations and the sensitivity of the amplification step. The assay had good specificity and detected all the genotypes and subtypes tested. The analytical sensitivity of the entire assay was 100 IU/mL for HCV and 200 IU/mL for HIV-1, while the amplification step detected ten copies/reaction for HCV and 20 copies/reaction for HIV-1. The multiplex assay allowed the simultaneous extraction, amplification and detection of two virus genomes, thereby providing an important practical advantage and an efficient approach for analysing individual and pooled plasma donations.

New trends in umbilical cord blood transplantation

Since the first report of a successful umbilical cord blood transplantation in 1988, there has been great interest in the use of cord blood as an alternative stem cell source to treat cancer and genetic diseases. More than 4000 cord blood transplantations have been performed worldwide. In this review, the scientific rationale for this therapy, as well as related preclinical studies, cord blood banking issues, and ethical concerns, will be addressed. Results of studies in both pediatric and adult transplantation will be discussed. Finally, new indications for cord blood use and emerging technologies will be addressed.

Cord blood banking

Cord blood (CB) is a unique product, rich in haemopoietic stem cells (HSC), that is currently used in the transplantation setting to restore haemopoiesis. It restores haemopoietic stem cell function in patients suffering from malignancies, bone marrow (BM) failure disorders and inherited metabolic and immunological disorders. Related and unrelated CB donations have been successfully transplanted in both the paediatric and adult settings. CB, previously considered a waste product, can be collected from both vaginal deliveries and caesarean sections, either in utero or ex utero, at no risk to the donor, processed to remove excess plasma and red cells, cryopreserved, tested, HLA-typed and stored to provide an 'off-the-shelf' product. CB has a lower risk of some important viral infections and a lower incidence and severity of acute and chronic graft versus host disease (GvHD) than BM. CB transplantation is under innovative development and international collaborative studies are investigating ways to improve transplant outcomes. Other uses for CB remain speculative and it is premature to speculate whether non-haemopoietic stem cells are present in cord blood in sufficient numbers for use against degenerative conditions, as is currently postulated by some commercial organisations. Cord blood banking in EU member countries is now regulated by an EU Directive, which provides a statutory basis for regulation safety to ensure efficacy. Compliance is required by 2006. It requires that all banking establishments are inspected and accredited by a Competent Authority. This includes public altruistic banking as well as directed banking activities.

Utility of bag segment and cryovial samples for quality control and confirmatory HLA typing in umbilical cord blood banking

Many cord blood (CB) banks have been established worldwide as a response to the increasing number of CB transplantations. In this study, we describe a quality control program in which the utility of an integral bag segment and cryovial containing aliquots of cryopreserved product as haematopoietic content control and HLA typing confirmation for CB units has been evaluated. For this purpose, every month one stored CB unit and its satellite cryovials were thawed and washed. Nucleated cell counts, viability and clonogenic assays were performed from the bag and cryovial before washing. After washing, total nucleated cell, CD34+ counts, viability, and clonogenic assays were performed from the bag. In order to assure the ability of bag segments to confirm hematopoietic potential of CB units, clonogenic assays and viability were performed from attached segments of 10 CB units and the results were compared with those from bags and cryovials. When comparing all variables between thawed bag and cryovial samples, they showed similar results. Mean colony-forming unit (CFU) content of segment samples was 118.8 +/- 93.72 x 10(4) that resulted similar to bags and cryovials haematopoietic content. In conclusion, the quality control system described in this paper demonstrates that CB units are processed preserving the quantity and quality of the progenitor cells. The contiguous segment haematopoietic content is representative of the final product.

Autologous cord blood transfusion in an infant with a huge sacrococcygeal teratoma

We describe a case of cord blood harvest for autologous transfusion in a neonate weighing 3,992 g with a giant sacrococcygeal teratoma. The umbilical vein was pierced with an 18-gauge needle, and placental blood was withdrawn into two 50-ml syringes filled with 4 ml of citrate-phosphate-dextrose solution. Resection of the sacrococcygeal teratoma was performed on day one. During the operation the infant lost 46 ml of whole blood, more than 15% of the estimated total blood volume, and thus underwent autologous transfusion with 27.8 ml of packed red cells obtained from autologous cord blood. Consequently, she could avoid homologous blood transfusion during the hospital stay. This case highlights the safety of this procedure, with no evidence of consumption coagulopathy, hemolysis or bacterial infection.

The London Cord Blood Bank: analysis of banking and transplantation outcome

Cord blood units (n = 5500) stored at the London Cord Blood Bank, including 59 units transplanted into a high risk and heterogeneous group of patients, were analysed. Transplant outcome data was available for 44 patients with a median clinical follow-up of 14 months (range 3-44 months). Over 40% of the collected units were of ethnic minority origin with a median volume of 79 ml (range 40-240 ml) and a median total nucleated cell (TNC) count of 11.9 x 10(9)/l (range 10.0-24.8 x 10(9)/l). The average patient's weight was 28 kg (range 5-80 kg) and the median age was 8 years (range 0.7-40 years). The median number of nucleated cells infused was 4 x 10(7)/kg (range 1.10-16 x 10(7)/kg). Neutrophil engraftment of 0.5 x 10(9)/l was observed in 33 (74+/-%) patients with an average time of 28 days (range 11-60). The Kaplan-Meier estimate of acute graft-versus-host disease (grade II >) at day 100 was 37 +/- 7% and in 27 (62%) patients, it was grade I or absent. The overall survival and disease-free survival at 2 years was 49 +/- 8% and 41 +/- 8%, respectively. Two years after transplantation the survival rate was 69% and 54% for patients receiving a 6/6 or 5/6 HLA matched units, respectively. Infection was the main cause of transplanted related mortality in these patients.

Racial diversity with high nucleated cell counts and CD34 counts achieved in a national network of cord blood banks

Banked, unrelated, partially HLA-matched, umbilical cord blood is an alternative stem cell source for patients in need of transplantation therapy who lack traditionally matched donors. A presumed advantage of cord blood is the ability to increase recruitment of donors of minority ethnic backgrounds. The American Red Cross Cord Blood Program was established in 1999 with 6 banks and 10 collection sites throughout the country. Cord blood donors self-report racial designations on questionnaires, and donor race was collected from each site. Postprocessing nucleated cell counts and CD34(+) counts were obtained on the cord blood units, and results from each racial group (white, black, Asian, Hispanic, and Native American) were compared in the natural logarithmic scale by using analysis of variance. A total of 18878 donors consented: 64% white, 16% black, 12% Hispanic, 4% Asian, 1% Native American, and 3% other. The Detroit area consented the highest percentage of black donors (87%), San Diego consented the highest percentage of Hispanic donors (59%), and Oakland consented the highest percentage of Asian donors (15%). Seven thousand eight hundred sixty-six cord blood units have been banked for transplantation. The mean preprocessing nucleated cell count was 1220 x 10(6) (range, 327-7300 x 10(6)). There was no difference among racial groups when controlled for site (P =.395). The mean CD34(+) count was 3.28 x 10(6). Blacks had a significantly lower CD34(+) count than the other racial/ethnic groups in the Midwest, Northwest, and North Carolina collection sites. A racially diverse cord blood bank can be achieved. Nucleated cell counts were similar among the different racial/ethnic groups. CD34(+) counts were lower for blacks in some collection sites.

Associations among nucleated cell, CD34+ cell and colony-forming cell contents in cord blood units obtained through a standardized banking process

BACKGROUND AND OBJECTIVES

Nucleated cell content is one of the main components used when evaluating cord blood (CB) units for clinical use. However, other indicators of the haematopoietic potential of a CB unit, such as CD34+ cell and colony-forming cell (CFU-TOT) content, have also been investigated. The aim of this study was to determine whether the CD34+ cell content could be used in selecting CB collections for banking.

MATERIALS AND METHODS

The collection data, as well as cellular contents of 588 CB collections obtained using a standardized CB banking process, were analysed.

RESULTS

Altogether, 526 CB units from the 588 collections accepted for processing were included in international search registries. The volume collected was, as expected, 69 ml (range 28-116 ml). The correlation between total CD34+ cell and CFU-TOT (n = 88) content in the CB collection was higher (r = 0.87) than the correlation between the total nucleated cell and CFU-TOT content (r = 0.69, both P < 0.0001). The correlations of pre- and postvolume reduction values of the total nucleated cell and CD34+ cell numbers were highly significant (r = 0.96, P < 0.0001, both). The total CFU-TOT content of the CB collection correlated significantly with the total CD34+ cell content of the CB unit before cryopreservation (but after volume reduction) (r = 0.89, P < 0.0001).

CONCLUSIONS

CD34+ cell content predicts the haematopoietic potential of a CB unit better than nucleated cell content. Accordingly, the CD34+ cell content of CB could be used to select CB for banking purposes and for transplantation.

Racial and ethnic composition of volunteer cord blood donors: comparison with volunteer unrelated marrow donors

BACKGROUND

Umbilical cord blood is an alternative peripheral blood progenitor cell source for patients who need transplantation. A presumed advantage of cord blood is the ability to increase minority recruitment.

STUDY DESIGN AND METHODS

The racial composition of five member cord blood banks of the National Marrow Donor Program (NMDP) was compared, representing 9020 cord blood donors with NMDP marrow donors from comparable geographic areas, representing 417,676 donors. Cord blood and marrow donors self-reported racial designations on questionnaires. Donor statistics were compared with baseline racial data of deliveries from participating hospitals for cord blood donors and with geographic census data for marrow donors.

RESULTS

The California, Florida, and Massachusetts cord blood banks recruited a lower percentage of minorities than the corresponding marrow donor centers. In New York and Colorado, minority recruitment was equivalent. In California, Florida, Massachusetts, and New York, the cord blood banks recruited a lower percentage of minorities than those delivering at the respective hospitals. The cord blood banks in California, Colorado, Florida, and Massachusetts recruited a lower percentage of minorities compared with delivery data than the corresponding marrow donor centers compared with census population (p < 0.001). In New York, the percentages were similar.

CONCLUSION

The problem of insufficient minority recruitment of cord blood has not yet been solved. Better strategies are needed to recruit minority donors.

In vitro expansion of cord blood does not prevent engraftment of severe combined immunodeficient repopulating cells

This study aimed to assess the potential of human cord blood (CB) cells to engraft in the xenogenic non-obese diabetic/severe combined immunodeficient (NOD/SCID) mouse model after in vitro expansion culture. We also studied the quality of human haemopoiesis arising from the transplantation of fresh or expanded cells in this model. Cord blood CD34(+) cells were cultured for 3, 7 or 10 d with stem cell factor, Flt3, thrombopoietin, interleukin 3 (IL-3), IL-6 and granulocyte colony-stimulating factor, all at 10 ng/ml in serum-replete conditions. Transplantation of mice with fresh CB containing 3 x 10(4) CD34(+) cells and 1-2 SCID repopulating cells (SRC) resulted in a median of 7.4% (0.4%-76.8%) human engraftment. When mice received the expanded product of 1-2 SRC, the ability to repopulate NOD/SCID mice was maintained even after 10 d of in vitro culture. Serial dilution of the expanded cells suggested that in vitro expansion had increased SRC numbers two- to fourfold. Expanded SRC produced long-term culture-initiating cells, clonogenic cells and CD34(+) cells in the same proportions as fresh cells after successful engraftment. Therefore, expanded SRC were able to differentiate in the same way as fresh SRC. There was a trend towards lower levels of engraftment when d 7 cultured cells were transplanted (median engraftment 0.8%, range 0.0-24.0%) compared with 1-2 fresh SRC. Our data suggest that this is owing to reduced proliferation of cultured cells in vivo. By utilizing limiting numbers of CB SRC, we confirmed that the engraftment potential of SRC in the NOD/SCID model was preserved after in vitro expansion. Furthermore, dilution experiments strongly suggest two- to fourfold expansion of SRC in vitro. These studies are relevant for developing clinical stem cell expansion strategies.

Microbial contamination of cord blood stem cells

BACKGROUND AND OBJECTIVES

After storage, low levels of contaminating bacteria in standard blood components can reach bacteraemic levels, causing severe transfusion-associated sepsis. For cord blood (CB), the significance of low levels of contaminating bacteria and the optimal detection method is unknown and not supported by available guidelines.

MATERIALS AND METHODS

Spiking experiments and testing of various subfractions of CB units were used to determine the behaviour of bacteria during centrifugation, freezing and thawing. For routine testing of CB, different volumes were compared for the detection of potential pathogens and micro-organisms of low pathogenicity.

RESULTS

Centrifugation, as applied to CB fractionation, does not show concentration of bacteria in any particular fraction and supports the possibility of culture of waste fractions. Dimethylsulphoxide (DMSO) and freezing does not affect the viability of bacteria under the conditions used in this study. Owing to the low contamination level, a large sample volume of 20 ml was more sensitive than a 10-ml sample volume. Eighty five per cent of the isolated strains can be considered to be of low pathogenicity.

CONCLUSION

When an optimal waste fraction sample volume of 20 ml was cultured, the contamination rate of CB was found to be approximately 13%, with low levels of < 1 colony-forming unit (CFU)/ml. Such levels of bacteria of low pathogenicity are expected to be of clinical importance only when CB is expanded in vitro for a prolonged period of time.

Status of umbilical cord blood transplantation in the year 2001

Umbilical cord blood (UCB) transplantation is limited to small recipients because of the low haemopoietic cell dose. Children from ethnic minority groups may benefit most from cord blood transplantation. Cohort controlled retrospective data indicate that there is significantly less acute and chronic graft versus host disease associated with the transplantation of human major histocompatibility complex (HLA) identical sibling cord blood compared with HLA identical sibling marrow. Controlled data are not yet available to confirm this observation in unrelated donor cord blood transplantation. The difference in leukaemic relapse seen after cord blood compared with bone marrow transplantation is also unknown. Tentative recommendations for the use of umbilical cord blood for transplantation are as follows. Collection is indicated from healthy newborn siblings when urgent transplantation is required for an older child in a family. The haematologist responsible for the older child, with the approval of the family and the obstetric team, should contact the medical director of the nearest cord blood bank to discuss arrangements for the UCB to be collected and HLA typed. Antenatal blood sampling to HLA type the fetus is not recommended. Umbilical cord blood should be considered when allogeneic transplantation is the treatment of choice for a child who does not have an HLA identical sibling, or a well matched unrelated adult volunteer donor. The potential advantages and disadvantages of using an HLA haplotype matched peripheral blood stem cell family donor rather than an unrelated cord blood donation should be discussed. There are no comparative data available as yet. At present, UCB transplantation should only be considered if a suitably matched donation contains at least 2 x 10(7)/kg nucleated cells. Effectively, this means that most adults and larger children are not suitable recipients.

An international survey of unrelated umbilical cord blood banking

OBJECTIVES

To investigate operational and technical practices within the field of cord blood banking.

MATERIALS AND METHODS

Cord blood banks world-wide were invited to participate in a survey of collection, processing and testing. The survey covered a 12-month period up to August 1998.

RESULTS

Replies were received from 18 cord blood banks. Analysis of the survey responses demonstrated wide variations in many aspects of cord blood banking.

CONCLUSION

There is a need for standardization to ensure adoption of best practice.

A simple and reliable procedure for cord blood banking, processing, and freezing: St Louis and Ohio Cord Blood Bank experiences

BACKGROUND

In UC blood banking, volume and RBC reduction of the collected UC blood allows more efficient long-term storage and decreases infusion-related hemolysis and DMSO toxicity. However, high cell yields are imperative. At the St Louis Cord Blood Bank, we have systematically addressed processing/freezing and have developed a simple processing/freezing procedure.

METHOD

The methodology is a modification of the hetastarch sedimentation and volume reduction approach of Rubinstein at the New York Placental Blood Program. Cord blood is mixed with a 1:5 v/v ratio of hetastarch. The product is incubated for 45 min in an inverted position in a refrigerated centrifuge (4 degrees C), and then is spun for 5 min at 50 g. RBC concentrate is drained from the bottom. The volume drained is calculated to remove 80% of RBC. The UC blood unit is then resuspended and spun for 13 min at 420 g. Plasma is expressed from the top.

RESULTS

A final product volume of 27 mL (range 16-58 mL) was obtained from an original 50-200 mL of UC blood collected. The average yield of total nucleated cells pre- and post-processing was 90% for the first 4055 UC blood units banked. Pre- and post-processing CFU and CD34 yields were tested in a cohort and were similarly conserved. With a processing time of 3 h for a single cord, this process is time efficient and lends itself well to processing several units at the same time. The technique has been exported to other laboratories with similar yields.

DISCUSSION

This simple methodology results in reliable yields and is well suited to larger scale banking.

Human UC-blood banking: impact of blood volume, cell separation and cryopreservation on leukocyte and CD34(+) cell recovery

BACKGROUND

UC blood represents an increasingly useful source of hematopoietic stem cells for BMT, although, currently, low cell numbers generally limit its use to pediatric patients. We have determined parameters that influence the recovery of viable cells during processing and cryopreservation, in an effort to set guidelines for determining whether a sample will yield sufficient cells to be of use in the transplant setting.

METHODS

UC blood was collected from donors from January 1996 to December 1999. Volume was reduced using Ficoll, followed by cryopreservation under liquid nitrogen. Total leukocyte and CD34(+)-cell counts were determined prior to processing and a subset of samples was also assessed post-processing and post-cryopreservation.

RESULTS

Outcomes for 3816 samples were analyzed to determine the correlation between cell number, cell type, volume, and time between collection and processing. A positive relationship was observed between volume and cell number for both leukocytes and the CD34(+) cells. This correlation allowed us to determine the number of leukocytes and CD34(+) cells expected from a sample based on volume, and to set guidelines for determining the practicality of storing any given sample prior to processing and cryopreservation.

DISCUSSION

Measuring blood volume gives a very useful indication of the total leukocyte and CD34(+) cell number. The majority (75%) of cord-blood samples contain sufficient leukocytes for a pediatric transplant, and the number of cells available can be determined prior to processing by measuring blood volume.

Collection, processing and cryopreservation of umbilical cord blood for unrelated transplantation

Umbilical cord blood (UCB) transplantation is being used as an alternative source of hematopoietic stem cells for bone marrow reconstitution. Separation and processing of UCB samples in large numbers for storage in cord blood banks ideally needs to be partially automated. The aim of this study was to establish and standardize a method for unrelated cord blood banking as well as the biological characterization of the samples. Up to October 1999, a total of 938 UCB units (mean volume 84.6 +/- 23.6 ml, nucleated cell (NC) count 0.90 +/- 0.37 x 109, total CFU-GM 79 +/- 72 x 104, CD34+ cell count 2.46 +/- 2.72 x 106) had been collected. Twenty-three per cent of all UCB samples had a NC count below 0.4 x 109 and were discarded. The initial bacterial contamination rate was reduced to less than 5% as a result of extensive training in collection procedures. Using a modification of a triple bag system and adding a solution of 6% hydroxyethyl starch, the UCB was separated by two centrifugation steps into three components: buffy coat, red cell and plasma fractions. The overall recoveries for NC, CFU-GM and CD34+ cells were 87.4 +/- 8.5%, 88.8 +/- 6.6% and 90.3 +/- 12.4%, respectively, in a mean final volume of 27 +/- 4.2 ml.

Umbilical cord blood transplants

With the establishment of cord blood banks, the number of related and unrelated umbilical cord blood transplants is increasing worldwide. Close links have been established with the cord blood banks. Available data showed that umbilical cord blood transplants offer overall results comparable to those obtained with related or unrelated bone marrow transplants. Several differences were found: engraftment with cord blood was delayed, resulting in an increased incidence of early transplant complications, and the incidence of acute and chronic graft-versus-host disease was significantly reduced with cord blood grafts, even in HLA-mismatched transplants and in adults. In patients with leukemia, the rate of relapse appeared to be similar to that documented in bone marrow transplant recipients. These data confirm the potential benefit of using umbilical cord blood hematopoietic stem cells for allogeneic transplants.

Development of a district Cord Blood Bank: a model for cord blood banking in the National Health Service

The Bristol Cord Blood Bank was established as a pilot project within existing health services to establish cost-effective recruitment, collection and processing suitable for use in the NHS should cord blood become a routine source of haemopoietic stem cells for transplantation in the UK. An important aim of the project was to evaluate the feasibility of establishing a midwifery-based collection network, thus utilising expertise already in place. Collection was performed on the delivery suite immediately after the placenta was delivered. The clinical experience of the midwife collector/counsellors allowed rapid pre-collection assessment of the condition of the cord and placenta. This prevented collection attempts from diseased or otherwise damaged placentas, leading to conservation of resources by preventing collection of most small volume donations. The bank was established within the National Blood Service, Bristol Centre to achieve Good Manufacturing Practice standards and ensure that processing was subject to the same stringency required for other sources of haemopoietic stem cells. Cord blood is an expensive resource. By utilising existing expertise in district Obstetric and National Blood Services, the Bristol Cord Blood Bank may serve as a model for health economic evaluation of cord blood banking of volunteer donations within the NHS.