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.     

Issues in the quality of umbilical cord blood stem cells for transplantation

BACKGROUND: Because the frequency of umbilical cord blood (UCB) stem cell transplantation has increased, the quality of UCB available in banks is an important part of the success of UCB stem cell transplants. STUDY DESIGN AND METHODS: A quality assurance monitoring system was used to evaluate 268 UCB units provided to us for transplant by UCB banks in the United States and Europe. RESULTS: Quality issues were found in 151 (56%) of 268 units, and there were a total of 246 specific issues in 151 units. The issues involved quality control (54%), medical history (40%), and labels and documentation (6%). Risks to patients from these issues were likely in 10 percent, potential in 35 percent, and unlikely in 55 percent. CONCLUSION: Because standards have evolved over time, cord blood banks contain units that have different levels of quality. Some units have been placed in the usable inventory with incomplete test results and/or documentation or that may not meet the bank's own current criteria. Information about any quality or operating procedure deviation should be provided in sufficient detail and at the initiation of the search process so that transplant physicians can consider these quality issues against the unique value of a particular UCB unit.     

Related cord blood banking for haematopoietic stem cell transplantation

The aims of this single centre study were to assess the feasibility of related cord blood collecting, the appropriateness of storage and the final suitability for transplantation. Since September 1994, 63 families were enrolled in this study. Families were eligible if they were caring for a patient with a disorder treatable by haematopoietic stem cell transplantation and were experiencing a pregnancy. A total of 72 cord blood units were collected and stored for 64 patients (both siblings and parents). We focussed on human leucocyte antigen (HLA) compatibility and cell content as critical requirements to unit's suitability for transplantation. HLA‐typing was carried out for 34 donor–recipient couples and most units (72%) mismatched with the related patients. About 60% of collections had a minimum cell dose considered acceptable for transplantation. Only 21% of units had both compatibility degree and cell content suitable for transplantation. When applicable, information on the compatibility degree between the foetus and the patient should be obtained during pregnancy. Appropriateness of related cord blood banking for parents should be further investigated and cost‐effective guidelines policies should be provided. Finally, as banking of related cord blood units is an important resource then, this public service should be supported and enhanced.     

非血缘脐血移植的展望

近年,非血缘脐血移植(UCBT)的广泛开展,为恶性及非恶性血液病患者的治疗提供了更多选择.本文将从脐血的选择、预处理方案、植入前综合征(PES)、植入失败和复发的处理等方面,对UCBT的最新进展及前景进行总结.     

Cost of umbilical cord blood units released for transplantation

BACKGROUND: A large number of institutions have started programs banking umbilical cord blood (UCB) for allogeneic unrelated-donor and related-donor transplantation. However, limited information is available on the financial issues surrounding these activities. STUDY DESIGN AND METHODS: The aim of this study was to determine the fee per UCB unit released for transplantation that would allow cost recovery after 10 years. Three organizational models were considered suitable to provide units for five UCB transplants per 1 million population per year, a figure that would translate into an annual need for 280 units in Italy. Models A, B, and C included, respectively, seven networked banks, each with an inventory of 1,500 units; two networked banks, each with an inventory of 5,000 units; and one bank with an inventory of 10,000 units. It was estimated that it would take 3 years to develop the cryopreserved inventory and that approximately 3 percent of the inventory could be released and replaced each year during the 7-year interval between the fourth and tenth years of activity. The data on the costs of labor, reagents and diagnostics, disposables, depreciation and maintenance, laboratory tests, and overhead, as well as the operational data used in the analysis were collected at the Milano Cord Blood Bank in 1996. RESULTS: Fees of US $15,061, $12,666, and $11,602 per unit released during the fourth through the tenth years of activity allow full cost recovery (principle and interest) under Models A, B, and C, respectively. CONCLUSION: Although UCB procurement costs compare favorably with those of other hematopoietic cell sources, these results and the current fee of US $15,300 used in some institutions show that UCB is an expensive resource. Therefore, judicious planning of banking programs with high quality standards is necessary to prevent economic losses. The advantages of lower fees associated with the centralized banking approach of Model C should be balanced with the more flexible collection offered by Model A.     

Dextran sedimentation in a semi-closed system for the clinical banking of umbilical cord blood

BACKGROUND: The results of current processing procedures for reducing volume and recovering HPCs from umbilical cord blood (UCB) before cryopreservation vary. STUDY DESIGN AND METHODS: Dextran was added to bags containing UCB, followed by sedimentation for 30 minutes. The processed UCB was then frozen. RBCs, nucleated cells, MNCs, CD34+ cells, CFUs and long-term culture-initiating cells (LTC-ICs), viability, and sterility were evaluated. Fractionations in ficoll-hypaque and hydroxyethyl starch (HES) were also run in parallel for comparison. RESULTS: The nucleated cell (NC) recovery and RBC depletion were 86.1 percent and 94.3 percent, respectively (n = 50). Sedimentation with dextran also enabled the recovery of 80.7 percent MNCs and 82.6 percent CD34+ cells (n = 30). Postsedimentation samples displayed no impairment of CFU growth (n = 42, 108.7% CFU-C, 104.6% CFU-GEMM, 107% CFU-GM, and 95.7% BFU-E). Long-term cultures on five paired samples before and after sedimentation generated similar numbers of CFU-C each week (p = 0.88). Limiting dilution analysis of 12 paired pre/postsedimentation samples showed comparable median proportions of LTC-ICs (1/6494 vs. 1/5236; p = 0.18). The cell viability of 24 samples of thawed UCB after sedimentation was 90.3 percent (77.5-96%) and the recovery of CFU-C, CFU-GEMM, CFU-GM, and BFU-E of 11 postsedimentation samples was 93.4 percent, 84.9 percent, 92.3 percent, and 83.4 percent, respectively. NC recovery was significantly higher after treatment with dextran than with ficoll-hypaque (n = 30; 88.5% vs. 29.1%; p<0.005) and HES treatment (n = 21; 88.5% vs. 76.4%; p = 0.004). However, MNCs, CD34+ cells, CFUs, LTC-ICs, and RBCs were comparable. Two cycles of dextran sedimentation recovered 93.9 percent of NCs with cell viability of 98.6 percent (96.5-100%), whereas 11.7 percent of RBCs were retained (n = 20). The final yield volume was 33.5 (28-41) mL. CONCLUSION: In a semi-closed system, dextran sedimentation enabled volume reduction of UCB without significant quantitative and qualitative losses of HPCs.     

Associated factors of umbilical cord blood collection quality

After 30 years of hematopoietic stem cell use for various indications, umbilical cord blood is considered as an established source of cells with marrow and postmobilization peripheral blood. The limited number of cells still remains a problematic element restricting their use, especially in adults who require to be grafted with a higher cell number. Improving the quality of harvested cord blood, at least in terms of volume and amount of cells, is essential to decrease the number of discarded units. In this review, we examine several variables related to parturient, pregnancy, labor, delivery, collection, the newborn, umbilical cord, and placenta. We aim to understand the biologic mechanisms that can impact cord blood quality. This knowledge will ultimately allow targeting donors, which could provide a rich graft and improve the efficiency of the collection.     

脐带血干细胞制备的检测分析

目的对脐带血干细胞制备进行检测,为临床安全、有效地应用提供依据。方法测定母体和脐带血标本的人类免疫缺陷病毒(HIV)、乙型肝炎病毒表面抗原(HBsAg)、丙型肝炎病毒(HCV)、梅毒螺旋体(TP)、巨细胞病毒(CMV)、内毒素、支原体和病原微生物。应用体外分离纯化试剂盒,分离干细胞,计数提取后单个核细胞数,经台酚兰染色检测干细胞活力。应用流式细胞仪检测CD34干细胞、淋巴细胞亚群。结果提取后有核细胞数为(5.4±1.09)×107,脐血的量和提取干细胞数成正相关。干细胞活力检测分离的活性率为(98.7±1.3)%。流式细胞仪测得脐血干细胞CD34+为(1.55±0.67)%(n=19)。淋巴细胞亚群检测结果显示,脐血CD3细胞数较少,CD4和CD8细胞数之和明显高于CD3细胞数,且选择脐血CD4/CD8小于1.3,这也是脐血移植时GVHD表现轻微的一个重要原因。结论脐血干细胞制剂的制备,符合细胞治疗的相关安全性指标。     

脐血干细胞移植治疗脑卒中的研究现状

学术背景：目前传统的方法无法从根本上改善脑卒中后所造成的神经功能缺损，欲达到理想的恢复还赖于脑功能的重建。近年研究发现，脐血干细胞在特定诱导条件下可分化为神经细胞，修复受损的神经。 目的：总结脐血干细胞移植治疗脑卒中的研究进展。检索策略：由第一作者应用计算机检索PubMed数据库与万方数据库1995／2007年期间相关文献，检索词为“cord blood stem cells，Stroke，脐血干细胞，脑卒中”，并手工查阅相关书籍。对资料进行初审，选择脐血干细胞研究及采用脐血干细胞移植治疗脑卒中的研究，排除综述及重复文献。共检索到50篇相关文献。 文献评价：选择其中的31篇，文献的来源主要是脐血干细胞研究及采用脐血干细胞移植治疗脑卒中的动物及基础实验研究。 资料综合：脐血干细胞具有自我更新、增殖和多向分化潜能，在合适诱导下可分化为神经细胞。研究表明，脐血干细胞在体外诱导及体内移植能生成神经样细胞，能表达神经元表达神经元特异性标志物nestin、NF-M、NeuN、MAP2等。脐血干细胞治疗脑卒中在动物及实验研究基础上已取得了较大成就，但仍存在许多问题，细胞体外培养中分化增值的调控机制不十分清楚，临床研究报道甚少，诱导生成的神经细胞存活的时间,能否跟正常神经细胞一样发挥功能等，待进一步探讨。 结论：用来源丰富、免疫排斥概率小的脐血干细胞治疗多发的脑卒中，具有明显的优越性，为脑血管疾病患者神经功能的恢复带来新的希望。     

超声诊断胎儿脐带绕颈的影响因素及其对策

对９６０例孕妇作产前超声检查,并与分娩结果进行对照分析。认为超声较难确定脐带绕颈３周以上的绕颈圈数,而孕周的大小、超声检查距分娩时间的长短,胎儿的位置都可影响超声诊断胎儿脐带绕颈的准确性。并提出解决方法。     

Prenatal identification of potential donors for umbilical cord blood transplantation for Fanconi anemia

Reported here are studies of Fanconi anemia fetal cells that led to the first use of umbilical cord blood for hematopoietic reconstitution in a clinical trial. Prenatal diagnosis and HLA typing were performed in fetuses at risk for Fanconi anemia (FA) to identify, prior to birth, those that were unaffected with the syndrome and were HLA-identical to affected siblings. Umbilical cord blood was harvested at the delivery of these infants; assays of progenitor cells indicated the presence of colony-forming units-granulocyte-macrophage (CFU-GM) in numbers similar to those of bone marrow CFU-GM that are associated with successful engraftment in HLA-matched allogeneic bone marrow transplantation. The possibility that umbilical cord blood from a single individual can be used as an alternative to bone marrow for hematopoietic reconstitution has now been demonstrated by the successful engraftment of two patients with FA. Progenitor cell assays of umbilical cord blood collected at the birth of a child affected with FA, who had been misdiagnosed on the basis of chorionic villus sampling (CVS) studies, indicated a profound deficiency in colony formation, consistent with previously reported abnormalities in the growth of FA cells in vitro. These results suggest that the hematopoietic disorder in FA is related to an underlying problem with cell proliferation.