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

BACKGROUND: Various processing methodologies are routinely used to reduce volume and red blood cell content of umbilical cord blood (UCB) units collected for hematopoietic stem cell transplantation. There is limited information regarding effects of UCB processing techniques on clinical outcomes. STUDY DESIGN AND METHODS: Retrospective data analysis compared laboratory and clinical outcomes following single-unit UCB transplantation performed between 1999 and 2015. All UCB units were from St. Louis Cord Blood Bank and all were manually processed with either Hetastarch processed cord blood units (HCB) (n = 661) or PrepaCyte processed cord blood units (PCB) (n = 84). Additional sensitivity analysis focused on units transplanted from 2010 to 2015 and included 105 HCB and 84 PCB. RESULTS: There were no significant differences in patient characteristics between the two groups. Pre-freeze total nucleated and CD34+ cell counts, cell doses/kg of recipient weight, and total colony-forming units (CFUs) were higher in PCB compared with HCB. Post-thaw, the PCB group had a significantly better total nucleated cell recovery, while there were no significant differences in cell viability, CFU recovery, or CD34+ cell recovery. Primary analysis demonstrated faster neutrophil and platelet engraftment for PCB but no differences in overall survival (OS), whereas sensitivity analysis found no effect of processing method on engraftment, but better OS in the HCB group compared with PCB group. CONCLUSION: The UCB processing method had no significant impact on engraftment. However, we cannot completely exclude the effect of processing method on OS. Additional studies may be warranted to investigate the potential impact of the PCB processing method on clinical outcomes.

How transplant centers deal with the dextran shortage: recommendations for comparing alternatives.

BACKGROUND: In the United States, dextran 40 in 0.9% NaCl is the preferred reagent for the thawing and preparation of cord blood units for hematopoietic stem cell transplantation. The recurring nationwide shortage of this reagent could have implications that extend to the avoidance of cord blood for transplantation. STUDY DESIGN AND METHODS: To address the shortage, the National Marrow Donor Program and its Cord Blood Advisory Group sought to identify available alternative reagents or manufacturers. A sample of transplant centers (TCs) were surveyed to determine their process to compare these alternatives. The TCs were then asked to share their comparability protocols for review. RESULTS: The 12 TCs that responded to the survey studied various types of alternative reagents and manufacturers of the standard dextran 40 in 0.9% NaCl. Four TCs submitted their protocols from which a model comparability protocol was created for centers who need assistance. CONCLUSION: Whether comparing dextran 40 in 0.9% NaCl to that of a different manufacturer or a different reagent, the results of the comparability studies submitted by the TCs indicated equivalency. During a shortage, the model comparability study protocol can be used as a reference to establish an alternative to dextran 40 in 0.9% NaCl.

Impact of cord blood banking technologies on clinical outcome: a Eurocord/Cord Blood Committee (CTIWP), European Society for Blood and Marrow Transplantation and NetCord retrospective analysis.

BACKGROUND: Techniques for banking cord blood units (CBUs) as source for hematopoietic stem cell transplantation have been developed over the past 20 years, aimed to improve laboratory efficiency without altering the biologic properties of the graft. A large-scale, registry-based assessment of the impact of the banking variables on the clinical outcome is currently missing. STUDY DESIGN AND METHODS: A total of 677 single cord blood transplants (CBTs) carried out for acute leukemia in complete remission in centers affiliated with the European Society for Blood and Marrow Transplantation were selected. An extensive set of data concerning CBU banking were collected and correlations with clinical outcome were assessed. Clinical endpoints were transplant-related mortality, engraftment, and graft-versus-host disease (GVHD). RESULTS: The median time between collection and CBT was 4.1 years (range, 0.2-16.3 years). Volume reduction (VR) of CBUs before freezing was performed in 59.2% of available reports; in half of these the frozen volume was less than 30 mL. Cumulative incidences of neutrophil engraftment on Day 60, 100-day acute GVHD (II-IV), and 4-year chronic GVHD were 87, 29, and 21 ± 2%. The cumulative incidence of nonrelapse mortality (NRM) at 100 days and 4-year NRM were, respectively, 16 ± 2 and 30 ± 2%. Neither the variables related to banking procedures nor the interval between collection and CBT influenced the clinical outcome. CONCLUSION: These findings indicate a satisfactory validation of the techniques associated with CBU VR across the banks. Cell viability assessment varied among the banks, suggesting that efforts to improve the standardization of CBU quality controls are needed.

Current thawing and infusion practice of cryopreserved cord blood: the impact on graft quality, recipient safety, and transplantation outcomes.

Methods of handling, thawing, and infusion of cord blood (CB) products vary substantially among thaw/transplant centers (TCs). This review 1) compares currently available CB product types and thaw methods recommended by CB banks (CBBs), 2) discusses causes of inconsistency in thaw method application at TCs, 3) advises elements to consider in thaw method approval or selection at the TC, 4) provides a procedural template for the traditional thaw methods, and 5) suggests acceptable time from product thaw to infusion and other considerations for safe infusion. It also compares postinfusion adverse reaction and engraftment data as functions of thaw methods. Remarks and suggestions made throughout this review are: 1) not intended to supersede manufacturer's instructions but meant to support the standardization of preparative procedures recommended by CBBs and 2) intended to help TCs to investigate relevant quality issues and handle challenges, especially when the TC is unable to follow recommendations due to foreseeable technical, quality, and/or clinical factors.

Hematopoietic cell transplantation with cord blood for cure of HIV infections.

Hematopoietic cell transplantation (HCT) using CCR5-Δ32/Δ32 stem cells from an adult donor has resulted in the only known cure of human immunodeficiency virus (HIV) infection. However, it is not feasible to repeat this procedure except rarely because of the low incidence of the CCR5-Δ32 allele, the availability of only a small number of potential donors for most patients, and the need for a very close human leukocyte antigen (HLA) match between adult donors and recipients. In contrast, cord blood (CB) transplantations require significantly less stringent HLA matching. Therefore, our hypothesis is that cure of HIV infections by HCT can be accomplished much more readily using umbilical CB stem cells obtained from a modestly sized inventory of cryopreserved CCR5-Δ32/Δ32 CB units. To test this hypothesis, we developed a screening program for CB units and are developing an inventory of CCR5-Δ32/Δ32 cryopreserved units available for HCT. Three hundred such units are projected to provide for white pediatric patients a 73.6% probability of finding an adequately HLA matched unit with a cell dose of ≥2.5 × 10(7) total nucleated cells (TNCs)/kg and a 27.9% probability for white adults. With a cell dose of ≥1 × 10(7) TNCs/kg, the corresponding projected probabilities are 85.6% and 82.1%. The projected probabilities are lower for ethnic minorities. Impetus for using CB HCT was provided by a transplantation of an adult with acute myelogenous leukemia who was not HIV infected. The HCT was performed with a CCR5-Δ32/Δ32 CB unit, and posttransplantation in vitro studies indicated that the patient's peripheral blood mononuclear cells were resistant to HIV infection.

Sterility testing of minimally manipulated cord blood products: validation of growth-based automated culture systems.

BACKGROUND: The St Louis Cord Blood Bank submitted a biologics license application for cord blood (CB) products processed by PrepaCyte-CB (BioE), supported with a validation study of a microbial detection system for product sterility testing (BACTEC-FX, Becton Dickinson). This article provides the validation approach followed to fulfill Food and Drug Administration requirements pertinent to sterility testing method. STUDY DESIGN AND METHODS: System qualification, culture media quality verification, and validation of CB processing by-product (CB-BP) sample as surrogate to final product for sterility testing were followed by studies evaluating method sensitivity, specificity, reproducibility, ruggedness or robustness, and bacteriostatic or fungistatic effect of CB-BP sample. CB-BP cultures and control samples were formulated using BACTEC Plus Aerobic/F, Plus Anaerobic/F, and Myco F/Lytic media. Samples were seeded with selected test organisms (n = 13 at 10-100 colony-forming units [CFUs] per vial) and cultured for 14 days (bacterial) and 30 days (fungal). RESULTS: Under testing conditions, no stasis effect of test sample on microbial growth and no false-positive or false-negative results were reported. Although a 7-day culture was sufficient to detect all validation test organisms seeded at ≤ 26 CFUs/vial, growth in actual product sterility testing practice may require a 10- to 14-day culture. Assay reproducibility was uncertain at very low bioburden (< 10 CFUs/vial). Growth time to detection neither varied between different media lots nor prolonged in culture vials with loading delay (6-8 hr at room temperature). CONCLUSION: BACTEC-FX culture and detection system and BACTEC media formulae have high detection capability and can be effectively validated for sterility testing of CB products.

Impact of selection of cord blood units from the United States and swiss registries on the cost of banking operations.

BACKGROUND: Over the last 2 decades, cord blood (CB) has become an important source of blood stem cells. Clinical experience has shown that CB is a viable source for blood stem cells in the field of unrelated hematopoietic blood stem cell transplantation. METHODS: Studies of CB units (CBUs) stored and ordered from the US (National Marrow Donor Program (NMDP) and Swiss (Swiss Blood Stem Cells (SBSQ)) CB registries were conducted to assess whether these CBUs met the needs of transplantation patients, as evidenced by units being selected for transplantation. These data were compared to international banking and selection data (Bone Marrow Donors Worldwide (BMDW), World Marrow Donor Association (WMDA)). Further analysis was conducted on whether current CB banking practices were economically viable given the units being selected from the registries for transplant. It should be mentioned that our analysis focused on usage, deliberately omitting any information about clinical outcomes of CB transplantation. RESULTS: A disproportionate number of units with high total nucleated cell (TNC) counts are selected, compared to the distribution of units by TNC available. Therefore, the decision to use a low threshold for banking purposes cannot be supported by economic analysis and may limit the economic viability of future public CB banking. CONCLUSIONS: We suggest significantly raising the TNC level used to determine a bankable unit. A level of 125 × 10(7) TNCs, maybe even 150 × 10(7) TNCs, might be a viable banking threshold. This would improve the return on inventory investments while meeting transplantation needs based on current selection criteria.

Guidelines for the development and validation of new potency assays for the evaluation of umbilical cord blood.

The following commentary was developed by the National Marrow Donor Program Cord Blood Advisory Group and is intended to provide an overview of umbilical cord blood (UCB) processing, summarize the current state of potency assays used to characterize UCB, and define limitations of the assays and future needs of the cord blood banking and transplant community. The UCB banking industry is eager to participate in the development of standardized assays to uniformly characterize cellular therapy products that are manufactured in a variety of ways. This paper describes the desired qualities of these assays and how the industry proposes to co-operate with developers to bring relevant assays to market. To that end, the National Marrow Donor Program (NMDP) Cord Blood Bank Network is available to serve as a resource for UCB testing material, research and development consulting, and product/assay testing in an accredited UCB manufacturing environment.

Comparison of cord blood thawing methods on cell recovery, potency, and infusion.

BACKGROUND: Umbilical cord blood (UCB) products have traditionally been thawed using a washing method intended to stabilize the cells, reduce dimethyl sulfoxide (DMSO) toxicity, and remove potentially ABO-incompatible red blood cell (RBC) stroma and plasma. Concerns with this approach include loss of total nucleated cells (TNCs), bag breakage during centrifugation, and poor reproducibility by transplant centers unfamiliar with this technique. We rationalized that a simple 1:1 dilution without centrifugation would stabilize the product and reduce the DMSO concentration by 50%, allowing for a controlled thaw in the laboratory without the risks of cell loss. STUDY DESIGN AND METHODS: We compared the traditional wash method with albumin reconstitution (dilution) and thaw only (no dilution or wash), assessing measurements of viability, TNC, CD34, and colony-forming cell (CFC) recovery post-thaw. Ten cryopreserved UCB products were thawed, split equally into three parts, and treated using each method. Product stability was measured at multiple time intervals up to 48hours post-thaw. RESULTS: Throughout the entire evaluation, traditional wash and dilution methods performed equally well with no significant differences observed in 7-aminoactinomycin viability, TNC, CD34, or CFC recovery. For 163 patients in which diluted products were administered, there were no serious adverse effects at infusion and similar time to engraftment was observed when compared to historical experiences with traditional wash and direct infusion. CONCLUSION: We conclude that removing DMSO, RBC stroma, and plasma post-thaw using a wash method is not necessary when UCB products are RBC and plasma reduced before cryopreservation.

Factors influencing cord blood viability assessment before cryopreservation.

BACKGROUND: Cord blood (CB) viability determines product quality and varies with time and temperature of exposure before cryopreservation. Global viability assessment may not reflect viability of white blood cell (WBC) subsets, CD34+ cell viability, or hematopoietic stem/progenitor cells function. STUDY DESIGN AND METHODS: We compared trypan blue (TB) and acridine orange/propidium iodide (AO/PI) staining with flow-cytometric (7-aminoactinomycin D [7-AAD]) viability in total WBCs (Tot-AAD), granulocytes, monocytes, lymphocytes, and CD34+ cells and total nucleated cell, CD34+, and colony-forming cell (CFC) recovery as a function of time and temperature (4, 24, and 37 degrees C) before cryopreservation. RESULTS: TB, AO/PI, and Tot-AAD viability was concordant up to 72 hours (4 degrees C) and 48 hours (24 degrees C) postcollection; however, CD34+ viability was significantly higher due to loss of viable granulocytes. In contrast, at "physiologic" temperature (37 degrees C), the decline in TB, AO/PI, and Tot-AAD viability was significantly lower than the rate of viable CD34+ and CFC loss. At all times and temperatures, CFC recovery correlated best with CD34+ viability and recovery. CONCLUSIONS: CB cell populations exhibit differential time- and temperature-dependent susceptibility to in vitro cell death; consequently, global viability measurements using TB, AO/PI, or 7-AAD (Tot-AAD) significantly underestimate (4-24 degrees C) or overestimate (24-37 degrees C) CD34+ viability and CFC recovery. Our results demonstrate the limitations of global viability assessment with TB, AO/PI, and total AAD; endorse the routine use of CD34+ cell viability measurements; emphasize the importance of temperature control during shipment; and have implications with regard to establishing acceptable "cutoff" values for viability measurements and CB collection through processing time.

Evaluation of Tissue Homogenization to Support the Generation of GMP-Compliant Mesenchymal Stromal Cells from the Umbilical Cord.

Recent studies have demonstrated that the umbilical cord (UC) is an excellent source of mesenchymal stromal cells (MSCs). However, current protocols for extracting and culturing UC-MSCs do not meet current good manufacturing practice (cGMP) standards, in part due to the use of xenogeneic reagents. To support the development of a cGMP-compliant method, we have examined an enzyme-free isolation method utilizing tissue homogenization (t-H) followed by culture in human platelet lysate (PL) supplemented media. The yield and viability of cells after t-H were comparable to those obtained after collagenase digestion (Col-D). Importantly, kinetic analysis of cultured cells showed logarithmic growth over 10 tested passages, although the rate of cell division was lower for t-H as compared to Col-D. This slower growth of t-H-derived cells was also reflected in their longer population doubling time. Interestingly, there was no difference in the expression of mesenchymal markers and trilineage differentiation potential of cells generated using either method. Finally, t-H-derived cells had greater clonogenic potential compared to Col-D/FBS but not Col-D/PL and were able to maintain CFU-F capacity through P7. This bench scale study demonstrates the possibility of generating therapeutic doses of good quality UC-MSCs within a reasonable length of time using t-H and PL.

Progress toward curing HIV infection with hematopoietic cell transplantation.

HIV-1 infection afflicts more than 35 million people worldwide, according to 2014 estimates from the World Health Organization. For those individuals who have access to antiretroviral therapy, these drugs can effectively suppress, but not cure, HIV-1 infection. Indeed, the only documented case for an HIV/AIDS cure was a patient with HIV-1 and acute myeloid leukemia who received allogeneic hematopoietic cell transplantation (HCT) from a graft that carried the HIV-resistant CCR5-∆32/∆32 mutation. Other attempts to establish a cure for HIV/AIDS using HCT in patients with HIV-1 and malignancy have yielded mixed results, as encouraging evidence for virus eradication in a few cases has been offset by poor clinical outcomes due to the underlying cancer or other complications. Such clinical strategies have relied on HIV-resistant hematopoietic stem and progenitor cells that harbor the natural CCR5-∆32/∆32 mutation or that have been genetically modified for HIV-resistance. Nevertheless, HCT with HIV-resistant cord blood remains a promising option, particularly with inventories of CCR5-∆32/∆32 units or with genetically modified, human leukocyte antigen-matched cord blood.