Cord blood transplantation in adults

[Update for cord blood unit selection in hematopoietic stem cell transplantation (workshop SFGM-TC)]

Changing practices and the limited use of cord blood units as a source of cells for allogeneic hematopoietic stem cell transplants (HSC) led us to reconsider the recommendations established in 2011 and 2012, and to propose an update incorporating recent bibliographic data. If HLA compatibility was until now established at low resolution for HLA-A and B loci, and at high resolution for HLA-DRB1, the recent papers are converging towards an increase in the level of resolution, making way for a compatibility now defined in high resolution for all the considered loci, and the inclusion of the HLA-C locus, in order to establish a level of HLA compatibility on 8 alleles (HLA-A, B, C and DRB1). The CD34+ dose is a determining factor in hematopoietic reconstitution but it is not correlated with the total nucleated cells content. This is why we recommend taking these two data into account when choosing a cord blood unit. The recommendations established by our group are presented as a flow chart taking into account the characteristics of the underlying pathology (malignant or non-malignant), the cell dose and the HLA compatibility criteria, as well as criteria linked to the banks in which units are stored.

Umbilical Cord Blood Hematopoietic Cells: From Biology to Hematopoietic Transplants and Cellular Therapies

Umbilical cord blood (UCB) is a rich source of hematopoietic stem and progenitor cells that are biologically superior to their adult counterparts. UCB cells can be stored for several years without compromising their numbers or function. Today, public and private UCB banks have been established in several countries around the world. After 35 years since the first UCB transplant (UCBT), more than 50,000 UCBTs have been performed worldwide. In pediatric patients, UCBT is comparable to or superior to bone marrow transplantation. In adult patients, UCB can be an alternative source of hematopoietic cells when an HLA-matched unrelated adult donor is not available and when a transplant is urgently needed. Delayed engraftment (due to reduced absolute numbers of hematopoietic cells) and higher costs have led many medical institutions not to consider UCB as a first-line cell source for hematopoietic transplants. As a result, the use of UCB as a source of hematopoietic stem and progenitor cells for transplantation has declined over the past decade. Several approaches are being investigated to make UCBTs more efficient, including improving the homing capabilities of primitive UCB cells and increasing the number of hematopoietic cells to be infused. Several of these approaches have already been applied in the clinic with promising results. UCB also contains immune effector cells, including monocytes and various lymphocyte subsets, which, together with stem and progenitor cells, are excellent candidates for the development of cellular therapies for hematological and non-hematological diseases.

Effect of methotrexate dose in graft-versus-host disease prophylaxis after single-unit cord blood transplantation in adult acute myeloid leukemia

To investigate the association between methotrexate (MTX) dosage and engraftment, graft-versus-host disease (GVHD) incidence, and survival in umbilical cord blood transplantation (UCBT), we compared transplant outcomes after UCBT with various GVHD prophylaxis regimens, using registry data with additional data collection. Patients transplanted for acute myeloid leukemia with a calcineurin inhibitor (CNI) and either MTX or mycophenolate mofetil (MMF) combination were selected. In total, 888 single-unit UCBTs (MTX_15-10-10, 415; MTX_10-7-7, 294; MTX_5-5-5, 71; MMF, 108) were included. In multivariate analyses with MTX_15-10-10 as the reference, the likelihood of neutrophil and platelet engraftment was significantly worse in the MTX_10-7-7 group, and similarly better in MMF group compared with MTX_15-10-10. All variables including CyA vs Tac and 4-group GVHD prophylaxis became significant for the risk of grade II-IV acute GVHD in the final multivariate model. We observed significant additional effects of combined MTX dose in the Tac group, which were larger with lower MTX dose and MMF. No significant difference was observed in survival risk among GVHD prophylaxis groups. Despite the potential background differences in the combined CNI and conditioning regimen, we conclude that the recommended GVHD prophylaxis is a combination of CyA plus MTX_15-10-10 or Tac plus MMF.

A hands-on resident umbilical cord blood educational curriculum compared to online education of post-residency obstetricians: comparison of the volume of collected cord blood units

BACKGROUND

Umbilical cord blood unit (CBU) volume is a predictor of its later clinical utility. Many studies suggest the need to increase the volume of CBU collected, but most obstetrical providers receive no formal collection training.

STUDY DESIGN AND METHODS

We designed and implemented an educational curriculum for obstetrics residents aimed at improving collection methods and increasing CBU volumes (CBUV). Residents were required to attend grand rounds and interactive didactic sessions on CBU collection followed by work with a simulated collection kit and then performed training collections under observation by a trained collector. Residents completed a self-assessment after each collection and received immediate personal feedback. Outside providers (non-UAMS physicians) received written instructional materials with the collection kits and had access to online training materials. They received feedback regarding their collection via standard mail. CBU donated to Cord Blood Bank of Arkansas for public use from 2014-2016 were analyzed. CBUV from residents were compared to those from outside providers.

RESULTS

After adjusting for maternal age and race, infant gender, gestational age, and birth weight, the least-squared mean CBUV was 92.1 mL for UAMS collections and 65.5 mL for outside provider collections. The improved CBUV of UAMS providers is statistically significant (p < 0.0001).

CONCLUSION

Our educational intervention was successful, and we believe that it can be replicated in other obstetrical residency programs. Cord blood collection education involving hands-on training with a model and immediate feedback improves CBUV, decreases kit waste, increases likelihood of CBU storage, and, therefore, inventory for transplantation.

Cord blood research, banking, and transplantation: achievements, challenges, and perspectives

The first hematopoietic transplant in which umbilical cord blood (UCB) was used as the source of hematopoietic cells was performed in October 1988. Since then, significant achievements have been reported in terms of our understanding of the biology of UCB-derived hematopoietic stem (HSCs) and progenitor (HPCs) cells. Over 40,000 UCB transplants (UCBTs) have been performed, in both children and adults, for the treatment of many different diseases, including hematologic, metabolic, immunologic, neoplastic, and neurologic disorders. In addition, cord blood banking has been developed to the point that around 800,000 units are being stored in public banks and more than 4 million units in private banks worldwide. During these 30 years, research in the UCB field has transformed the hematopoietic transplantation arena. Today, scientific and clinical teams are still working on different ways to improve and expand the use of UCB cells. A major effort has been focused on enhancing engraftment to potentially reduce risk of infection and cost. To that end, we have to understand in detail the molecular mechanisms controlling stem cell self-renewal that may lead to the development of ex vivo systems for HSCs expansion, characterize the mechanisms regulating the homing of HSCs and HPCs, and determine the relative place of UCBTs, as compared to other sources. These challenges will be met by encouraging innovative research on the basic biology of HSCs and HPCs, developing novel clinical trials, and improving UCB banking both in the public and private arenas.

Functional Integrity and Gene Expression Profiles of Human Cord Blood-Derived Hematopoietic Stem and Progenitor Cells Generated In Vitro

To date, different experimental strategies have been developed for the ex vivo expansion of human hematopoietic stem (HSCs) and progenitor (HPCs) cells. This has resulted in significant advances on the use of such expanded cells in transplantation settings. To this day, however, it is still unclear to what extent those stem and progenitor cells generated in vitro retain the functional and genomic integrity of their freshly isolated counterparts. In trying to contribute to the solving of this issue, in the present study we have selected and purified three different hematopoietic cell populations: HSCs (CD34+ CD38- CD45RA- CD71- Lin- cells), myeloid progenitor cells (CD34+ CD38+ CD45RA+ CD71- Lin- cells), and erythroid progenitor cells (CD34+ CD38+ CD45RA- CD71+ Lin- cells), obtained directly from fresh human umbilical cord blood (UCB) units or generated in vitro under particular culture conditions. We, then, compared their functional integrity in vitro and their gene expression profiles. Our results indicate that in spite of being immunophenotipically similar, fresh and in vitro generated cells showed significant differences, both in functional and genetic terms. As compared to their fresh counterparts, those HSCs generated in our culture system showed a deficient content of long-term culture-initiating cells, and a marked differentiation bias toward the myeloid lineage. In addition, in vitro generated HSCs and HPCs showed a limited expansion potential. Such functional alterations correlated with differences in their gene expression profiles. These observations are relevant in terms of HSC biology and may have implications in UCB expansion and transplantation. Stem Cells Translational Medicine 2018;7:602-614.

[Efficacy analysis of unrelated cord blood transplantation in the treatment of refractory and relapsed adult acute leukemia]

Objective: To explore the clinical efficacy and safety of unrelated umbilical cord blood transplantation (UCBT) in the treatment of refractory and relapsed acute leukemia (AL) patients. Methods: The clinical data of 22 refractory and relapsed AL patients who were treated with UCBT as salvage therapy from November 2009 to May 2017 were retrospectively analyzed. All patients received a myeloablative conditioning regimen for prevention of graft-versus-host disease (GVHD) with cyclosporine A (CSA)/short course of mycophenolate mofetil (MMF). Results: ①Of 22 patients, 9 cases were male and 13 female. The median age was 23 (15-44) years and median weight of 52.5 (43-82) kg. All patients were transplanted with a median umbilical cord blood nucleated cells of 3.07 (1.71-5.30)×107/kg (by weight), the median CD34+ cells was 1.60 (0.63-3.04)×105/kg (by weight). ②The myeloid cumulative implantation rate was 95.5% (95%CI 45.2-99.7%) after transplantation of 42 d, with the median implantation time of 19 (13-27) d. The platelet cumulative implantation rate after transplantation of 120 d was 81.8% (95%CI 54.2-93.6%), the median implantation time of 42 (20-164) d. ③The incidence of Ⅱ-Ⅳ, Ⅲ-Ⅳ aGVHD and the 2 year cumulative incidence of cGVHD were 36.4%, 13.6% and 40.3% respectively. ④ The transplant related mortality (TRM) after transplantation of 180d was 22.7%, 2 year cumulative rate of relapse was 18.7% (95%CI 3.6-42.5%), 2 year disease-free survival rate (DFS) and overall survival rate (OS) were 53.7% and 58.1%, respectively. Conclusion: The preliminary results show that the use of UCBT is safe and effective for refractory and relapsed AL patients who fail to respond to conventional chemotherapy.

GvHD prophylaxis after single-unit reduced intensity conditioning cord blood transplantation in adults with acute leukemia

To investigate better GVHD prophylaxis in reduced intensity conditioning umbilical cord blood transplantation (RIC-UCBT), we compared transplant outcomes after UCBT among GvHD prophylaxes using the registry data. We selected patients transplanted for AML or ALL with a calcineurin inhibitor and methotrexate (MTX)/mycophenolate mofetil (MMF) combination. A total of 748 first RIC-UCBT between 2000 and 2012 (MTX+ group, 446, MMF+ group, 302) were included. The cumulative incidence of neutrophil and platelet counts higher than 50 000/μL was significantly better in the MMF+ group (relative risk (RR), 1.55; P<0.001: RR, 1.34; P=0.003, respectively). In multivariate analyses, the risk of grade II-IV and III-IV acute GvHD was significantly higher in the MMF+ group than in the MTX+ group (RR, 1.75; P<0.001: RR, 1.97; P=0.004, respectively). In disease-specific analyses of AML, the risk of relapse of high-risk disease was significantly lower in the MMF+ group (RR, 0.69; P=0.009), whereas no significant difference was observed in the risk of relapse-free and overall survival in high-risk disease. In patients with standard-risk disease, no significant differences were noted in the risk of relapse or survival between the MTX+ and MMF+ groups. Collectively, these results suggest that MMF-containing prophylaxis may be preferable in RIC-UCBT, particularly for high-risk disease.

Exploratory research for optimal GvHD prophylaxis after single unit CBT in adults: short-term methotrexate reduced the incidence of severe GvHD more than mycophenolate mofetil

In order to examine GvHD prophylaxis in umbilical cord blood transplantation (UCBT) in more detail, we compared transplant outcomes after UCBT for acute leukemia among GvHD prophylaxes using registry data. We selected patients transplanted with a calcineurin inhibitor and methotrexate (MTX)/mycophenolate mofetil (MMF) combination. A total of 1516 first myeloablative UCBT between 2000 and 2012 (Cyclosporine A (CyA) plus MTX, 824, Tacrolimus (Tac) plus MTX, 554, Tac plus MMF, 138) were included. With adjusted analyses, Tac plus MMF showed a significantly higher risk for grade II-IV and III-IV acute GvHD than CyA or Tac plus MTX. Although NRM was similar, Tac plus MMF showed a significantly lower risk of relapse than CyA or Tac plus MTX. A significant difference was observed in the risk of overall mortality (OM) between the MTX-containing group and MMF-containing group. In patients with standard-risk disease, there was no significant difference in the risk of OM in any GvHD prophylaxis. However, in patients with advanced-risk disease, Tac plus MMF showed a significantly lower risk of OM. Therefore, MTX-containing prophylaxis is preferred in UCBT for standard-risk disease, whereas MMF-containing prophylaxis is preferred for advanced-risk disease. A prospective study to identify optimal GvHD prophylaxis for UCBT is warranted.

Systematic investigation of oxygen and growth factors in clinically valid ex vivo expansion of cord blood CD34(+) hematopoietic progenitor cells

BACKGROUND AIMS

Cord blood is considered to be a superior source of hematopoietic stem and progenitor cells for transplantation, but clinical use is limited primarily because of the low numbers of cells harvested. Ex vivo expansion has the potential to provide a safe, effective means of increasing cell numbers. However, an absence of consensus regarding optimum expansion conditions prevents standard implementation. Many studies lack clinical applicability, or have failed to investigate the combinational effects of different parameters.

METHODS

This is the first study to characterize systematically the effect of growth factor combinations across multiple oxygen levels on the ex vivo expansion of cord blood CD34(+) hematopoietic cells utilizing clinically approvable reagents and methodologies throughout.

RESULTS

Optimal fold expansion, as assessed both phenotypically and functionally, was greatest with thrombopoietin, stem cell factor, Flt-3 ligand and interleukin-6 at an oxygen level of 10%. With these conditions, serial expansion showed continual target population expansion and consistently higher expression levels of self-renewal associated genes.

CONCLUSIONS

This study has identified optimized fold expansion conditions, with the potential for direct clinical translation to increase transplantable cell dose and as a baseline methodology against which future factors can be tested.

Awareness and acceptance of public cord blood banking among practicing obstetricians in the United States

BACKGROUND

This study measured: 1) levels of awareness and understanding among practicing obstetricians regarding umbilical cord blood (UCB) donation and the use of UCB in transplant therapy, 2) motivations for obstetricians to support donation and collection for donation to a public cord blood bank (CBB), and 3) current practices for discussing this option with their patients.

STUDY DESIGN AND METHODS

Obstetricians practicing in major metropolitan areas in the United States were randomly surveyed in 2009. Of 2041 surveys mailed, 295 were returned, 139 from obstetricians with privileges at hospitals affiliated with a public CBB (affiliated) and 156 from obstetricians without such privileges (nonaffiliated). Cross-tabulation analyses were conducted to compare responses between these two groups.

RESULTS

Both affiliated and nonaffiliated obstetricians report being somewhat or very familiar with the use of cord blood in transplant therapy (88% vs. 82%, respectively; p = NS), but some misperceptions concerning clinical application exist. Eighty percent of affiliated obstetricians feel confident discussing cord blood options with their patients; however, 49% indicated that they have insufficient knowledge of cord blood donation to effectively answer patients' questions about donation.

CONCLUSION

Obstetricians are generally familiar with the utility of donated cord blood in transplantation, but could benefit from additional information regarding how cord blood is used in transplantation. Further, obstetricians play an important role in encouraging women to donate their baby's cord blood to a public CBB, are willing to do so, and indicate a desire for more information so they can effectively educate their patients.

Informed consent for cord blood donation. A theoretical and empirical study

BACKGROUND AND OBJECTIVES

Umbilical cord blood (CB) banking and therapeutic use raise several ethical issues: medical indications, legal framework, public versus private biobanks, autologous versus allogeneic use, ownership, commercialisation, quality assurance and many others. Surrogate informed consent is one of the most notable controversial ethical issues. The aim of this study was to analyse and compare informed consent forms for CB collection, storage and use in the 18 accredited biobanks of the Italian Network.

MATERIAL AND METHODS

The first part of the article gives a brief overview of the scientific framework, the comparison of allogeneic and autologous use and Italian regulations. In the second part the contents of the consent forms from the 18 Italian biobanks are compared with the "NetCord-FACT International Standards for Cord Blood Collection, Banking, and Release for Administration".

RESULTS

Most of the Italian consent forms differ significantly from the NetCord-FACT Standards, with regards both to formal and substantial aspects.

CONCLUSION

Italian forms for CB collection, storage and use need standardisation to meet international criteria.