Ethnically mismatched cord blood transplants in African Americans: the Saint Louis Cord Blood Bank experience

Ethical challenges of cord blood banks: a scoping review

Cord blood is a rich source of hematopoietic stem cells used to treat many diseases of blood origin. Thus, storage banks were created to store and provide umbilical cord cells. With the development of diagnostic and therapeutic technologies and techniques in medicine, ethical issues have also become more widespread and complex. After the creation of the cord blood banks, efforts were made to address the ethical issues associated with such banks. The present study attempts to identify the ethical challenges in these banks in the published studies. Databases including PubMed, Scopus, Web of Science (WOS), Embase, Proquest, and Google Scholar were searched from January 1996 to January 2021. Then, the ethical challenges of the cord blood bank were extracted from the results section using thematic content analysis. 22 studies were selected based on inclusion and exclusion criteria. The ethical challenges raised in the studies included private or public ownership of the bank, fair access to banking services, informed and voluntary consent, failure to provide sufficient information to individuals about the process, confidentiality of user's information, conflict of interest of bank founders (who are commonly doctors). The findings of this study indicated that there are serious ethical concerns regarding umbilical cord blood banks. Responding clearly to these ethical challenges calls for the attention of policymakers and medical ethics professionals; this will require a clear statement of the various aspects of these banks for society.

Allogeneic stem cell transplantation with omidubicel in sickle cell disease

Many patients with sickle cell disease (SCD) do not have HLA-matched related donors for hematopoietic stem cell transplantation (HSCT). Unrelated cord blood (UCB) is an alternative graft option but is historically associated with high graft failure rates, with inadequate cell dose a major limitation. Omidubicel is a nicotinamide-based, ex vivo-expanded UCB product associated with rapid engraftment in adults with hematologic malignancies. We hypothesized that increasing the UCB cell dose with this strategy would lead to improved engraftment in pediatric patients undergoing myeloablative HSCT for SCD. We report the outcomes of a phase 1/2 study in 13 patients with severe SCD who received omidubicel in combination with an unmanipulated UCB graft and 3 who received a single omidubicel graft. Grafts were minimally matched with patients at 4 of 6 HLA alleles. Median age at transplant was 13 years. A median CD34+ expansion of ∼80-fold was observed in omidubicel and led to rapid neutrophil engraftment (median, 7 days). Long-term engraftment was derived from the unmanipulated graft in most of the double cord blood recipients. Two of the 3 single omidubicel recipients also had sustained engraftment. Incidence of acute graft-versus-host disease (GVHD) was high, but resolved in all surviving patients. Event-free survival in the double cord group was 85% (median follow-up 4 years). All 3 patients in the single cord group were alive at 1 year after transplantation. Ex vivo expansion of UCB with omidubicel supports engraftment in patients with SCD. This approach to decreasing the incidence of GVHD should be optimized for general use in patients with SCD. This study was registered at www.clinicaltrials.gov as #NCT01590628.

Awareness of cord blood collection and the impact on banking

BACKGROUND

Umbilical cord blood (UCB) is an important source of hematopoietic stem cells for transplantation especially in minority populations with limited chances of finding a histocompatible volunteer donor in the registry. UCB has the advantages of early availability, successful outcomes despite some histocompatibility mismatch, and low incidence of chronic graft-versus-host disease. Public cord blood banks that disseminate UCB products for transplant depend on voluntary donation at participating hospitals and obstetrical providers for collection.

PROCEDURE

Using survey questionnaires, we evaluated attitudes toward UCB donation, the frequency of donation, and provider opinions on UCB collection in the greater St. Louis metropolitan area that caters to minority ethnicities in significant numbers.

RESULTS

Our data suggest that nervousness and lack of information regarding the donation and utility of the product were ubiquitous reasons for not donating. Additionally, irrespective of age or level of education, women relied on healthcare providers for information regarding UCB donation. Providers reported primarily time constraints to discussing UCB donation at prenatal visits (54%). Of the interviewees, 62% donated UCB. Fallout due to refusal or preferring private banking was miniscule.

CONCLUSIONS

These results suggest that dedicated personnel focused on disseminating information, obtaining consent, and collecting the UCB product at major hospitals can enrich cord blood banks especially with minority cords. Sustained and focused efforts could improve upon a relatively high wastage rate and ensure a robust supply of UCB products at local public banks.

Plasma-depleted versus red cell-reduced umbilical cord blood

Umbilical cord blood banks use two methods to store frozen umbilical cord blood (UCB): red cell reduction (RCR) or plasma depletion (PD). The RCR method centrifuges cord blood in hetastarch or albumin to isolate 21 ml of cord blood containing mostly white blood cells, adds 4 ml of 50% dimethyl sulfoxide (DMSO), and then freezes the resulting 25 ml of cell suspension. The PD method removes plasma, saves all the cells, and freezes the cells in 10% DMSO. PD UCB units are cheaper to process but more expensive to store and somewhat more troublesome to thaw. However, when properly thawed and washed, PD UCB units have as many or more total nucleated cells (TNCs), CD34(+) cells, and colony-forming units (CFU) than RCR units. Two studies suggest that PD units have 20-25% more TNCs, MNCs, and CD34(+) cells, as well as two to three times more CFU than RCR units. Higher TNC, CD34(+), and CFU counts predict engraftment rate with faster neutrophil and platelet recovery. PD units have high engraftment rates with low mortality and high disease-free survival, comparable with clinical results of treatments with RCR units. One recent series of studies suggests that PD units are more effective for treating thalassemia with 2-year survival rates of 88%, disease-free survival rates of 74%, and 100% cure rate for children under age 7, compared to only 61% overall survival and 23% disease-free survival rate in thalassemic children treated with RCR units. These findings suggest that PD units not only have more TNCs, CD34(+) cells, and CFU than RCR units but also have high engraftment rates and may be more effective for treating certain conditions such as β-thalassemia.

What are the most important donor and recipient factors affecting the outcome of related and unrelated allogeneic transplantation?

Several recipient and donor risk factors affect outcome after transplantation with allogeneic hematopoietic stem cells. The most important recipient risk factors are patient age, comorbidity, performance status, cytomegalovirus (CMV) status, and disease considerations, such as diagnosis, stage, and cytogenetic risk. Prior chemotherapy regimens, patient race, and IL10 promoter polymorphism also appear to have some impact, but to a lesser extent. The most important donor factor is the level of HLA mismatch. Donor gender, relation, age, and KIR genotype also affect outcome. Donor CMV serology, parity, and race do not appear to affect outcome. These factors must all be considered in relation to one another when selecting whether to recommend patients for transplant.

Unrelated cord blood transplantation for severe congenital neutropenia: report of two cases with very different transplant courses

SCN is characterized by neutropenia, life-threatening infections, and progression to myelodysplastic syndrome/acute myelogenous leukemia. The only curative option is SCT, but few reports using UCB as a stem cell source exist. Here, we report two SCN patients transplanted with UCB. Patient 1 was transplanted at seven yr of age due to increasingly large injections of G-CSF (>100 microg/kg/day) and the risk of developing leukemia. He engrafted promptly and is clinically well and immune reconstituted >2 yr post-transplant. Patient 2 underwent UCB SCT at nine months of age for recurrent severe infections, despite high doses of G-CSF. He rejected his first graft, having 100% host cells on day +35, and immediately underwent a second UCB SCT. He engrafted but experienced late graft rejection six months after the second transplant. He received a third UCB SCT following a more immunosuppressive conditioning regimen. His course was complicated by HHV-6 viremia and gut GVHD, but he is now clinically well and has 99% donor engraftment >20 months post-transplant. We conclude that UCB is an acceptable stem cell source for SCN patients, but conditioning must be adequately immunosuppressive to ensure engraftment in patients without prior chemotherapy.