Impact of ethnicity on human umbilical cord blood banking: a systematic review

Ethnic diversity and cord blood banking: satisfying the unmet need

BACKGROUND AIMS

In this study, the authors sought to assess whether cord blood units (CBUs) collected from donors of non-European ethnic backgrounds are utilized for umbilical cord blood transplantation (UCBT) at a different rate than those of European ethnic backgrounds. The authors also examined potential methods of enriching these under-represented ethnic backgrounds in cord blood bank (CBB) inventories without increasing financial overheads and without compromising total inventory utilization or post-transplant outcomes.

METHODS

Data from N = 6506 searchable or shipped Anthony Nolan Cell Therapy Centre grafts were used in this study. Banked grafts were graded from A+ to D based on total nucleated cell and CD34+ cell content. Utilizations of each grade group were further stratified by graft ethnic background. The Mantel-Cox log-rank test was performed in conjunction with Kaplan-Meier survival analysis to compare utilization rates and post-transplant outcomes. For shipped grafts, levels of HLA matching at HLA-A, HLA-B and HLA-DR loci were also analyzed by graft ethnic background and grade using data from the Eurocord/EBMT registry.

RESULTS

Overall utilization of non-European grafts did not significantly differ from that of European grafts (2.5% versus 2.2%, P = 0.23). However, significant differences were found when stratifying utilization rates by cell content. The probability of non-European D grade grafts being utilized was 3-fold higher than that of European D grade grafts (1.1% versus 0.4%, P = 0.03) and comparable to that of European C grade grafts (1.1% versus 0.9%, P = 0.90). No significant differences were found between D and C grade grafts in terms of overall survival (OS) (P = 0.12), in part due to a disproportionate utilization of D grade grafts for pediatric UCBT (74% versus 39%, age difference P < 0.001). Furthermore, non-European graft shipments were 4-fold less likely to be a 6/6 HLA match to their recipients relative to European graft shipments (7% versus 29%).

CONCLUSIONS

The authors have identified a niche for CBUs of low cell content collected from donors of non-European ethnic backgrounds that has been overlooked by previous studies. Banking of these CBUs for pediatric UCBT instead of CBUs from European donors containing modestly higher cell content is an ethical approach to increasing the ethnic diversity of CBB inventory-and, consequently, the probability of non-European recipients finding a 6/6 HLA-matched graft-without compromising post-transplant OS or overall rate of inventory utilization.

[Influence of maternal and infant factors on CD34+ hematopoietic stem/progenitor cells in umbilical cord blood]

OBJECTIVE

To study the association of different maternal and infant factors with the number of total nucleated cells and CD34⁺ hematopoietic stem/progenitor cells in umbilical cord blood, and to provide a reference for reasonable selection of umbilical cord blood in the cord blood bank.

METHODS

A prospective study was performed for the umbilical cord blood samples of 130 neonates who were born in Dalian Women and Children's Medical Center from June 2019 to January 2020, with a male/female ratio of 1:1. Related perinatal information was collected, including maternal age and blood type, presence or absence of gestational diabetes or gestational hypertension, pregnancy method, mode of delivery, singleton pregnancy/twin pregnancy, body weight and sex of neonates, Apgar score after birth, and the conditions of placenta, amniotic fluid, and umbilical cord.

RESULTS

The neonates were grouped according to maternal blood type, gestational diabetes, gestational hypertension, pregnancy method, mode of delivery, singleton pregnancy/ twin pregnancy, sex of neonates, Apgar score after birth, placental morphology, meconium staining of amniotic fluid, and umbilical cord around the neck. The comparison between groups showed no significant differences in the numbers of total nucleated cells and CD34⁺ cells in umbilical cord blood (P > 0.05). Maternal age and neonatal body weight were not correlated with the number of total nucleated cells in umbilical cord blood (P > 0.05), and neonatal body weight was not correlated with the number of CD34⁺ cells (P > 0.05), while maternal age was positively correlated with the number of CD34⁺ cells (P < 0.05).

CONCLUSIONS

The number of CD34⁺ cells in umbilical cord blood increases with the increase in maternal age, and therefore, umbilical cord blood in the cord blood bank may be selected based on maternal age.

Factors associated with blood cord unit bankability: an analysis of a 15-year-long case series

Blood banking is a long and complex process requiring an accurate screening of potential donors and high-quality control systems. Previous studies in literature investigated factors potentially determining a higher cell levels with the aim of optimizing donors' selection and improving banking process. This study aims to identify factors associated with the concentration of stem cells in umbilical cord blood, so increasing the probability of bankability, focusing on the possible implications in terms of obstetric and resources management. This is a retrospective study conducted in the Obstetric Units of two Italian Hospitals in Montebelluna and Castelfranco Veneto. Study has been conducted on cord blood units banked between 1999 and 2015. Data on medical histories and clinical characteristics of mother and baby have been retrieved via a retrospective examination of medical records. A total of 869 cord blood units were studied. At multivariable analysis, in agreement with literature, birthweight and placental weight have been found to be associated with higher concentration of total nucleated cells. As additional factor, amount of fluid infused was associated with cord blood units' count. This study is the first one to clearly identify the role of fluid infusion on cord blood units' counts in addition to placental weight and delivery. Some non-modifiable features can help in predicting bankability from pre-natal aspects to factors more related with obstetric management is suggested.

Evaluation of Cord Blood Total Nucleated and CD34+ Cell Content, Cell Dose, and 8-Allele HLA Match by Patient Ancestry

How cord blood (CB) CD34⁺ cell content and dose and 8-allele HLA match vary by patient ancestry is unknown. We analyzed cell content, dose, and high-resolution HLA-match of units selected for CB transplantation (CBT) by recipient ancestry. Of 544 units (286 infused, 258 next-best backups) chosen for 144 racially diverse adult patients (median weight, 81 kg), the median total nucleated cell (TNC) and CD34⁺cell ⁺contents were higher for Europeans than for non-Europeans: 216 × 10⁷versus 197 × 10⁷ (P = .002) and 160 × 10⁵ versus 132 × 10⁵ (P = .007), respectively. There were marked cell content disparities among ancestry groups, with units selected for Africans having the lowest TNC (189 × 10⁷) and CD34⁺ cell (122 × 10⁵) contents. Units for non-Europeans were also more HLA-mismatched (P = .017). When only the 286 transplanted units were analyzed, the adverse effect of reduced cell content was exacerbated by the higher weights in some groups. For example, northwestern Europeans (high patient weight, high unit cell content) had the best-dosed units, and Africans (high weight, low unit cell content) had the lowest. In Asians, low cell content was partially compensated for by lower weight. Marked differences in 8-allele HLA-match distribution were also observed by ancestry group; for example, 23% of units for northwestern Europeans were 3/8 to 4/8 HLA-matched, compared with 40% for southern Europeans, 46% for white Hispanics, and 51% for Africans. During the study period, 20 additional patients (17 non-Europeans; median weight, 98 kg) did not undergo CBT owing to the lack of a suitable graft. CB extends transplantation access to most patients, but racial disparities exist in cell content, dose, and HLA match.

Contextual factors influencing donor recruitment and cord blood collection: perspectives of frontline staff of the Canadian Blood Services' Cord Blood Bank

BACKGROUND

Umbilical cord blood (CB) is an important source of hematopoietic stem cells that are used to treat blood- and immune-system disorders. Public CB banks aim to build inventories with high-quality CB units to meet healthcare needs. While research has noted the influence of broader contextual factors on donor recruitment and CB collection processes, to date, no published study has identified the specific contextual factors and challenges to donor recruitment and CB collection. This paper addresses this gap in the literature.

STUDY DESIGN AND METHODS

A qualitative case study focusing on donor recruitment and CB collection processes was conducted to identify the contextual factors influencing these processes. This paper reports the findings from in-depth, semi-structured interviews conducted with 15 frontline staff of the Canadian Blood Services' Cord Blood Bank. Interview data were analyzed using inductive interpretive methods to identify the contextual conditions and factors that influence recruitment and collection.

RESULTS

Frontline staff described various social factors that influenced and challenged the processes of donor recruitment and CB collection. These were categorized into four overlapping contexts: birthing context, hospital context, CB bank organizational context, and sociocultural context.

CONCLUSION

Consideration of social context is necessary in order to effectively address the factors and challenges that influence the successful development of high-quality CB inventories, and to guide resource allocation. Further examination of contextually-rooted factors and their interactions is necessary to optimize donor recruitment and CB collection processes.

Reducing ethnic disparity in access to high-quality HLA-matched cord blood units for transplantation: analysis of the Canadian Blood Services' Cord Blood Bank inventory

BACKGROUND

Launched in 2013, Canadian Blood Services' Cord Blood Bank (CBS' CBB) has built a high-quality, ethnically diverse cord blood repository that aims to reduce ethnic disparity in accessing suitable units for transplantation.

METHODS AND RESULTS

As of December 2016, 2000 units have been banked. The self-reported maternal ethnicity was 58% non-Caucasian. Overall, 26% of units were classified as multi-ethnicity with Caucasian (84%) most frequently observed in combination with Asian, First Nations (predominant indigenous peoples in Canada south of the Arctic Circle), or African ethnicity. Utilization scores that incorporate total nucleated and CD34+ cell counts in the CBS' CBB were associated with greater likelihood of utilization compared with the international inventory of units (p < 0.05). The distribution of utilization scores was similar for Caucasians compared with non-Caucasians (p < 0.05). Using HLA genotypes of cord blood units and their mothers, we determined probable ethnic assignments for each haplotype using HaploStats (National Marrow Donor Program). Significant increases in HLA-match likelihoods are predicted for all ethnicities as the inventory grows to its target of 10,000 units and the gap in HLA-match likelihoods for Caucasian and non-Caucasian patients progressively declines.

CONCLUSIONS

The CBS' CBB inventory is predicted to have high HLA-matching likelihoods across a broad spectrum of ethnic groups, improving access to high-quality stem cell products for all patients.

On the Value of the Umbilical Cord Blood Supply

BACKGROUND

Several public cord blood banks are struggling financially, and the question remains as to whether additional allocations of funds to them are justified.

OBJECTIVES

To estimate the social benefits of public cord blood bank inventory net of cord blood banks' operational costs.

METHODS

We used publicly available data from the Health Resources and Service Administration on the number of annual cord blood transplants as well as the patient age distribution in 2010, and the survival estimates between 2008 and 2012 for the several diseases treated by cord blood transplantation. Data on aggregate annual costs to the cord blood industry for recruitment, processing, and storage were obtained from published work. We used estimated increases in life expectancy due to treatment using umbilical cord blood and value for life-years gained to estimate the social benefits of the public cord blood inventory annually.

RESULTS

We found that the annual social benefits of between $500 million and $1.5 billion outweigh the current operational annual costs of running cord blood banks of $60 to $70 million by a significant margin.

CONCLUSIONS

We estimated that the annual social benefit of having a cord blood system far outweighs its costs, by more than an order of magnitude. Thus, the social benefits of maintaining the US public cord blood banking system at the present time far outweigh the costs of collecting, storing, and distributing cord blood. This suggests that there is a potential justification for government intervention to align social benefits and costs. Nevertheless, simple fixes may produce unintended consequences, and so a careful design for subsidies is needed.

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.

The circadecadal rhythm of oscillation of umbilical cord blood parameters correlates with geomagnetic activity - An analysis of long-term measurements (1999-2011)

Recently, we have shown that the contents of total nucleated cells (TNCs) and CD34⁺ hematopoietic stem and progenitor cells (CD34⁺ HSPCs) as well as the cord blood volume (CBV) in umbilical cord blood (UCB) show a circadecadal (~10 years) rhythm of oscillation. This observation was based on an analysis of 17,936 cord blood donations collected during 1999-2011. The aim of the present study was to investigate whether this circadecadal rhythm of oscillation in TNCs, CD34⁺ HSPCs and CBV is related to geomagnetic activity. For the analysis, the yearly averages of TNCs, CD34⁺ HSPCs and CBV in UCB were correlated with geomagnetic activity (Dcx index). Our analysis revealed that (i) all three UCB parameters were statistically significantly correlated with the level of geomagnetic activity, (ii) CBV showed a linear correlation with the Dcx index (r = 0.5290), (iii) the number of TNCs and CD34⁺ HSPCs were quadratic inversely correlated with the Dcx index (r = -0.5343 and r = -0.7749, respectively). Furthermore, (iv) CBV and the number of TNCs were not statistically significantly correlated with the number of either modest or intense geomagnetic storms per year, but (v) the number of CD34⁺ HSPCs was statistically significantly correlated with the number of modest (r = 0.9253) as well as intense (r = 0.8683) geomagnetic storms per year. In conclusion, our study suggests that UCB parameters correlate with the state of the geomagnetic field (GMF) modulated by solar activity. Possible biophysical mechanisms underlying this observation, as well as the outcome of these findings, are discussed.

Use of Valacyclovir for the treatment of cytomegalovirus antigenemia after hematopoietic stem cell transplantation

BACKGROUND

Valacyclovir has been used for prophylaxis against cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT). We investigated the efficacy and safety of high-dose Valacyclovir as pre-emptive therapy in patients with CMV antigenemia after HSCT.

METHODS

In a retrospective single center study of 61 patients, we compared the rates of viral clearance, recurrent antigenemia and adverse events in patients with pp65 CMV antigenemia who received high dose Valacyclovir (n = 15), Valganciclovir (n = 16), and Foscarnet (n = 30).

RESULTS

Overall, 60/61 (98 %) of cases achieved CMV antigenemia clearance by day 28, and no patient developed CMV disease. After adjusting for age, sex, diagnosis, CMV serological status, donor type, CMV antigen level, graft-versus-host disease (GVHD) therapy, and conditioning regimen, there were no significant differences in the rates of viral clearance at day 14 in patients who received Valganciclovir (0.18, 95 % confidence interval (CI) 0.01 to 2.15, p = 0.17) and Foscarnet (OR 0.22, 95 % CI 0.03 to 2.40, p = 0.22), compared with Valacyclovir (assigned OR = 1.00). Recurrent antigenemia by day 180 after clearance of the initial CMV episode occurred in 34/61 (56 %) of patients. Using the multivariate model adjusting for the same covariates, there were also no significant differences in secondary episodes of CMV between treatment groups. With regards to adverse effect monitoring, Foscarnet led to significantly increased creatinine levels (P = 0.009), while Valganciclovir led to significant decrease in neutrophil counts (P = 0.012).

CONCLUSION

High dose Valacyclovir is a potential alternative to Valganciclovir and Foscarnet in the stable post-HSCT patient who has cytopenia and is not keen for inpatient treatment of CMV antigenemia.

Cord blood collection and banking from a population with highly diverse geographic origins increase HLA diversity in the registry and do not lower the proportion of validated cord blood units: experience of the Marseille Cord Blood Bank

Several Cord Blood (CB) Bank studies suggested that ethnicity impaired CB unit (CBU) qualification. The Bone Marrow Donors Worldwide registries present an over-representation of unrelated donors (UD) from Northwestern European descent. This raises the question of equality of access to hematopoietic stem cells transplant, especially in the Mediterranean zone, which has taken in many waves of immigration. The aim of our study is to address whether, in the Marseille CB Bank, CBU qualification rate is impaired by geographic origin. The study compared biological characteristics of 106 CBU disqualified for total nucleated cell (TNC) count (dCBU) and 136 qualified CBU in relation to registry enrichment and haplotype origin. A high proportion (>80%) of both dCBU and CBU had at least one non-European haplotype and enrich CB and UD registries to a higher extent than those with two European haplotypes (P<0.001). No difference was observed between TNC count and volume according to geographic origin. Our study shows that diverse Mediterranean origins do not have an impact on the CBU qualification rate. Partnership with Mediterranean birth clinics with highly trained staff is a reasonable option to increase the HLA diversity of CB Bank inventories and to improve the representation of minorities.