One Chance in a Million: Altruism and the Bone Marrow Registry

Providing hematopoietic stem cell products from unrelated donors to the world: DKMS donor centers and DKMS Registry

Allogeneic hematopoietic stem cell (HSC) transplantation is a curative therapy for many severe blood diseases. As many patients have no suitable family donor, large unrelated donor registries and donor centers have been established in many countries, along with an international system for the provision of unrelated donor HSC products. As an essential part of this system, DKMS operates donor centers in 7 countries with a total of 12.2 million donors and over 114,000 donations so far, and a multinational donor registry. In 2022, DKMS donors contributed 57.5% of all cross-border donations worldwide. In this review, we describe the international system for the provision of unrelated donor HSC products as well as tasks and responsibilities of donor registries and donor centers. We also discuss relevant aspects of DKMS donor centers, namely donor file composition, matching and donation probabilities and actual donations, and the unique multinational approach of the DKMS Registry.

Social preferences or sacred values? Theory and evidence of deontological motivations

Recent advances in economic theory, largely motivated by experimental findings, have led to the adoption of models of human behavior where decision-makers take into consideration not only their own payoff but also others' payoffs and any potential consequences of these payoffs. Investigations of deontological motivations, where decision-makers make their choice based on not only the consequences of a decision but also the decision per se, have been rare. We provide a formal interpretation of major moral philosophies and a revealed preference method to distinguish the presence of deontological motivations from a purely consequentialist decision-maker whose preferences satisfy first-order stochastic dominance.

Estimating HLA haplotype frequencies from homozygous individuals - A Technical Report

We estimated HLA haplotype frequencies based on individuals homozygous for 4, 5 or 6 loci. Validation of our approach using a sample of over 3.4 million German individuals was successful. Compared to an expectation‐maximization algorithm, the errors were larger. However, our approach allows the unequivocal detection of rare haplotypes.

High-resolution HLA allele and haplotype frequencies of the Saudi Arabian population based on 45,457 individuals and corresponding stem cell donor matching probabilities

We estimated HLA allele and haplotype frequencies of the Saudi Arabian population from a sample of 45,457 registered stem cell donors. The most frequent HLA alleles were A*02:01g (18.5%), C*06:02g (16.1%), B*51:01g (14.1%), DRB1*07:01g (16.2%), DQB1*02:01g (30.5%), and DPB1*04:01g (33.6%). The most frequent 5-locus haplotypes were A*02:05g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.73%), A*02:01g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.66%), and A*26:01g~C*07:02g~B*08:01g~DRB1*03:01g~DQB1*02:01g (1.38%). Furthermore, we used the calculated haplotype frequencies to estimate stem cell donor matching probabilities for Saudi Arabian donor and patient populations under various matching requirements. These results are relevant for strategic donor registry planning in the Kingdom of Saudi Arabia.

How Ancestry Influences the Chances of Finding Unrelated Donors: An Investigation in Admixed Brazilians

A match of HLA loci between patients and donors is critical for successful hematopoietic stem cell transplantation. However, the extreme polymorphism of HLA loci - an outcome of millions of years of natural selection - reduces the chances that two individuals will carry identical combinations of multilocus HLA genotypes. Further, HLA variability is not homogeneously distributed throughout the world: African populations on average have greater variability than non-Africans, reducing the chances that two unrelated African individuals are HLA identical. Here, we explore how self-identification (often equated with "ethnicity" or "race") and genetic ancestry are related to the chances of finding HLA compatible donors in a large sample from Brazil, a highly admixed country. We query REDOME, Brazil's Bone Marrow Registry, and investigate how different criteria for identifying ancestry influence the chances of finding a match. We find that individuals who self-identify as "Black" and "Mixed" on average have lower chances of finding matches than those who self-identify as "White" (up to 57% reduction). We next show that an individual's African genetic ancestry, estimated using molecular markers and quantified as the proportion of an individual's genome that traces its ancestry to Africa, is strongly associated with reduced chances of finding a match (up to 60% reduction). Finally, we document that the strongest reduction in chances of finding a match is associated with having an MHC region of exclusively African ancestry (up to 75% reduction). We apply our findings to a specific condition, for which there is a clinical indication for transplantation: sickle-cell disease. We show that the increased African ancestry in patients with this disease leads to reduced chances of finding a match, when compared to the remainder of the sample, without the condition. Our results underscore the influence of ancestry on chances of finding compatible HLA matches, and indicate that efforts guided to increasing the African component of registries are necessary.

#BeTheMatch: Assessing How Testimonials on Reddit Promote the Importance of Donating Bone Marrow

This study explores how sharing testimonials on the social media network Reddit may encourage individuals to donate bone marrow. The theory of planned behavior guided a quantitative content analysis of 1,015 Reddit comments about donation. Research questions asked how individuals post about donation and how Redditors engage with this content. Overall, comments addressed more positive than negative outcome, efficacy, and normative beliefs. Comments that discussed beliefs related to registering to donate and the process of donating received significantly higher engagement than other comments. Additionally, comments that included positive outcome beliefs related to registering, positive efficacy beliefs related to registering and donating, and positive normative beliefs related to donating received higher engagement than other comments. Results suggest testimonials may be most effective if they focus on behavior facilitators and if they present donation as a positive norm deviant behavior. Finally, the Reddit forums functioned as places for individuals to seek out and share information. Comments included calls to action and hyperlinks for health resources. This research reveals how organic conversations on Reddit may promote health information seeking and advocacy behavior adoption. Implications for the theory of planned behavior and the use of Reddit as a platform for health promotion are discussed.

Ethical challenges regarding the use of stem cells: interviews with researchers from Saudi Arabia

Background

With the huge number of patients who suffer from chronic and incurable diseases, medical scientists continue to search for new curative methods for patients in dire need of treatment. Interest in stem cells is growing, generating high expectations in terms of the possible benefits that could be derived from stem cell research and therapy. However, regardless of the hope of stem cells changing and improving lives, there are many ethical, religious, and political challenges and controversies that affect the research, and mandated to establish ethical guidelines and regulations. In Saudi Arabia, key stakeholders play an active role in discussing the ethics of stem cell research and therapy. The focus of the study was to explore professionals’ perceptions related to the ethical challenges of using stem cells in research and treatment in Saudi Arabia.

Results

A qualitative research study was conducted to explore and describe the perceptions of 25 professionals employed at different tertiary hospitals in the various regions of Saudi. A thematic analysis was performed to search for and identify the most significant perceptions shared by the participants. Four themes were generated based on the ethical challenges of four areas related to stem cell use, including (1) forbidden and permitted sources of stem cells, (2) informed consent, (3) beneficence, and (4) ethical regulations and guidelines.

Conclusion

The study identified that there is a growing need to advance the knowledge, education, and awareness related to stem cell research and treatment in Saudi Arabia.

Spillovers of prosocial motivation: Evidence from an intervention study on blood donors

Blood donations are increasingly important for medical procedures, while meeting demand is challenging. This paper studies the role of spillovers arising from social interactions in the context of voluntary blood donations. We analyze a large-scale intervention among pairs of blood donors who live at the same street address. A quasi-random phone call provides the instrument for identifying the extent to which the propensity to donate spills over within these pairs. Spillovers transmit 41% to 46% of the behavioral impulse from one donor to the peer. This creates a significant social multiplier, ranging between 1.7 and 1.85. There is no evidence that these spillovers lead to intertemporal substitution. Taken together, our findings indicate that policy interventions have a substantially larger effect when targeted towards pairs instead of isolated individuals.

Immunogenetics in stem cell donor registry work: The DKMS example (Part 1)

Currently, stem cell donor registries include more than 35 million potential donors worldwide to provide HLA-matched stem cell products for patients in need of an unrelated donor transplant. DKMS is a leading stem cell donor registry with more than 9 million donors from Germany, Poland, the United States, the United Kingdom, India and Chile. DKMS donors have donated hematopoietic stem cells more than 80,000 times. Many aspects of donor registry work are closely related to topics from immunogenetics or population genetics. In this two-part review article, we describe, analyse and discuss these areas of donor registry work by using the example of DKMS. Part 1 of the review gives a general overview on DKMS and includes typical donor registry activities with special focus on the HLA system: high-throughput HLA typing of potential stem cell donors, HLA haplotype frequencies and resulting matching probabilities, and donor file optimization with regard to HLA diversity.

Psychology of personal data donation

Advances in digital technology have led to large amounts of personal data being recorded and retained by industry, constituting an invaluable asset to private organizations. The implementation of the General Data Protection Regulation in the EU, including the UK, fundamentally reshaped how data is handled across every sector. It enables the general public to access data collected about them by organisations, opening up the possibility of this data being used for research that benefits the public themselves; for example, to uncover lifestyle causes of poor health outcomes. A significant barrier for using this commercial data for academic research, however, is the lack of publicly acceptable research frameworks. Data donation—the act of an individual actively consenting to donate their personal data for research—could enable the use of commercial data for the benefit of society. However, it is not clear which motives, if any, would drive people to donate their personal data for this purpose. In this paper we present the results of a large-scale survey (N = 1,300) that studied intentions and reasons to donate personal data. We found that over half of individuals are willing to donate their personal data for research that could benefit the wider general public. We identified three distinct reasons to donate personal data: an opportunity to achieve self-benefit, social duty, and the need to understand the purpose of data donation. We developed a questionnaire to measure those three reasons and provided further evidence on the validity of the scales. Our results demonstrate that these reasons predict people’s intentions to donate personal data over and above generic altruistic motives. We show that a social duty is the strongest predictor of the intention to donate personal data, while understanding the purpose of data donation also positively predicts the intentions to donate personal data. In contrast, self-serving motives show a negative association with intentions to donate personal data. The findings presented here examine people’s reasons for data donation to help inform the ethical use of commercially collected personal data for academic research for public good.

The degree of major histocompatibility complex matching between purebred Maltese and mongrel dogs using microsatellite markers

Long-term maintenance of transplanted organs is one of the major factors that increases survival time of recipients. Although obtaining a major histocompatibility complex (MHC)-matched donor with the recipient is essential for successful organ transplantation, there have been limited reports on MHC matching between dogs. In this study, we analyzed the canine MHC matching rates using Maltese, one of the most popular purebred dogs, and mongrel dogs in Korea. Genomic DNA was extracted from blood leukocytes and DNA was amplified by polymerase chain reaction with primers specific to MHC microsatellite markers. The MHC matching degree was confirmed by the microsatellite markers using polyacrylamide gel electrophoresis. The MHC matching rates of each donor-recipient groups including Maltese-Maltese, mongrel-mongrel and Maltese-mongrel were 4.76%, 5.13% and 6.67%, respectively. There were no significant differences in the MHC matching degree between each group. These results demonstrate that MHC-matched donors could be selected from other breeds as much as from the same breed for transplantation. Knowledge of the MHC matching degree of purebred and mongrel dogs would offer valuable information not only for improving the success rate of organ transplantation surgery in canine patients but also for transplantation research using experimental canine models.

Ethically Acceptable Compensation for Living Donations of Organs, Tissues, and Cells: An Unexploited Potential?

The number of living donations of human organs, tissues, and cells falls far short of the need. Market-like arrangements to increase donation rates have been proposed, but they are broadly considered unacceptable due to ethical concerns and are therefore not policy relevant in most countries. The purpose of this paper is to explore a different approach to increasing living donations, namely through the use of ethically acceptable compensation of donors. We review the compensation practices in Europe and find a lack of reimbursement of incurred costs and lack of compensation for non-monetary losses, which create disincentives for donation. We draw on a well-known philosophical theory to explain why donors are rarely fully compensated and why many existing proposals to raise donation rates are seen as controversial or even unethical. We present and discuss three categories of compensation with the potential to increase donation rates in an ethically acceptable way.

Altruism in preventive health behavior: At-scale evidence from the HIV/AIDS pandemic

Preventive behavior with regards to disease transmission offers a promising context in which to provide empirical evidence on altruism in human populations. I examine the association between HIV status, own knowledge about status, and preventive health behavior using household survey data from over 200,000 individuals in 25 sub-Saharan African countries. I find that individuals who are HIV positive and have taken a standard HIV test are much more likely to engage in efforts to prevent HIV transmission than are individuals who are HIV negative and have taken a standard HIV test. Moreover, this difference is greater than the difference between HIV positives and HIV negatives for individuals who have not taken a standard HIV test. Consistent with an altruistic motivation, this double-difference is larger for individuals who are married than for individuals who are not married. These results appear to be the first evidence on the change in risky sexual behavior associated with HIV testing at scale and are consistent with altruism dominating any self-interested response to HIV testing.

Genetic Diversity and Societally Important Disparities

The magnitude of genetic diversity within human populations varies in a way that reflects the sequence of migrations by which people spread throughout the world. Beyond its use in human evolutionary genetics, worldwide variation in genetic diversity sometimes can interact with social processes to produce differences among populations in their relationship to modern societal problems. We review the consequences of genetic diversity differences in the settings of familial identification in forensic genetic testing, match probabilities in bone marrow transplantation, and representation in genome-wide association studies of disease. In each of these three cases, the contribution of genetic diversity to social differences follows from population-genetic principles. For a fourth setting that is not similarly grounded, we reanalyze with expanded genetic data a report that genetic diversity differences influence global patterns of human economic development, finding no support for the claim. The four examples describe a limit to the importance of genetic diversity for explaining societal differences while illustrating a distinction that certain biologically based scenarios do require consideration of genetic diversity for solving problems to which populations have been differentially predisposed by the unique history of human migrations.

Simulation shows that HLA-matched stem cell donors can remain unidentified in donor searches

The heterogeneous nature of HLA information in real-life stem cell donor registries may hamper unrelated donor searches. It is even possible that fully HLA-matched donors with incomplete HLA information are not identified. In our simulation study, we estimated the probability of these unnecessarily failed donor searches. For that purpose, we carried out donor searches in several virtual donor registries. The registries differed by size, composition with respect to HLA typing levels, and genetic diversity. When up to three virtual HLA typing requests were allowed within donor searches, the share of unnecessarily failed donor searches ranged from 1.19% to 4.13%, thus indicating that non-identification of completely HLA-matched stem cell donors is a problem of practical relevance. The following donor registry characteristics were positively correlated with the share of unnecessarily failed donor searches: large registry size, high genetic diversity, and, most strongly correlated, large fraction of registered donors with incomplete HLA typing. Increasing the number of virtual HLA typing requests within donor searches up to ten had a smaller effect. It follows that the problem of donor non-identification can be substantially reduced by complete high-resolution HLA typing of potential donors.

Giving blood and enrolling on the stem cell donor registry: ranking of obstacles and motives in Switzerland

BACKGROUND

To obtain a better understanding of factors affecting blood and blood stem cell donation behavior in Switzerland, a series of studies has been performed. In the recent study of this series, which is described here, motivators and barriers in the field of blood and blood stem cell donation were identified.

METHODS

Web-based survey data from a non-random sample of the Swiss population 2012/2013 (n = 3,153) were used to describe and compare the ranking of motives and obstacles to donate blood and to enroll on the Swiss blood stem cell registry. Wilcoxon rank-sum test and Spearman's rank correlations were used to assess differences and associations between ranks and groups.

RESULTS

The prospect of saving lives and solidarity were the top two motives to donate blood or to enroll on the blood stem cell registry. The top two obstacles to enroll on the blood stem cell registry were lack of general information on blood stem cell donation and on its risks, whereas the top two obstacles to donate blood were the lack of information where and when to donate and deferral of or exclusion from blood donation.

CONCLUSION

Classical altruistic motives are top drivers for giving blood as well as registering for blood stem cell donation. Recruitment campaigns should focus on these motivators. Similarities in motivational factors as well as in obstacles regarding blood and blood stem cell donation can be found.

Toward an optimal global stem cell donor recruitment strategy

Population-specific matching probabilities (MP) are a key parameter to assess the benefits of unrelated stem cell donor registries and the need for further donor recruitment efforts. In this study, we describe a general framework for MP estimations of specific and mixed patient populations under consideration of international stem cell donor exchange. Calculations were based on population-specific 4-locus (HLA-A, -B, -C, -DRB1) high-resolution haplotype frequencies (HF) of up to 21 populations. In various scenarios, we calculated several quantities of high practical relevance, including the maximal MP that can be reached by recruiting a fixed number of donors, the corresponding optimal composition by population of new registrants, and the minimal number of donors who need to be recruited to reach a defined MP. Starting at current donor numbers, the largest MP increases due to n = 500,000 additional same-population donors were observed for patients from Bosnia-Herzegovina (+0.25), Greece (+0.21) and Romania (+0.20). Especially small MP increases occurred for European Americans (+0.004), Germans (+0.01) and Hispanic Americans (+0.01). Due to the large Chinese population, the optimal distribution of n = 5,000,000 new donors worldwide included 3.9 million Chinese donors. As a general result of our calculations, we observed a need for same-population donor recruitment in order to increase population-specific MP efficiently. This result was robust despite limitations of our input data, including the use of HF derived from relatively small samples ranging from n = 1028 (Bosnia-Herzegovina) to n = 33,083 (Turkey) individuals. National strategies that neglect domestic donor recruitment should therefore be critically re-assessed, especially if only few donors have been recruited so far.

Removing financial barriers to organ and bone marrow donation: the effect of leave and tax legislation in the U.S

Many U.S. states have passed legislation providing leave to organ and bone marrow donors and/or tax benefits for live and deceased organ and bone marrow donations and to employers of donors. We exploit cross-state variation in the timing of such legislation to analyze its impact on organ donations by living and deceased persons, on measures of the quality of the transplants, and on the number of bone marrow donations. We find that these provisions do not have a significant impact on the quantity of organs donated. The leave laws, however, do have a positive impact on bone marrow donations, and the effect increases with the size of the population of beneficiaries and with the generosity of the legislative provisions. Our results suggest that this legislation works for moderately invasive procedures such as bone marrow donation, but these incentives may be too low for organ donation, which is riskier and more burdensome.

Organ Allocation Policy and the Decision to Donate

Organ donations from deceased donors provide the majority of transplanted organs in the United States, and one deceased donor can save numerous lives by providing multiple organs. Nevertheless, most Americans are not registered organ donors despite the relative ease of becoming one. We study in the laboratory an experimental game modeled on the decision to register as an organ donor and investigate how changes in the management of organ waiting lists might impact donations. We find that an organ allocation policy giving priority on waiting lists to those who previously registered as donors has a significant positive impact on registration.

Cord blood stem cells for hematopoietic stem cell transplantation in the UK: how big should the bank be?

BACKGROUND

A stored cord blood donation may be a valuable source of hemopoietic stem cells for allogeneic transplantation when a matched sibling donor is not available. We carried out a study to define the optimal size of a national cord blood bank for the UK.

DESIGN AND METHODS

We calculated the actual numbers of possible donors and the chance of finding at least one donor for 2,000 unselected and for 722 non-North Western European patients for whom searches had been initiated as a function of three levels of HLA matching (4, 5 and 6 out of 6 alleles by HLA-A, -B low and -DRB1 high resolution HLA typing) according to various donor bank sizes.

RESULTS

With a bank size of 50,000, 80% of patients will have at least one donor unit available at the 5 out of 6 HLA allele match level (median 9 donors per patient), and 98% will have at least one donor at the 4 out of 6 allele match level (median 261). Doubling the size of the bank yields at least one donor for only an additional 6% of patients at the 5 of 6 allele match level. Moreover, for non-North Western European patients a 50,000 unit bank provides a donor for 50% at the 5 allele match level, and for 96% at the 4 allele match level.

CONCLUSIONS

A bank containing 50,000 units is optimal for the UK and larger banks would only marginally increase the chance of finding suitable units.