Introduction

The WMDA (World Marrow Donor Association) envisions a world where access to live-saving cellular therapies is assured, and donors’ rights and safety are protected. This includes standardising ethical, technical, medical, and financial aspects of cellular therapy involving volunteer donors from different countries. In 1992 [1], WMDA published global guidelines for international bone marrow transplants, updated in 1994 [2] to address second-time donations and the use of peripheral blood stem cells.

Between 1994 and 2025, hematopoietic stem cell transplantation evolved significantly, reshaping donor registries’ roles. In 1994, donor registries operated as the sole national hubs to recruit donors and procure products in their respective jurisdictions. Today, WMDA lists unrelated donors and cord blood units from 99 different organisations from 57 countries (Fig. 1) [3]. The benefits and challenges of this expansion are explored later.

Fig. 1
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WMDA member organisations (number of donors by continent).

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WMDA operates as a global membership association, fostering registry collaboration. Governed by a Membership Board, its mission includes advocacy, standard-setting, and data sharing to enhance patients’ outcomes and protect donors. WMDA focuses on five pillars: (1) Optimising ‘Search, Match & Connect’; (2) Supporting Global Development; (3) Promoting Donor Care; (4) Ensuring Quality -Certification Body and (5) Driving Member Engagement. This paper updates prior WMDA publications, detailing key developments in activities and responsibilities.

Pillar 1: Optimising ‘Search, Match & Connect’ - a global environment facilitating the most suitable cell source for patients

Purpose and goals

WMDA maintains a secure, real-time database, the Search & Match Service (formerly BMDW), providing potential sources for cellular therapy. Donor registries upload data daily, ensuring up-to-date searches [3]. WMDA develops tools [4, 5] for transplant centres to identify optimal matches through advanced algorithm and donor recruitment insights. The WMDA will be working towards supporting multiple mismatch searches with antibody filtering [6]. Two matching algorithms (Hap-E Search [7], supported by Deutsche Knochenmarkspenderdatei [DKMS)] and Atlas, supported by Anthony Nolan/National Donor Marrow Program) deliver results within seconds. WMDA is also launching a communication platform, Match-Connect, operational by the end of 2025.

Key achievements

WMDA facilitates 60,000+ annual patient searches via its Search & Match Service [8]. A diverse donor pool reduces unsuccessful searches. In 2023 10.3% of the searches did not result in a potential donor. (see Fig. 2).

Fig. 2
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Historic performance on the WMDA’s Search & Match Service.

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The different colour-boxes represent the search result distributions (in percentages) of potential donor availability for a patient search at a given year. The annual data demonstrate the search performances observed from 2017 to 2023.

WMDA is merging European Marrow Donor Information System, and Bone Marrow Donors Worldwide (BMDW), into Match-Connect, streamlining global processes, and overcoming technical, organisational, and financial challenges. Stringent data privacy standards (e.g., General Data Protection Regulation (GDPR) [9] guide WMDA operations. A GDPR -compliant cloud architecture safeguards sensitive data across registries.

Goals and challenges

Match-Connect will centralise communication, automate search and request processes, and minimise errors. Its Application Programming Interfaces (APIs) architecture, include Patient, Search, and the Connect APIs for seamless international collaboration.

A major challenge is aligning legal frameworks with technical requirements. WMDA members collaborate with software engineers to refine data management and data processing.

Privacy breaches pose risks, mitigated through GDPR-compliance, strict access controls, and encryption. Only WMDA-compliant [10, 11] organisations may participate in Match-Connect.

Success depends on full adoption by WMDA registries by 2027. Early adopters report faster searches and improved data exchange. Match-Connect reduces Information Technology burdens, eliminating the need for a local infrastructure. Complementary projects, such as standardising donor work-up and digitising forms, will further enhance efficiency and reduce transplantation timelines, improving patient outcomes.

Pillar 2: Supporting global development for stem cell provision

Purpose and goals

Providing the right stem cell product at the right time requires global collaboration amongst healthcare professionals. Safe practices rely on clear communication, standardised policies, and training. With 47% of stem cell donations crossing international borders [12] (Table 1), WMDA supports members in maintaining high standards through sharing best practices, regulatory engagement, training and facilitating knowledge exchange.

Table 1 Hematopoietic cell product exchange between continents (2023).
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WMDA’s global Standards [10] and Certification Programme ensures compliance with internationally accepted standards.

Key achievements

For patients to receive the optimal stem cell transplant, it is requiring well-informed stakeholders. WMDA provides diverse training approaches (Table 2) and promotes standardised processes.

Table 2 WMDA educational approaches.
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A significant achievement was the development of the Global Registration Identifier for Donors with International Council for Commonality in Blood Banking Automation [13]. Other achievements include standardised key performance indicators [14], back-up donor strategies [15], audit guidelines [16, 17], crisis response plans [18], and quality manuals [19], requirements on training of donor recruiters [20] and globally accepted template forms. WMDA played a critical role in sharing real-time COVID-19 policies to international transplants. In collaboration with European Society for Blood and Marrow Transplantation (EBMT), cryopreservation guidelines were developed to harmonise global practices [21]. Committed to equitable care, WMDA supports new and emerging countries establish donor registries, through education, networking, and travel grants. World Marrow Donor Day [22] annually raises awareness on promoting voluntary, non-remunerated stem cell donation and expressing gratitude to donors who selflessly save lives.

Growth

Since 1997, WMDA expanded from 36 registries from 32 countries to 99 registries across 57 countries. In 2023, members facilitated 2750 bone marrow donations, 20,759 peripheral blood stem cell donations, and 2330 cord blood shipments [12] (compared with 3033 bone marrow donations, 113 peripheral blood stem cell donations and 14 cord blood shipments in 1997). Selection now prioritises donor quality, younger age, and detailed HLA typing (Table 3). Research [23, 24] shows younger donors improve survival rates, with transplant centres favouring male donors. WMDA supports recruiting underrepresented groups—particularly younger male donors, to enhance ethnic diversity. Despite an 83% increase in global registry size over 10 years, younger male donors grew only 23%.

Table 3 Growth of young male donors and 12 loci typed donors.
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Goals and outlook

WMDA aims to drive the global standard for safe, efficient stem cell donation and delivery. Developing a centralised auditing service, based on transport incident reports from the Serious (Product) Adverse Events and Reactions (SPEAR) Reporting Service, will improve safety and reduce compliance burdens.

Initially, registries operated nationally to recruit donors and procure products. Over time, registries have chosen to expand beyond their borders. In some cases, registries expanded into countries lacking existing registry infrastructure, thereby providing services where previously none existed. In other cases, registries have established services in countries where existing registry(ies) already operated. Prior to entering the country, WMDA recommends consultation and coordination between co-existing organisations to ensure that donors, donor- and collections centres and other registries have a clear understanding of that region’s available services.

Future efforts will address climate change, new cell and gene therapies, donor aging and diversity. WMDA continuously adapt to the evolving landscape of donor registries.

Pillar 3: Promoting donor care – establishing evidence-based ethical standards

Purpose and goals

WMDA is committed to donor safety, ethical treatment, and the integrity of stem cell products in transplantation and cellular therapies. As a global resource, WMDA provides medical and ethical guidance on hematopoietic progenitor cells (HPC) donations, including marrow and blood cells. This pillar prioritises donor safety through systematic collection and analysis of Serious (Product) Adverse Events and Reactions affecting donors, patients, and products. It also sets global guidelines for donor eligibility, medical evaluation, and follow-up care, and addressing challenges in emerging cell and gene therapy (CGT).

Key achievements

WMDA’s online reporting service for reporting of SPEARs related to stem cell donation or affecting product quality [25]. This system evolved from a paper-based process to a secure digital tool, now handling up to 351 reports annually [26]. WMDA Certification requires mandatory reporting, improving donor safety through analysis and integration into WMDA Standards [10] and international quality and traceability standards [27].

Donor eligibility guidelines have expanded significantly since the 1990s, evolving beyond infectious diseases and physical examination [2]. Updated suitability recommendations were published on behalf of the WBMT Standing Committee on Donor Issues, in collaboration with WMDA experts and experts from different scientific organisations [28]. WMDA is operating a publicly available donor suitability recommendations service that emphasises health equity alongside donor safety [29], incorporating lifestyle factors and emerging infectious diseases such as COVID-19 and Monkeypox (Mpox) [30].

WMDA also addresses emerging donor care concerns. For instance, long-term safety concerns associated with Granulocyte colony-stimulating factor (G-CSF) for apheresis collection, where WMDA issued multiple statements on its safe use [31,32,33]. Additional key publications focus on donor genetic findings post-donation [34], subsequent donations [35], and care for related donors [36, 37].

Goals and challenges

With the rising demand for allogeneic cells in cell and gene therapy, ethical concerns have emerged regarding volunteer donors for commercial purposes. WMDA has issued resources on donor consent [38], engagement, and remuneration [39] and is developing an ethical framework for cell and gene therapy, shaping future WMDA Standards [10].

The Council of Europe published recommendations on establishing harmonised measures for the protection of haematopoietic progenitor cell donors [40]. The long-term follow-up should be submitted one year after the donation and subsequently, every two years up to 10 years after the last donation procedure [41]. To facilitate the donor long-term follow-up EBMT has established a donor outcome registry since 2013, that collects data from both related and unrelated donors. In addition to this, several countries operate national-level registries that monitor donor outcome data.

WMDA members are collecting donor follow-up data in the unrelated donor setting. To gain insight in the occurrence of serious events and adverse effects, WMDA is operating an online reporting service (SPEAR) that will be expanded to enhance data collection and improve monitoring of related donor health and donors involved in cell and gene therapy. In response to the new European Substances of Human Origin (SoHO) regulations adopted [42], WMDA is strengthening ties with EU vigilance authorities, aiming to become the primary vigilance reporting service despite challenges in aligning national regulations.

WMDA actively collaborates with commercial service providers and regulators to uphold donor safety and ethical standards. Engagement with regulatory agencies and professional societies (such as EBMT, International Society of Cellular Therapy (ISCT), Asia Pacific Blood and Marrow Transplantation Group (APBMT), Worldwide Network for Blood and Marrow Transplantation (WBMT), Foundation for the Accreditation of Cellular Therapy (FACT), Joint Accreditation Committee of ISCT-EBMT (JACIE), European Federation for Immunogenetics (EFI), American Society for Histocompatibility and Immunogenetics (ASHI) remains crucial to advancing donor well-being and supporting hematopoietic stem cell transplantation and cellular therapy worldwide.

Pillar 4: Ensuring quality through certification

Purpose and goals

The 1994 paper [2] proposed an accreditation programme for national hubs, with WMDA overseeing registry accreditation to standardise international transplants. The national hubs would then accredit donor, collection, and transplant centres in their countries.

Since 2004, the WMDA Certification Programme has formally certified donor registries, ensuring compliance with global standards throughout the donor journey. The first WMDA Standards were approved in 2003 [43] covering (1) general organisation of registries; (2) donor recruitment; (3) donor characterisation; (4) information technology; (5) facilitation of search requests; (6) second/subsequent donations; (7) collection/processing/transport of stem cells; (8) follow-up of patient/donor; and (9) financial/legal responsibilities. A section covering cord blood standards was added in 2014 [10]. The WMDA Standards are updated regularly to address compliance with other professional societies (e.g. FACT-JACIE, EFI-ASHI, NetCord-FACT), and international regulatory requirements, most recently in 2024. By improving relationships between different registries and professional societies positive patient and professional outcomes have been achieved through certification programmes.

Key achievements

The first donor registries were certified in 2004 through policy reviews, with on-site audits introduced in 2009. WMDA follows a two-set process. The first step, called “Benchmark”, is focused on compliance with a set of basic WMDA Standards that are critical for the international exchange of donors. Once achieved, after a cycle of four years, the registry may apply for Full Standards which can be renewed every four years.

After two decades, WMDA Certification covers 90.5% of 43 million volunteer donors and cord blood units from 39 registries (53% of the registries). The WMDA Certification Programme continuously adapts to field needs, including challenges faced during the pandemic, and aligns with ISO-17065 for products, processes, and service certification. Impartiality remains a core value with a robust system for addressing complaints. A list of organisations that have been certified by WMDA can be found on the WMDA membership website [44].

Goals and challenges

WMDA aims to leveraging its expertise to facilitate regulatory compliance, adapting standards to address three rapidly evolving fields: data protection, related donor safety, and donors involved in cell and gene therapy. Changes often result of political decisions that are published in legislation [42], WMDA committee recommendations [38], and SPEAR reports [26].

Conclusion

As WMDA marks its 30th anniversary, we reflect on the global evolution of donor registries. Since 1994, the practice of hematopoietic cell transplantation has expanded worldwide, improving patient outcomes by reducing the time to transplant. Peripheral blood cells and placental cord blood are now routinely used, while bone marrow remains essential for some patients. Emerging cell and gene therapies continue to evolve.

WMDA and its member organisations play a key role in ensuring safe, ethical, and accessible exchange of donor cells globally. The commercialisation of cell and gene therapy products, unforeseen 30 years ago, is now a reality. WMDA remains committed to ensuring these products are subject to rigorous oversight, similar to traditional stem cell transplantation.