The increase of the global donor inventory is of limited benefit to patients of non-Northwestern European descent

Abstract

© Ferrata Storti Foundation IntroductionAllogeneic hematopoietic progenitor cell transplantation plays an important role in treatment of hematooncological diseases. For patients lacking a matched related donor, an unrelated donor (UD) or cord blood unit (CBU) may provide a valuable alternative. Alternative donors are identified through registries of volunteer unrelated donors or public cord blood banks. In the past decade, the identification and availability of UD and UCB have improved. Bone Marrow Donors Worldwide (BMDW), the file of registered unrelated donors, almost tripled (from 7.4 million donors in 2001 to over 21 million in December 2012), while the inventory of unrelated CBU grew from 87,000 in 2001 to over 500,000.1 To date (2016) the number of registered donors has increased to over 27 million, and currently over 650.000 CBU are registered. Increased knowledge of the HLA system, more well-typed donors, and the availability of several search-related software tools 2-5 have facilitated and speeded up the efficiency of the search process. [6][7][8] Simultaneously searching for a back-up donor can minimize the delay if a donor is unexpectedly not fit or unavailable to donate.9 Given these recent improvements, we set out to address the questions of whether a higher percentage of patients in need of an UD/CBU may actually reach transplantation nowadays, whether the time needed to identify an UD/CBU has decreased, and whether possible factors can be identified for potential improvement. We addressed the questions in a large cohort of 3,365 consecutive UD searches performed between 2001-2012 in the Netherlands, including searches for Dutch patients of Northwestern European (NWE) and non-Northwestern European (non-NWE) descent. Methods The patients and donor searchesEuropdonor Foundation, the Dutch Stem cell donor registry, coordinates the UD searches in the Netherlands, serving a population of 16.8 million inhabitants. There were eight adult and two pediatric stem cell transplantation units in 2012 in the Netherlands, and the number of new searches increased to approximately 500 annually. All UD and CBU searches performed from 2001 until 2012 for the patients of all Dutch transplantation centers were included (n=3,365, Figure 1) for the initial 'donor found' analysis, and divided into two periods: cohort I, 2001-2006 (n=1,093) and cohort II, 2007II, -2012. Patients for whom a search was cancelled in less time than the median search time for the given year, and for whom no donor was yet identified were excluded for the 'donor found' analysis (cohort I, n=75; cohort II, n=131), leaving 3,124 evaluable search cases. Each cohort was split according to NWE and non-NWE descent. Patients were assigned to NWE or non-NWE background based upon self-identified descent.10 Descendants from the Netherlands, Germany, Belgium, Luxembourg, Great Britain, Ireland, and Scandinavia were considered NWE. The non-NWE group consisted of patients with self-reported genetic ancestry in Northern Africa (n=51), Sub-Saharan A...

Haploidentical versus matched donor stem cell transplantation for patients with hematological malignancies: a systemic review and meta-analysis

“…Given these issues, HLA-matched donors have been and continue to be the preferred choice for SCT [15][16][17]. However, recent studies have documented a substantial lack of matched donors for many patients, particularly those who are not Caucasian [18][19][20][21]. As a result, the use of donors who are not matched at all classic HLA loci (HLA-A, -B, -C, DRB1, and DQB1) will continue to increase.…”

Immunogenetics in stem cell donor registry work: The DKMS example (Part 2)

“…With respect to the touch points of population genetics and donor registry work, the main challenge for donor registries lies in smart donor file growth, that is growth that specifically addresses the needs of populations that have been underserved so far. This goal was not optimally achieved in the past (van Walraven et al, ). As allogeneic transplant activities are growing globally with a focus on developing countries (Aljurf et al, ), stem cell donor recruitment from non‐Northwestern European populations will be of increasing importance in the future.…”

Ensuring HLA‐matched platelet support requires an ethnic diverse donor population

“…Nevertheless, the HLA system is highly polymorphic. So, even with increasing genetic variability, disparities between patients and donors will sustain, and as a consequence, providing completely HLA‐matched platelets to every patient with antibodies will not be feasible . The benefits of additional typing of ethnic minorities would differ per population of origin.…”