Key Points
Black South African were found to be a homogeneous group with similar matching probabilities as White.
The data indicate that Black South African patients will benefit considerably from intra-population donor recruitment.
Abstract
More than 41 million potential unrelated donors are currently listed in registries worldwide. However, these donors are not evenly distributed. In particular, individuals from sub-Saharan Africa are underrepresented, complicating unrelated donor searches for patients from this region. Here, we analyzed HLA allele and haplotype frequencies as well as resulting matching probabilities of the four South African population groups (Black African, Coloured, Indian/Asian and White) based on a data set (n=56,961) of potential stem cell donors registered with DKMS. Our large data set of well-typed and -characterized individuals allowed unprecedentedly accurate results for these population groups. One major finding was that the haplotypic diversity of Black South African and White was almost identical. The cumulative frequencies of the 50 most frequent 5-locus (HLA-A, -B, -C, -DRB1 and -DQB1) haplotypes were f=38.9% for Black African and f=38.5% for White. Indian/Asian (27.5%) and especially Coloured (20.8%) had lower cumulative frequencies, indicating higher intra-population diversity. Consequently, when donors and patients from the same population group were considered, matching probabilities of Black African and White were about the same and significantly greater than those of Indian/Asian and particularly of Coloured. With n=1,000,000 registered Black African donors, the probability for Black African patients to find at least one fully matched donor would be 80%. Donor recruitment in the Black African population is therefore very promising. For Indian/Asian and Coloured, there is at least a good chance of finding a suitable mismatched donor, e.g. 51% (92%) for 9/10 (8/10) matched donors at registry size n=100,000 for Coloured.
Author notes
The authors contributed equally to this work
Data sharing statement
The aggregated and anonymized data underlying the findings described and used to reach the conclusions of the manuscript are provided in this article and the Supplementary Material. Further inquiries can be directed to the corresponding author. Raw data cannot be made publicly available for data protection reasons.
