Although this study had a limited sample size of 237, we provide an in-depth analysis of HLA diversity in a subset of donors in the SABMR. Mixed resolution HLA typing data with multiple allele codes (https://hml.nmdp.org/MacUI) were analyzed using a robust Hapl-o-Mat  package to compute allele and haplotype frequencies through the EM algorithm.
It is important to note that the fifth most common allele in our study, namely, A * 30:02g (5% frequency in Table 3 and Table S1), is identical (exon 2 and 3 amino acid sequence) to a novel A* 30:02:01:03 allele previously reported in a SABMR donor .
A complete list of donor registry HLA haplotype frequencies better informs donor-patient matching tools like EasyMatch[R] , NMDP HapLogic [61, 62], and OptiMatch  especially for patients of African origin who might benefit from donors in the SABMR. These tools use haplotype frequencies to compute the likelihood of a donor-patient match and also anticipate the most likely mismatches.
Allele and haplotype frequencies from this study highlight the need for continued analysis by the SABMR for a better understanding of HLA diversity in the region.
Although results reported here are from a small subset of SABMR registered donors, allele and haplotype frequencies generated by Hapl-o-Mat tool  could be a useful resource for future anthropological and population genetics studies in South Africans.
The authors thank the SABMR donors for their willingness to participate in this study.
Owing to lack of funding and donor awareness, the SABMR grew more slowly for the next 7 years.
Unfortunately only 6% of the potential SABMR donors have been HLA-DR typed (Fig.
Following the recruitment of the first donors, the World Marrow Donor Association (WMDA) recognised the SABMR as the HUB centre for South Africa in September 1991.
In 1999 the first SABMR donor provided peripheral blood stem cells to a South African patient.
The growth and development of the SABMR is essential in our quest for donors, especially for patients of black African origin, and needs support from the public, donor funds, universities, private corporations and the government.
Paul Ruff is Professor and Head of Medical Oncology, University of the Witwatersrand Faculty of Health Sciences and Donald Gordon Medical Centre, Johannesburg, and a member of the SABMR Board.