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Five locus allele-level HLA-A, -B, -C, -DRB1, -DQB1 allele and haplotype frequencies have been calculated for almost 29,000 people from three Arab populations that live in Israel and were recruited as donors to the Hadassah bone marrow donor registry. These groups are of Muslim, Christian and Bedouin Arab descent which represent more than 90% of the Arabs that live in Israel. The goal of the study was to describe the HLA genetic profiles of the Hadassah Arab registry donors and investigate the utility of these donors for the local and international hematopoietic stem-cell transplant community. The results demonstrate that the analyzed Arab populations share at least seven of the top ten most frequent alleles. Comparison with other populations confirmed the proximity of the three Arab populations to each other and to the Be The Match® Middle Eastern population. Despite these similarities, some alleles are private to each of the three groups, possibly because of historical, environmental or societal events. Clinical data showed that Arab donors were HLA matched with Arab and international patients. This analysis indicates the value added by the Hadassah Arab donors to the local and global transplant community., (Copyright © 2019 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

Aim: The Arab Bone Marrow Registry in Hadassah Medical Center collected HLA typings for 18,000 Arab adult donors. We used this information to estimate population allele and haplotype frequencies (HFs). Methods: We calculated HLA A∼B∼DRB1 HFs from 1,541 Christian Arab (CA) and 16,129 Muslim Arab (MA) donors typed by SBT, resolving phase and allelic ambiguity using Expectation Maximization. HFs were estimated at the four-digit level. Results: The most common CA haplotype was A∗33:01∼B∗14:02∼DRB1∗01:02 at a frequency of 1.6%, which is the fifth most common MA haplotype at 0.9%. This haplotype was the second ranked in the US Middle Eastern/North Coast of Africa (MENAFC) at 0.8% and is also a common Jewish haplotype. The most common MA haplotype was A∗01:01∼B∗52:01∼DRB1∗15:02 at 1.4%, which is ranked 41st in CA at 0.04%. This haplotype was ranked 12th in MENAFC at 0.26%. The fourth ranked haplotype for both CA and MA, A∗02:05∼B∗50:01∼DRB1∗07:01, is the most common in Saudi Arabia, Kuwait and Qatar and the fourth most common among Jewish populations. Average homozygosity for CA and MA for HLA-A, -B and -DRB1 was estimated at 6.7% and 6.2% while the top 30 haplotypes had a cumulative frequency of 25% and 19% respectively indicating higher MA genetic diversity. Interestingly, eight DRB1 alleles: 01:02, 03:01, 04:03, 07:01, 11:01, 11:04, 13:03 and 15:02 constituted over 63% of the allele frequencies for both CA and MA while 97% and 30% of patients served by the Arab registry had one or two of these alleles respectively. Additionally, DRB1∗03:01 occurred without the common Caucasian B∗08:01 association in about 85% of CA and MA donors. Clinical data showed that 40% of transplants were for Arab patients while others were for patients worldwide. Conclusions: Comparing CA and MA to other published HFs, it is clear that some haplotypes have migrated across populations while others remain isolated, thus adding these donors to the world registry is vital to increase genetic diversity for the benefits of all patients. [Copyright &y& Elsevier]