%0 Journal Article
%T Frequencies and haplotype associations of non-expressed HLA alleles in ethnically diverse populations on the National Marrow Donor Program's Be The Match Registry.
%A Bauer M
%A Kempenich J
%A Wadsworth K
%A Malmberg C
%A Beduhn B
%A Dehn J
%J Hum Immunol
%V 81
%N 10
%D Oct 2020 0
%M 32684409
%F 2.211
%R 10.1016/j.humimm.2020.07.004
%X HLA allele matching is critical to successful bone marrow transplantation between a patient and donor. Non-functional HLA alleles, so called 'null alleles', are not well described within a large population of well HLA-typed ethnically diverse individuals despite their impact on donor selection. A retrospective analysis was performed on 833,789 unrelated donors (URDs) in the National Marrow Donor Program's Be The Match Registry® typed for HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1 by next-generation DNA sequencing. Results showed that null alleles occur in low frequency (2.30E-04) compared to expressed alleles. Their overall frequency ranged from 6.00E-07 to 9.25E-04 with a median of 1.20E-06. The expected allele associations were commonly observed for HLA-A*24:09N, HLA-B*51:11N, and HLA-C*04:09N; however, associations outside of the expected were also observed. Notably, 82% of the National Marrow Donor Program Registry URDs carrying HLA-A*24:11N showed a different HLA-C allele association, HLA-C*05:01, compared to the allele described by prior published work characterizing German donor populations, HLA-C*04:01. The frequencies of these observed null alleles and linkage disequilibrium information could be invaluable and helpful in guiding the HLA testing decisions.