The deduced probable human leukocyte antigen haplotype associated with human leukocyte antigen low incidence allele B∗40:36 (A∗02-B∗40:36-DRB1∗12) in Taiwanese unrelated hematopoietic bone marrow stem cell donors

ObjectiveHuman leukocyte antigen (HLA)-B∗40:36 is a low incidence allele in the HLA-B locus. This study reports the ethnicity of B∗40:36 and the deduced probable HLA haplotype associated with HLA-B∗40:36 in Taiwanese unrelated bone marrow hematopoietic stem cell donors.Materials and methodsA sequence-based typing method was employed to confirm that the low incidence allele was present. Polymerase chain reaction was performed to amplify exons 2 and 3 in the HLA-A and HLA-B loci and exon 2 in the HLA-DRB1 locus using group-specific primer sets. The amplicons were sequenced using the BigDye Terminator Cycle Sequencing Ready Reaction Kit in both directions.ResultsThe DNA sequence of B∗40:36 is identical to B∗40:01:01 in exons 2 and 3, except for a one nucleotide substitution at residue 419 (A→T), which results in a one amino acid replacement at position 116 (Y→F; tyrosine→phenylalanine). We deduced the probable HLA haplotype in an association with B∗40:36 in Taiwanese to be A∗02-B∗40:36-DRB1∗12.ConclusionInformation on the deduced probable HLA haplotype in an association with the low incidence B∗40:36 allele that we report here is of value for HLA testing laboratories for reference purposes. In addition, it can be used by stem cell transplantation donor search coordinators to determine the likelihood of finding compatible donors in unrelated bone marrow donor registries when a patient has this uncommon HLA allele.