Objectives: HLA-C*07:66 is a low-incidence HLA-C allele. The aim of the study is to report the Taiwanese and mainland Chinese ethnicities of individuals with C*07:66, together with its uniqueness and polymorphism.
Materials and methods: A sequence-based typing method was employed to confirm this low-incidence allele. Polymerase chain reaction was performed to amplify exons 2, 3, and 4 of the HLA-A, HLA-B, and HLA-C loci and exon 2 of the HLA-DRB1 and HLA-DQB1 loci using group-specific primer sets. The amplicons were sequenced in both directions using BigDye Terminator Cycle Sequencing Ready Reaction kit. The blood donors in this study consisted of randomized Taiwanese and mainland Chinese individuals and family members with the C*07:66 allele.
Results: The DNA sequence of C*07:66 is identical to that of C*07:02:01:01 for exons 2, 3, and 4, except for residue 688 in exon 4. This nucleotide substitution causes a single amino acid alteration to the protein sequence of C*07:02:01:01. Confirmation of the DNA and protein sequences of C*07:66 and the Taiwanese and mainland Chinese ethnicities of individuals with this allele were established in this study. One probable HLA C*07:66-associated HLA haplotype may be deduced from these individuals.
Conclusion: The information on the ethnicity of the C*07:66 allele and the deduced probable HLA haplotype associated with the low-incidence C*07:66 allele reported in this study may aid in HLA testing laboratories for reference purposes. In addition, they can be used by stem cell transplant donor search coordinators to help create, for patients bearing this uncommon HLA allele, strategies for finding compatible donors using bone marrow donor registries comprising unrelated individuals.
Keywords: C*07:66; HLA; Haplotype; Hematopoietic stem cell; Sequence-based typing; Transplantation.