[Cloning and sequencing analysis of a novel allele HLA-A*02:251].

Objective To identify a novel human leukocyte antigen (HLA) allele A*02:251 and analyze the sequences in Chinese population. Methods Routine HLA-A, -B, -DRB1 high resolution genotyping for healthy Chinese donors and patients was performed with polymerase chain reaction-sequence based typing. An unknown HLA-A allele was initially detected by HLA typing in the healthy donor. Genomic DNA of the HLA-A locus in the proband was amplified, the amplified product was cloned by PMD18-T to split the two alleles, and selected clones were sequenced. Results The sequencing results showed that a normal A*02:06:01 and a novel A*02:251 variant allele were identified. The sequence of the novel allele has been submitted to GenBank (HM245348). Nucleotide sequence alignments with HLA-A allele from the IMGT/HLA Sequence Database showed that the novel A*02 variant allele differed from the closest allele A*02:01:01:01 by nt 383 G>C (codon 128 GAG>GAC) in exon 3, which resulted in one amino acid substitution of Glu>Asp. The HLA-A, B, C and DQB1 alleles of the healthy donor did not match with that of the patient. Conclusion This novel allele is officially designated as HLA-A*02:251 by World Health Organization(WHO) Nomenclature Committee (Submission ID HWS10010755). The sequence of HLA-A locus in exon 3 is confirmed to be polymorphic in Chinese population. Key words: human leukocyte antigen; allele; exon