[Identification and sequence analysis of a null HLA-B allele HLA-B*5408N newly detected]

The study was purposed to investigate the molecular genetic basis for HLA novel allele HLA-B*5408N in Chinese population. DNA was extracted from whole blood by commercial DNA extraction kit, the HLA-B exons 2 - 4 of the proband was amplified by allele specific primers PCR and the amplified product was sequenced for exons 2, 3 and 4 bidirectionally. The sequencing results showed HLA-B alleles of the proband as B*1527 and the novel allele. The sequences of the novel allele have been submitted to Genbank (DQ295998, DQ295999, DQ296000). After blast analysis, the novel allele showed a single nucleotide mismatch with HLA-B*5401 in exon 3 at position 553 G-->T, which resulted in an amino acid changing from Glu to premature stop codon at position 161. No the HLA-B54 antigen specificity expression in the proband cells was found using HLA-AB serological Typing Trays. It is concluded that this allele is a novel null allele and has been officially named B*5408N by the WHO Nomenclature Committee.