[Identification of a novel allele HLA-DRB1*1218]

To identify a novel human leukocyte antigen (HLA) allele by cloning and sequence-based typing in Chinese population, and analyzing the sequence of the introns 1 and 2.

The routine HLA-A, -B, -DRB1 low resolution genotyping for stem cell donor from Guangdong province was performed with polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP). An unknown HLA-DRB1 allele was initially detected by HLA typing. Genomic DNA of the proband was amplified by using HLA-DRB1 locus group-specific primer, the amplified product was cloned, sequenced, and compared to the closest DRB1*120201 allele and the closest intron sequence of the DRB1*030101 allele.

The sequencing results showed that a normal DRB1*080302 and a novel DRB1*1218 variant allele were identified. The sequence of the novel allele has been submitted to GenBank (FJ481086). The novel allele had 1 nucleotide substitution of the closest matching allele HLA-DRB1*120201 at nt262(G-->C) in exon 2,resulting in an amino acid change from Glu(GAG)-->Gln (CAG) at codon 59.The intron 2 sequence is identical between the novel HLA-DRB1*1218 and DRB1*030101, but there are 12 nucleotides substitution in intron 1.

A novel HLA allele was confirmed by cloning and sequence-based typing in Chinese. It was officially designated as HLA-DRB1*1218 by WHO Nomenclature Committee.