由HLA-B位点SSP的异常格局发现HLA-C位点新等位基因

目的鉴定HLA-C位点的新等位基因。方法采用PCR-SSP进行HLA低分辨分型,引用DNA亚克隆加DNA序列分析,鉴定HLA-C位点的新等位基因。结果 PCR-SSP常规进行临床患者的HLA基因分型,发现1名患者B位点反应格局异常,但序列分析表明B位点2个等位基因无异常。进一步分析出现在B位点SSP异常反应格局中的额外特异性扩增片段,其碱基序列同源于C位点基因序列。测序分析发现该病例C位点存在1个新等位基因,比对分析表明新等位基因序列与Cw*031101相比较,第97位碱基由T→G,第105位由T→C,相应编码的第9位氨基酸由酪氨酸(Y)→天门冬氨酸(D)。但相应编码第11位氨基酸的无变化。结论 DNA测序表明被测标本含有HLA-C新等位基因,被WHO HLA因子命名委员会正式命名为HLA-Cw*0339。

Identification of unusual amplification pattern by SSP HLA-B typing leading to discovery of a novel HLA-C allele

Objective To identify the unique sequence of a novel human leukocyte antigen (HLA)-C allele which obtained from amplification of a product with a primer pair used in sequence-specific primer (SSP) HLA-B typing. Methods HLA-A, -B and -DRB1 typing at low resolution with PCR-SSP ,DNA subcloning and DNA sequencing were performed for identification the new HLA allele. Results We found an unusual HLA-B amplification pattern in the routine HLA typings using PCR-SSP, but no allele variant was found in HLA-B locus by SBT. The extra band generated in PCR-SSP reaction of HLA-B typing was investigated further, the extra band sequence displayed strong homology with HLA-C gene, which gave a strong indication that it was the novel allele that we were researching, was actually an allele in C-locus. BLAST showed that the new allele was closely related to Cw031101 with only two nucleotide changes from T to G at position 97, an amino acid from tyrosine to aspartic at amino acid residue 9 (Y to D); T to C at position 105,with alanine at residue 11 unchanged. Conclusion A novel HLA allele was confirmed by the sequencing based typing(SBT) and it has beom officially designated as Cw0339 by WHO Nomenclature Committee for Factors of the HLA System in March 2007.