Distribution of HLA-DQA1*01, *03, *05 and DQB1*02 Subtypes and the Associated Haplotypes in the Korean Population

ABSTRACT

BACKGROUND: As all HLA class II genes, the DQ genes show their polymorphic variation mainly in the second exon, which encodes the first extracellular domain of the molecule. PCR-SSOP (Polymerase chain reaction-Sequence specific oligonucleotide probe) techniques were frequently used for HLA-DQA1 and DQB1 typing but certain alleles, DQA1*0101/0104/0105, *0302/0303, *0501/0505 and DQB1*0201/*0202, which differ from each other in segment other than exon 2, could not be unequivocally assigned. METHODS: To overcome this problem, we applied additional PCR-SSP (PCR-Sequence specific primer) method to analyze DQA1 exons 1, 3 and 4 and DQB1 exon 3. And we investigated the distributions and haplotypes of HLA-DRB1, DQA1 and DQB1 alleles in 406 unrelated Korean healthy individuals. RESULTS: Using this method the indistinguishable alleles of DQA1 and DQB1 in PCR-SSOP were typed definitively. We also found several important associations between DQA1 and DQB1 alleles in the Korean population; DQA1*0101-DQB1*0501, DQA1*0104-DQB1*0502 or -*0503, DQA1 *0105-DQB1*0501, DQA1*0302-DQB1*0303, DQA1*0303-DQB1*0401 or -*0402, DQA1 *0501-DQB1*0201, DQA1*0505-DQB1*0301, and DQA1*0201-DQB1*0202. The haplotypes of DRB1-DQA1-DQB1 associated with DQA1*01, *03, *05, and DQB1*02 subtypes were investigated. Several haplotypes associated with these alleles were observed in the Korean population. CONCLUSION: Our results can be helpful to find potential unrelated donors for bone marrow registries and study the HLA-associated disease and anthropology at high-resolution allelic level.