HLA class II allele and haplotype frequencies in Koreans based on 107 families.

We have investigated the distribution of HLA class II alleles and haplotypes in 107 Korean families (207 parents and 291 children) for the HLA-DRB1, DRB3/B4/B5, DQA1, DQB1 and DPB1 loci. Numbers of alleles observed for each locus were DRB1: 25, DQA1: 14, DQB1: 15, and DPB1: 13. Only two to three alleles were observed for the DRB3 (0101, 0202, 0301), DRB4 (0103, * 0103102 N), and DRB5 (0101, 0102) loci. These alleles showed strong associations with DRB1 alleles: DRB30101 with DRB11201, 1301 and 1403; DRB30301 with DRB11202 and 1302; DRB30202 with DRB10301, 1101, 1401 and 1405; DRB50101 and 0102 were exclusively associated with DRB11501 and 1502, respectively. The seven most common DRB1-DQB1 haplotypes of frequencies > 0.06 accounted for 52% of the total haplotypes. These haplotypes were exclusively related with the seven most common DRB1-DRB3/B4/B5-DQA1-DQB1 haplotypes: DRB11501-DRB50101-DQA10102-DQB10602 (0.085), DRB10405-DRB40103-DQA10303-DQB10401 (0.082), DRB109012-DRB40103-DQA10302-DQB103032 (0.082), DRB10101-DQA10101-DQB10501 (0.075), DRB10701-DRB40103-DQA10201-DQB10202 (0.065), DRB10803-DQA10103-DQB10601 (0.065), and DRB11302-DRB30301-DQA10102-DQB10604 (0.065). When these haplotypes were extended to the DPB1 locus, much diversification of haplotypes was observed and only one haplotype remained with a frequency of > 0.06: DRB10405-DRB40103-DQA10303-DQB10401-DPB10501 (0.062). Such diversification would have resulted from cumulated events of recombination within the HLA class II region, and the actual recombination rate observed between the HLA-DQB1 and DPB1 loci was 2.3% (10/438 informative meioses, including 2 recombinants informative by analysis of TAP genes). Comparison of the distribution of DRB1-DQB1 haplotypes with other populations revealed that Koreans are closest to Japanese people. However, Koreans share a few haplotypes with white people and Africans, which are rare in Japanese: DRB10701-DQB10202 and DRB11302-DQB1*0609. The results obtained in this study will provide useful information for anthropology, organ transplantation and disease association studies.