HLA-A, -B and -DRB1 polymorphism in Koreans defined by sequence-based typing of 4128 cord blood units.

ABSTRACT

Human leucocyte antigen (HLA) alleles and haplotypes differ significantly among different ethnic groups, and high-resolution typing methods allow for the detection of a wider spectrum of HLA variations. In this study, HLA-A, -B and -DRB1 genotypes were analysed in 4128 cord blood units obtained from Korean women using the sequence-based typing method. A total of 44 HLA-A, 67 HLA-B and 48 HLA-DRB1 most probable alleles were identified. Of these, high-frequency alleles found at a frequency of ≥5% were 6 HLA-A (A*0201, A*0206, A*1101, A*2402, A*3101, A*3303), 5 HLA-B (B*1501, B*4403, B*5101, B*5401, B*5801) and 7 HLA-DRB1 (DRB1*0101, DRB1*0405, DRB1*0701, DRB1*0803, DRB1*0901, DRB1*1302, DRB1*1501) alleles. At each locus, A*02, B*15 and DRB1*04 generic groups were most diverse at allelic level, consisting of 8, 11 and 10 different alleles, respectively. Two- and three-locus haplotypes estimated by the maximum likelihood method revealed 73 A-B, 74 B-DRB1 and 42 A-B-DRB1 haplotypes with frequencies of ≥0.3%. A total of 193 A-B-DRB1 haplotypes found at a frequency of ≥0.1% were presented, and the six most common haplotypes were A*3303-B*4403-DRB1*1302 (4.6%), A*3303-B*5801-DRB1*1302 (3.0%), A*2402-B*0702-DRB1*0101 (2.7%), A*3303-B*4403-DRB1*0701 (2.5%), A*3001-B*1302-DRB1*0701 (2.2%) and A*2402-B*5201-DRB1*1502 (2.1%). Compared with previous smaller scale studies, this study further delineated the allelic and haplotypic diversity in Koreans including low-frequency alleles and haplotypes. Information obtained in this study will be useful for the search for unrelated bone marrow donors and for anthropologic and disease association studies.