title: A comparison of molecular HLA-DR and DQ allele profiles forming DR51-, DR52-, and DR53-related haplotypes in five ethnic Thai populations from mainland southeast Asia.
abstract: Using PCR-SSOP typing we have deduced the composition and frequency of HLA-DRB1, -DRB3, -DRB4, -DRB5, -DQA1, and -DQB1 alleles present in DR51-, DR52-, and DR53-related haplotypes, in 519 individuals representative of five ethnic Thai populations recruited in central, northeastern and northern Thailand. In total, we have unequivocally detected at varying frequencies, 17 DR51-related haplotypes, 24 DR52 haplotypes, and 12 DR53 haplotypes in the study groups. We document evidence of north-south gradients of DR51-related haplotypes, whereby the overall frequency of DR51-containing haplotypes is relatively more common in the northern Thai groups. Similarly, within DR53-related haplotypes the frequency of DRB1*0901-containing haplotypes increases in the more northerly groups, and an inverse effect was observed with DRB1*0701-containing haplotypes that were relatively more common in the northeastern and central Thais. We have also compared the class II haplotype profiles of the Thais with the equivalent profiles reported in other non-Thai ethnic groups from mainland and insular SE Asia. One DR51-related haplotype DRB1*1502x, DRB5*0102x, DQA1*0101/4, DQB1*0501, would appear to be characteristic of Thai populations, as it was the most common DR2 haplotype in all five study groups and is also prevalent in other mainland southeast Asians, but is much less evident in the more northern populations of eastern Asia or China.
authors.affiliation: Department of Transfusion Medicine, Siriraj Hospital and Medical School, Mahidol University, Bangkok, Thailand. h.stephens@ucl.ac.uk
authors.forename: H A
authors.initials: HA
authors.lastname: Stephens
authors.forename: D
authors.initials: D
authors.lastname: Chandanayingyong
authors.forename: W
authors.initials: W
authors.lastname: Kunachiwa
authors.forename: M
authors.initials: M
authors.lastname: Sirikong
authors.forename: K
authors.initials: K
authors.lastname: Longta
authors.forename: R
authors.initials: R
authors.lastname: Maneemaroj
authors.forename: D
authors.initials: D
authors.lastname: Wongkuttiya
authors.forename: N
authors.initials: N
authors.lastname: Sittisombut
authors.forename: E
authors.initials: E
authors.lastname: Rungruang
mesh_terms: D000483:Alleles; D044466:Asian People / Q000235:genetics*; D006683:HLA-DQ Antigens / Q000145:classification / Q000235:genetics*; D006684:HLA-DR Antigens / Q000145:classification / Q000235:genetics*; D059845:HLA-DRB4 Chains; D059847:HLA-DRB5 Chains; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D013785:Thailand
chemical_list: D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; C050610:HLA-DR53; D059845:HLA-DRB4 Chains; D059847:HLA-DRB5 Chains