THE DAI MINORITY POPULATION OF SOUTHWEST CHINA - HETEROGENEITY OF DR2-ASSOCIATED HLA-DRB1,DRB5,DQA1, AND DQB1 HAPLOTYPES

HLA-DR2 is the most common DR specificity (60.3%) identified in the Da i minority population of Xishuangbanna, Yunna Province, China. We char acterized the DRB1, DRB5, DQAl, and DQB1 alleles of 44 unrelated DR2-p ositive individuals, 11 of whom (15%) were DR2 homozygous. Four DRB1 a nd four DRB5 alleles encoding DR2 were identified in this population. The most frequent DR2-associated DRB1 alleles were 1602 (gf = 0.164) and 1502 (gf = 0.151). DRB1*1501 (gf = 0.048) and a new allele design ated DRB11504 (gf = 0.014) were also detected, but *1601 and *1503 we re absent. The most frequent DR2-associated DRB5 alleles were 0101(gf = 0.233) and 0102 (gf = 0.110). Nine different DR2-associated DR/DQ haplotypes were iden- tified. The two most common DR2 haplotypes were DRB11602,DRB5*0101,DQA1*0102,DQB1*0502 (hf = 0.142) and DRB1*1502,DRB 50102,DQA1*0101, DQB1*0501 (hf = 0.075). The new DRB1*1504 allele was found on a single haplotype: DRB11504, DRB5*0101,DQA1*0102,DQB1*0502 (hf = 0.017). The Dw2, Dw12, Dw21, and Dw22 haplotypes, present in ma ny other Asian and Mongoloid populations, were not identified in this unique group. However, the Dai minority population is characterized by a relatively large number of diverse DR2 haplotypes and a new DRB1 al lele encoding DR2.