RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM OF HLA-DQ AND HLA-DR ALLOGENOTYPES IN NORMAL SOUTHERN CHINESE

We have examined the Tag I restriction fragment length polymorphism (R FLP) of the MHC class II regions of 96 normal Southern Chinese with re spect to the HLA-DRB, -DQA, and -DQB genes. The data were compared wit h the DR and DQ serotyping. RFLP correlates well with the serological typing of the DR types of Chinese. Variants are seen in DR2 and DR12. The variant in DR12 with a 10 kb at the upper band (DR12b) is not foun d in Caucasoids and is more frequent in Chinese (19.4% of the alleles) . With the help of DQA and DQB RFLP the assignment of genotyping of DR B types is facilitated. Some of the linkage disequilibrium patterns am ong DRB, DQA and DQB are different from Caucasoids. This is particular ly obvious in the DR2, and DR5 haplotypes. In the 96 Southern Chinese, the 3 commonest haplotype frequencies are: DR12b, DQ alpha 1b, DQ bet a 3b (18.3%); DR9, DQ alpha 3, DQ beta 3a (15.7%); DR4, DQ alpha 3, DQ beta 3a (14.2%). The various DR beta, DQ alpha. DQ beta genes can be accurately defined in Chinese by RFLP. Polymerase chain reactions usin g sequence-specific primers were performed to confirm the various HLA- DRB and -DQB alleles. The use of RFLP is important in the study of HLA matching and HLA-disease association in Southern Chinese.