ROLE OF HLA-CLASS-II ALLELES IN KOREAN PATIENTS WITH IDDM

MHC associations with IDDM in the Korean population were studied to in vestigate genetic susceptibility to this disorder. The frequencies of HLA-DR3, -DR4 and -DR9 were significantly higher in diabetic patients. However, the frequency of DR2 was significantly decreased in diabetic patients. DQA10301 and DQA1*0501 were positively and DQA1+0102 and D QA10201 negatively associated with IDDM. DQB1*0301 and DQB1*0601 were negatively associated with IDDM. Heterodimers DQA10301-DQB1*0201, DQ A10501-DQB1*0201 and DQA1*0501-DQB1*0302 were positively associated a nd DQA10102-DQB1*0601 negatively associated with IDDM. The frequencie s of DR3-DQA10301-DQB1*0201 and -DQA1*0501-DQB1*0201 were significant ly higher in diabetic patients. The frequencies of DR4-DQA10301-DQB1* 0201 and DR9-DQA10301-DQB1*0303 were significantly higher in diabetic patients, The presence of non-aspartic acid at position 57 of the DQ beta-chain was not associated with susceptibility to IDDM. However, th e frequency of Arg 52 homozygotes was significantly higher in diabetic patients. These results suggest a role of the MHC molecule and also s uggest racial differences in susceptibility to IDDM even within the As ian populations.