Identification of HLA-DRB1 alleles associated with Graves' disease in Koreans by sequence-based typing

The human leukocyte antigen (HLA) region, particularly class II genes, plays a primary role in the susceptibility to development of GD. We investigated the allelic polymorphism of HLA class II DRB1 genes to examine its association with GD in Koreans. We performed the high resolution polymerase chain reaction-sequence based typing (PCR-SBT) of HLA-DRB1 in 133 patients with GD and 200 healthy controls. Compared to healthy controls, the patients with GD had increased frequencies of DRB1*030101 (4.9% vs.1.8%, p = 0.034), DRB1*080201 (5.3% vs. 2.3%, p = 0.050) and DRB1*140301 (3.4% vs. 1.0%, p = 0.043). In contrast, the frequencies of DRB1*070101 (3.0% vs. 7.3%, p = 0.024) and DRB1*130201 (4.1% vs. 9.0%, p = 0.010) were decreased in the patients with GD. However, the corrected p values were not significant in above all alleles. Patients with DRB1*040301 were significantly older than controls (45 years vs. 35 years, p = 0.017). DRB1*040301, DRB1*150201, DRB1*120101 and DRB1*120201 were associated with male predominance, strong familial associations, thyroid ophthalmopathy and radioactive iodine therapy, respectively. In conclusion, there were no significant HLA-DRB1 alleles associated with GD in Koreans, although some alleles were correlated with the clinical characteristics.