HLA-DRB1 and rheumatoid arthritis: For example the DRB1 SE alleles were associated with both ACPA-positive RA cases (OR = 5.18) and ACPA-negative RA cases (OR = 2.31) in a Korean study, while no association between the DRB1 SE alleles and subsets of RA was observed in the Chinese patients from China (OR = 0.52) [10], [20].