HLA-DRB1 and rheumatoid arthritis: Further stratification analysis by ethnicity revealed the strongest association signal at amino acid position 96 within HLA-DRB1 peptide with histidine residue (i.e., HLA-DRB1 His96) among Indian patients with ACPA-positive RA (OR = 0.48, 95% CI = 0.37–0.62, PGWAS = 2.58 × 10−08) (Table 2).