Predisposing effects of the *04:05 allele were confirmed in ACPA(+) RA (Table 5, P = 3.64×10−35, Pc = 1.13×10−33, OR 3.59, 95% CI 2.91–4.42), whereas DRB1*13:02 was negatively associated with ACPA(+) RA (P = 3.95×10−8, Pc = 1.22×10−6, OR 0.42, 95% CI 0.31–0.58). Here, HLA-DRB1 is linked to rheumatoid arthritis.