HLA-DRB1 and rheumatoid arthritis: However, anti-CPP3 IgG was associated with RA, but only when adjusting for age, sex and HLA-DRB1 SE (OR = 3.12; 95 % CI 1.06–9.19, p < 0.039) or the PTPN22 T-variant (OR = 2.96; 95 % CI 1.02–8.57, p < 0.045) (data not shown).