The HLA-DRB1 allele is responsible for 25–50% of vulnerability to RA and, more recently, authors identified this allele as a mass producer of cyclic citrullinated autoantibody peptides (anti-CCP).43 These macromolecules are the first epitopes that provoke autoimmune activity by macrophages on joints.44 The possible association between periodontitis and RA converges to the central hypothesis of the relationship, in which the citrullinated antigens can cause changes in synovial joints.45 Here, HLA-DRB1 is linked to rheumatoid arthritis.