The contribution of the HLA-DRB1 allele classification in accounting for the genetic contribution of the HLA-DRB1 gene was previously analyzed in terms of RA severity and in terms of autoantibody production such as anti-cyclic citrullinated peptide (anti-CCP) antibodies and anti-deiminated human fibrinogen autoantibodies. The gene discussed is HLA-DRB1; the disease is rheumatoid arthritis.