In particular, the interaction of citrulline vimentin with the P4 pocket of HLA-DRB1*04:01/04, which is specific for RA and called the shared epitope, increased detection of CD4+ T-cells against citrullinated vimentins in the peripheral blood of RA patients and presence of plasma cells producing ACPA are the route of the classical RA autoimmunity (27, 28). This evidence concerns the gene CD4 and rheumatoid arthritis.