As Figure 5A shows, in sera of RA patients there were only minimal amount of autoantibodies of IgG, IgA or IgM isotypes against the arginine-containing form of fibrinogen β chain peptide (60RPAPPPISGGGYRAR74) in sharp contrast to its citrullinated form (60XPAPPPISGGGYXAX74). The gene discussed is CD40LG; the disease is rheumatoid arthritis.