[Novel autoantibodies and their target antigens in rheumatoid arthritis]

Recently identified autoantibodies in rheumatoid arthritis are targeting autoantigen molecules, such as calpastatin, a novel form of soluble gp130, and follistatin-related protein, that appear to play a role in protecting effects in joint inflammation. These autoantibodies inhibit the function of target molecules and may be involved in the pathogenic mechanisms by upregulating inflammation and joint destruction. Another autoantibody targets filaggrin, a citullurinated protein distributed in keratinated epithelia. Although the pathogenic effect of anti-filaggrin antibody is not elucidated, this autoantibody has a potentiality of a new diagnostic marker of RA because of its high sensitivity and specificity.