Interleukin-22 and rheumatoid arthritis: emerging role in pathogenesis and therapy.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by synovial inflammation and resultant progressive joint damage. It has become increasingly evident that cytokines play an important role in the pathogenesis of RA. Interleukin-22 (IL-22) is a member of the IL-10 cytokine family. Recent findings suggest that not only the expression of IL-22 is abnormal both in RA patients and in arthritis mice but also the aberrant IL-22 performs significantly in disease onset of RA. In this paper, we focus on the critical role of IL-22 in RA. Hopefully, the information obtained may lead to a better understanding of the pathogenesis and development of novel therapeutic strategies for this systemic autoimmune disease.