Background In autoimmune diseases including rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), cytokines play a central role in initiating and maintaining diverse immune and inflammatory responses.In addition to IL-17A and F, Th17 cells also secrete IL-21, IL-22, and granulocyte macrophage colony-stimulating factor (GM-CSF). IL-22, member of IL-10 cytokine family, has been believed as an important player in regulating inflammatory responses associated with many inflammatory diseases. There is apparently a strong functional synergism of TNF-α and IL-22; the interaction of IL-22 & TNF-α is mediated through TNFR I and IL-22R heterodimer and intracellularly by MAP kinases. The combination of IL-22 & TNF-α strongly induced the phosphorylation and translocation of MAP kinases to the nucleus whereas the single cytokine only weakly contributed to MAP kinase activation. The discovery of the IL-22/TNF-α axis gives a first insight that could lead to new therapeutic approaches of RA.
Objectives to evaluate the role of IL-22 and TRAF1 in patients (pts) with RA & SLE, and their association to the disease activity.
Methods 70 RA pts, 64 SLE pts aged & 45 healthy matched controls were enrolled. DAS28 & SLEDAI were used to assess activity.
Results IL-22 was significantly higher in RA&SLE pts than healthy controls. significant positive correlation was found between IL-22 levels and tender joints count, CRP and ESR. However, In SLE pts CRP only showed a positive correlation with IL-22 levels
Analysis of TRAF1 polymorphism: in RA pts; the magnitude of association was increased in those patients who were autoantibody positive either RF+ or anti- CCP+. TRAF1 A allele was significantly associated with RF+ and anti-CCP+ RA patients when compared withcontrol. (OR =3.344 CI: 1.79–6.24, P<0.001, OR =1.881 CI: 1.03–3.41 P<0.034)respectively,in SLE pts, TRAF1 rs10818488 was not significantly different in pts and control
Conclusions Theses results indicate that IL-22 is associated with inflammatory process and it has a role in RA and SLE pathogenesis and prognosis.Although there are inconsistent findings which need to be resolved, there are a synergism between TNF-α, IL 17 & IL-22,mso,targeting IL-22 cytokine may be an effective therapeutic approach for chronic inflammation in the future.Also TRAF1 was significantly associated with RF positive, anti-CCP positive pts, ESR and tender joints count and this confirm importance of TRAF1 in progression of RA
Da Rocha et al. Increased serum interleukin 22 in patients with rheumatoid arthritis and correlation with disease activity. J Rheumatol 2012
Disclosure of Interest None declared