Abstract
Purpose:
Scleritis may be a chronic, painful, progressive, potentially blinding condition often associated with systemic connective tissue or vasculitic diseases, some of them potentially lethal. Serum cytokine profiling may contribute to the understanding of the physiopathology processes underlying scleral inflammation. Our purpose is to evaluate serum cytokine profile from patients with active scleritis.
Methods:
Two-center prospective case-control study. The serum of 16 active scleritis patients not treated with any local, periocular, or systemic immunomodulatory therapy (IMT) was analyzed with the Luminex platform (Millipore's MILLIPLEX® Human Cytokine/Chemokine kit) to determine the levels of 11 cytokines including interleukin (IL)-1β, IL-6, IL-2, IFN-γ, IL-10, IL-12p40, IL-13, IL-17A, IL-5, TNFα, and TNFβ) and with ELISA to determine the levels of TGF-β1, IL-22, and IL-23. Serum of 17 age-matched healthy volunteers was used as control. Non-parametric analysis was performed using the Mann-Whitney test for comparison of unpaired data from two groups. Cytokine profile from patients with scleritis were correlated with type of scleritis (non-necrotizing and necrotizing), degree of inflammation (0-4+:≤ 2+ and >2+), and systemic associated disease (yes or no).
Results:
Serum levels of interleukin IL-22 were elevated in active scleritis patients naïve to IMT compared with that of controls (4,66+/-0,84 pg/mL vs 1,91+/-0,39 pg/mL, P=0.008). Those levels trended down after scleritis remission with the use of IMT (P<0.05). The serum levels of other cytokines were not significantly different from control levels. No significant correlations were found with specific cytokine profiles and type of scleritis or systemic associate disease, probably limited by the small number of patients. Serum levels of IL-2, IL-6 and TNFβ were significantly elevated in patients with >2+ inflammation (P<0.05).
Conclusions:
Serum levels of IL-22 are significantly elevated in active scleritis patients naïve to IMT. IL-22, a T helper (Th)17 and Th22 derived cytokine, may play a critical role in the physiopathology of scleritis and could be a promising therapeutic target.