Proinflammatory and anti-inflammatory cytokine profiles in psoriasis: use as laboratory biomarkers and disease predictors

Objective The objectives of this study were to delineate the pro and anti-inflammatory cytokine profiles of psoriasis and cytokine profile models that externally validate the diagnosis. Subjects and Methods This study recruited 70 patients with psoriasis and 76 healthy controls. Cytokine profiles were evaluated, including pro-inflammatory M1 (IL-1 + IL-6 + TNF-α), Th1 (IL-2 + IL-12 + IFN-γ), Th17 (IL-6 + IL-17), and immune-inflammatory response system (IRS = M1 + Th1 + Th17) profiles. Moreover, the anti-inflammatory potential included Th2 (IL-4), Th2 + T regulatory (Th2 + Treg, namely IL-4 + IL-10 + TGF-β), anti-inflammatory (Th2 + Treg + adiponectin), and the pro-inflammatory/anti-inflammatory index. Results There was a highly significant association between psoriasis and cytokine levels with an effect size of 0.829 and a particularly strong impact on IL-2 (0.463), IL-12 (0.451), IL-10 (0.532) and adiponectin (0.401). TGF-β and adiponectin were significantly lower while all other cytokines (except IFN-γ) were significantly higher in psoriasis than in controls. In addition, M1, Th1, Th17, Th2 + Treg, and IRS/Anti-inflammatory index were significantly higher in psoriasis patients than in controls. The IRS index, Th2 + Treg, and adiponectin predicted psoriasis with 97.1% sensitivity and 94% specificity. Conclusion In conclusion, psoriasis is characterized by increased M1, Th1, Th2 and Th17 profiles together with lowered TGF-β and adiponectin. In addition, we propose a model based on a higher IRS and Th2 + Treg index coupled with lower adiponectin values, which may be used to externally validate the diagnosis of psoriasis. The most important single biomarker of psoriasis is adiponectin. Because the latter may play a role in the modulation of the chronic inflammatory response in psoriasis, adiponectin could be a new drug target to treat psoriasis.