Assessment of serum level of IL-6 and IL-37 cytokines in patients with psoriasis

Objectives. Psoriasis is a chronic, proliferative, inflammatory disorder of the skin that affects roughly 2-3% of individuals globally. The pathology arises from irregular communications between skin keratinocytes and infiltrating cells of the immune system, resulting in epidermal thickening and inflammation. While the exact pathogenesis is unclear, data indicates disturbance levels of both pro- and anti-inflammatory cytokines. Interleukin-6 (IL-6) is a prominent proinflammatory mediator, whereas interleukin-37 (IL-37) has been more recently evident as an anti-inflammatory cytokine. This research aimed to quantify serum IL-6 and IL-37 in psoriasis patients versus healthy controls and to evaluate their correlations with disease severity. Materials and methods. Blood samples were collected from 60 psoriasis patients and 30 healthy individuals. IL-6 and IL-37 concentrations were measured by sandwich ELISA. Outcomes. Psoriasis patients displayed notably elevated serum IL-6 and reduced IL-37 compared to healthy controls (p=0.003 and p=0.006, respectively). IL-6 amounts inversely correlated with patient age (p=0.021) but did not correlate with psoriasis severity per psoriasis area and severity index (PASI) score. IL-37 levels did not correlate with any clinical features. At a cut-off of 27.67 ng/L, IL-6 showed 83.3% sensitivity and 76.7% specificity for differentiating psoriasis patients from controls. For IL-37 at a cut-off of 21.57 ng/L, the sensitivity was 83.3% and the specificity was 69.7%. Conclusions. These results confirm the proinflammatory effect of IL-6 and anti-inflammatory effect of IL-37 in psoriasis. The imbalance between these two cytokines may facilitate disease pathogenesis. IL-6 and IL-37 quantification could have utility as biomarkers in psoriasis. Further studies are required to clarify the intricate cytokine networks driving psoriasis immunopathology.