Serum levels of interleukin‐18 and s‐ICAM‐1 in patients affected by psoriasis: preliminary considerations

Abstract

ABSTRACT Objective To find new aspects of the systemic involvement of the Immune System in psoriasis, we determined serum levels of interleukin‐18 (IL‐18) (Th1‐inducing factor cytokine), CD30 (Th2 marker) and sICAM‐1 (adhesion molecule). In addition we evaluated the correlation between these molecules and psoriasis area and severity index (PASI). Background Psoriasis is associated to an overexpression of Th1 cytokines and a relative underexpression of Th2 cytokines. IL‐18 plays an important role in inducing Th1 response because it is a potent inductor of synthesis of IFN‐γ, TNF and other mediators. The two major sources of IL‐18 are monocytes and macrophages but also human keratinocytes constitutively synthesized IL‐18. Subjects and methods We selected two groups of subjects: 16 healthy donors (HD) and 16 patients affected by psoriasis, matched for sex and age. Serum IL‐18, CD30 and sICAM‐1 levels were assayed by immunoenzymatic method with commercial kits. Results IL‐18 and sICAM‐1 levels in the patients were significantly higher than in the HDs (385.94 ± 193.89 vs. 227.38 ± 92.76 pg/mL, P = 0.005 and 445.00 ± 152.67 vs. 317.88 ± 107.20 ng/mL, P = 0.02, respectively). On the contrary, no significant difference was found between serum sCD30 levels of patients in respect to those of HDs. A significant correlation was found between serum IL‐18 and PASI (Rho = 0.695, P = 0.0071), serum IL‐18 and sICAM‐1 (Rho = 0.543, P = 0.0356) and between sICAM‐1 and PASI (Rho = 0.659, P = 0.0107).