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

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 constitutive…