Open Access

ARTICLE

Elevated interleukin-18 protein expression in early active and progressive plaque-type psoriatic lesions

Arjen Companjen, Leontine van der Wel¹, Leslie van der Fits¹, Jon Laman, Errol Prens

Departments of Immunology and Dermatology¹ , Erasmus MC, Rotterdam, The Netherlands

* Corresponding Author: Errol P. Prens,

European Cytokine Network 2004, 15(3), 210-216.

Accepted 17 May 2004;

Abstract

Psoriasis is a T cell-mediated inflammatory skin disease characterized by an elevated IFN-γ and IL-12p70 expression in skin lesions. Interleukin-18 (IL-18) synergizes with IL-12 to induce IFN-γ production and a strong T-helper-1-mediated immune response, or to induce Th2 polarization depending on the immunological context. We have previously shown that keratinocytes in normal skin produce and store large amounts of pro-IL-18. In this study, we hypothesized that the expression of IL-18 in psoriatic lesional skin might be altered compared to normal skin. Therefore, IL-18 expression was assessed in psoriatic, stable, plaque-type lesions and early active and progressive lesions. IL-18 mRNA and protein concentrations were constitutively high, and did not differ between normal and stable, plaque-type epidermis. In active and progressive lesions an elevated expression of total IL-18 protein relative to normal and stable, plaque-type epidermis was detected using ELISA, while on Western blot, the differences in pro- or mature IL-18 were less clear. Our results indicate that the role of IL-18 in the pathogenesis of early phases of psoriasis may be more prominent than in established psoriatic lesions.

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