Abstract: Objective To investigate the role of IL-1βin the initiation of psoriatic phenotype in the transwell skin organ culture model using biopsies from healthy human skin and non lesional skin from patients with psoriasis. Methods The skin biopsies were cultured for 24 hours and stimulated with IL-1βor IL-1 receptor antagonist (IL-1ra), and the induction of epidermal psoriatic phenotype was analysed using immunostaining (APAAP). Results In the presence of IL-1β, the psoriasiform epidermal phenotype was clearly induced, i.e. a strong upregulation of keratin 16, keratin 17 and transglutaminase type Ⅰwas found in the suprabasal layers of cultured normal skin; the expression of ICAM-1 and HLA-DR was induced on basal keratinocytes, epidermal dendritic cells as well as endothelial cells in the dermis. Integrin β1 was also upregulated by IL-1βfrom the basal to suprabasal keratinocytes. The effects of IL-1βon the skin organ cultures could be completely neutralized by anti-IL-1 polyclonal antibodies. Conclusion IL-1βis able to induce a series of psoriasis related markers in cultured normal human skin, which suggests that IL-1 be involved in the initiation of psoriasis.

Key words: Psoriasis, Interleukin-1, Cytokine