Abstract: Objective To study the effects of TNF-αand sTNFRⅠon IL-8 production and proliferation of psoriatic keratinocytes.Methods In vitro cultured keratinocytes were treated with TNF-α,sTNFRⅠand anti-TNFRⅠ.IL-8 levels in supernatants were me asured by enzyme-linked immunosobent assay.Expression of IL-8 mRNA in keratinocytes was observed by semiquantitive RT-PCR and Southern blotting.Proliferation index was measured by MTT colorimetry.Results IL-8 levels,mRNA expression and proliferation index were significantl y higher in psoriatic patients than those in control group(P<0.05).IL-8 production and proliferation index of keratinocytes were significantly h igher in TNF-αtreated group than those in control group(P<0.05).No significant difference was found in IL-8 production and keratinocyte proliferation between sTNFRⅠ/anti-TNFRⅠ/TNF-αtreated group and control group.Conclusions Activated keratinocytes secrete ab undant cytokines crucial to the development of psoriatic lesions.By binding to TNFRⅠrather than TNFRⅡon the membrane surface,TNF-α enhances IL-8 production and proliferation of keratinocytes,and sTNFRⅠpartly neutralizes functions of TNF-α.

Key words: Psoriasis, Tumor necrosis factor, Interleukin-8, Keratinocyte