IL-8 is a chemotactic cytokine with proinflammatory and growth promoting activities. Recently it has been shown to influence several functions of keratinocytes, including HLA-DR expression, chemotaxis and proliferation by binding to a specific receptor. Since psoriasis vulgaris is characterized by epidermal hyperproliferation and infiltration of inflammatory cells, we investigated the expression of IL-8 and its receptor in normal and psoriatic epidermis using semiquantitative reverse-transcriptase-PCR. In addition the mRNA levels of the protooncogenes c-ras, c-raf, c-myc and HER-2 were also investigated as potential growth promoting stimuli in psoriatic epidermis. IL-8 mRNA was only detected in lesional psoriatic epidermis, and IL-8R specific mRNA was found to be ten times increased in lesional psoriatic epidermis. There was no significant difference in the protooncogene mRNA levels. In order to test the relevance of the massively increased IL-8 receptor levels in psoriatic epidermis, we investigated the effect of the antipsoriatic drug FK-506 on specific IL-8 and IL-8 receptor mRNA expression. FK-506 dose dependently inhibited IL-8 receptor expression and function. Our data suggest that in psoriatic skin, elevated IL-8 levels and markedly increased IL-8 receptor expression may act in concert to induce the cardinal signs of psoriasis - epidermal hyperproliferation and leukocyte infiltration. IL-8 receptor may prove a molecular target for antipsoriatic drugs such as FK-506.
|Number of pages||14|
|Publication status||Published - Dec 1 1994|
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