Expression of endoglin in psoriatic involved and uninvolved skin.

Endoglin is a glycoprotein with TGF-beta binding capacity and is predominantly expressed on endothelial cells. In psoriasis, TGF-beta has appeared to play a role in the extravasation of peripheral blood mononuclear cells via the endothelium. In order to find out more about the role of endoglin in psoriasis, immunohistochemical staining with PN-E2, a novel anti-endoglin, and of PAL-E, recognizing vascular endothelium, was carried out in psoriatic involved, psoriatic uninvolved and normal skin. The expression of the antigens was assessed semi-quantitatively using a five-point scale. In psoriatic involved skin, a high endoglin expression was found. In psoriatic uninvolved skin, however, we found that endoglin expression was significantly decreased compared with normal skin. The relevance of these findings to the pathogenesis of psoriasis is discussed.