In chronic inflammatory diseases, such as psoriasis, Thy-1/CD90 is highly expressed in skin lesions, and experiments performed with polymorphonuclear (PMN) cells from psoriatic patients have shown that Thy-1/CD90 is involved in the process of adhesion of these cells to activated endothelial cells in an αMβ2 integrin (CD11b/CD18; Mac-1)-dependent manner (Wetzel et al., 2006). This evidence concerns the gene THY1 and psoriasis.