[Adhesion molecules and inflammatory dermatoses]

In inflammatory dermatoses, adhesion molecules are involved in the interaction of leukocytes with endothelial cells, extra-cellular matrix and epidermal cells. In dermatosis where epidermal cells are the main targets of inflammation, the keratinocytes are activated and participate to the local immune reaction through the secretion of cytokines and the expression of the adhesion molecule ICAM-1 and the HLA-DR antigens. Induction of ICAM-1 by IFN gamma or TNF alpha on keratinocytes that do not express this molecule in normal skin may account for the recruitment of T cells into the epidermis. In the dermis, an up-regulation of ICAM-1 expression occurs on endothelial cells activated by cytokines (IL-1, TNF alpha...) and is usually correlated with an induction of ELAM-1 and less frequently VCAM-1. These adhesion molecules are involved in the recruitment of inflammatory cells but also in the control of their retention and migration through the skin.