[Adhesion molecules: their potential implication for dermatology].

Many biological events involve an initial stage of adhesion. The molecules that are responsible for the process of adhesion have been studied extensively in recent years. The most widespread receptors taking part in cell-external matrix and cell-cell reactions are from the families of integrins and immunogloblins. In normal skin, the keratinocytes and fibroblasts essentially express beta 1 (VLA) receptors and the cells of Langerhans the beta 2 receptors of the integrin family. Their pathological modification is under study. In contrast, involvement of the ICAM-1 molecule (ligand of receptor LFA-1) in pathology seems to be considerable. ICAM-1 is expressed by keratinocytes in many benign and malignant skin diseases and this makes possible interaction with LFA-1 lymphocytes. The passage of lymphocytes towards the epidermis is the basis of all inflammatory and immune reactions and is dependent on adhesion molecules. It will doubtless, in the future, be possible to explain the physiopathology of inflammatory skin reactions in terms of excessive expression or insufficient ICAM-1 by pathological keratinocytes.