[Role of endothelial activation in urticaria]

The endothelial cells, because of their privileged situation between the tissues and the vessels, play an important role in the inflammatory reaction. Expression of adhesion molecules (ELAM 1 especially) allows adhesion of circulating neutrophils to the epithelial cell and thus initiates the reaction. During the reactions of immediate hypersensitivity, the flow of leucocytes observed in the late phase is dependent on mastocytes, the recruitment being under the positive or negative influence of several cytokines.