The endothelium and early immune activation:: New perspective and interactions

Far from being just a membrane for the passive transport of cells, molecules, and water between blood vessels and their interstitium or a passive target for humoral immunological reactions, the endothelium is now being viewed as an active modulator of both normal physiological homeostasis and the early inflammatory response. The repertoire of receptors and mediators produced by endothelial cells overlap those traditionally assigned to the immune system. This new paradigm together with the changes caused by brain death in the cadaver donor have far-reaching repercussions on how rejection is conceived, while opening new venues for its prevention. The respective theoretical roles of the neuroendocrine-immunological axis and of syndecans are highlighted.