Despite progressive improvement in the early outcome of solid organ transplants, their long-term rate of success remains limited, primarily by chronic rejection and patient death. Although the pathogenesis of chronic rejection is not completely understood, two major types of risk factors have been identified. The most important are immunological, related to genetic differences between donor and recipient and orchestrating a cascade of interrelated events which include the interaction between the major histocompatibility complex (MHC) antigens and T lymphocytes, the influence of co-stimulatory molecules, the activation of different leukocyte populations and the differential regulatory roles of cellassociated chemokines and other inflammatory molecules.

Keywords: adhesion molecules, oxygen-free radicals, polymorphonuclear luekocytes, Organ Transplantation