title: [Destruction of the allograft].
abstract: Allograft rejection is an immunological process which appears as a two-step phenomenon: during the first step, alloantigens are recognized as foreign, or "non-self", and production of "killer agents" is initiated. During the second step, the target organ is invaded by these killer agents and destroyed. Recognition, attack and destruction of the target are the different phases of rejection step II, and its clinical and/or pathological expression is generally referred to as a rejection episode. There is only one mechanism leading to the destruction of the allograft. However, its clinical or pathological expression can vary according to its severity and to the predominance of one of the effector agents (antibody or cytotoxic cell). Although permanent, the rejection process usually progresses in a wave motion; first waves are sharp and severe, but with time they become smoother and less severe. Rejection episodes are, therefore, generally described as hyperacute, acute and chronic. Endothelial cells of the allograft arteries are the main target although all the various histological structures of the graft can be injured. Immuno-suppressive agents as well as good histocompatibility can drastically modify both the course of rejection and its expression.
mesh_terms: D000208:Acute Disease; D002908:Chronic Disease; D006084:Graft Rejection; D006801:Humans; D007668:Kidney / Q000276:immunology / Q000473:pathology; D016030:Kidney Transplantation; D014184:Transplantation, Homologous
vernacular_title: La destruction de l'allogreffe.