Transplant Immunobiology

When a solid organ is transplanted from a nonidentical individual into a recipient, several actors start to play a role to develop an immune response aiming at getting rid of the foreign tissue. This response is called “allorecognition” and involves cells belonging to the recipient’s immune system and to the graft, interacting in a process ultimately evolving to rejection if not properly prevented pharmacologically. Some events occur before donation and induce pro-inflammatory asset of the vascular tree of the organ, The ischemic phase further amplify the inflammatory asset of endothelial cells which represent the first contact site between donor and recipient. Both professional and non-professional antigen presenting cells are recruited to present the graft antigens, as whole molecules or processed, to the lymphoid cells and start the adaptive immune response. Multiple cellular components of the graft and the recipient participate in allorecognition and from the comprehension of these mechanisms new drugs are continuously proposed to modify the phenomenon and allow the long term tolerance of the foreign transplanted organ.