The biology of allograft rejection

Organ transplantation is the treatment of choice for patients with several end-stage renal diseases. Despite improvements in immunosuppression and posttransplantation management of patients, allograft rejection remains a problem. In this review, we focus on the recent advances in molecular biology that have provided new opportunities to explore questions regarding the mechanisms of allograft rejection. We have concentrated on antigen presentation and the role of the direct and indirect pathway in allorecognition; effector mechanisms; adhesion molecules and lymphocyte homing; and the role of cytokines in regulating the different steps of rejection.