With the use of potent immunosuppressive agents immediately following and in the maintenance phase after renal transplantation, the incidence of acute rejection, generally defined as rejection within the first year following transplantation, has fallen dramatically over time. With current immunosuppressive protocols, acute rejection rates have fallen to approximately 10 percent at most transplant centers [1,2].
When acute rejection occurs, it is an important clinical problem. As an example, the relative risk for transplant failure associated with an acute rejection episode has increased from 1.7 in 1988 to 5.2 in 1997 .
Early episodes (occurring within 60 days of engraftment) may have a major effect on allograft survival. Some of these kidneys will not regain function, even with maximal antirejection therapy. Kidneys that recover function may still have a decreased survival when compared with rejection-free kidneys, especially if the serum creatinine concentration does not return to near baseline levels.
Acute rejection episodes are also the major predictor of the occurrence of chronic allograft nephropathy, which is responsible for most death-censored graft loss after the first year. (See "Chronic renal allograft nephropathy", section on 'Importance of acute rejection'.)
The treatment of acute rejection of the renal allograft will be reviewed here. The diagnosis of acute rejection is discussed separately. (See "Clinical manifestations and diagnosis of acute renal allograft rejection" and "C4d staining in renal allografts and treatment of antibody-mediated rejection".)