Chronic rejection: an enduring enigma of transplantation biology.

Renal transplantation has achieved reasonably good success over the years in controlling acute rejection episodes; however, the immunology of chronic rejection is still not well understood. The problem haunts transplanters across the globe. We describe the presentation, brief immunopathological events, and recent advances suggested by pathologists to define chronic rejection and differentiate it from chronic allograft nephropathy. Our experience using tolerance induction is briefly mentioned including a reduced incidence of acute rejection episodes, chronic rejection events, or calcineurin inhibitor toxicity using lower drug levels.