Increasing amounts of older recipients are listed for transplantation. Several clinical trials have therefore been initiated recently using age-adapted immunosuppressive regimens. Preliminary data in an "old-for-old" kidney transplant program at our center suggest that the approach favouring reduced immunosuppression in aged subjects might not be the best choice. We performed an experimental study to investigate the effects of donor and recipient age on renal allograft outcome and age associated alterations of the immune response. Modifications of the immune response in older recipients were associated with increased amounts of memory and alloreactive T-cells and an altered cytokine response. Recipient age dependent immune responses contributed to an acceleration of chronic graft deterioration, so that recipient age may need to be considered as a separate and independent risk factor. Although our experimental data need to be confirmed clinically, they suggest a modified and age-adapted immunosuppression in elderly recipients during the early posttransplant period.