To further develop personalized medicine in kidney transplantation and improve transplant patient outcomes, attention has been given to define early surrogate endpoints that might aid therapeutic interventions, and help clinical decision-making. To adequately predict transplant patients' individual risks of allograft loss and patients' complications, this would require a complex integration of data, including: donor data, recipient characteristics, transplant characteristics, biopsies results, immunosuppressive regimen, allograft infections, acute kidney injuries, recipient immune profiles, protocol and per cause biopsies and imaging (PET/CT imaging). This project aims: 1. Assessed the usefulness of 18F-FDG PET/CT imaging in kidney transplantation recipients presenting with suspected acute rejection who underwent a transplant needle biopsy; 2. To develop a prognostic risk score to predict kidney allograft survival; 3. To evaluate the impact of corticoids withdrawal on long term outcomes (risk of rejection and impact on bone mineral density); 4. Evaluate the type and the frequencies of complications in our kidney transplant population