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

1. The detection of acute rejection in kidney transplant recipients, depends critically on assessments of serum creatinine, an insensitive measure of renal injury and the diagnosis relies on renal transplant needle biopsy which is an invasive procedure associated with a significant risk of bleeding and graft loss and is limited by sampling error and/or interobserver variability. Moreover, repeated biopsies to evaluate a renal graft's status pose challenges, including practicability and cost. Consequently, other sensitive and less invasive modalities, including gene expression profiling and omic analyses of blood and urine samples as well as in vivo imaging, are currently under investigation to reinforce our clinical armamentarium for acute rejection diagnosis. Likewise, it would be useful to non-invasively predict rejection in kidney transplant recipients with acute renal dysfunction and suspected acute rejection, thereby avoiding unnecessary transplant biopsy.
2. This study aims to generate a scoring system that predicts individual patients' risk of long-term kidney allograft failure.
3. Since 2007, the protocol in our institution is to withdraw the corticoids after 3 months after the protocol biopsy if no sign of rejection is demonstrated. We would like to evaluate the impact of such decision in the risk of rejection and the long-term allograft outcome in our patients. We are looking also to the impact on bone mineral density after corticoids withdrawal in those patients.
4. Evaluate the type and the frequencies of complications in our kidney transplant population to adapt our daily basis clinical practice.

Inclusion Criteria:

• Kidney recipient transplanted after 2007
• Kidney recipient over 18 years of age
• Clinical, biological, immunological and follow up data available

Exclusion Criteria:

• Combined transplantation

Kidney recipients aged over 18 of all sexes recruited between 2007 and 2020 from the Centre Hospitalier Universitaire of Liege, who have e-GFR follow-up and data from protocol and for cause biopsies available at 1-year post transplant. PET/CT imaging will be performed with patient's approval for protocol and per cause biopsies we performed. Data will be collected in the follow up such as clinical, biological and histological data.