Early prediction of renal graft function: Analysis of a multi-center, multi-level data set.

PURPOSE OF THE STUDY: Long-term graft survival rates after renal transplantation are still poor. We aimed to build an early predictor of an established long-term outcomes marker, the estimated glomerular filtration rate (eGFR) one year post-transplant (eGFR-1y). MATERIALS AND METHODS: A large cohort of 376 patients was characterized for a multi-level bio-marker panel including gene expression, cytokines, metabolomics and antibody reactivity profiles. Almost one thousand samples from the pre-transplant and early post-transplant period were analysed and employed for machine learning-assisted prediction. RESULTS: Pre-transplant data led to a prediction achieving a Pearson's correlation coefficient of r=0.38 between measured and predicted eGFR-1y. Two weeks post-transplant, the correlation was improved to r=0.63, and at the third month, to r=0.76. eGFR values were stable throughout the first post-transplant year. Several characteristics were predictive for eGFR, including age of donor and recipient, body mass index, HLA mismatch, cytomegalovirus mismatch and valganciclovir prophylaxis. Additionally, a subset of 19 nuclear magnetic resonance bins of the urine metabolome data was shown to have potential applications in non-invasive eGFR monitoring. Importantly, we identified the expression of the genes TMEM176B and HMMR as potential prognostic markers for changes in the eGFR after the second post-transplantation week. CONCLUSIONS: Our multi-center, multi-level data set represents a milestone in the efforts to predict transplant outcome. While an acceptable predictive capacity was achieved, we are still far from predicting changes in the eGFR precisely. Additional studies employing further marker panels are needed to establish predictors of eGFR-1y for clinical application; herein, gene expression markers seem to hold the most promise.

Risk factors for Epstein-Barr virus reactivation after renal transplantation: Results of a large, multi-centre study.

Epstein-Barr virus (EBV) reactivation is a very common and potentially lethal complication of renal transplantation. However, its risk factors and effects on transplant outcome are not well known. Here, we have analysed a large, multi-centre cohort (N = 512) in which 18.4% of the patients experienced EBV reactivation during the first post-transplant year. The patients were characterized pre-transplant and two weeks post-transplant by a multi-level biomarker panel. EBV reactivation was episodic for most patients, only 12 patients showed prolonged viraemia for over four months. Pre-transplant EBV shedding and male sex were associated with significantly increased incidence of post-transplant EBV reactivation. Importantly, we also identified a significant association of post-transplant EBV with acute rejection and with decreased haemoglobin levels. No further severe complications associated with EBV, either episodic or chronic, could be detected. Our data suggest that despite relatively frequent EBV reactivation, it had no association with serious complications during the first post-transplantation year. EBV shedding prior to transplantation could be employed as biomarkers for personalized immunosuppressive therapy. In summary, our results support the employed immunosuppressive regimes as relatively safe with regard to EBV. However, long-term studies are paramount to support these conclusions.