Epithelial-to-mesenchymal transition predicts cyclosporine nephrotoxicity in renal transplant recipients.

Maintenance immunosuppression with cyclosporine A (CsA) can cause nephrotoxicity in renal transplant recipients. Identifying patients at increased risk for CsA nephrotoxicity may allow interventions to prolong graft survival. Here, we studied the effect of early CsA withdrawal or maintenance among 96 kidney recipients at risk for interstitial fibrosis and tubular atrophy (IF/TA) on the basis of tubular expression of vimentin and β-catenin in a protocol biopsy performed 3 months after transplant. In this retrospective analysis of biopsies collected during a randomized trial of early withdrawal of CsA or mycophenolate mofetil, the semiquantitative score of early phenotypic changes suggestive of epithelial-to-mesenchymal transition (EMT) progressed with time among those maintained on a CsA-containing regimen. EMT-positive grafts displayed a significantly higher IF/TA score and greater progression of the IF/TA score at 12 months (P=0.001 and 0.008, respectively). EMT-positive grafts exposed to CsA also had a greater decrease in estimated GFR compared with EMT-negative grafts exposed to CsA and EMT-positive grafts withdrawn from CsA exposure. Multivariable analysis revealed that the presence of EMT was an independent risk factor for a 10% decline in graft function up to 4 years posttransplant (odds ratio 4.49; 95% confidence interval 1.02 to 19.9). Collectively, these data demonstrate that changes consistent with EMT are strong prognostic biomarkers in renal transplant recipients exposed to CsA.