The Immunohistochemical Expression of the Von Willebrand Factor: A Potential Tool to Predict Kidney Allograft Outcomes.

Few reports assessed endothelial activation biomarkers in kidney allograft biopsies using immunohistochemistry. This retrospective cohort study evaluated the association between posttransplant outcomes and the immunohistochemistry expression of Caveolin-1, Von Willebrand Factor (Vwf), and T-Cadherin in for-cause biopsies diagnosed as interstitial fibrosis and tubular atrophy of unknown etiology. Samples with antibody-mediated changes were excluded. The patients were followed for 3 years after the biopsy or until graft loss/death. Seventy-one (71) samples from 66 patients were included. Eighteen (25.4%) patients lost their grafts, mainly due to chronic rejection (33.3%). Caveolin-1 and T-Cadherin were not associated with graft loss. Vwf had good accuracy in predicting graft failure (AUC 0.637, 95% CI 0.486 to 0.788 P =0.101). The presence of more than 10% of Vwf positivity in the microvasculature (Vwf >10%) was associated with reduced death-censored graft survival (58.2% vs. 85.4% P =0.006), and this result was also observed in the subgroup presenting mild interstitial fibrosis (ci=1) (65.7% vs. 88.6% P =0.033). The multivariate analysis showed that Vwf >10% was an independent risk factor for graft loss (HR=2.88, 95% CI 1.03 to 8.02 P =0.043). In conclusion, Vwf might be an additional tool to predict allograft outcomes in kidney transplant recipients with interstitial fibrosis and tubular atrophy of unknown etiology, probably reflecting immune endothelial activation.