Predictive Values of Urinary Interleukin 18 and Neutrophil Gelatinase-Associated Lipocalin for Delayed Graft Function Diagnosis in Kidney Transplantation

BACKGROUND Delayed graft function is a main complication after deceased donor kidney transplantation that adversely affects graft outcome. Difficulties in prediction and early detection of delayed graft function have hindered the ability to perform proper therapeutic interventions. We investigated whether measuring urinary interleukin 18 and neutrophil gelatinase-associated lipocalin as markers of ischemia reperfusion injury could predict delayed graft function in deceased donor kidney transplant patients. METHODS We studied 69 patients undergoing kidney transplantation from deceased donor during early October 2013 to December 2014 at the Urology Research Center, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran. Serial urine samples at 2, 24, and 48 h after transplantation were analyzed for interleukin 18 and neutrophil gelatinase-associated lipocalin levels. RESULTS Thirteen patients (18.9%) developed delayed graft function. Urine interleukin 18 to urine creatinine ratio was significantly higher in patients with delayed graft function compared to those with non-delayed graft function, at 2 (P=0.003), 24 (P<0.001) and 48 h (P=0.018) points. The levels of neutrophil gelatinase-associated lipocalin to urine creatinine ratio were significantly higher in the group with delayed graft function at the 24 (P=0.004) and 48 h (P=0.015) points. The receiver-operating characteristic curve analysis suggested that both urinary biomarkers at 24 h after transplantation had better accuracies for prediction of delayed graft function. In multivariate analysis, only urinary interleukin 18 to urine creatinine ratio improved the ability of clinical model for predicting delayed graft function. CONCLUSION Urinary interleukin 18 to urine creatinine ratio at 24 h post-transplantation, along with traditional markers such as relative fall in serum creatinine, urine output and other risk factors for delayed graft function, increased the ability to predict delayed graft function.