Serum Neutrophil Gelatinase-Associated Lipocalin and Interleukin-18 as Predictive Biomarkers for Delayed Graft Function After Kidney Transplantation

Background: Early biomarkers for acute kidney injury after kidney transplantation have been studied because delayed graft function (DGF) is associated with increased risk of acute rejection and graft loss. We investigated the usefulness of serum neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) for the prediction of DGF after kidney transplantation. Materials and Methods: Fifty-nine kidney transplant recipients were included and they were separated into DGF and immediate graft function (IGF) groups. Serum samples were collected on the preoperative day as well as days 1, 5, and 14 after the transplantation, and assayed for NGAL and IL-18. Results: After transplantation, serum levels of NGAL were significantly higher at any time in patients with DGF compared to those with IGF. Serum concentrations of IL-18 were not different between both groups. The receiver operating characteristics(ROC)-area under the curve (AUC) values of NGAL, IL-18, and creatinine on day 1 for the discrimination of DGF from IGF were 0.86, 0.63, and 0.65. On POD1, the sensitivities of NGAL and creatinine were respectively 78.6%, and 50.0% at 77.8% specificity, and the AUC values for any combinations including NGAL and that for NGAL alone were higher than that of creatinine. Conclusion: Serum NGAL is an early and sensitive marker of graft dysfunction in kidney transplantation, while serum IL-18 showed limited values.