Background: Interleukin 18 (IL-18) promoter polymorphisms (-656G > T, -607C > A, and -137G > C) affect serum IL- 18 (sIL-18) levels and are associated with renal injury.
Purpose: This study aimed to determine the diagnostic utility of sIL-18 and urine IL-18 (uIL-18) as biomarkers for acute kidney injury (AKI) and analyse the association of IL-18 polymorphisms to AKI in preterm infants.
Methods: Blood and urine samples were collected from 56 preterm infants with AKI and 56 without AKI to measure serum creatinine (SCr), sIL-18, and uIL-18. Genotyping of polymorphisms was performed and analysed, with AUC-ROCs analysis used to evaluate the diagnostic utility of s-/uIL-18 levels.
Results: The median sIL-18 and uIL-18 levels were significantly higher than those without AKI. For a cutoff of >132 pg/mL, the sIL-18 expression had sensitivity and specificity of 80.36% and 60.71%, respectively, while for uIL-18, a cutoff of >900.7 pg/mL had sensitivity and specificity of 51.79% and 78.57%, respectively. The odds ratio of sIL-18 and uIL-18 to predict AKI in preterm infants was 5.89 (95%CI:2.31-15.02) and 4.15 (95%CI:1.58-10.89), respectively. The polymorphisms -137G > C and -656G > T were significantly associated with sIL-18 expression.
Conclusion: Serum and urine IL-18 levels are risk factors for and a moderate predictor of AKI in preterm infants.
Keywords: Acute renal injury; Polymorphism; Premature; Serum IL-18; Urine IL-18.
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