Urine Level of Interleukin-8 as a Non-Invasive Marker for Diagnosis of Vesicoureteral Reflux in Children

摘要

The objective of this study is to assess the urinary levels of IL-8 as a noninvasive marker of VUR in children after resolution of acute UTI. The study was conducted over a 6 month period on 45 children, aged 1-5 years. They were suffering from symptoms of UTI and attending the Pediatric Outpatient and Urology Clinic at Pediatric Specialized Hospital. These children underwent renal ultrasonography (RUS) and voiding cystourethrography (VCUG).The patients were subdivided into two groups: group A (n = 13), children with proven VUR and group B (n = 32), children with negative investigation for VUR. Thirty-nine healthy children with no history of UTI or a known underlying condition that might impair renal function were recruited as control group (group C). Urinary levels of IL-8 were evaluated in all cases using a sandwich enzyme-linked immunosorbant assay for the quantitative measurement of urinary IL-8. To avoid dilution effects, urinary levels of IL-8 were expressed as the ratio of cytokine-to-urinary creatinine. The mean urinary IL-8 levels standardized to the urinary creatinine levels were significantly higher in group A than in group B and C (p-value0.05). A positive correlation was noted between the urinary IL-8/creatinine concentrations and reflux grade (r = 0.338, p-value>0.05). While, no statistical significant difference was observed between the level of urinary IL-8/creatinine and age and sex of the patients and RUS abnormalities. Optimum limit of urinary IL-8/creatinine to establish presumptive diagnosis of VUR obtained by ROC analysis was found to be 10 pg μmol^-1, with sensitivity and specificity of 84.6 and 64.8%, respectively. This study demonstrates that urinary IL-8 levels are higher in children with VUR even in the absence of UTI and that it may be considered as an effective noninvasive marker for screening of VUR with high sensitivity and adequate specificity.