Urine interlukein-8 as a diagnostic test for vesicoureteral reflux in children.

BACKGROUND: Vesicoureteral reflux (VUR) is a common finding in children with urinary tract infection (UTI), mostly diagnosed by voiding retrograde cystogram (VCUG). Children with VUR are at higher risk of renal damage with recurrent infections. Detecting VUR and renal scarring currently depends on imaging modalities with interventional invasive diagnostic methods. Noninvasive methods would greatly facilitate diagnosis and also help in identifying VUR in siblings of index cases who should be screened. Various imaging and biochemical methods with different specificity and sensitivity have been presented as substitute diagnostic tool for VCUG to identify VUR. Interleukin-8 (IL-8), a chemokine produced by damaged epithelial cells of the renal tract in response to inflammation, has been shown to increase during acute UTI. We have scarce data considering the cut point of urine IL-8 as a diagnostic method of VUR in children. The objective of this study was to assess the urine levels of IL-8 as a noninvasive marker of VUR in infants in the absence of a recent UTI episode.

METHODS: This cross sectional study was conducted on28 patients with UTI and VUR (group 1), 28 patients with VUR and without UTI (group 2), and 28 healthy children/infants(control group)in St. Alzahra hospital, Esfahan, from January 2009 until March 2010.. Urine IL-8 level was measured for all children. The data was analyzed by SPSS soft ware version 17. The t-student test, ?2, and ANOVA were used as statistical method.

RESULTS: The mean age of group 1, group 2 and control group were 4.3 +/- 2.9, 4 +/- 2.6 and 4 +/- 2.1 years respectively, p > 0.05. The mean level of IL-8 in group 1 was significantly higher than group 2 and control group 10 +/- 14.8 versus 6.5 +/- 8.4, and 2.9 +/- 4.5 respectively (P = 0.039).

CONCLUSIONS: Although urinary IL-8 may be helpful in determining high grade VUR, but the results of this study showed that the sensitivity, specificity, PPV, and NPV of this marker were not satisfactory in cutoff point of 5 pg/pmol and other variables must be controlled.