INTRODUCTION AND OBJECTIVES: Vesicoureteral reflux (VUR) is a common finding in children with urinary tract infection (UTI) and/or prenatal diagnosis of uropathy. Voiding cystourethrography (VCUG) performed for the evaluation of VUR may result invasive, not existing currently biochemical markers as a method of screening. A recent study suggests that children less than two years old with VUR maintain high urinary concentrations of interleukins (IL), remaining a question whether this also happens in older children. Other factors such as degree of reflux or coexistence of nephropathy and other inflammatory diseases have not been evaluated to date. Objective: To assess the usefulness of detection of IL-1 beta, IL-6 and IL-8 urinary levels for the diagnosis of VUR in children.

METHODS: Case-Control study in children less than 14 years old who underwent a VCUG. Concentrations of IL-1 beta, IL-6 and IL-8 related to creatinine levels (pg/µmol) have been determined in urine samples obtained at the time of VCUG. Forty cases were selected among children diagnosed of any degree of VUR and 80 controls in a sampling by density with individual pairing 1:2 by age among children without evidence of VUR in VCUG.

RESULTS: Sixty two patients were males and fifty eight females, with a mean age of 2,4 years (range: 0-11,5 years). Indications for VCUG were previous UTI in 78 cases (65%), prenatal diagnosis of uropathy in 24 cases (20%), postnatal diagnosis of uropathy in 16 cases (13,4%) and family history of urinary malformations in 2 cases (1,7%). No significant difference was observed between cases and controls in IL-1 beta/creatinine and IL-6/creatinine levels. However, IL-8/creatinine levels were almost- significant higher in case group (median 3,5 pg/µmol; SD 9) than in control group (median 1,6 pg/µmol; SD 3) (P=0,008). A significant correlation for IL-8/creatinine levels was observed between cases and controls (P=0,002) when comparing low (I, II) and high (III, IV and V) grades of VUR.

CONCLUSIONS: According to our study, urinary levels of IL-8/creatinine are elevated in children with high grade VUR, even in absence of UTI. We have not found utility in the determination of IL-1 beta and IL-6 for the diagnosis of VUR. Elevated levels IL-8/creatinine can be valuable as non-invasive marker not only for the initial screening of high-grade VUR, but to diagnose persistent reflux after failed treatment of VUR.

Source of Funding: Grant PI077057, Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III, Fondo de Investigación Sanitaria.