Purpose: We established whether the urinary cytokines interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha and soluble TNF receptor-1 have a role as noninvasive markers of renal damage in children with vesicoureteral reflux.
Materials and methods: We performed an observational study in a surgical and urological unit at a pediatric teaching hospital. Urine cytokine levels of IL-6, TNF-alpha and soluble TNF receptor-1 were measured using a standard enzyme-linked immunosorbent assay technique in children stratified into group 1--11 with vesicoureteral reflux and reflux nephropathy, group 2--6 with vesicoureteral reflux only and no associated nephropathy, and group 3--15 age and sex matched controls.
Results: Urinary levels of the cytokines IL-6 and soluble TNF receptor-1 were significantly elevated in group 1 versus group 3 (0.048 to 13.25 pg./micromol. creatinine, mean 3.658 versus 0.027 to 0.677, mean 0.247 and 102.89 to 4,502.9 pg./micromol. creatinine, mean 1,395.3 versus 13.06 to 569.6, mean 145.357, respectively). Neither cytokine in group 2 (0.074 to 10.96 pg./micromol. creatinine, mean 2.94 and 51.52 to 1,115.48, mean 413.137, respectively) was elevated compared to that in group 3. TNF-alpha was not elevated in group 1 or 2 compared to that in group 3 (0.104 to 2.518 pg./micromol. creatinine, mean 0.56, 0.094 to 1.278, mean 0.334 and 0.065 to 0.694, mean 0.241, respectively).
Conclusions: Measuring the urinary levels of the cytokines IL-6 and soluble TNF receptor-1 may be useful as a noninvasive marker of reflux associated renal damage. Further studies with larger patient groups are necessary to locate the source of production of the elevated urinary cytokines measured in our study.