Lack of association of IL8 gene polymorphisms with familial vesico-ureteral reflux

Vesico-ureteral reflux (VUR) is the most common inherited disorder of the lower urinary tract. Children with VUR are at risk for ongoing renal damage with subsequent infections. IL8 is an important inflammatory mediator which can be produced by epithelial cells of the renal tract in response to a variety of inflammatory stimuli. High serum concentrations of IL-8 have been reported in patients with chronic renal failure. Elevated IL-8 levels have been reported in the urine of patients with VUR and renal parenchymal scarring (RPS). More recently it was reported that urine IL-8 levels remain elevated in infants with VUR even in the absence of a urinary tract infection (UTI). Increased IL-8 expression has been shown to be associated with polymorphism at position -251 (rs4073) of the IL-8 promoter. The aim of this study was to examine the association of IL-8 gene polymorphism with familial VUR in a cohort of 219 siblings from 109 families affected with VUR, the largest such cohort tested to date. RPS was assessed using dimercaptosuccinic acid scintigraphy. Genotyping was performed in 219 siblings with VUR (157 without RPS, 62 with RPS) and 292 controls for the position -251 of IL-8 gene by polymerase chain reaction with tetra primers and gel analysis. Genotype was compared using the chi square test. Statistical significance was taken as a value of P < 0.05. There were no significant differences in IL-8 -251 genotype frequency between VUR patients and controls. Similarly, gender, severity of VUR and renal parenchymal scarring had no effect on IL-8 -251 genotype frequency. Although IL-8 urinary levels have been reported to be elevated in VUR, our data indicate that IL-8 gene is not involved in the pathogenesis of familial VUR or reflux nephropathy.