The association of cytokine gene polymorphism with reflux nephropathy

ObjectiveTo identify genetic risk factors for the progression of vesicoureteral reflux (VUR) to reflux nephropathy, we examined polymorphisms of multiple cytokine genes among VUR patients with or without renal scarring.MethodsA total of 238 VUR patients aged between 1 and 18 years with (n = 113) or without renal scarring (n = 125) were included. The presence of renal scarring was demonstrated by renal parenchymal examination using Technetium-99m dimercaptosuccinate scintigraphy. Sera of the patients were examined for tumor necrosis factor-alpha (TNF-α, −308), transforming growth factor-beta1 (TGF-β1, +869, +915), interleukin-6 (IL-6, −174), interleukin-10 (IL-10, −1082, −819, −592) and interferon-gamma (IFN-γ, +874) gene polymorphisms using the polymerase chain reaction sequence-specific primer method.ResultsAmong patients with renal scarring, frequencies for the T/T G/C and C/C G/C genotypes of TGF-β1 gene (p = 0.003), GCC/GCC genotype of IL-10 gene (p = 0.015), GC phenotype of IL-6 gene (p = 0.001) and T/T genotype of IFN-γ gene (p = 0.001) were higher compared to patients without renal scarring. Regarding the TNF-α gene, among patients with low grade VUR only, the G/G genotype was associated with an increased risk.ConclusionsCertain genotypes of cytokine gene polymorphisms seem to be associated with an increased or decreased susceptibility to reflux nephropathy, which may explain why only a proportion of VUR patients progress to reflux nephropathy. This information may aid in prediction of prognosis and implementing more aggressive management strategies at earlier stages. Further immunogenetic studies may identify novel targets for the management and prevention of the condition.