Significant impact of +105 A>C promoter polymorphism in IL-18 cytokine in patients with kidney stone disease.

Background: Inflammation may be one cause of nephrolithiasis and the interleukin-18 (IL-18) encoding gene   polymorphisms at +105 A>C has been implicated in several inflammation related diseases. The aim of this study was to test whether IL-18+105 A>C polymorphisms could act as genetic marker for renal stone disease. A case-control study was conducted to observe the genotype distribution of IL-18+105 A>C, to elucidate the possible role of this SNP as risk factor in renal stone development and to examine its correlation with the clinico-pathologic variables. Methods: Using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique, we tested the genotype distribution of 160 nephrolithiasis patients in comparison with 200 disease free controls from the same geographical region. Results: We observed significant differences of IL-18+105 A to C between the controls and patients with odds ratio 5.4 (P = 0.001). The prevalence of the variant genotypes AC + CC in the patients was higher than that in the controls (45% v/s 30%) and showed a significant association (P = 0.003). Moreover, the frequency per copy of the C allele of IL-18+105 A>C was found to be implicated more in patient group 0.27 as against only 0.16 in controls (P = 0.0003). Further, males and subjects with C is implicated in renal stone disease, and that the rare, C related allele is connected with higher susceptibility to nephrolithiasis.