Objectives: Genetic variations of the inflammatory IL-8 and TNF-alpha genes can influence the outcome of gastric alterations. Our aims were to determine the prevalence and effect of the T-251A functional polymorphism of IL-8 and the G-308A polymorphism of TNF-alpha in histological and macroscopic gastric diseases related to Helicobacter pylori infection.
Methods: Genomic DNA was extracted from biopsy samples from patients with gastritis (n=86, H. pylori positive=41), atrophy (n=32, H. pylori positive=13), intestinal metaplasia (IM) (n=43, H. pylori positive=22) and from histologically negative patients (n=57). The samples were divided by macroscopic diagnosis into erosion and negative groups. The T-251A polymorphism was examined with the amplification refractory mutation system method; the G-308A polymorphism was determined by the polymerase chain reaction-restriction fragment length polymorphism method. For statistical evaluation, Fischer's exact test was used.
Results: In the case of T-251A of IL-8, the frequency of the A/A genotype was significantly increased in gastritis (P=0.049) and IM (P=0.038) groups as compared with the histologically negative ones. No relationship was found between macroscopic erosions and H. pylori infection. In the case of G-308A, the G/G genotype frequency was statistically increased in erosions as compared with negative groups (P=0.035). No difference in the distribution of G-308A genotypes in relation to histological alterations and the H. pylori infection was observed.
Conclusions: The effect of the polymorphism of IL-8 seems to be relevant in the pathogenesis of histological gastritis and IM, and the effect of the polymorphism of TNF-alpha is relevant in the pathogenesis of macroscopic erosive gastritis.