Background: Secretor ( Se) and Lewis ( Le) genes are involved in the synthesis of Lewis b (Le(b)) and type I antigens throughout the body, especially in the epithelial cells of gastric mucosa. Helicobacter pylori can attach to the gastric epithelial cells with the blood group antigen-binding adhesin, which binds to Le(b) or H type I carbohydrate structures. In a previous study, a marked association between H. pylori seropositivity and polymorphism of the Se and Le genes was observed among Japanese outpatients of a gastroenterology clinic. The present work aims to investigate the associations between Se and Le gene polymorphisms and H. pylori infection among Japanese-Brazilians.
Methods: The subjects consisted of 942 healthy volunteer Japanese-Brazilians, who were tested for the presence of anti- H. pylori IgG antibodies and genotyped for Se and Le polymorphisms.
Results: The sex-age-adjusted odds ratios (aORs) for H. pylori seropositivity were 0.99 for the Sese genotype relative to the SeSe genotype (95% confidence interval [CI], 0.73-1.33), and 1.03 for sese relative to SeSe (95% CI, 0.71-1.48). On the other hand, the aOR for the subjects with the le allele ( Lele or lele) relative to the LeLe genotype was 1.48 (95% CI, 1.07-1.79). When the Se and Le genotypes were analyzed in combination according to risk group, no statistically significant association was observed.
Conclusions: These results are inconsistent with previous work and may have been modulated by an external factor or some other unidentified factor. Japanese-Brazilians are genotypically the same as Japanese, but their lifestyle is adapted to that of Brazil. Further investigations are necessary to clarify this influence on susceptibility to H. pylori infection.