Helicobacter pylori cagA polymorphism and gastric inflammation: An international comparison between Japanese and Brazilian patients

Objective. Gastritis induced by Helicobacter pylori can cause the onset of gastric cancer, and H. pylori cytotoxin associated gene A (cagA) is considered to be an important factor for its development. We investigated the relationship between the grades of gastritis and cagA phenotype in Japanese and Brazilian patients. Material and methods. We studied 47 Brazilian and 47 age-, gender-matched Japanese patients. Status of H. pylori infection, the degree of histologic gastritis, and the levels of serum pepsinogen levels were evaluated. DNA was extracted from paraffin-embedded sections and a portion of the cagA gene was amplified using the polymerase chain reaction, followed by direct sequencing of the fragment. We investigated the cagA subtype using a newly developed restriction fragment length polymorphism (RFLP) system. Results. In H. pylori-positive patients, the grades of histological and serological gastritis were more prominent in the Japanese subjects than their Brazilian counterparts, although no difference was detected in the H. pylori-negative subjects. According to cagA phenotype analysis, our RFLP system was helpful for evaluating cagA phenotype, and we found that the prevalence of the East Asia subtype was significantly higher in the Japanese subjects than in the Brazilian. Conclusion. Infection with H. pylori possessing the East Asian cagA gene contributes to the progression of gastritis.