Lack of correlation of vacA genotype, cagA gene of Helicobacter pylori and their expression products with various gastroduodenal diseases

Abstract:Objective To investigate the correlation among vacA genotypes, cagA gene, VacA, serum CagA antibodies of Helicobacter pylori (H. pylori) and gastroduodenal diseases. Methods vacA genotypes and cagA gene of 62 H. pylori strains isolated from patients with chronic gastritis, peptic ulcer and gastric cancer were tested by polymerase chain reaction, and Hela cell assay for VacA activity in vitro. Serum CagA antibodies were measured by EIA method in the same patients.Results All 62 H. pylori strains possessed the vacA gene and vacA genotypes of all strains were type s1a/m2. Total positive rate of cagA gene was 56.45%; the positive rates of cagA gene of H. pylori strains isolated from patients with chronic gastritis, peptic ulcer and gastric cancer were 55.56%, 54.17% and 63.64%, respectively (P>0.05). The total positive rate of VacA was 37.10%; the positive rates of VacA produced by H. pylori strains isolated from patients with chronic gastritis, peptic ulcer and gastric cancer were 33.33%, 29.17% and 63.64%, respectively (P>0.05). The positive rates of CagA antibodies in patients with chronic gastritis, peptic ulcer and gastric cancer were 70.37%, 79.17% and 40.00%, respectively (P>0.05). The total positive rate of CagA antibodies was 68.85%.Conclusion There was no correlation among cagA gene and vacA genotypes of H. pylori, VacA, serum CagA antibodies and various gastroduodenal diseases.