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

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 wit h chronic gastritis, peptic ulcer and gastric cancer were tested by polymerase c hain reaction, and Hela cell assay for VacA activity in vitro.Serum CagA antib odies were measured by EIA method in the same patients. Results All 62 H.pylori strains possessed the vacA gene and vacA genotypes of all stra ins were type s1a/m2.Total positive rate of cagA gene was 56. 45%; the positiv e rates of cagA gene of H.pylori strains isolated from patients with chron ic g astritis, peptic ulcer and gastric cancer were 55. 56%, 54. 17% and 63. 64%, res pectively (P>0. 05).The total positive rate of VacA was 37. 10%; the posit i ve rates of VacA produced by H.pylori strains isolated from patients with chro nic 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% a nd 40. 00%, respectively (P>0. 05).The total positive rate of CagA antibod ies was 68. 85%. Conclusion There was no correlation among cagA gene and vacA genotypes of H.pylori, V acA, serum CagA antibodies and various gastroduodenal diseases.