Association of CagPAI integrity with severeness of Helicobacter pylori infection in patients with gastritis

Background and aim

The Helicobacter pylori cag pathogenicity island (cagPAI) is involved in delivery of CagA effector protein and peptidoglycan into host cells and also in IL-8 induction in the human gastric tissue. Diversity of cagPAI may affect disease status and clinical outcome of the infected patients. Our study was aimed to investigate diversity of this island and its intactness in Iranian patients to investigate possible associations between cagPAI integrity and pathological changes of the infected tissue.

Material/Patients and methods

Out of the 75 patients, H. pylori strains were obtained from 30 patients with severe active gastritis (SAG) (n = 11), moderate chronic gastritis (CG) (n = 14) and intestinal metaplasia/dysplasia (IM) (n = 5). Intactness of the cagPAI was determined using 12 sets of primer pairs specific for functionally important loci of cagPAI by polymerase chain reaction (PCR).

Results

The cagPAI positive strains were significantly observed in patients with SAG (52.4%) in comparison to those presenting CG (33.3%) and IM (14.3%). In addition, the presence of intact cagPAI was 87.5% in H. pylori strains isolated from patients with SAG, which was higher than those obtained from patients with CG (12.5%) or IM (0%). A significant increase in the frequency of cagα-cagY and cagW-cagT segments, as exterior proteins of the CagPAI, was illustrated in strains from SAG patients compared with those from patients with CG.

Conclusions

Overall, these results strongly proposed an association between the severity of histopathological changes and intactness of cagPAI in the gastric tissue of patients infected with H. pylori.