DNA sequence analysis of cagA 3' motifs of Helicobacter pylori strains from patients with peptic ulcer diseases.

The Helicobacter pylori cagA gene is a major virulence factor that plays an important role in gastric pathologies. DNA sequence data for the cagA 3' region of Western isolates differ markedly in their EPIYA motifs from those of East Asian isolates. An increase in the number of these motifs is known to be associated with gastric cancer. Whether such an association is also the case for peptic ulceration was investigated in this study. Gastric biopsies were collected from 96 patients with duodenal ulcer (DU), gastric ulcer (GU) and gastritis. The types of EPIYA motif detected by PCR among 28 DU strains were 13 ABC, eight ABCC, six ABCCC, and in one patient both ABC and ABCCCCC; among nine GU strains were two ABC, five ABCC and two ABCCC; and among 40 gastritis strains were 35 ABC and five ABCC. DNA sequencing was carried out to confirm the detection of the EPIYA motif types and to analyse their peptide sequences. A significant association was found between the number of the EPIYA-C motifs (>or=2) and peptic ulceration (P=0.00001) compared with gastritis. In conclusion, this study shows that our patients harboured cagA-positive H. pylori strains with EPIYA motifs of the Western type and that the increase in the number of EPIYA-C motifs was significantly associated with DU and GU but not with gastritis, indicating predictive association with the severity of the disease.