[Association between Helicobacter pylori virulence and duodenal ulcer disease in patients from Hong Kong in China]

Abstract

Objective: A number of putative virulence factors have been postulated to be relevant to the clinical outcome of Helicobacter pylori infection based on strains identified in the western countries. The aim of this study was to investigate the association between genotypes of vacA, cagA and iceA and duodenal ulcer disease in patients from Hong Kong.

Methods: Seventy-two dyspeptic patients with or without duodenal ulcer disease, with proven H.pylori infection, were studied. Gastric biopsy specimens were analyzed by specific polymerase chain reaction and Southern blot to determine the genotypes of these virulence factors.

Results: Except 6 (8.3%) cases with evidence of multiple infections, all of the remaining 66 cases had vacA signal sequence s1 type strains. Twenty-seven (90%) of the 30 cases with duodenal ulcers were infected with cagA-positive strains, compared with 32 (88.9%) of 36 with non-ulcer dyspepsia (P > 0.05). Similarly, vacA middle region sequences were detected with no significant difference in the two groups, 9 (30.0%) versus 13 (36.1%) for m1b and 21 (70.0%) versus 23 (63.9%) for m2 type. IceA1 subtype was detected in the same frequency in 42 (63.6%) of the 66 cases. Neither cagA nor vacA and iceA were associated with duodenal ulcer disease.

Conclusion: No clear differences were found in the distribution of cagA, vacA and iceA genotypes among patients with duodenal ulcer or non-ulcer dyspepsia. The association of these virulence genes and duodenal ulcer disease needs reappraisal, particularly under geographic considerations.