Abstract
BackgroundhomB encodes a Helicobacter pylori outer membrane protein. This gene was previously associated with peptic ulcer disease (PUD) and was shown to induce activation of interleukin-8 secretion in vitro, as well as contributing to bacterial adherence. Its 90%-similar gene, homA, was previously correlated with gastritis. The present study aimed to evaluate the gastric disease association with homB and homA, as well as with the H. pylori virulence factors cagA, babA and vacA, in 415 H. pylori strains isolated from patients from East Asian and Western countries. The correlation among these genotypes was also evaluated.ResultsBoth homB and homA genes were heterogeneously distributed worldwide, with a marked difference between East Asian and Western strains. In Western strains (n = 234, 124 PUD and 110 non-ulcer dyspepsia (NUD), homB, cagA and vacA s1 were all significantly associated with PUD (p = 0.025, p = 0.014, p = 0.039, respectively), and homA was closely correlated with NUD (p = 0.072). In East Asian strains (n = 138, 73 PUD and 65 NUD), homB was found more frequently than homA, and none of these genes was associated with the clinical outcome.Overall, homB was associated with the presence of cagA (p = 0.043) and vacA s1 (p < 0.001), whereas homA was found more frequently in cagA-negative (p = 0.062) and vacA s2 (p < 0.001) strains.Polymorphisms in homB and homA copy number were observed, with a clear geographical specificity, suggesting an involvement of these genes in host adaptation. A correlation between the homB two-copy genotype and PUD was also observed, emphasizing the role of homB in the virulence of the strain.ConclusionThe global results suggest that homB and homA contribute to the determination of clinical outcome.
Highlights
HomB encodes a Helicobacter pylori outer membrane protein
Helicobacter pylori colonization of the human stomach is associated with chronic gastritis and an increased risk of peptic ulcer disease (PUD), gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue lymphoma [13]
In vitro assays showed that HomB contributes to the proinflammatory characteristics of H. pylori and is involved in bacterial adherence, these two phenomena being more pronounced when homB is present in two copies in a given strain, compared to one copy only [7]
Summary
HomB encodes a Helicobacter pylori outer membrane protein. This gene was previously associated with peptic ulcer disease (PUD) and was shown to induce activation of interleukin-8 secretion in vitro, as well as contributing to bacterial adherence. The present study aimed to evaluate the gastric disease association with homB and homA, as well as with the H. pylori virulence factors cagA, babA and vacA, in 415 H. pylori strains isolated from patients from East Asian and Western countries. The correlation among these genotypes was evaluated. The homB 90%-similar gene, designated homA, was found to be associated with non-ulcer dyspepsia (NUD) in that same population [7]
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