Introduction: H.pylori is the causative agent of most cases of chronic superficial gastritis in humans and a risk factor for the development of peptic ulcer disease and gastric cancer. Our understanding of the early host response toH.pylori infection is limited. We and others have previously shown increased expression of the anti-microbial peptide hBD2 by gastric epithelial cell lines in response toH.pylori infection. In the present study we investigated the mRNA and protein expression of hBD1 and hBD2 inH.pylori-positive and -negative gastric biopsy samples.

Methods: Gastric biopsies were obtained from patients with H.pylori-positive (n=11) and H.pylori-negative (n=5) gastritis and control subjects (n=8). hBD1 and hBD2 mRNA was quantified by quantitative and semi-quantitative RT-PCR. Immunohistochemistry was performed on archival gastric paraffin-blocked samples from patients with H.pylori- and non-H.pylori-related gastritis.

Results: A marked increase in hBD2 mRNA expression was observed in both groups of gastritis compared to control tissue (H.pylori-positive, p=0.006;H.pylori-negative, p=0.02).The constitutive hBD1 mRNA expression observed in control tissue was also upregulated (H. pylori-positive p=0.035;negative group p=0.01). A parallel increase was also observed in hBD1and hBD2 peptides with the positive staining confined to the surface epithelium.

Conclusion: This is the firstin vivo study showing increased expression of hBD1 and hBD2 in H.pylori-positive and-negative gastritis. These results suggest an important role for these peptides in the innate host defence during inflammatory episodes and infection.