Key importance of the Helicobacter pylori adherence factor blood group antigen binding adhesin during chronic gastric inflammation

Helicobacter pylori has been assigned as a class 1 carcinogen because of it s relation to gastric adenocarcinoma. Chronic H. pylori infection may lead to severe gastritis, glandular atrophy (AT), and intestinal metaplasia (IM) . Strains secreting the vacuolating toxin VacA and producing the cytotoxin- associated antigen CagA (type 1 strains), as well as the blood group antige n binding adhesin (BabA) targeting Lewis(b) antigens, have been associated previously with distal gastric adenocarcinoma (M. Gerhard et al., Proc. Nat l, Acad. Sci, USA. 96: 12778-12783, 1999) and may therefore also be related to lesions preceding gastric cancer. Antral and corpus biopsies were colle cted from 451 patients: 151 were H. pylori positive, as determined by PCR, Gastric biopsies were histologically evaluated for activity of gastritis (G 0-G3, granulocyte infiltration), chronicity of gastritis (L1-L3, lymphocyte infiltration), and the presence of IM and/or AT according to the Sydney cl assification. Simultaneously, the presence of bacterial genes encoding viru lence and adherence factors (vacAs1/s2, cagA, and babA2) was determined by PCR, The presence of cagA+ and vacAs1 (alone or combined) both correlated w ith activity and chronicity of gastritis: (P < 0.05); however, the overall prevalence of these genes was 60 or 72%, respectively, and was thus relativ ely frequent. The babA2 gene, encoding the adhesin BabA, was detected in 38 % of infected patients and was correlated with the activity of gastritis in antrum and corpus (P < 0.005). cagA+/vacAs1+ strains (suggesting the prese nce of type 1 strains) that were also babA2 positive were detected more fre quently in patients with severe histological alterations (such as G3, IM, o r AT) compared with subjects without these changes (P < 0.01), cagA+/vacAs1 + strains that were babA2 negative, however, lacked a significant correlati on with severe histological changes, activity, or chronicity of gastritis i n antrum and corpus. Adherence of H. pylori via BabA appears to be of impor tance for efficient delivery of VacA and CagA and may play a special role i n the pathogenesis of severe histological changes.