Clinical relevance of the Helicobacter pylori gene for blood-group antigen-binding adhesin

Infection with Helicobacter pylori is associated with different human gastr ic diseases. Biochemical studies, in vitro adherence assays, and in vivo an imal models revealed that epithelial attachment of H. pylori can be mediate d by the blood-group antigen-binding adhesin (BabA) targeting human Lewis(b ) surface epitopes, Studies with transgenic mice expressing the Lewis(b) ep itope have shown that such attachment can alter disease outcome. In the cur rent study, the presence of the babA2 gene encoding the adhesin was investi gated in clinical isolates from a German population by using PCR and revers e transcription-PCR. A positive genotype was correlated to allelic variatio ns in the genes encoding VacA and CagA and also to the prevalence of duoden al ulcer, distal gastric: adenocarcinoma, mucosa-associated lymphoid tissue lymphoma, and antral gastritis. The presence of babA2 was significantly as sociated with duodenal ulcer (P = 0.0002) and adenocarcinoma (P = 0.033). I n contrast, type 1 strains (vacAs1- and cagA-positive) were associated with only duodenal ulcer (P = 0.004) but not adenocarcinoma (P = 0.235). Genoty pe presence of babA2, vacAs1, and cagA ("triple-positive" strains) showed a highly significant correlation to the prevalence of ulcer (P = 0.000002) a nd adenocarcinoma (P = 0.014) and discriminated significantly better betwee n disease outcome than did the current type 1 classification. These results indicate that the babA2 gene is of high clinical relevance and would he a useful marker to identify patients who are at higher risk for specific H. p ylori-related diseases.