MOST HELICOBACTER-PYLORI-INFECTED PATIENTS HAVE SPECIFIC ANTIBODIES, AND SOME ALSO HAVE HELICOBACTER-PYLORI ANTIGENS AND GENOMIC MATERIAL IN BILE - IS IT A RISK FACTOR FOR GALLSTONE FORMATION

Bile may contain a 130-kDa protein endowed with aminopeptidase activit y and the ability to promote cholesterol crystallisation. As >90% of H . pylori strains have a similar peptidase activity, and half the isola tes express a 110- to 14O-kDa antigen, the CagA protein, we investigat ed a possible association between H. pylori infection and gallstones, and the presence in bile samples of factors related to PI. pylori that could increase cholesterol crystallization. The prevalence of H. pylo ri infection was 82.1% in 112 patients with gallstones and 80.3% in 11 2 controls (NS). Fifteen bile samples out of 23 specimens from infecte d patients (65.2%) contained anti-CagA antibodies. A similar to 60-kDa antigen only reacting with an anti-CagA antibody was found in five bi le samples (21.7%) from 23 infected patients. One bile sample (4.1%) c ontained ureA and cagA genes of H.pylori. The homology of CagA with th e N-terminal sequence of aminopeptidase N was very low. We concluded t hat the presence of specific antibody to H. pylori in most bile sample s tested and of an H. pylori putative antigen in a discrete number of cases may represent factors that increase the risk of gallstone format ion.