Most Helicobacter pylori infected patients have specific antibodies, and some also have H. pylori antigens and genes in the bile: is it a risk factor for gallstone formation ?

Bile may contain a 130-kDa prote in endowed with aminope ptidase activity and the ability to promote chole ste rol crystallisation. As . 90% of H. pylori strains have a similar pe ptidase activity, and half the isolate s expre ss a 110- to 140-kDa antigen, the CagA prote in, we inve stigate d a possible association between H. pylori infe ction and gallstone s, and the presence in bile samples of factors related to H. pylori that could increase chole sterol crystallization. The prevale nce of H. pylori infe ction was 82.1% in 112 patients with gallstone s and 80.3% in 112 controls (NS) . Fifteen bile samples out of 23 specimens from infe cted patie nts (65.2% ) containe d anti-CagA antibodie s. A ; 60-kDa antigen only reacting with an anti-CagA antibody was found in ® ve bile samples (21.7% ) from 23 infected patients. One bile sample (4.1% ) containe d ureA and cagA genes of H. pylori. The homology of CagA with the N-te rminal seque nce of aminope ptidase N was very low. We conclude d that the pre sence of speci® c antibody to H. pylori in most bile sample s tested and of an H. pylori putative antigen in a discre te number of case s may repre sent factors that incre ase the risk of gallstone formation.