Helicobacter pylori and other Helicobacter species in gallbladder and liver of patients with chronic cholecystitis detected by immunological and molecular methods

Objective. Despite several recent reports on the detection of Helicobacter DNA in human bile, there are still uncertainties concerning the correlation of these findings with biliary tract and liver diseases. Material and methods. Using molecular methods and immunohistochemistry (IHC), we investigated gallbladder and liver biopsy specimens from 22 adult Ukrainian patients with chronic cholecystitis for the presence of Helicobacter species. Patient sera were collected and tested for antibody reactivity to antigens of three Helicobacter spp. Detection of Helicobacter DNA was performed using a Helicobacter genus-specific 16S rDNA PCR. Amplified DNA was identified by PCR-denaturating gradient gel electrophoresis (DGGE) and DNA sequencing. Tissue sections of gallbladder and liver were examined by IHC with antibodies specific to H. pylori, the CagA and VacA cytotoxins of H. pylori, H. hepaticus and to Campylobacter jejuni. Patient sera were analysed by immunoblot for IgG antibodies to soluble surface proteins of H. pylori, H. hepaticus and H. bilis. Results. Helicobacter DNA was found in 16/22 (73%) of the gallbladder samples and in 11/22 (50%) of the liver samples. IHC showed the presence of the H. pylori specific cytotoxins CagA and VacA inside the gallbladder epithelial cells without co-localization of H. pylori at the epithelial lining. Immunoblot analysis of the patient sera did not show any correlation between the presence of Helicobacter DNA and IgG antibody responses. Conclusions. The high prevalence of Helicobacter DNA and the positive findings by IHC in gallbladder and liver raise questions concerning an infectious role of Helicobacter in patients with chronic cholecystitis.