Abstract

Background: Primary biliary cholangitis (PBC) is a chronic cholestatic inflammatory liver disease of unknown cause. Several viral and bacterial pathogens have been proposed as factors that could either trigger an immune response by molecular mimicry or directly be involved in the persistence of biliary damage. There are conflicting reports respecting the role of Chlamydophila pneumoniae in the pathogenesis of PBC. Aim: To investigate markers of C. pneumoniae infection in serum and liver tissue from patients with PBC. Patients and Methods: Twenty patients with diagnosis of PBC and 20 control patients with other non-cholestatic chronic liver diseases were studied. Serum anti-C. pneumoniae antibodies (IgG) were determined. Liver tissue was available for immunohistochemistry detection of C. pneumoniae antigens. DNA was extracted from liver tissue and a specific sequence of C. pneumoniae 16S rRNA gene was amplified by CPR. Adequate controls of bacterial and human DNA amplification were used. Informed consent was obtained from patients. A meta-analysis of risk difference of PBC in Chlamydophila pneumoniae infected patients and in the control group was performed. Results: Serum antibodies were positive in 30% of patients with PBC and 50% of controls (p = NS). C. pneumoniae antigens were not detected in liver tissue neither of patients with PBC nor controls. Bacterial DNA did not amplify in any of the samples, despite good amplification of internal and external controls. Risk difference meta-analysis showed high heterogeneity between studies. Therefore, we did not estimate a pooled risk difference. Discussion: Our results do not support the association between C. pneumoniae infection and PBC. In the current literature only one study shows an association between C. pneumoniae and PBC, but other three studies do not support it