<p>This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.</p> <p>Over the past two decades, a number of studies have failed to provide direct evidence of specific microbial chronic infection in primary biliary cirrhosis (PBC). However, a recent report suggests that there is a specific association of <italic>Chlamydia pneumoniae</italic> in patients with PBC and that <italic>C. pneumoniae</italic> or similar antigens might play a role in the pathogenesis of disease. To determine if <italic>Chlamydia</italic> infection is associated with PBC, we applied a combination of immunological and molecular approaches to investigate (a) the serological reactivity against two common <italic>Chlamydia</italic> human pathogens, <italic>C. pneumoniae</italic> and <italic>C. trachomatis</italic>, by immunoblotting, (b) the presence of <italic>Chlamydia</italic> in liver samples of patients with PBC and controls by PCR amplification of <italic>Chlamydia</italic> specific 16S rRNA and (c) the presence of <italic>Chlamydia</italic> proteins in liver samples of patients with PBC and controls by immunohistochemical staining. By immunoblotting, <italic>C. trachomatis</italic> and <italic>C. pneumoniae</italic> specific serological antibodies were found in 52/57 (91.2%) AMA positive PBC, 7/33 (21/2%) of AMA negative PBC, 1/25 (4%) PSC, 0/15 (0%) Sjorgen's syndrome and 0/20 (0%) systemic lupus erythematosus patients and 0/20 (0%) healthy volunteers at 1:200 sera dilution. PBC sera reacted to <italic>Chlamydia</italic> and <italic>E. coli</italic> lysates in western blots up to a maximum of 10<sup>-4</sup> dilution. However, PCR amplification of the <italic>Chlamydia</italic> specific 16S rRNA gene was negative in 25/25 PBC livers but positive in 1/4 PSC liver, 3/6 in other liver disease controls and 1/4 normal liver samples. While two commercially available specific monoclonal antibodies stained positive controls (<italic>Chlamydia</italic> infected HEp-2 cells) they failed to detect <italic>Chlamydia</italic> antigens in PBC livers. The detection of <italic>Chlamydia</italic> specific antibodies but not <italic>Chlamydia</italic> rRNA gene and <italic>Chlamydia</italic> antigens in PBC suggests that <italic>Chlamydia</italic> infection is not involved in PBC.</p>
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Clin Dev Immunol. 2003 Jun-Dec; 10(2-4):227-233