Objective: The aim of this study was to evaluate the association between Chlamydia pneumoniae (CP) infection and primary biliary cirrhosis (PBC).
Methods: Chlamydia pneumoniae IgG and IgM were determined by enzyme-linked immunosorbent assay (ELISA) in 41 well-established PBC patients and two race-matched control groups, PHC, n = 70; healthy controls, HC, n =57).
Results: The mean levels and seroprevalence of CP IgG in PBC group and PHC group were significantly higher than in the HC [(46.8 +/- 43.4) RU/ml, (49.5 +/- 45.2) RU/ml vs (28.3 +/- 32.7) RU/ml, P = 0.042 and P < 0.001 respectively; 68.3%, 71.4% vs 42.1%, chi2 values were 5.389 and 11.110 respectively]. There was a markedly elevated seroprevalence of CP IgM in patients with PBC (22.0%) compared with the PHC and HC groups. The odds ratios (ORs) for the presence of CP IgG and IgM for the PBC patients versus the HC were 2.7 (95% CI 0.9 to 6.1) and 5.1 (95% CI 1.4 to 18.5). Though there was no correlation in the level of CP IgG with total IgG in sera of patients with PBC (r=-0.857, p=0.344), CP IgM was related with the abnormally high concentrations of total IgM in the PBC group.
Conclusions: The results of this study do not support the hypothesis that infection with Chlamydia pneumoniae may be a triggering agent for PBC, but suggest that Chlamydia pneumoniae infection probably contributes to the high level of IgM presented in most of the patients with PBC