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Mediators of Inflammation
Volume 2015, Article ID 378658, 9 pages
Review Article

Chlamydia pneumoniae-Mediated Inflammation in Atherosclerosis: A Meta-Analysis

1Section of Microbiology, Department of Public Health and Infectious Diseases, “Sapienza” University, Rome, Italy
2Section of Statistic, Department of Public Health and Infectious Diseases, “Sapienza” University, Rome, Italy

Received 8 May 2015; Accepted 15 July 2015

Academic Editor: Uma Nagarajan

Copyright © 2015 Simone Filardo et al. 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.


Several studies have attempted to relate the C. pneumoniae-mediated inflammatory state with atherosclerotic cardiovascular diseases, providing inconsistent results. Therefore, we performed a meta-analysis to clarify whether C. pneumoniae may contribute to the pathogenesis of atherosclerosis by enhancing inflammation. 12 case-control, 6 cross-sectional, and 7 prospective studies with a total of 10,176 patients have been included in this meta-analysis. Odds Ratio (OR) with a 95% confidence interval was used to assess the seroprevalence of C. pneumoniae and differences between levels of inflammatory markers were assessed by standard mean differences. Publication bias was performed to ensure the statistical power. hsCRP, fibrinogen, interleukin- (IL-) 6, TNF-α, and IFN-γ showed a significant increase in patients with atherosclerosis compared to healthy controls (), along with a higher seroprevalence of C. pneumoniae (OR of 3.11, 95% CI: 2.88–3.36, ). More interestingly, hsCRP, IL-6, and fibrinogen levels were significantly higher in C. pneumoniae IgA seropositive compared to seronegative atherosclerotic patients (). In conclusion, the present meta-analysis suggests that C. pneumoniae infection may contribute to atherosclerotic cardiovascular diseases by enhancing the inflammatory state, and, in particular, seropositivity to C. pneumoniae IgA, together with hsCRP, fibrinogen, and IL-6, may be predictive of atherosclerotic cardiovascular risk.