C-Reactive Protein Levels and Viable Chlamydia pneumoniae in Carotid Artery Atherosclerosis

Abstract

Background and Purpose-An elevated serum level of C-reactive protein, an inflammatory marker, is an independent predictor of stroke and coronary artery disease. To determine whether chronic infection with Chlamydia pneumoniae, which has been identified in atherosclerotic plaques, is responsible for systemic inflammation, we studied the association between serum C-reactive protein levels and infection of carotid artery atherosclerotic plaque with viable C pneumoniae. Methods-Serum C-reactive protein levels were obtained before endarterectomy for carotid artery stenosis. Plaques were tested for C pneumoniae mRNA, an indicator of viability, and DNA by polymerase chain reaction of DNA and cDNA, respectively. Results-Forty-eight samples were studied, of which 18 (38%; 95% CI, 23 to 50) were infected with viable C pneumoniae as evidenced by isolated chlamydial mRNA. All 18 of these samples, plus 1 additional sample, were positive for chlamydial DNA. Serum C-reactive protein levels were higher in those with viable C pneumoniae compared with those without infection (median, 8 mg/L versus undetectable; Pϭ0.045 by Wilcoxon rank-sum test). In multivariable models, the only independent predictor of the presence of viable C pneumoniae was a detectable C-reactive protein level (odds ratio, 4.2; 95% CI, 1.1 to 17; Pϭ0.04). Conclusions-Viable C pneumoniae are present in a substantial portion of carotid artery atherosclerotic plaques and are associated with increased serum C-reactive protein levels. These findings may explain the link between elevated C-reactive protein levels and the risk of cardiovascular disease and stroke but should be reproduced in a larger cohort.

Inflammation and Infections as Risk Factors for Ischemic Stroke

“…71 In some 61 but not in other studies, 67 C pneumoniae was particularly associated with more advanced atherosclerotic lesions and with plaque thrombosis. 62 Viability of C pneumoniae was shown by detection of specific mRNA in a substantial proportion of carotid plaques 72 and by culturing the pathogen from a few specimens, 73,74 whereas other studies did not detect viable bacteria. 75 C pneumoniae can infect and was detected in EC, macrophages, and SMC.…”

The glycolipid exoantigen derived from Chlamydia muridarum activates invariant natural killer T cells

“…EDTA (5 mM) was added and the cell suspension was pipetted up and down and filtered. The single-cell suspension so prepared was then subjected to red blood cell lysis by ACK lysis buffer (150 mM NH 4 Cl, 10 mM KHCO 3 and 0.1 mM EDTA). The cells were washed and resuspended in RPMI 1640 for further applications.…”

“…Recently, C. pneumoniae has also been implicated in the pathogenesis of atherosclerosis, Alzheimer's disease and multiple sclerosis. [4][5][6] To date, there is no effective vaccine available against human chlamydial diseases. Considering the public health significance of chlamydial diseases, it is highly desirable to have an effective and safe chlamydial vaccine.…”

Distinct NKT Cell Subsets Are Induced by Different Chlamydia Species Leading to Differential Adaptive Immunity and Host Resistance to the Infections

“…In particular, Abs specific for C. pneumoniae can be detected in the serum of up to 70% of healthy human beings implying that most individuals have had contact with these organisms (22). More recently, C. pneumoniae has been implicated in the pathogenesis of diverse diseases such as atherosclerosis, Alzheimer's disease, and multiple sclerosis (23)(24)(25). The pathogenesis of these conditions is considered to be immunopathologically mediated.…”