Association of Peripheral Mononuclear Cells Containing Chlamydia Pneumoniae DNA with Acute Coronary Syndrome and Stable Coronary Artery Disease in Japanese Subjects

Investigation of Chlamydia pneumoniae infection in Moroccan patients suffering from cardiovascular diseases

Chlamydia pneumoniae is an intracellular bacterium responsible for respiratory diseases and is highly involved in cardiovascular disease development, mainly atherosclerosis. The main objective of our study was to evaluate C. pneumoniae prevalence in Moroccan patients suffering from cardiovascular diseases. A total of 115 patients with cardiovascular diseases were enrolled, and their clinical and behavioral information was recorded. Blood was sampled from all patients as well as the atheroma plaques from 36 patients undergoing surgery. Nested PCR was performed for C. pneumoniae DNA detection in both peripheral blood mononuclear cells (PBMCs) and atheroma plaques. Statistical analysis was performed using EpiInfo software. Data analysis showed cardiovascular disease dominance in men, with a sex ratio M/F of 3.4, a majority of tobacco users (52.2%), and many diabetics (44.3%). A significant difference between genders was shown for tobacco use (p<0.05). Positive cases for PBMCs and atheroma plaques were 61% and 86%, respectively, and a significant difference between PBMCs and atheroma plaque infection was identified (p=0.02). Data analysis also showed that 12% of patients presented only C. pneumoniae infection as a risk factor. Therefore, the high prevalence of C. pneumoniae suggests its involvement in atherosclerosis, and further investigation is recommended for confirmation.

Immunoproteomic identification and serological responses to novel Chlamydia pneumoniae antigens that are associated with persistent C. pneumoniae infections

The controversial discussion about the role of Chlamydia pneumoniae in atherosclerosis cannot be solved without a reliable diagnosis that allows discrimination between past and persistent infections. Using a proteomic approach and immunoblotting with human sera, we identified 31 major C. pneumoniae Ags originating from 27 different C. pneumoniae proteins. More than half of the proteins represent Chlamydia Ags not described previously. Using a comparative analysis of spot reactivity Pmp6, OMP2, GroEL, DnaK, RpoA, EF-Tu, as well as CpB0704 and CpB0837, were found to be immunodominant. The comparison of Ab-response patterns of sera from subjects with and without evidence for persisting C. pneumoniae, determined by multiple PCR analysis of PBMC and vasculatory samples, resulted in differential reactivity for 12 proteins, which is not reflected by reactivity of the sera in the microimmunofluorescence test, the current gold standard for serodiagnosis. Although reactivity of sera from PCR-positive donors was increased toward RpoA, MOMP, YscC, Pmp10, PorB, Pmp21, GroEL, and Cpaf, the reactivity toward YscL, Rho, LCrE, and CpB0837 was decreased, reflecting the altered protein expression of persisting C. pneumoniae in vitro. Our data provide the first evidence of a unique Ab-response pattern associated with persistent C. pneumoniae infections, which is a prerequisite for the serological determination of persistently infected patients.

Role of Chlamydia pneumoniae in atherosclerosis

Cardiovascular disease, resulting from atherosclerosis, is a leading cause of global morbidity and mortality. Genetic predisposition and classical environmental risk factors explain much of the attributable risk for cardiovascular events in populations, but other risk factors for the development and progression of atherosclerosis, which can be identified and modified, may be important therapeutic targets. Infectious agents, such as Chlamydia pneumoniae, have been proposed as contributory factors in the pathogenesis of atherosclerosis. In the present review, we consider the experimental evidence that has accumulated over the last 20 years evaluating the role of C. pneumoniae in atherosclerosis and suggest areas for future research in this field.

Inflammatory responses associated with acute coronary syndrome up-regulate IRAK-M and induce endotoxin tolerance in circulating monocytes

Acute coronary syndrome (ACS) groups different cardiac diseases whose development is associated with inflammation. Here we have analyzed the levels of inflammatory cytokines and of members of the TLR/IRAK pathway including IRAK-M in monocytes from ACS patients classified as either UA (unstable angina), STEMI (ST-elevation myocardial infarction) or NSTEMI (non-ST-elevation myocardial infarction). Circulating monocytes from all patients, but not from healthy individuals, showed high levels of pro-inflammatory cytokines, TNF-alpha and IL-6, as well as of IRAK-M and IL-10. TLR4 was also up-regulated, but IRAK-1, IRAK-4 and MyD88 levels were similar in patients and controls. Further, we investigated the consequences of cytokines/IRAK-M expression on the innate immune response to endotoxin. Ex vivo responses to LPS were markedly attenuated in patient monocytes compared to controls. Control monocytes cultured for 6 h in supplemented medium (10% serum from ACS patients) expressed IRAK-M, and LPS stimulation failed to induce TNF-alpha and IL-6 in these cultures. Pre-incubation of the serum with a blocking anti-TNF-alpha antibody reduced this endotoxin tolerance effect, suggesting that TNF-alpha controls this phenomenon, at least partially. We show for the first time that inflammatory responses associated with ACS induce an unresponsiveness state to endotoxin challenge in circulating monocytes, which correlates with expression of IRAK-M, TLR4 and IL-10. The magnitude of this response varies according to the clinical condition (UA, STEMI or NSTEMI), and is regulated by TNF-alpha.

Chlamydia pneumoniae and coronary artery disease: controversial results of serological studies

I have read with great interest the article published by Carratelli et al. Briefly they have reported increased levels of inflammatory markers and elevated titers of IgG and IgA of C. pneumoniae by using both ELISA and MIF method. There are several factors which may underly the controversial results of seroepidemiological studies. I have commented on the report of Carratelli et al. regarding some of these factors.