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Chlamydia pneumoniae-specific circulating immune complexes in patients with chronic coronary heart disease
E Linnanmäki1, M Leinonen, K Mattila
1Department of Virology, University of Helsinki, Finland.
Insights
Chronic Chlamydia pneumoniae infection is linked to coronary heart disease. Study found C. pneumoniae-specific immune complexes in 41% of patients, suggesting a chronic infection plays a role in heart disease.
Area of Science:
- Cardiovascular Research
- Infectious Diseases
- Immunology
Background:
- Emerging evidence suggests a link between chronic Chlamydia pneumoniae infection and coronary heart disease (CHD).
- Previous research identified genus-specific chlamydial lipopolysaccharide immune complexes in CHD patients.
- This study aimed to determine if species-specific C. pneumoniae immune complexes are present in chronic CHD.
Purpose of the Study:
- To investigate the presence and specificity of Chlamydia pneumoniae-specific circulating immune complexes in patients with chronic coronary heart disease.
Main Methods:
- Employed an antigen-specific capture method to detect chlamydial lipopolysaccharide-containing immune complexes.
- Utilized microimmunofluorescence testing and immunoblotting to analyze antibodies from isolated immune complexes.
- Calculated C. pneumoniae indexes comparing immune complex-derived antibodies to free antibodies.
Main Results:
- Chlamydia-specific circulating immune complexes were detected in 41% of chronic coronary heart disease patients versus 15% of controls (p < 0.01).
- Patients exhibited significantly higher C. pneumoniae indexes (median, 1/8) compared to controls (median, 1/16; p < 0.001).
- Antibodies within immune complexes specifically targeted 98-kd and 42-kd C. pneumoniae proteins.
Conclusions:
- Findings suggest a chronic C. pneumoniae infection in a majority of chronic coronary heart disease patients.
- Chlamydial components readily access circulation, forming immune complexes with antibodies.
- This provides further evidence supporting the association between chronic C. pneumoniae infection and coronary heart disease.
Background:
An association of chronic Chlamydia pneumoniae infection to coronary heart disease has been suggested recently. In a recent study, we demonstrated circulating immune complexes containing chlamydial genus-specific lipopolysaccharide in patients with coronary heart disease. The objective of the present study was to investigate whether C. pneumoniae species-specific immune complexes are present in chronic coronary heart disease.
Methods And Results:
The presence of Chlamydia-specific circulating immune complexes was studied in 46 patients with chronic coronary heart disease and in control subjects. Chlamydial lipopolysaccharide-containing immune complexes were detected with the antigen-specific capture method, and they were present in 41% of patients and 15% of control subjects (p < 0.01). The presence of C. pneumoniae antibodies in circulating immune complexes was studied by testing the specificity of antibodies derived from isolated and dissociated immune complexes by microimmunofluorescence testing and immunoblotting. The C. pneumoniae indexes based on the relative amount of immune complex-derived antibodies and free antibodies were significantly higher among patients compared with control subjects (median, 1/8 versus 1/16; p < 0.001). Immune complex bound antibodies showed specificity for 98-kd and 42-kd proteins of C. pneumoniae.
Conclusions:
The results suggest that the majority of the patients with chronic coronary heart disease have a chronic C. pneumoniae infection in which chlamydial components have an easy access to circulation to form immune complexes with preexisting antibodies. These findings give further evidence for the association of chronic C. pneumoniae infection with coronary heart disease.