Acute and chronic Chlamydia pneumoniae infection and inflammatory markers in coronary artery disease patients

Abstract

We evaluated the role of inflammation and acute or persistent Chlamydia pneumoniae infection in coronary artery disease (CAD). The study involved 63 cardiovascular disease patients diagnosed with angina and myocardial infarction (MI) and 40 healthy controls. ELISA was performed for detection of C. pneumoniae IgA antibodies and for quantitative analysis of IFN-γ. PCR was performed for detection of the C. pneumoniae 16 SrRNA gene in blood. C. pneumoniae IgA antibodies were detected in 66.66% cases and 41.37% controls. Of IgA seropositive cases 71.43% were MI patients, 61.90% were stable angina patients, and 64.29% unstable angina patients. Of 40 patients whose PCR was done 32.5% were positive of which 76.92% were IgA seropositive. Traditional risk factors were not significantly associated with CAD. The mean value of IFN-γ in cases was 32.12pg/ml and 11.32pg/ml in controls. Elevated IFN-γ was observed in 76.92% of C. pneumoniae IgA seropositives with a mean value of IFN-γ in angina patients of 3.39pg/ml, in unstable angina of 12.91 pg/ml and in MI patients of 23.89 pg/ml. IFN-γ levels in cases who were positive for C. pneumoniae infection by serology and PCR was 55.21 pg/ml. C. pneumoniae infection was significantly associated with CAD risk. The role of acute or persistent infection in progression of CAD to adverse clinical outcome was evident by a high percentage of seropositives among PCR positives. Although IFN-γ alone had a role to play in development of CAD, its values were further enhanced due to recurrent C. pneumoniae infection.