Chronic infections & coronary artery disease with special reference to Chalmydia pneumoniae

BACKGROUND & OBJECTIVES: Studies on cardiovascular diseases (CVD) in India have shown about 10-20 per cent of cases with no obvious risk factors, raising a suspicion of infections as a cause. There is a paucity of data on this possible role of infections. This study was, therefore, undertaken to find out the association between infection due to Chlamydia pneumoniae and other organisms and coronary artery disease (CAD). METHODS: Patients with CAD were selected in group I (acute myocardial infarction, AMI) and group III (patients undergoing coronary artery bypass graft (CABG) surgery), and normal controls in group II. Routine biochemical, haematological and inflammatory tests [C-reactive protein (CRP), total leucocyte count (TLC), fibrinogen, ESR], serodiagnostic tests for IgA and IgG antibodies to C. pneumoniae, Helicobacter pylori, cytomegalovirus (CMV), Mycoplasma pneumoniae and Parvovirus B-19 by ELISA kits, C. pneumoniae antigen by microimmunofluorescence and PCR from endothelial tissue obtained at CABG were carried out. Aortic punch biopsies were done in patients who underwent CABG. RESULTS: Acute MI patients had a significantly higher association with accepted cardiac risk factors, lipid profile, inflammatory and thrombogenic tests. IgG and IgA antibodies levels against C. pneumoniae were not significantly different in the controls as against the AMI group. However, C. pneumoniae antigen seropositive group had significant association with HDL cholesterol, lipid tetrad index (P<0.001) and with triglycerides. Parvovirus B antigen was detected in 8.3 per cent of tissue specimens by PCR and of 44 patients with AMI (6.8%) were also positive for parvovirus B-19 IgG antibodies. INTERPRETATION & CONCLUSIONS: There was no direct evidence of the involvement of C. pneumoniae and other infective agents and viruses in CAD. It is possible that such infections produce an indirect adverse effect on the lipid profile.