Methods: The IgG antibodies to Chlamydial lipopolysaccharide in 49 patient with extracardiac atherosclerotic artery disease and 34 healthy people which were recruited as control subjects were examined. Thirty eight atherosclerotic artery biopsy specimens obtained from these patients were tested by enzyme linked immunosorbent assay (ELISA) to investigate the presence of Chlamydia pneumoniae lipopolysaccharide antigen.
Results: Thirty one of the 49 (63.26%) patients, 12 of the 34 (35.29%) control subjects had a positive IgG response [Odds ratio = 3.16 (1.16-8.75), 95% CI, p = 0.0223]. Chlamydia pneumoniae lipopolysaccharide antigen were positive in 8 of the 38 (21.05%) atherosclerotic plaques.
Conclusion: These data support the hypothesis that infection with Chlamydia pneumoniae might be a major risk factor for atherosclerosis. Our results also indicate the possibility of a direct involvement of Chlamydia pneumoniae in atherosclerosis.