Chlamydia pneumoniae antibody titers in patients with coronary artery disease: relation to age and clinical stage

Background and aim Atherosclerosis and its clinical sequelae are responsibl e for the highest death rate in industrialized countries. Seroepidemiologic al pathological and immunohistochemical studies have suggested a relation b etween Chlamydia pneumoniae infection and the development of coronary scler osis. Aim of this study was to investigate the frequency distribution of Ch lamydia pneumoniae antibody titers in patients with different clinical stag es of coronary artery disease (CAD) and patients without CAD as well as a p ossible age dependence of antibody titers within the study groups. For this purpose, 522 consecutive patients of a cardiology ward were invest igated, over a period of 10 months, for the presence of Chlamydia pneumonia e antibodies (IgG, IgA, IgM) using specific ELISA's. In general, there was no difference in the frequency of positive Chlamydia antibody titers between CAD patients and the control group. Only in the sub group of unstable CAD-patients <50 years a tendency of increased antibody t iters was present. Patients with stable angina, unstable angina, or acute m yocardial infarction exhibited no significant differences in the rate of in fection between the different age groups (p<0.117). In contrast, there was a significant increase in positive Chlamydia pneumoniae antibodies with inc reasing age in the control group (p=0.002). The relatively high incidence of positive Chlamydia pneumoniae antibody tit ers in young CAD patients, which is associated with a loss of age-dependent Increase of the antibody titers in the CAD group, might indicate a specifi c role of Chlamydia pneumoniae infections for the manifestation of prematur e CAD (before the age of 50). Due to the increased rate of Chlamydia pneumoniae Infections with increasin g age, the determination of Chlamydia pneumoniae antibody titers does not a llow reliable conclusions on the infectious pathogenesis of CAD. Furthermor e, our unability to demonstrate differences In antibody titers between CAD patients with stable angina, unstable angina, and acute myocardial infarcti on suggests that acute Chlamydia pneumoniae infections are not responsible for the development of acute coronary syndromes.