[Chlamydia antibody titers in patients with coronary disease: relations to age and clinical stage]

Abstract

Atherosclerosis and its clinical sequelae are responsible for the highest death rate in industrialized countries. Seroepidemiological, pathological and immunohistochemical studies have suggested a relation between Chlamydia pneumoniae infection and the development of coronary sclerosis. Aim of this study was to investigate the frequency distribution of Chlamydia pneumoniae antibody titers in patients with different clinical stages of coronary artery disease (CAD) and patients without CAD as well as a possible age dependence of antibody titers within the study groups. For this purpose, 522 consecutive patients of a cardiology ward were investigated, over a period of 10 months, for the presence of Chlamydia pneumoniae 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 subgroup of unstable CAD-patients < 50 years a tendency of increased antibody titers was present. Patients with stable angina, unstable angina, or acute myocardial infarction exhibited no significant differences in the rate of infection between the different age groups (p < 0.117). In contrast, there was a significant increase in positive Chlamydia pneumoniae antibodies with increasing age in the control group (p = 0.002). The relatively high incidence of positive Chlamydia pneumoniae antibody titers 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 specific role of Chlamydia pneumoniae infections for the manifestation of premature CAD (before the age of 50). Due to the increased rate of Chlamydia pneumoniae infections with increasing age, the determination of Chlamydia pneumoniae antibody titers does not allow reliable conclusions on the infectious pathogenesis of CAD. Furthermore, our unability to demonstrate differences in antibody titers between CAD patients with stable angina, unstable angina, and acute myocardial infarction suggests that acute Chlamydia pneumoniae infections are not responsible for the development of acute coronary syndromes.