Chlamydia pneumonia seropositivity correlates with serum fibrinogen and lipoprotein a levels: any role in atherosclerosis?

The aim of the study is to determine the impact of Chlamydial seropositivity on atherosclerosis in a group of patient requiring coronary and/or carotid revascularization. A population of 30 diabetic patients (group 3) and 26 nondiabetic patients (group 2) with angiographically documented coronary and/or carotid artery disease were enrolled for the study. Volunteers from the relatives of hospital staff with no known disease (n=29; group 1) were included as the control group. Serum samples from the participants were assayed for cardiovascular risk factors including total serum cholesterol, triglyceride and lipoprotein levels, fibrinogen, Hb A1c levels and IgG titers for Chlamydia pneumonia (C. pneumonia). Chlamydial seropositivity was analysed further to determine a possible impact on atherogenesis. Serum LDL cholesterol levels revealed statistically significant difference between groups 1 and 2 (p=0.001). There was no difference between groups 2 and 3 regarding LDL cholesterol levels. There was no significant difference among the groups with respect to C. pneumonia seropositivity and the other atherosclerotic risk factors. Chlamydial seropositivity was found to be more frequent in males than in females (p=0.008). In the C. pneumonia seropositive group, serum fibrinogen and lipoprotein a levels were found to be significantly higher than the seronegative group (p=0.0001 and p=0.001, respectively). Other atherogenic risk factors were similar in the seropositive and negative groups. The causal role of Chlamydial infections in atherosclerotic plaque formation might be due to their influence on the serum fibrinogen and lipoprotein a levels.