Is Chlamydia pneumoniae a risk factor for peripheral atherosclerosis?

Seroepidemiological studies have shown a relationship between Chlamydia pneumoniae and coronary atherosclerosis. It is not clear whether Chlamydia pneumoniae is also a risk factor for peripheral atherosclerosis. Chlamydia pneumoniae antibodies were measured by a microimmunofluorescence method in 75 patients who underwent surgery for peripheral atherosclerosis, and the seroprevalence was compared with that in the normal population. Chlamydia pneumoniae immunoglobulin-G seroprevalence was 80% in the study group vs. 40% in controls. More foam cells were noted on light microscopy in atherosclerotic plaques from the infected patients. The 60 infected patients were divided into: group A (n = 35) given both anti-chlamydial and antiplatelet agents for 1 year; and group B (n = 25) given antiplatelet therapy only. The groups were compared on the basis of clinical findings, ankle-brachial index, and antibody titers. Decreasing Chlamydia pneumoniae immunoglobulin-G seroprevalence in group A correlated significantly with increasing ankle-brachial index and improvement in clinical findings. It was concluded that Chlamydia pneumoniae may be a risk factor for peripheral atherosclerosis.