Presence of Chlamydia pneumoniae in Human Symptomatic and Asymptomatic Carotid Atherosclerotic Plaque

Abstract

Background-Chlamydia pneumoniae has been identified in atherosclerotic plaques of patients with cerebrovascular and cardiovascular disease. However, the direct causative effect of C pneumoniae infection in the activation of atherosclerotic plaque to a prothrombotic state remains to be established. The aim of the present study is to examine the correlation between intraplaque presence of chlamydiae and symptomatic carotid disease in humans. Methods-Plaques from 37 symptomatic and 57 asymptomatic consenting patients undergoing carotid endarterectomy were snap-frozen, and the tissue was prepared for polymerase chain reaction analysis for Chlamydia pneumoniae per Institutional Review Board-approved protocol. Blood was drawn from each patient at the time of surgery for serological analysis. Results-The overall rate of plaques positive for C pneumoniae was 14.82%, with 5 of 37 (13.5%) plaques from symptomatic patients and 9 of 57 (15.8%) from asymptomatic patients, which revealed a definitive presence of the organism. No association existed between C pneumoniae presence and symptomatic disease (Pϭ1.0). Also, no association existed between presence of C pneumoniae and severity of stenosis. Finally, seropositivity for antichlamydial IgG, IgA, and IgM anti-chlamydial antibodies did not correlate with identification of C pneumoniae in the plaques. However, high-serum anti-chlamydial IgA levels (Ն1:128) were associated with occurrence of symptomatic disease (Pϭ0.03; odds ratio, 2.86; 95% CI, 1.12 to 7.28). Conclusions-Presence of C pneumoniae as a single factor does not appear to be sufficient to explain the occurrence of cerebrovascular symptoms. Low sensitivity of seropositivity for IgG, IgA, or IgM associated with PCR-identified C pneumoniae presence in the plaque makes it unlikely to be valuable as the single determining factor for actively infected plaque. Association of high-level anti-chlamydial IgA with symptomatic disease suggests that chronic or acute chlamydial infection anywhere in the body could play a role in atherosclerotic plaque activation and be used as a marker to target populations in future stroke prevention trials. (Stroke. 2001;32:855-860.)

C-Reactive Protein Levels and Viable Chlamydia pneumoniae in Carotid Artery Atherosclerosis

“…Infection appeared to be unrelated to vascular risk factors, signs and symptoms suggestive of infection, or presentation with stroke or transient ischemic attack. Similar to results of prior studies, 12,15,20 we found that vascular infection with C pneumoniae appears to be asymptomatic.…”

Role of Infectious and Immune Factors in Coronary and Cerebrovascular Arteriosclerosis

“…In patients undergoing carotid endarterectomy, the plaques were investigated for C. pneumoniae and the blood was examined for antichlamydial antibodies. Associated with symptomatic disease was a highlevel of antichlamydial IgA, whereas no association between C. pneumoniae presence in the plaque and symptomatic disease could be detected (52).…”

Is the Perceived Association between Chlamydia pneumoniae and Vascular Diseases Biased by Methodology?

“…Reviewing the literature on the use of AmpliTaq Gold DNA polymerase in C. pneumoniae PCR assays, we found that in the majority of the studies, the type of DNA polymerase enzyme used was not identified. In a study that explicitly mentioned the use of AmpliTaq Gold DNA polymerase, the detection rate of C. pneumoniae DNA was 14.8% (30).…”