Presence of Chlamydia pneumoniae in human symptomatic and asymptomatic carotid atherosclerotic plaque

Background-Chlamydia pneumoniae has been identified in atherosclerotic plaq ues of patients with cerebrovascular and cardiovascular disease. However, t he direct causative effect of C pneumoniae infection in the activation of a therosclerotic plaque to a prothrombotic state remains to be established. T he aim of the present study is to examine the correlation between intraplaq ue 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 pre pared for polymerase chain reaction analysis for Chlamydia pneumoniae per I nstitutional Review Board-approved protocol. Blood was drawn from each pati ent at the time of surgery for serological analysis. Results-The overall rate of plaques positive for C pneumoniae was 14.82%, w ith 5 of 37 (13.5%) plaques from symptomatic patients and 9 of 57 (15.8%) f rom asymptomatic patients, which revealed a definitive presence of the orga nism. No association existed between C pneumoniae presence and symptomatic disease (P=1.0), Also, no association existed between presence of C pneumon iae and severity of stenosis. Finally, seropositivity for antichlamydial Ig G, IgA, and IgM anti-chlamydial antibodies did not correlate with identific ation of C pneumoniae in the plaques. However, high-serum anti-chlamydial I gA levels (greater than or equal to1:128) were associated with occurrence o f symptomatic disease (P=0.03; 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 se nsitivity of seropositivity for IgG, IgA, or IgM associated with PCR-identi fied C pneumoniae presence in the plaque makes it unlikely to be Valuable a s the single determining factor for actively infected plaque. Association o f high-level anti-chlamydial IgA with symptomatic disease suggests that chr onic or acute chlamydial infection anywhere in the body could play a role i n atherosclerotic plaque activation and be used as a marker to target popul ations in future stroke prevention trials.