SPECIFICITY OF DETECTION OF CHLAMYDIA-PNEUMONIAE IN CARDIOVASCULAR ATHEROMA - EVALUATION OF THE INNOCENT BYSTANDER HYPOTHESIS

Chlamydia pneumoniae has been detected in atherosclerotic plaque, rais ing the question of whether this detection is specific to atheromatous tissue. To evaluate this question, we tested cardiovascular and non-c ardiovascular tissue samples from 38 autopsy cases by polymerase chain reaction and immunocytochemistry. We also tested 33 granuloma biopsy specimens, as the organism has been detected in macrophages. C. pneumo niae was detected in coronary artery tissue from 13 (34%), lung from 5 (13%), liver from 4 (10%), and spleen from 2 (5%) of the 38 autopsy c ases (P < 0.05 for comparison or proportion of positive coronary arter ies with that of each of the other types of tissue). Of the 21 cases w ith at least one positive tissue sample, 11 had only a positive cardio vascular tissue (coronary artery, venous bypass graft, or myocardium), 7 had both cardiovascular and noncardiovascular positive tissues, and 3 had only a noncardiovascular positive tissue. C. pneumoniae was thu s detected relatively infrequently in noncardiovascular tissues, and i ts detection in these tissues was usually in association with its dete ction in cardiovascular tissue from the same patient. The organism was also infrequently detected in granulomatous tissue (3/33 specimens). These findings demonstrate that C. pneumoniae is more frequently found in atherosclerotic than normal tissue and support the hypothesis that C. pneumoniae has a role in the pathogenesis of atherosclerosis.