DETECTION OF CHLAMYDIA-PNEUMONIAE IN HUMAN NONRHEUMATIC STENOTIC AORTIC VALVES

Objectives. We sought to study the possible presence of Chlamydia pneu moniae in aortic valve stenosis (AVS). Background. Inflammation and im mune mechanisms are considered important for the pathogenesis of nonrh eumatic AVS. All chlamydial species are able to cause heart infections , and seroepidemiologic studies have indicated an association between chronic C. pneumoniae infection and coronary artery disease. Furthermo re, the organism has been demonstrated in atherosclerotic lesions. Met hods. Aortic valve specimens with varying degrees of macroscopic disea se were obtained from 35 subjects-17 consecutive patients undergoing a ortic valve replacement for treatment of nonrheumatic AVS and 18 age-m atched subjects at autopsy. The possible presence of C. pneumoniae in aortic valves was studied by immunohistochemical analysis, polymerase chain reaction or transmission electron microscopy, or a combination o f these. Results. Positive immunohistochemical staining with C. pneumo niae specific antibody was found in 9 (53%) of 17 patients with advanc ed aortic valve disease requiring surgical treatment (group A), 8 (80% ) of 10 cadavers with clearly macroscopic aortic valve pathology (grou p B) and 1 (12%) of 8 grossly normal cadaver control subjects (group C ). Statistical significance with regard to the presence of C. pneumoni ae was found when combined diseased subjects (groups A and B: total 17 of 27 subjects) were compared with group C (p = 0.018). However, when group A was compared with group C, there was only marginal statistica l significance (p = 0.088), Finally, there was a strong statistical si gnificance (p = 0.015) when groups B and C were compared. Chlamydia pn eumoniae DNA was also found in three stenotic valves, and in two of th e three tested valve specimens chlamydia-like particles were seen by e lectron microscopy. Conclusions. Chlamydia pneumoniae is frequently pr esent in nonrheumatic AVS. Similarly, the high number of C. pneumoniae infections detected in the early lesions of ''degenerative'' AVS sugg est that this pathogen may play an etiologic role in the development o f this disease. The validity of this relation requires additional stud y. (C)1997 by the American College of Cardiology.