Detection of Chlamydia pneumoniae in unexplained pulmonary hypertension

The pathogenesis of primary pulmonary hypertension is still unclear. The case of a 68-yr-old female patient who complained of recurrent dizzy spells and collapses over a period of 6 weeks and died of global cardiac failure is presented. Autopsy revealed severe pulmonary hypertension, slight chronic bronchitis, and bronchiolitis as well as intra-alveolar accumulation of macrophages. Chlamydiae were detected within the pulmonary arteries and in intramural and intra-alveolar macrophages by immunofluorescence, confocal laser scanning microscopy, scanning and transmission electron microscopy. Nested-polymerase chain reaction (PCR) and nonradioactive deoxyribonucleic acid (DNA) hybridization of PCR products from pulmonary arteries revealed Chlamydia pneumoniae DNA. Chlamydia pneumoniae has already been detected in atherosclerosis and in pulmonary emphysema. It can induce proliferation of smooth muscle cells. Chlamydia pneumoniae might be relevant in aggravation of primary pulmonary hypertension and might perhaps be a trigger factor in some cases.