Chlamydia pneumoniae DNA detection in peripheral blood mononuclear cells is predictive of vascular infection

Abdominal aortic aneurysm tissue and peripheral blood mononuclear cells (PB MC) of 41 consecutive subjects undergoing abdominal aortic aneurysm surgery were analyzed by polymerase chain reaction (PCR) for the presence of Chlam ydia pneumoniae, Mycoplasma pneumoniae, and Helicobacter pylori DNA. Twenty patients (49%) were positive for C, pneumoniae DNA-16 (39%) in both PBMC a nd aneurysm tissue, 3 (7.3%) in PBMC only, and 1 (2.4%) in the artery speci men only. Previous exposure to C. pneumoniae was confirmed in 19 (95%) of t he 20 PCR positive subjects by C, pneumoniae-specific serology, using the m icroimmunofluorescence test. None was positive for H. pylori or M pneumonia e DNA, either in the PBMC or in the artery specimens. In conclusion, carria ge of C. pneumoniae DNA is common both in PBMC and in abdominal aortic tiss ue from patients undergoing abdominal aneurysm surgery. Blood PCR may be a useful tool for identifying subjects carrying C. pneumoniae in the vascular wall.