Discordant detection of Chlamydia pneumoniae in patients with carotid artery disease using polymerase chain reaction, immunofluorescence microscopy and serological methods.
OBJECTIVE
To determine the presence of Chlamydia pneumoniae in carotid plaque and peripheral blood mononuclear cells (PBMCs) using a combination of serology, direct antigen detection by immunofluorescence (IF) microscopy and polymerase chain reaction (PCR), and to compare the results obtained from each assay.


METHODS
A total of 54 atherosclerotic carotid plaques were tested for the presence of Chlamydia by PCR and IF methods. Of these 54 patients with carotid artery disease (CAD), 43 were also tested for the presence of C. pneumoniae DNA in PBMCs and for Chlamydia antibodies using two methods, the Medac Chlamydien rELISA and Focus Chlamydia microimmunofluorescence (MIF) methods.


RESULTS
Eighteen of the 54 (33%) carotid specimens were positive for the presence of C. pneumoniae DNA, whereas only two of 43 (5%) patients had C. pneumoniae DNA present within their PBMC fraction. Chlamydial antibodies were detected by MIF and/or rELISA in 56% (24/43) of the patients tested. None of the 43 patients was C. pneumoniae positive in all of the test specimens (plaque, PBMCs and serum).


CONCLUSIONS
Chlamydia pneumoniae is commonly found in Australian patients with CAD. Serology and PCR-based detection of C. pneumoniae in PBMCs and plaque give highly discordant results.
Cochrane
Melanie
M
School of Life Sciences, Queensland University of Technology, Brisbane, Australia.
Pospischil
Andreas
A
Walker
Philip
P
Gibbs
Harry
H
Timms
Peter
P
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000907:Antibodies, Bacterial; D002340:Carotid Artery Diseases / Q000382:microbiology*; D002690:Chlamydia Infections / Q000175:diagnosis*; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification*; D004269:DNA, Bacterial; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000382:microbiology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D012307:Risk Factors
D000907:Antibodies, Bacterial; D004269:DNA, Bacterial