Distribution of Chlamydia pneumoniae infection in the athersclerotic carotid artery.
OBJECTIVE
Chlamydia pneumoniae infection has recently become noteworthy in relation to atherosclerosis. We investigated by immunohistochemistry the distribution of C pneumoniae infection in the atherosclerotic carotid artery.


METHODS
Twenty carotid atherosclerotic lesions that were resected during carotid endarterectomy were investigated. Parallel sections were stained immunohistochemically with monoclonal antibodies for a C pneumoniae-specific antigen, macrophages, and smooth muscle cells.


RESULTS
Immunoreactivity for the C pneumoniae-specific antigen was observed in 11 of 20 specimens (55%), and intense immunoreactivity was observed in 7 of 20 (35%). C pneumoniae infection was observed in endothelial cells, macrophages and in smooth muscle cells that had migrated into the atheromatous plaque, as well as in smooth muscle cells and small arteries in the media underlying the atheromatous plaques. C pneumoniae infection was most prominently observed in smooth muscle cells. The severity of the infection as demonstrated by immunohistochemistry was not significantly related to general risk factors for atherosclerosis.


CONCLUSIONS
C pneumoniae widely infects endothelial cells, macrophages, and smooth muscle cells in the atherosclerotic carotid artery. The results of the present study can help us to understand how C pneumoniae infection contributes to the progression of carotid atherosclerosis.
Yamashita
K
K
Department of Neurosurgery, Yamaguchi University, School of Medicine, Ube, Japan. yamasita-ygc@umin.u-tokyo.ac.jp
Ouchi
K
K
Shirai
M
M
Gondo
T
T
Nakazawa
T
T
Ito
H
H
D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial / Q000032:analysis; D001161:Arteriosclerosis / Q000382:microbiology*; D002340:Carotid Artery Diseases / Q000382:microbiology*; D002690:Chlamydia Infections / Q000473:pathology*; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification*; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000473:pathology; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D012307:Risk Factors
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial