Prevalence of viable Chlamydia pneumoniae in peripheral blood mononuclear cells of healthy blood donors.
BACKGROUND
Demonstration of viable Chlamydia (Chlamydophila) pneumoniae in peripheral blood mononuclear cells (PBMNCs) is essential to understand the involvement of C. pneumoniae in atherosclerosis. Nevertheless, the prevalence of viable C. pneumoniae in the blood of healthy donors has not yet been studied.


METHODS
The presence of C. pneumoniae transcript in PBMNCs from blood of healthy human donors was assessed by real-time reverse transcription-polymerase chain reaction (RT-PCR) with primers for C. pneumoniae 16S rRNA, which is more sensitive than genomic-DNA-based analysis, and by the use of staining with fluorescein isothiocyanate-conjugated chlamydia monoclonal antibody (MoAb).


RESULTS
Thirteen of 70 donors (18.5%) showed the presence of bacterial transcript in cultured PBMNCs. The prevalence of bacterial detection and bacterial numbers was significantly increased in PBMNC cultures incubated with cycloheximide. Immunostaining of PBMNCs with antichlamydial MoAb also revealed the presence of bacterial antigen in the PBMNCs judged as positive. Nevertheless, cultivation of C. pneumoniae from all PCR-positive donors was unsuccessful. There was no significant correlation between the presence of chlamydia and either sex or current smoking habits. A possible age variation, however, in the presence of chlamydia in blood of healthy donors was suggested by the results obtained.


CONCLUSIONS
The bacterial transcripts in PBMNCs obtained from healthy donors were detected by the RT-PCR method. Viable C. pneumoniae may be present in healthy human PBMNCs.
Yamaguchi
Hiroyuki
H
Department of Infectious Disease, Division of Microbiology, Kyorin University School of Medicine, Tokyo, Japan. hiroyuki@sahs.med.osaka-u.ac.jp
Yamada
Masako
M
Uruma
Tomonori
T
Kanamori
Masato
M
Goto
Hajime
H
Yamamoto
Yoshimasa
Y
Kamiya
Shigeru
S
D000328:Adult; D000942:Antigens, Bacterial / Q000097:blood; D016470:Bacteremia / Q000382:microbiology*; D001782:Blood Donors; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000942:Antigens, Bacterial