C-Reactive Protein Levels and Viable Chlamydia
pneumoniae in Carotid Artery Atherosclerosis
S. Claiborne Johnston, MD, PhD; Louis M. Messina, MD; Warren S. Browner, MD, MPH;
Michael T. Lawton, MD; Caroline Morris, RN, CNS; Deborah Dean, MD, MPH;
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
Background and Purpose—An elevated serum level of C-reactive protein, an inflammatory marker, is an independent
predictor of stroke and coronary artery disease. To determine whether chronic infection with Chlamydia pneumoniae,
which has been identified in atherosclerotic plaques, is responsible for systemic inflammation, we studied the
association between serum C-reactive protein levels and infection of carotid artery atherosclerotic plaque with viable
C pneumoniae.
Methods—Serum C-reactive protein levels were obtained before endarterectomy for carotid artery stenosis. Plaques were
tested for C pneumoniae mRNA, an indicator of viability, and DNA by polymerase chain reaction of DNA and cDNA,
respectively.
Results—Forty-eight samples were studied, of which 18 (38%; 95% CI, 23 to 50) were infected with viable C pneumoniae
as evidenced by isolated chlamydial mRNA. All 18 of these samples, plus 1 additional sample, were positive for
chlamydial DNA. Serum C-reactive protein levels were higher in those with viable C pneumoniae compared with those
without infection (median, 8 mg/L versus undetectable; P⫽0.045 by Wilcoxon rank-sum test). In multivariable models,
the only independent predictor of the presence of viable C pneumoniae was a detectable C-reactive protein level (odds
ratio, 4.2; 95% CI, 1.1 to 17; P⫽0.04).
Conclusions—Viable C pneumoniae are present in a substantial portion of carotid artery atherosclerotic plaques and are
associated with increased serum C-reactive protein levels. These findings may explain the link between elevated
C-reactive protein levels and the risk of cardiovascular disease and stroke but should be reproduced in a larger cohort.
(Stroke. 2001;32:2748-2752.)
Key Words: atherosclerosis 䡲 carotid arteries 䡲 Chlamydia pneumoniae 䡲 C-reactive protein 䡲 inflammation
C
-reactive protein is a sensitive indicator of acute and
chronic inflammation.1 In apparently healthy men and
women, an elevated serum level of C-reactive protein is a
predictor of long-term risk of myocardial infarction and
stroke.2– 4 It is also an independent predictor of the risk of
cardiovascular events in patients with coronary artery disease.5 The association between serum C-reactive protein
levels and subsequent risk of stroke, myocardial infarction,
and death from cardiac causes supports the importance of
inflammation in the pathogenesis of cerebrovascular and
coronary artery disease.5,6
Focal inflammation is present in atherosclerotic plaques
and has been associated with the progression of vascular
stenosis and its complications.6 –9 Chronic infection of arteries
has been proposed as a cause of inflammation and a contributor to the initiation and progression of atherosclerosis.
Polymerase chain reaction (PCR), immunocytochemical
staining, and electron microscopy are among the techniques
that have demonstrated evidence of Chlamydia pneumoniae
infection in coronary and carotid artery plaques.10 –16 Detection of viable organisms, a clearer indicator of ongoing
infection, has been more difficult. In 4 studies, viable
C pneumoniae has been cultured from a small proportion of
atherosclerotic plaques.12,14,17,18 In another study, evidence of
viable C pneumoniae was found in 10 of 30 patients by
isolation of RNA and reverse-transcriptase (RT) PCR.19
Chronic infection of blood vessels with C pneumoniae
could lead to elevation of C-reactive protein levels and
contribute to the instability or progression of atherosclerotic
plaques.20 –23 Several studies have found an association
between C-reactive protein and serological evidence of
C pneumoniae infection, whereas others have not.24 –29 These
variable results may be explained by poor correlation between positive chlamydial serologies and evidence of plaque
Received July 16, 2001; final revision received August 21, 2001; accepted September 5, 2001.
From Neurovascular Service, Department of Neurology (S.C.J., C.M.); Division of Vascular Surgery, Department of Surgery (L.M.M.); Department
of Neurological Surgery (M.T.L.); and Division of Infectious Diseases, Department of Medicine (D.D.), University of California, San Francisco;
California Pacific Medical Center Research Institute, San Francisco (W.S.B.); and Children’s Hospital of Oakland Research Institute, Oakland, Calif
(D.D.).
Correspondence to S. Claiborne Johnston, MD, PhD, Department of Neurology, Box 0114, University of California, San Francisco, 505 Parnassus Ave,
M-798, San Francisco, CA 94143-0114. E-mail [email protected]
© 2001 American Heart Association, Inc.
Stroke is available at http://www.strokeaha.org
2748
Johnston et al
infection.12,16,18,30 One study compared C-reactive protein
levels in patients with and without PCR evidence of
C pneumoniae in atherosclerotic plaques and failed to find a
statistically significant difference.16 Thus, the connection
between C pneumoniae plaque infection, systemic inflammation, and symptomatic vascular disease remains uncertain. To
determine whether viable C pneumoniae organisms are present in atherosclerotic plaques and whether these organisms
are associated with inflammation and the risk of stroke, we
evaluated vascular risk factors, signs and symptoms of
infection, preoperative serum C-reactive protein levels, and
presence of viable C pneumoniae in carotid tissue in a
prospective study of patients undergoing elective carotid
endarterectomy.
Subjects and Methods
Subjects
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
Between March 1998 and August 2000, all patients scheduled for
elective carotid endarterectomy with preoperative evaluations at the
University of California, San Francisco, were approached for participation in the study, which was approved by the local institutional
review board for human research. All those providing consent from
whom carotid plaque was available were enrolled. A clinician
completed a structured interview to obtain information on risk
factors for atherosclerosis (including elevated cholesterol, hypertension, diabetes, obesity, coronary artery disease, and smoking history), recent use of antibiotics, and signs and symptoms that might be
considered compatible with C pneumoniae infection (questionnaire
available at www.neurology.ucsf.edu), although these infections
may be asymptomatic in many cases. Medical records were reviewed
to obtain information about medical history and medications during
the prior year and at presentation.
Symptomatic carotid arteries were defined as those associated
with stroke or transient ischemic attack. An operation on a previously treated artery was defined as a repeated endarterectomy.
Antibiotics considered effective in treating C pneumoniae included
tetracycline, doxycycline, erythromycin, clarithromycin, azithromycin, and ofloxacin. Symptoms and diagnoses of infection and
antibiotic usage were recorded if they occurred during the year
before surgery. Cough, sore throat, nasal congestion, and sinus
congestion were defined as symptoms of upper respiratory infection.
Respiratory infections included diagnoses of common cold, flu,
pneumonia, bronchitis, and sinusitis.
C-Reactive Protein Assay
All blood samples were drawn before surgery. C-reactive protein
levels were determined with fixed-rate nephelometry (Nichols Institute, Quest Diagnostics), the most sensitive test available at study
initiation; the technique is sensitive to levels ⬎4 mg/L.31 Levels
below the detection threshold (⬍4 mg/L) were defined as not
detectable.
Carotid Samples
Atherosclerotic tissue was removed by the operating physician using
standard surgical techniques. The tissue was sectioned immediately
through the center of the widest portion of arterial wall. One section
was placed in a sterile Eppendorf tube and another in a tube
containing 500 ␮L RNAzol B (Tel-Test, Inc). Both vials were stored
at ⫺80°C until processed. DNA was extracted and purified as
previously described.32–34 We performed PCR to identify chlamydial
infection in carotid atherosclerotic plaques using genus-specific
primers to detect any of the 3 chlamydial species (C trachomatis,
C pneumoniae, or C psittaci). We used nested PCR in positive-PCR
specimens to determine the chlamydial species present.33–35 To
confirm appropriate size, PCR products were compared with
molecular-weight markers by electrophoresis on an agarose gel.
C-Reactive Protein and C pneumoniae
2749
Messenger RNA was extracted from the tissue samples in accordance with the manufacturer’s protocol (Tel-Test, Inc) and subjected
to RT-PCR to generate cDNA for PCR amplification.36 The cDNA
was subjected to PCR and agarose gel size verification as described
above. In addition, primers specific for HPRT, a housekeeping gene,
were used in PCR for each cDNA sample to determine the adequacy
of the sample; all samples were amplified by these primers. Quantification of bacterial load was measured in all samples positive for
C pneumoniae by use of competitive PCR with known amounts of a
polycompetitor cDNA containing C pneumonia. The polycompetitor
contains an insert that increases its molecular weight compared with
the wild type.37 Briefly, the polycompetitor was used in concentrations of 1, 10, 50, and 100 copies and run with each batch of patient
samples for the PCR. A master mix was created that included all the
ingredients for PCR except for the patient and polycompetitor
samples. The master mix was divided equally among these samples;
the respective sample cDNA or polycompetitor sample was added to
the respective tube; and all tubes were subjected to the same PCR
thermocycling parameters at the same time. Ten microliters of each
patient and polycompetitor sample was run on a 1.5% agarose gel
stained with ethidium bromide. The quantity of cDNA in the sample
was determined by comparison with the results for the 4 concentrations of polycompetitor with the use of a Bio-Rad gel documentation
system according to the manufacturer’s instructions. Samples that
contained ⱖ1 copy of mRNA in the quantitative assay were
considered to have viable organisms.
Statistical Analysis
Dichotomous variables were compared with Pearson’s ␹2 test or
Fisher’s exact test when any cell of a 2⫻2 table was ⬍5. Exact 95%
CIs for prevalent C pneumoniae were calculated by use of exact
binomial probabilities. C-reactive protein levels, age, and pack-years
of smoking were compared with the Wilcoxon rank-sum test,
because these variables were not normally distributed. Multivariable
logistic regression analysis was performed, including all variables
associated with the presence of viable C pneumoniae (at P⬍0.20)
and removing those no longer contributing (at P⬎0.10) in a stepwise
manner. All statistical analyses were performed with the STATA
statistical package (version 6.0).
Results
Seventy-four patients were scheduled for elective carotid
endarterectomy during the study period. Scheduling prevented enrollment of 26 patients (most commonly because
the carotid plaque was removed when laboratory staff was
unavailable); 1 patient refused consent; and plaque could not
be removed intact in 2 others.
A total of 48 endarterectomy samples were obtained from
46 patients (mean⫾SD age, 72⫾8 years), 14 (30%) of whom
were female. In 15 patients (31%), the treated carotid artery
was associated with symptoms caused by stroke or transient
ischemic attack; the remaining patients were asymptomatic.
The procedure was a reoperation in 4 patients (8%). Vascular
risk factors were common, including smoking (n⫽37), hypercholesterolemia (n⫽33), hypertension (n⫽31), and diabetes mellitus (n⫽10). Of the 44 patients who provided information on signs and symptoms of infection, 35 (80%)
identified a diagnosis or symptoms of infection in the year
before endarterectomy, most frequently consistent with respiratory infection (n⫽32, 73%).
Serum C-reactive protein levels before endarterectomy
ranged from undetectable to 86 mg/L, with a median below
the detection threshold; 21 patients had detectable levels.
Detectable C-reactive protein levels were associated with a
2750
Stroke
December 2001
Characteristics of Patients by Presence of Viable C pneumoniae and Detectable Serum C-Reactive Protein
Viable C. pneumoniae
Present
(n⫽18)
C-Reactive Protein
Absent
(n⫽30)
P*
Detectable
(n⫽21)
Not Detectable
(n⫽27)
P*
Age (mean⫾SD) y
71⫾11
73⫾8
0.42
70⫾10
73⫾8
0.25
Female sex, n (%)
5 (28)
10 (33)
0.69
7 (33)
8 (30)
0.78
18 (100)
25 (83)
0.14
19 (90)
24 (89)
1.00
Symptomatic carotid, n (%)
6 (33)
9 (30)
0.81
6 (29)
9 (33)
0.72
Repeated endarterectomy, n (%)
1 (6)
3 (10)
1.00
2 (10)
2 (7)
1.00
15 (88)
22 (79)
0.69
18 (86)
19 (79)
0.71
5 (29)
4 (14)
0.27
4 (19)
5 (21)
1.00
Smoking (mean⫾SD), pack-y
47⫾37
40⫾41
0.41
45⫾40
41⫾39
0.84
Hypercholesterolemia, n (%)
10 (56)
23 (77)
0.13
13 (62)
20 (74)
0.53
Hypertension, n (%)
11 (61)
20 (67)
0.70
13 (62)
18 (67)
0.73
5 (28)
5 (17)
0.36
4 (19)
6 (22)
1.00
10 (56)
14 (47)
0.55
12 (57)
12 (44)
0.38
7 (41)
8 (29)
0.38
8 (38)
7 (29)
0.53
0.14
13 (65)
8 (30)
0.02
Non-Hispanic, white
Ever smoker, n (%)
Current smoker, n (%)
Diabetes mellitus, n (%)
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
Coronary artery disease, n (%)
Overweight, n (%)
Antibiotics, symptoms, and diagnosed infections in the prior year, n (%)
Prescribed antibiotics
10 (59)
11 (39)
Prescribed antibiotics covering chlamydia
3 (18)
3 (10)
0.65
2 (10)
4 (15)
0.69
Fever
4 (25)
5 (18)
0.70
7 (33)
2 (9)
0.06
Cough
4 (25)
8 (29)
1.00
7 (33)
5 (22)
0.39
Nasal congestion
7 (44)
9 (32)
0.44
9 (43)
7 (30)
0.39
Sinus congestion
6 (38)
7 (25)
0.38
5 (24)
8 (35)
0.43
Sore throat
6 (38)
5 (18)
0.15
8 (38)
3 (13)
0.08
Vomiting
4 (25)
0 (0)
0.01
4 (19)
0 (0)
0.04
Diarrhea
4 (25)
3 (11)
0.23
6 (29)
1 (4)
0.04
Bladder discomfort
2 (13)
1 (4)
0.54
3 (14)
0 (0)
0.10
Any symptom of respiratory infection
9 (56)
16 (57)
1.00
12 (57)
13 (57)
1.00
Any symptom of infection
12 (75)
16 (57)
0.33
15 (71)
13 (57)
0.31
Common cold
10 (63)
15 (54)
0.56
13 (62)
12 (52)
0.52
Flu
2 (13)
2 (7)
0.61
2 (10)
2 (9)
1.00
Pneumonia
0 (0)
2 (7)
0.53
1 (5)
1 (4)
1.00
Bronchitis
3 (19)
3 (11)
0.65
3 (14)
3 (13)
1.00
Sinusitis
1 (6)
4 (14)
0.64
0 (0)
5 (22)
0.05
Respiratory infection
11 (69)
15 (54)
0.33
13 (62)
13 (57)
0.72
Any diagnosed infection
13 (81)
16 (57)
0.19
15 (71)
14 (61)
0.46
Any symptom or diagnosis of infection
15 (94)
20 (71)
0.12
17 (81)
18 (78)
1.00
*Derived from the Wilcoxon rank-sum test for age and pack-years; for dichotomous outcomes, Fisher’s exact test was used when
any cell value in a 2⫻2 table was ⬍5, and Pearson’s ␹2 test was used for others.
history of vomiting, diarrhea, or the taking of antibiotics in
the prior year (the Table).
PCR revealed evidence of C pneumoniae in 19 carotid
plaques (40%). Eighteen of these showed evidence of viable
C pneumoniae (38%; 95% CI, 23 to 50) on the basis of the
presence of chlamydial RNA. Two patients had bilateral
endarterectomies; 1 had evidence of viable C pneumoniae in
both plaques, whereas neither plaque from the other patient
was infected. Patients with viable C pneumoniae were somewhat more likely to report signs and symptoms of infections
in the prior year (the Table).
Serum C-reactive protein levels were greater in patients with
viable C pneumoniae than in those without evidence of viable
chlamydial organisms (median, 8 mg/L versus not detectable;
P⫽0.045; the Figure). Viable C pneumoniae were twice as
common in those with detectable serum C-reactive protein levels
than in other patients [52% (11 of 21) versus 26% (7 of 27);
P⫽0.06]. In multivariable models, the only independent predictor of the presence of viable C pneumoniae was a detectable
C-reactive protein level (odds ratio, 4.2; 95% CI, 1.1 to 17;
P⫽0.04); the presence of signs or symptoms of infection in the
prior year was retained in the model but was not a significant
predictor (odds ratio, 6.6; 95% CI, 0.7 to 64; P⫽0.10). No other
demographic characteristics or vascular risk factors were predictors. The presence of viable C pneumoniae was not associated
with neurological symptoms at presentation.
Johnston et al
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
C-reactive protein level by presence of viable C pneumoniae as
detected by PCR of cDNA generated by RT–PCR of mRNA isolated from carotid artery atherosclerotic plaques. Median serum
C-reactive protein levels (solid lines) were greater for those with
viable C pneumoniae (P⫽0.045). Dashed line represents the
detection limit of the test.
Discussion
Our study of atherosclerotic carotid arteries suggests that
chronic infection with viable C pneumoniae is common:
⬇40% of plaques removed at endarterectomy had evidence of
viable organisms. Infection appeared to be unrelated to
vascular risk factors, signs and symptoms suggestive of
infection, or presentation with stroke or transient ischemic
attack. Similar to results of prior studies,12,15,20 we found that
vascular infection with C pneumoniae appears to be
asymptomatic.
Other groups have demonstrated viable C pneumoniae
from cultures of atherosclerotic plaques in the coronary,12,18
femoral,17 and carotid arteries,14,17 albeit in only 4% to 16%
of specimens. A single study used RT-PCR in carotid
endarterectomy tissue and found evidence of viable C pneumoniae in 10 of 30 patients,19 a detection rate much greater
than those seen in studies that used culture. We found a
similar rate of infection, which was corroborated by PCR of
independently extracted DNA. Furthermore, we showed that
plaques with viable infections contained a large number of
organisms, suggesting that these infections could be clinically
relevant. Characteristics of the referral population we studied—largely non-Hispanic white and referred for elective
treatment—may have influenced the prevalence of C pneumoniae we found.
This is the first study to demonstrate higher serum
C-reactive protein levels in patients with viable carotid
C pneumoniae. This association may explain why the
C-reactive protein level is a risk factor for stroke and
cardiovascular events: Higher levels may indicate chronic
arterial wall infection with C pneumoniae, which in turn may
contribute to plaque progression.20 –23 Recent in vitro studies
have shown that C pneumoniae infection of human smooth
C-Reactive Protein and C pneumoniae
2751
muscle cells results in production of interleukin-6,38 which is
the major regulator of C-reactive protein production,39 providing a plausible pathophysiological link.
Our findings could also be explained by an unrecognized
factor that increases C-reactive protein levels and increases
the risk of C pneumoniae infection. For example, an underlying susceptibility to infection could be associated with both
elevated C-reactive protein levels and C pneumoniae infection without a causal link between the 2 factors. We did not
identify such a factor in this study, but our sample was small.
Others have studied C-reactive protein in C pneumoniae
infection, but they have not attempted to detect viable
organisms. One study that compared C-reactive protein levels
in those with and without PCR evidence of C pneumoniae
DNA16 reported that mean levels were higher (but not
significantly so) in those who were PCR positive. Several
groups have studied the association between C-reactive protein and positive serologies for C pneumoniae, with conflicting results.24 –29 Recent studies have shown, however, that
serology is a poor marker for the presence of C pneumoniae
DNA or RNA.12,16,18,30
If chronic vascular infection with C pneumoniae is responsible for C-reactive protein elevation, treatment should be
associated with reduced C-reactive protein levels. Three
small trials have tested whether antibiotics directed at
C pneumoniae reduce vascular events and inflammatory
markers in high-risk patients. All 3 studies demonstrated
reductions in C-reactive protein levels in those treated with
antibiotics,40 – 42 and 1 study demonstrated a reduction in
vascular events.40 The reduction in C-reactive protein after
treatment could be due to eradication of C pneumoniae or,
alternatively, of other infectious agents treated by these
antibiotics.
The association that we found between the presence of
viable C pneumoniae and detectable levels of C-reactive
protein should be reproduced in a larger group of patients.
More sensitive tests for C-reactive protein are now available
and could provide additional information, particularly because cohort studies have shown that differences in levels
below the detection limit of our assay are associated with the
risk of cardiovascular events.3,4 The fact that we detected a
difference with a less sensitive, first-generation test suggests
that the association between levels of C-reactive protein and
the presence of viable C pneumoniae is strong. However,
because the positive predictive value of a detectable
C-reactive protein level is low with the less sensitive test, it
should not be used as a screening test to identify those with
viable C pneumoniae.
Acknowledgments
This study was funded by the Pacific Vascular Research Foundation.
Dr Johnston is supported by NIH NS02042; Dr Browner is supported
by NIH NS36016; Dr Dean is supported by NIH EY/AI12219 and
AI39499. We thank Jocelyn Phegan and Amy Helmer for excellent
technical assistance.
References
1. Young B, Gleeson M, Cripps AW. C-reactive protein: a critical review.
Pathology. 1991;23:118 –124.
2752
Stroke
December 2001
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
2. Kuller LH, Tracy RP, Shaten J, Meilahn EN. Relation of C-reactive
protein and coronary heart disease in the MRFIT nested case-control
study: Multiple Risk Factor Intervention Trial. Am J Epidemiol. 1996;
144:537–547.
3. Ridker PM, Cushman M, Stampfer MJ, Tracy RP, Hennekens CH.
Inflammation, aspirin, and the risk of cardiovascular disease in apparently
healthy men. N Engl J Med. 1997;336:973–979.
4. Ridker PM, Buring JE, Shih J, Matias M, Hennekens CH. Prospective
study of C-reactive protein and the risk of future cardiovascular events
among apparently healthy women. Circulation. 1998;98:731–733.
5. Rader DJ. Inflammatory markers of coronary risk. N Engl J Med. 2000;
343:1179 –1182.
6. Ross R. Atherosclerosis: an inflammatory disease. N Engl J Med. 1999;
340:115–126.
7. Munro JM, Cotran RS. The pathogenesis of atherosclerosis: atherogenesis
and inflammation. Lab Invest. 1988;58:249 –261.
8. Kohchi K, Takebayashi S, Hiroki T, Nobuyoshi M. Significance of
adventitial inflammation of the coronary artery in patients with unstable
angina: results at autopsy. Circulation. 1985;71:709 –716.
9. Sato T, Takebayashi S, Kohchi K. Increased subendothelial infiltration of
the coronary arteries with monocytes/macrophages in patients with
unstable angina: histological data on 14 autopsied patients. Atherosclerosis. 1987;68:191–197.
10. Kuo CC, Grayston JT, Campbell LA, Goo YA, Wissler RW, Benditt EP.
Chlamydia pneumoniae (TWAR) in coronary arteries of young adults
(15–34 years old). Proc Natl Acad Sci U S A. 1995;92:6911– 6914.
11. Grayston JT, Kuo CC, Coulson AS, Campbell LA, Lawrence RD, Lee
MJ, Strandness ED, Wang SP. Chlamydia pneumoniae (TWAR) in atherosclerosis of the carotid artery. Circulation. 1995;92:3397–3400.
12. Ramirez JA. Isolation of Chlamydia pneumoniae from the coronary artery
of a patient with coronary atherosclerosis: the Chlamydia pneumoniae/
Atherosclerosis Study Group. Ann Intern Med. 1996;125:979 –982.
13. Maass M, Bartels C, Krüger S, Krause E, Engel PM, Dalhoff K. Endovascular presence of Chlamydia pneumoniae DNA is a generalized phenomenon in atherosclerotic vascular disease. Atherosclerosis. 1998;
140(suppl 1):S25–S30.
14. Jackson LA, Campbell LA, Kuo CC, Rodriguez DI, Lee A, Grayston JT.
Isolation of Chlamydia pneumoniae from a carotid endarterectomy
specimen. J Infect Dis. 1997;176:292–295.
15. LaBiche R, Koziol D, Quinn TC, Gaydos C, Azhar S, Ketron G, Sood S,
DeGraba TJ. Presence of Chlamydia pneumoniae in human symptomatic
and asymptomatic carotid atherosclerotic plaque. Stroke. 2001;32:
855– 860.
16. Berger M, Schröder B, Daeschlein G, Schneider W, Busjahn A,
Buchwalow I, Luft FC, Haller H. Chlamydia pneumoniae DNA in noncoronary atherosclerotic plaques and circulating leukocytes. J Lab Clin
Med. 2000;136:194 –200.
17. Apfalter P, Loidl M, Nadrchal R, Makristathis A, Rotter M, Bergmann M,
Polterauer P, Hirschl AM. Isolation and continuous growth of Chlamydia
pneumoniae from arterectomy specimens. Eur J Clin Microbiol Infect
Dis. 2000;19:305–308.
18. Maass M, Bartels C, Engel PM, Mamat U, Sievers HH. Endovascular
presence of viable Chlamydia pneumoniae is a common phenomenon in
coronary artery disease. J Am Coll Cardiol. 1998;31:827– 832.
19. Esposito G, Blasi F, Allegra L, Chiesa R, Melissano G, Cosentini R,
Tarsia P, Dordoni L, Cantoni C, Arosio C, Fagetti L. Demonstration of
viable Chlamydia pneumoniae in atherosclerotic plaques of carotid
arteries by reverse transcriptase polymerase chain reaction. Ann Vasc
Surg. 1999;13:421– 425.
20. Byrne GI, Kalayoglu MV. Chlamydia pneumoniae and atherosclerosis:
links to the disease process. Am Heart J. 1999;138:S488 –S490.
21. Danesh J, Collins R, Peto R. Chronic infections and coronary heart
disease: is there a link? Lancet. 1997;350:430 – 436.
22. Gurfinkel E, Bozovich G. Chlamydia pneumoniae: inflammation and
instability of the atherosclerotic plaque. Atherosclerosis. 1998;140(suppl
1):S31–S35.
23. Ridker PM. Inflammation, infection, and cardiovascular risk: how good is
the clinical evidence? Circulation. 1998;97:1671–1674.
24. Roivainen M, Viik-Kajander M, Palosuo T, Toivanen P, Leinonen M,
Saikku P, Tenkanen L, Manninen V, Hovi T, Mänttäri M. Infections,
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
inflammation, and the risk of coronary heart disease. Circulation. 2000;
101:252–257.
Toss H, Gnarpe J, Gnarpe H, Siegbahn A, Lindahl B, Wallentin L.
Increased fibrinogen levels are associated with persistent Chlamydia
pneumoniae infection in unstable coronary artery disease. Eur Heart J.
1998;19:570 –577.
Zhu J, Quyyumi AA, Norman JE, Csako G, Waclawiw MA, Shearer GM,
Epstein SE. Effects of total pathogen burden on coronary artery disease
risk and C-reactive protein levels. Am J Cardiol. 2000;85:140 –146.
Ridker PM, Hennekens CH, Buring JE, Kundsin R, Shih J. Baseline IgG
antibody titers to Chlamydia pneumoniae, Helicobacter pylori, herpes
simplex virus, and cytomegalovirus and the risk for cardiovascular
disease in women. Ann Intern Med. 1999;131:573–577.
Ridker PM, Kundsin RB, Stampfer MJ, Poulin S, Hennekens CH. Prospective study of Chlamydia pneumoniae IgG seropositivity and risks of
future myocardial infarction. Circulation. 1999;99:1161–1164.
Hoffmeister A, Rothenbacher D, Wanner P, Bode G, Persson K, Brenner
H, Hombach V, Koenig W. Seropositivity to chlamydial lipopolysaccharide and Chlamydia pneumoniae, systemic inflammation and stable coronary artery disease: negative results of a case-control study. J Am Coll
Cardiol. 2000;35:112–118.
Chiu B, Viira E, Tucker W, Fong IW. Chlamydia pneumoniae, cytomegalovirus, and herpes simplex virus in atherosclerosis of the carotid artery.
Circulation. 1997;96:2144 –2148.
Berk BC, Weintraub WS, Alexander RW. Elevation of C-reactive protein
in “active” coronary artery disease. Am J Cardiol. 1990;65:168 –172.
Dean D, Oudens E, Bolan G, Padian N, Schachter J. Major outer
membrane protein variants of Chlamydia trachomatis are associated with
severe upper genital tract infections and histopathology in San Francisco.
J Infect Dis. 1995;172:1013–1022.
Dean D, Shama A, Schachter J, Dawson CR. Molecular identification of
an avian strain of Chlamydia psittaci causing severe keratoconjunctivitis
in a bird fancier. Clin Infect Dis. 1995;20:1179 –1185.
Vichinsky EP, Neumayr LD, Earles AN, Williams R, Lennette ET, Dean
D, Nickerson B, Orringer E, McKie V, Bellevue R, Daeschner C, Manci
EA. Causes and outcomes of the acute chest syndrome in sickle cell
disease: National Acute Chest Syndrome Study Group. N Engl J Med.
2000;342:1855–1865.
Lietman T, Brooks D, Moncada J, Schachter J, Dawson C, Dean D.
Chronic follicular conjunctivitis associated with Chlamydia psittaci or
Chlamydia pneumoniae. Clin Infect Dis. 1998;26:1335–1340.
Phan R, Pham S, Dean D. Characterization of the immune response in
conjunctival scarring due to Chlamydia trachomatis among Vietnamese
patients. In: Proceedings of the American Society of Microbiology
Annual Meeting; May 4 – 8, 1997; Miami, Fla; 209.
Reiner SL, Zheng S, Corry DB, Locksley RM. Constructing polycompetitor cDNAs for quantitative PCR. J Immunol Methods. 1993;165:
37– 46.
Rödel J, Woytas M, Groh A, Schmidt KH, Hartmann M, Lehmann M,
Straube E. Production of basic fibroblast growth factor and interleukin 6
by human smooth muscle cells following infection with Chlamydia pneumoniae. Infect Immun. 2000;68:3635–3641.
Bataille R, Klein B. C-reactive protein levels as a direct indicator of
interleukin-6 levels in humans in vivo. Arthritis Rheum. 1992;35:
982–984.
Gurfinkel E, Bozovich G, Beck E, Testa E, Livellara B, Mautner B.
Treatment with the antibiotic roxithromycin in patients with acute nonQ-wave coronary syndromes: the final report of the ROXIS Study. Eur
Heart J. 1999;20:121–127.
Muhlestein JB, Anderson JL, Carlquist JF, Salunkhe K, Horne BD,
Pearson RR, Bunch TJ, Allen A, Trehan S, Nielson C. Randomized
secondary prevention trial of azithromycin in patients with coronary
artery disease: primary clinical results of the ACADEMIC study. Circulation. 2000;102:1755–1760.
Torgano G, Cosentini R, Mandelli C, Perondi R, Blasi F, Bertinieri G,
Tien TV, Ceriani G, Tarsia P, Arosio C, Ranzi ML. Treatment of Helicobacter pylori and Chlamydia pneumoniae infections decreases
fibrinogen plasma level in patients with ischemic heart disease. Circulation. 1999;99:1555–1559.
C-Reactive Protein Levels and Viable Chlamydia pneumoniae in Carotid Artery
Atherosclerosis
S. Claiborne Johnston, Louis M. Messina, Warren S. Browner, Michael T. Lawton, Caroline
Morris and Deborah Dean
Downloaded from http://stroke.ahajournals.org/ by guest on June 15, 2017
Stroke. 2001;32:2748-2752
doi: 10.1161/hs1201.099631
Stroke is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 2001 American Heart Association, Inc. All rights reserved.
Print ISSN: 0039-2499. Online ISSN: 1524-4628
The online version of this article, along with updated information and services, is located on the
World Wide Web at:
http://stroke.ahajournals.org/content/32/12/2748
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published
in Stroke can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office.
Once the online version of the published article for which permission is being requested is located, click
Request Permissions in the middle column of the Web page under Services. Further information about this
process is available in the Permissions and Rights Question and Answer document.
Reprints: Information about reprints can be found online at:
http://www.lww.com/reprints
Subscriptions: Information about subscribing to Stroke is online at:
http://stroke.ahajournals.org//subscriptions/