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Seropositivity against Chlamydia pneumoniae in patients with coronary atherosclerosis
F Romeo1, E Martuscelli, G Chirieolo
1Department of Cardiology, University of Rome Tor Vergata, Italy.
Insights
Antibiotic therapy for coronary artery disease (CAD) may only benefit a small subset of patients. This study found low Chlamydia pneumoniae seropositivity rates in CAD patients, suggesting targeted antibiotic use.
Area of Science:
- Cardiology
- Infectious Diseases
- Microbiology
Background:
- Antibiotic therapy for unstable coronary syndromes (ACS) has yielded variable results.
- Patient heterogeneity in previous trials may explain inconsistent outcomes.
- Chlamydia pneumoniae has been investigated as a potential contributor to atherosclerosis.
Purpose of the Study:
- To prospectively correlate the severity of coronary artery disease (CAD) with seropositivity against Chlamydia pneumoniae.
- To identify patient subgroups who might benefit from targeted antibiotic therapy.
Main Methods:
- Measured IgG and IgA seropositivity rates for Chlamydia pneumoniae in 110 CAD patients and 49 controls.
- Assessed traditional cardiovascular risk factors, including serum lipid profiles.
Main Results:
- No significant difference in Chlamydia pneumoniae IgG or IgA seropositivity rates between CAD patients (stable and unstable) and controls.
- Patients with CAD exhibited higher mean serum total cholesterol and triglyceride levels compared to controls.
- No significant differences were observed in HDL cholesterol or lipoprotein (a) levels between groups.
Conclusions:
- A small percentage of patients with CAD demonstrate seropositivity for Chlamydia pneumoniae.
- Antibiotic therapy may be rational only in selected CAD patients with confirmed Chlamydia pneumoniae infection.
- The lack of consistent benefits from antibiotic therapy in CAD trials may be due to treating patients without this specific infection.
Background:
Results of therapy in patients with unstable coronary syndromes with antibiotics directed against Chlamydia pneumoniae have been variable, perhaps due to the heterogeneity of patients in these trials.
Hypothesis:
The aim of the present study was to correlate the severity of coronary artery disease (CAD) with seropositivity against C. pneumoniae prospectively.
Methods:
We measured the frequency of seropositivity (IgG levels > or = 1/64 and IgA levels > or = 1/16 against Chlamydia pneumoniae) in 110 patients with CAD and in 49 controls.
Results:
As expected, traditional CAD risk factors were seen more often in patients with CAD than in controls. Mean values of total cholesterol (184 +/- 52 and 166 +/- 44 mg/dl, respectively) and triglyceride (143 +/- 60 and 112 +/- 63 mg/dl, respectively) in serum were significantly higher in patients with CAD than in controls (both p < 0.04). There were no significant differences between the two groups in serum high-density lipoprotein cholesterol (34 +/- 13 and 32 +/- 14 mg/dl, respectively) and lipoprotein (a) (Lp(a):241 +/- 247 and 223 +/- 263 mg/l, respectively) levels. The rate of IgG seropositivity was 52% (28/54) in patients with stable CAD, 41% (23/56) in patients with unstable CAD, and 35% in controls (p = NS). The rate of IgA seropositivity was 25% (14/54) in patients with stable CAD, 12% (6/49) in patients with unstable angina, and 12% (6/49) in controls (all p = NS).
Conclusions:
Only a small percentage of patients with CAD demonstrate seropositivity against Chlamydia pneumoniae. Antibiotic therapy in these selected patients, but not in the remaining patients, may be considered rational. These considerations may underlie the failure to see consistent benefits of antibiotic therapy in patients with CAD.