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Serological Response to Chlamydia
Pneumoniae (C pn) in Adults with
Atherosclerosis Coronary Artery
Disease (ACHD) and Nonatherosclerotic
Patients at Córdoba, Argentina

C. Cuffini1, P. Adamo1, S. Becher1, M. Pedranti1,
M. Valle1, A. Ruíz Díaz4, L. Caeiro1, N. Villegas2,
F. Campos2, S. Aguiar3, L. A. Guzmán3 and M. Zapata1

1Instituto de Virología, Fac de Cs Médicas, U.N.C - 2 Hospital Córdoba
3
Sanatorio Allende - 4Instituto Nacional de Servicios Sociales para Jubilados y Pensionados

SUMMARY
Introduction: Atherosclerosis is characteristically silent. However, when a major artery is acutely occluded, the symptoms and signs may be dramatic. It is being recognized that the traditional risk factors, such as smoking, dyslipemia, hypertension, etc; do not explain the presence of atherosclerotic coronary heart disease in all patients.
C pn chronic infection is a probably risk factor for atherosclerosis through an endothelial damage or a systemic endogenous procoagulant and inflammatory activity. The results of this relationship "C pn - ACHD" varies considerably among different studies: Andersen et al. (1998), and others don't reporter this relationship in their results. In another hand, Mahony et al. (1999) and others finding a positive relationship.
Objective: This study was undertaken to analyze the serological response against to C pn in the atherosclerotic and nonatherosclerotic subjects from Córdoba, Argentina, and to determine a relationship between C pn chronic infection and ACHD.
Material and Methods: Serum samples were obtained from the Blood Banks and from The Surgery and Cardiology Services from 85 incident cases of ACHD and 200 nonatherosclerotic. subjects (mean age 50 years +/- 20) without pathologies associated atherosclerosis.
The prevalence of antibodies to C pn was determined with a micro-IFI using C pn -Twar slides ( BION) as the antigen. Sera were diluted between 1/32 to 1/512 for IgG antibodies.
Results: Table 1 shows the antibody percentage to C pn in two different groups.


Ig G titres between 32 and 512 were considered as evidence of postinfection, but antibodies in the rest were undetectable <1/32.
Statistical Analyses: The statistical analyses was made with progression stadystical X2.
Discussion: The majority of the population has been exposed to the organism. In the group of patient with a history of ACHD the prevalence was higher than the group of blood donors. The increased prevalence of C pn specific Ab in ACHD patients may be explained by polyclonal B-cell activation due to exposure of C pn present in atherosclerotic plaques.
These results provide strong support for the hypothesis that chronic C pn infection would be an other risk factor for ACHD.
Therapy with antibiotics can be a logical choice. If patients with an infectious basis of atherosclerosis can be identified, a therapy directed at eradication of the offending organism may be appropriate.

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   The possibility in recent year that chronic infection with C pn may represent a risk factor for atherosclerosis or a mechanism of rapid progression of ischemic heart disease, or both, has attracted the attention of investigation and clinical all over the world. A prospective study from Finland has indicated that chronic C pn infection is a significant risk factor for ACHD. (Saikku et al 1988, Lancet)

   This study was undertaken to analyze the serological response against to C pn in the atherosclerotic patients by the indirect microimmunofluorescence (micro-IFI) test and determine specific reactivities which might serve as indicators of C pn-associated atherosclerosis.

   Serum samples were obtained from the Blood Banks and from The Surgery and Cardiology Services between years 1999 and 2000 from 85 incident cases of ACHD and 200 nonatherosclerotic. subjects (mean age 50 years +/- 20) without pathologies associated atherosclerosis.

   The prevalence of antibodies to C pn was determined with a micro-IFI using C pn -Twar slides ( BION) as the antigen. Sera were diluted two-fold in PBS (pH 7,2), and applied at a dilution 1/32 to 1/512 for IgG antibodies. Fluorescein isothiocyanate conjugated human antisera anti IgG were diluted and applied to the slide. Control of different reagents was used. Table 1

   This study like other previously has shown a positive association between this infection agent and coronary artery diseases. These results provide strong support for the hypothesis that chronic C pn infection would be a risk factor for clinical atherosclerosis heart disease in the population studied of Córdoba, Argentina.
Studies will be necessary to determine whether C pn infection is involved as an etiologic factor in earlier phases of atherogenesis.

INTRODUCTION
   Atherosclerosis is characteristically silent. However, when a major artery is acutely occluded, the symptoms and signs may be dramatic. (critical stenosis, thrombosis, aneurysm, acute myocardial infarction). It is being recognized that the traditional risk factors, such as smoking, dyslipemia, hypertension and Diabetes mellitus, etc; do not explain the presence of atherosclerotic coronary heart disease (ACHD) in all patients.

   Chlamydia pneumoniae (C pn) chronic infection is a probably risk factor for atherosclerosis through an endothelial damage or a systemic endogenous procoagulant and inflammatory activity. The results of this relationship "C pn - ACHD" varies considerably among different studies: Andersen et al. (1998), Lindholt et al. (1998), and others don't reporter this relationship in their results. In another hand, Saikku et al. (1997), Mahony et al. (1999) and others finding a positive relationship between C pn and ACHD. This can be explained by using of different techniques and populations.

   This study was undertaken to analyze the serological response against to C pn in the atherosclerotic and nonatherosclerotic subjects from Córdoba, Argentina, and to determine a relationship between C pn chronic infection and ACHD.

STUDY POPULATION
   The study population included two different groups. The first group consisted of 200 blood donors visiting the Hospital Córdoba, the Sanatorium Allende, and a National Institute of Health of Elderly People (INSSJyP) from Córdoba, Argentina. The donor´s age ranged from 30 to 70 years old, with a mean age of 50 years old.

   The second group consisted of 85 patients with ACHD attending of Cardiology Services at the Hospital Córdoba and the Sanatorium Allende from Córdoba, Argentina. The patient's age ranged from 40 to 60 years old, with a mean age of 50 years old. Every serum sample from each subject in both group was stored at -35° C for further testing.

METHODS
   The prevalence of antibodies (Ab) to C pn was determined with a microimmunofluorescence (mIF) using C pn-Twar slides (BION) as the antigen (Fig. 1). Serum were diluted two-fold in PBS (pH:7.2) and applied at a dilution 1:32 to 1:512. Fluorescein isothiocyanate conjugated human antiserum anti-IgG were incubated to the slide. Control of different reagents was used.

STATISTICAL ANALYSES
   The statistical analyses was made with progression statistical X2.

RESULTS
   The prevalence of C pn-specific IgG antibodies in the healthy blood donor group and the ACHD patient group were 63.19% and 91.43%, respectively, determined by the mIF assay. (p<0.0004 and odds ratio = 6) (Table 2)

    Concentrations of antibodies had significant differences between both group; 80.21% of seropositive patients of ACHD group was positive at dilution > 1:64. (Table 3)

DISCUSSION
   The mIF test remains as the method of choice for determing the prevalence of C pn infections in a given community. Some researches claim that the C pn mIF test is highly specific. We don't have noted cross-reactions between C pn and others chlamydial species.

   The prevalence of C pn specific IgG Ab were high in study population. The interpretation of these studies is that the majority of the population has been exposed to the organism.

   The presence of C pn organism has been demonstrated in the atherosclerotic plaque itself using a variety of techniques.

    In the group of patient with a history of ACHD the prevalence was higher than the group of blood donors. The increased prevalence of C pn specific Ab in ACHD patients may be explained by polyclonal B-cell activation due to exposure of C pn present in atherosclerotic plaques.

    These results provide strong support for the hypothesis that chronic C pn infection would be an other risk factor for ACHD.

    Therapy with antibiotics can be a logical choice. If patients with an infectious basis of atherosclerosis can be identified, a therapy directed at eradication of the offending organism may be appropriate.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
apacher@fac.org.ar
apacher@satlink.com

Copyright© 1999-2001 Argentine Federation of Cardiology
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