title: Chlamydia pneumoniae infection is associated with coronary artery disease but not implicated in inducing plaque instability.
abstract: BACKGROUND
  Many authors have shown an association between Chlamydia pneumoniae (C. pneumoniae) infection and coronary artery disease. However, whether C. pneumoniae infection plays an important role in triggering an acute coronary event remains to be elucidated.
  
  
  METHODS
  Sixty-four consecutive patients with unstable angina (group A), 56 consecutive patients with stable exertional angina (group B) and 74 control subjects (group C) were studied. The IgM, IgG and IgA anti-C. pneumoniae titers were assessed (microimmunofluorescence test Labsystem), values > or =1:16, > or =1:32 and > or =1:16 being respectively considered positive.
  
  
  RESULTS
  IgM antibodies were found in 10.9% of group A and 12.5% of group B patients, whereas no subject of group C showed IgM titers (A vs. B, p=ns; C vs. A and B, p<0.05). Positive IgG titers were found in 76.6%, 82% and 44.6% in groups A, B and C, respectively (A vs. B, p=ns; C vs. A and B, p<0.05). Positive IgA titers were found in 62.5%, 61% and 31.1% in groups A, B and C, respectively (A vs. B, p=ns; C vs. A and B, p<0.05). Acute infection was observed in 10.9% and 12.5% of patients in groups A and B, respectively (p=ns); reinfection in 17% and 11%; no patient of the control group had signs of acute infection or reinfection. Chronic infection was observed in 34.4% and 37.5% in group A and B, respectively (p=ns).
  
  
  CONCLUSIONS
  C. pneumoniae infection is associated with coronary artery disease, but no difference in serology is present between unstable and stable angina. Therefore, it does not seem implicated in triggering an acute coronary event.
authors.affiliation: Department of Cardiovascular and Respiratory Sciences, "La Sapienza" University, Rome, Italy. silvio.romano@uniroma1.it
authors.forename: Silvio
authors.initials: S
authors.lastname: Romano
authors.forename: Maria
authors.initials: M
authors.lastname: Penco
authors.forename: Simona
authors.initials: S
authors.lastname: Fratini
authors.forename: Marisa
authors.initials: M
authors.lastname: Di Pietro
authors.forename: Rosa
authors.initials: R
authors.lastname: Sessa
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Piano
authors.forename: Francesco
authors.initials: F
authors.lastname: Fedele
authors.forename: Armando
authors.initials: A
authors.lastname: Dagianti
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000150:complications / Q000276:immunology / Q000382:microbiology; D000918:Antibody Specificity / Q000276:immunology; D023521:Chlamydophila Infections / Q000150:complications / Q000276:immunology / Q000382:microbiology*; D016993:Chlamydophila pneumoniae; D015941:Complement Hemolytic Activity Assay; D003324:Coronary Artery Disease / Q000150:complications / Q000276:immunology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M