title: CagA antigen of Helicobacter pylori and coronary instability: insight from a clinico-pathological study and a meta-analysis of 4241 cases.
abstract: BACKGROUND
  Cytotoxin-associated gene-A (CagA) antigen is expressed by some virulent strains of Helicobacter pylori (H. pylori). The role of CagA antigen in coronary instability is unknown. We performed a clinico-pathological study and a meta-analysis in the attempt to shed new light on this complex issue.
  
  
  METHODS
  In the clinico-pathological study, 38 patients with unstable angina (UA), 25 patients with stable angina (SA), 21 patients with normal coronary arteries (NCA) and 50 age and sex matched healthy volunteers were enrolled. Serology for CagA was assessed in all patients. Specimens of atherosclerotic plaques were obtained from all patients by directional coronary atherectomy, and prepared for immunohistochemistry using anti-CagA monoclonal antibodies. The meta-analysis includes 9 studies assessing the association between seropositivity to CagA strains and acute coronary events.
  
  
  RESULTS
  The titre of anti-CagA antibodies was significantly higher in patients with unstable angina (161+/-90 RU/ml) compared to those with stable angina (83+/-59 RU/ml p<0.02), NCA (47.3+/-29 RU/ml p<0.01) and healthy controls (73+/-69 p<0.02). Anti-CagA antibodies recognized antigens localized inside coronary atherosclerotic plaques in all specimens from both stable and unstable patients. In the meta-analysis, seropositivity to CagA was significantly associated with the occurrence of acute coronary events with an odds ratio (OR) of 1.34 (95% CI, 1.15-1.58, p=0.0003).
  
  
  CONCLUSIONS
  Taken together these findings suggest that in a subset of patients with unstable angina, an intense immune response against CagA-positive H. pylori strains might be critical to precipitate coronary instability mediated by antigen mimicry between CagA antigen and a protein contained in coronary atherosclerotic plaques.
authors.affiliation: Emergency Department, Catholic University of Sacred Heart, Rome, Italy. francesco.franceschi@rm.unicatt.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Franceschi
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Niccoli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ferrante
authors.forename: Antonio
authors.initials: A
authors.lastname: Gasbarrini
authors.forename: Alfonso
authors.initials: A
authors.lastname: Baldi
authors.forename: Marcello
authors.initials: M
authors.lastname: Candelli
authors.forename: Florinda
authors.initials: F
authors.lastname: Feroce
authors.forename: Nathalie
authors.initials: N
authors.lastname: Saulnier
authors.forename: Micaela
authors.initials: M
authors.lastname: Conte
authors.forename: Davide
authors.initials: D
authors.lastname: Roccarina
authors.forename: Gaetano A
authors.initials: GA
authors.lastname: Lanza
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gasbarrini
authors.forename: Silveri Nicolò
authors.initials: SN
authors.lastname: Gentiloni
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D003324:Coronary Artery Disease / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D003331:Coronary Vessels / Q000276:immunology; D005260:Female; D016481:Helicobacter Infections / Q000453:epidemiology / Q000276:immunology* / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori