title: Neopterin levels in patients with coronary artery disease are independent of Chlamydia pneumoniae seropositivity.
abstract: BACKGROUND
  Chronic infection with Chlamydia pneumoniae (Cpn) has been associated with atherosclerotic cardiovascular disease in sero-epidemiological, pathological and animal-model studies. Inflammation and immune activation has been proposed as the pathophysiological link between chronic infection and atherosclerosis. The aim of this study was to assess whether Cpn seropositivity is associated with serum neopterin concentrations, a marker of macrophage activation, in patients with stable and unstable angina pectoris.
  
  
  METHODS
  We examined 100 patients with angiographically documented coronary artery disease: 60 patients had chronic stable angina and 40 had Braunwald class III unstable angina. Neopterin concentrations were measured with a commercially available immunoassay. Cpn titres were measured with a microimmunofluorescence (MIF) assay.
  
  
  RESULTS
  Neopterin concentrations were significantly higher in patients with unstable angina compared to those with chronic stable angina (6.30 [4.85-8.80] nmol/L vs 4.95 [3.35-7.05] nmol/L, P =.004), even after adjustment for variables that were significantly different between the 2 groups on univariate analysis. In contrast, the prevalence of positive Cpn serology did not differ significantly between the 2 angina patient groups (65% v 58%, P =.50). Neopterin levels were similar between Cpn-negative and Cpn-positive patients (P =.40) in both stable and unstable angina groups.
  
  
  CONCLUSIONS
  Patients with unstable angina had higher neopterin concentrations than patients with chronic stable angina, probably reflecting the higher degree of immune activation in acute coronary syndromes. Neopterin levels, however, were independent of Cpn serostatus when combining both stable and unstable angina patients. Thus, immune activation in patients with acute coronary syndromes appears to be unrelated to Cpn seropositivity.
authors.affiliation: Coronary Artery Disease Research Unit, Cardiological Sciences, St George's Hospital Medical School, London, United Kingdom.
authors.forename: David A
authors.initials: DA
authors.lastname: Smith
authors.forename: Emmanouil G
authors.initials: EG
authors.lastname: Zouridakis
authors.forename: Matteo
authors.initials: M
authors.lastname: Mariani
authors.forename: Salim
authors.initials: S
authors.lastname: Fredericks
authors.forename: Della
authors.initials: D
authors.lastname: Cole
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Kaski
mesh_terms: D000704:Analysis of Variance; D000787:Angina Pectoris / Q000097:blood* / Q000276:immunology; D000789:Angina, Unstable / Q000097:blood / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D023521:Chlamydophila Infections / Q000097:blood* / Q000276:immunology; D016993:Chlamydophila pneumoniae / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019798:Neopterin / Q000097:blood*
chemical_list: D015415:Biomarkers; D019798:Neopterin