title: Development of troponin autoantibodies in experimental coxsackievirus B3 myocarditis.
abstract: BACKGROUND
  Autoantibodies against various endogenous proteins are found in myocarditis. Troponin autoantibodies are detected in patients with chronic dilated cardiomyopathy, but their presence in myocarditis remains unknown. We set out to study the presence of troponin autoantibodies in experimental viral myocarditis.
  
  
  METHODS
  BALB/c mice infected with coxsackievirus B3 Nancy strain were followed-up at days 1-7 and 2, 4, 8 and 12 weeks after infection. Levels of circulating cardiac troponin I and circulating troponin autoantibodies were measured. Transthoracic echocardiography was performed. Myocarditis was histopathologically graded and cardiomyocyte apoptosis was quantified (TUNEL).
  
  
  RESULTS
  Histopathologically relatively mild acute myocarditis followed by persistent cardiomyocyte damage was observed. Rate of cardiomyocyte apoptosis was the highest on day 5 (0.16 +/- 0.01% vs. 0.03 +/- 0.01% in controls, P < 0.001). Circulating troponin I levels were increased to day 5 (45.2 +/- 6.5 ng mL(-1), P < 0.005 vs. controls). Troponin autoantibodies were detected from 2 weeks after infection (20% of animals had autoantibodies at 2 weeks, 60% at 4 and 8 weeks and 20% at 12 weeks, P < 0.05 vs. controls). Fractional shortening remained decreased after acute myocarditis (0.36 +/- 0.02 at 4 weeks, 0.30 +/- 0.02 at 8 and 12 weeks vs. 0.41 +/- 0.01 before infection, P < 0.01) parallel to development of troponin autoantibodies.
  
  
  CONCLUSIONS
  Troponin autoantibodies are formed in experimental virus induced myocarditis following troponin I release and cardiomyocyte apoptosis. The definite role of these autoantibodies remains to be further characterized.
authors.affiliation: University of Turku, Turku, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Latva-Hirvelä
authors.forename: V
authors.initials: V
authors.lastname: Kytö
authors.forename: A
authors.initials: A
authors.lastname: Saraste
authors.forename: S
authors.initials: S
authors.lastname: Eriksson
authors.forename: T
authors.initials: T
authors.lastname: Vuorinen
authors.forename: K
authors.initials: K
authors.lastname: Pettersson
authors.forename: P
authors.initials: P
authors.lastname: Saukko
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D003384:Coxsackievirus Infections / Q000150:complications / Q000276:immunology* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009205:Myocarditis / Q000276:immunology* / Q000473:pathology / Q000821:virology; D012367:RNA, Viral / Q000032:analysis; D014336:Troponin / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology
chemical_list: D001323:Autoantibodies; D012367:RNA, Viral; D014336:Troponin; D014764:Viral Proteins; C097017:coxsackie B3 virus protein 2B