title: Troponin T autoantibodies correlate with chronic cardiomyopathy in human Chagas disease.
abstract: OBJECTIVE
  To evaluate the potential involvement of anti-Trypanosoma cruzi and cardiac protein antibody (IgG total and isotypes) production and their possible association with different clinical forms of human chronic Chagas disease.
  
  
  METHODS
  IgG total and isotypes were measured by ELISA, using epimastigote and trypomastigote forms of T. cruzi as antigens and human cardiac proteins (myosin and troponin T) in sera of patients with indeterminate (IND, n = 72), cardiac (CARD, n = 47) and digestive/cardiodigestive (DIG/CARD-DIG, n = 12) clinical forms of the disease. Samples from uninfected health individuals (CONT, n = 30) and patients with ischaemic cardiomyopathy (ISCH, n = 15) were used as controls. Autoantibody levels were correlated with parameters of cardiac function obtained by electrocardiographic, radiographic and echocardiographic examinations.
  
  
  RESULTS
  Fifty five per cent of patients were classified as IND, 35.9% as CARD and 9.1% as DIG/CARD-DIG. Greater total IgG production was observed in IND, CARD and DIG/CARD-DIG chagasic patients than in CONT and ISCH, using trypomastigote, epimastigote and cardiac antigens. Moreover, patients with CARD and DIG/CARD-DIG presented greater total IgG production (trypomastigote and epimastigote antigen) than IND, and a negative correlation was determined between total IgG and left ventricular ejection fraction (LVEF). Patients with IND and CARD presented similar higher levels of total IgG specific to troponin T and myosin than CONT and ISCH individuals. Patients with chronic Chagas disease presented a negative correlation between left ventricular ejection fraction (LVEF) and the production of anti-myosin and troponin T autoantibodies. When grouped as low and high antibody producers and compared with LVEF, we observed that high anti-troponin T (P = 0.042) and myosin (P = 0.013) producers presented lower LVEF than low producers. Moreover, there was a positive correlation (r = 0.9508, P = 0.0001) between the production of troponin T and myosin autoantibodies.
  
  
  CONCLUSIONS
  These findings indicate that increased production of anti-cardiac troponin T and myosin autoantibodies probably influences the left ventricular ejection fraction and could be related to chagasic cardiomyopathy.
authors.affiliation: Graduate Program in Health Sciences, Center for Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil.
authors.forename: Daniela Ferreira
authors.initials: DF
authors.lastname: Nunes
authors.forename: Paulo Marcos da Matta
authors.initials: PM
authors.lastname: Guedes
authors.forename: Cléber de Mesquita
authors.initials: Cde M
authors.lastname: Andrade
authors.forename: Antonia Cláudia Jácome da
authors.initials: AC
authors.lastname: Câmara
authors.forename: Egler
authors.initials: E
authors.lastname: Chiari
authors.forename: Lúcia Maria da Cunha
authors.initials: LM
authors.lastname: Galvão
mesh_terms: D000328:Adult; D000368:Aged; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D002598:Chagas Cardiomyopathy / Q000150:complications / Q000276:immunology*; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009218:Myosins / Q000276:immunology; D012423:Rural Health; D020107:Troponin T / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology*; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D001323:Autoantibodies; D007074:Immunoglobulin G; D020107:Troponin T; D009218:Myosins
keywords: Trypanosoma cruzi; autoantibodies; human Chagas disease; immunopathogenesis; myosin; troponin T