TROPONIN T AUTOANTIBODIES CORRELATED WITH CHRONIC CARDIOMYOPATHY IN HUMAN CHAGAS’ DISEASE
Trypanosoma cruzi, Chagas disease, immunoglobulins, autoantibodies, immunopathogenicity
OBJECTIVE To evaluate the potential involvement of anti-T. cruzi and cardiac protein antibodies (IgG total and isotypes) production and 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 and human cardiac proteins (myosin and troponin T) as antigens using sera of patients with indeterminate (IND, n = 72), cardiac (CARD, n = 47) and digestive/mixed (DIG/MIX, n=12) clinical forms of the disease. Samples from uninfected individuals were used as controls. Autoantibodies levels were correlated with left ventricular ejection fraction (LVEF) and others clinical parameters of cardiac function obtained by echocardiography. RESULTS Chagasic patients with indeterminate, cardiac and digestive/mixed clinical forms presented higher levels of total immunoglobulin G (IgGt) specific troponin T (p=0.0001) and myosin (p=0.0002) antibodies than non-infected individuals. When grouped carriers patients of cardiac clinical form in autoantibodies producers and not producers, and compared with LVEF, we observed that anti-troponin T (p=0.042) and myosin (p=0.013) producers displayed lower LVEF than patients that not produce autoantibodies. However, neither difference in IgG1, IgG2, IgG3 and IgG4 production levels was observed in chagasic patients compared with non-infected group. Patients with indeterminate, cardiac and digestive/mixed clinical forms displayed a negative correlation between anti-troponin T/myosin levels in serum and left ventricular ejection fraction. CONCLUSION These findings indicate that increased production of anti-cardiac troponin T and myosin autoantibodies probably have influence on left ventricular ejection fraction and could be related with the severity of chagasic cardiomyopathy.