Organ-specific circulating heart autoantibodies in Chagas' cardiomyopathy: exploratory study

Chagas' disease can evolve to a chronic phase with cardiomyopathy that may include autoimmune mechanisms, among others. Recently an organ-specific anti-heart muscle antibody was detected in idiopathic cardiomyopathy, using human heart muscle as antigen. We decide to standardize an indirect immunofluorescence assay using rat organs in order to evaluate frequency of organ-specific anti-heart antibodies in chagasic cardiomyopathy. We tested 18 patients with chagasic cardiomyopathy for serum organ-specific anti-heart muscle antibodies. Nine patients were positive for organ-specific anti-heart antibodies (positive in heart muscle but negative in tongue muscle) and one was positive for non-organ-specific anti-heart muscle antibodies (positive in both heart and tongue muscle). We conclude that organ-specific anti-heart muscle antibodies can be detected using rat organs as antigens. Organ-specific anti-heart muscle antibodies are present in patients with chagasic cardiomyopathy.