Chronic Chagas' myocardiopathy. Demonstration of in vivo bound immunoglobulins in heart structures by the immunoperoxidase technique.

Chagas' disease (CHDis) has been described as the commonest form of chronic myocarditis. Although autoimmune phenomena involving the myocardium have been suggested in both human and experimental CHDis, no immunoperoxidase techniques have been used for the detection of immunological deposits in chronic Chagas' myocardiopathy (ChrCHM). The goal of this paper was to show that there is a coincidence between the immunoperoxidase and the immunofluorescence techniques in evidencing autologous deposits in ChrCHM. 4 patients suffering from ChrCHM were selected; their ages ranged from 39 to 52 years (means: 48.5 years). The Shültze and Caves endocavitary bioptome via the right internal jugular vein was used to obtain 3 to 4 right endomyocardial specimens measuring 1-2 mm each. Direct immunofluorescence examination, immunoperoxidase technique (PAP), and routine histological procedure were performed in all cases. Agreement between immunofluorescence and immunoperoxidase techniques was present in all chagasic specimens studied. Patients suffering from ChrCHM showed deposits of IgG, IgA, IgM, and C3 at the interstitial area, capillaries and endocardium and/or myocardial fiber surfaces when serum EVI antibody was positive. Serum EVI antibody was found to be positive in 3 out of 4 patients. The presence of the complement together with immunoglobulin may suggest an immune reaction (in vivo bound immunoglobulins in heart structures) and not just a passive deposition secondary to myocardial damage. As EVI antibody is present to a significant extent in CHDis, a reliable and simple technique like immunoperoxidase may be helpful to clarify the role of these antibodies in the pathogenesis of CHDis.