IMMUNOHISTOCHEMICAL LOCALIZATION OF LAMININ IN THE HEARTS OF PATIENTSWITH CHRONIC CHAGASIC CARDIOMYOPATHY - RELATIONSHIP TO THICKENING OF BASEMENT-MEMBRANES

Histologic, ultrastructural, and immunohistochemical studies were made of endomyocardial biopsy specimens from 10 patients with chronic chag asic cardiomyopathy. Histologic and electron microscopic observation d isclosed marked thickening of the basement membranes of the myocytes, endothelial cells, and vascular smooth muscle cells in all patients. L ight (peroxidase-labeled antibodies) and electron (gold-conjugated ant ibody) microscopic immunohistochemical methods revealed a positive rea ction for laminin in these thickened basement membranes. This thickeni ng of basement membranes may develop as a consequence of: (1) an immun ologic reaction that is triggered by the presence of a laminin-like mo lecule on the surfaces of Trypanosoma cruzi amastigotes and trypomasti gotes; (2) an immunologic response to direct injury of basement membra nes causing some of their components to become antigenic; (3) myocardi al fibrosis, with synthesis of new connective tissue components; and ( 4) a combination of the preceding factors. The relationship of these c hanges to antilaminin antibodies requires clarification.