ANTIBODIES TO LAMININ AND IMMUNOHISTOCHEMICAL LOCALIZATION OF LAMININ IN CHRONIC CHAGASIC CARDIOMYOPATHY - A REVIEW

Antibodies against laminin were determined by ELISA in forty six patients suffering from Chagas' disease and twenty healthy persons (control group). The patients were divided into three groups according to the severity of clinical, electrocardiographic and echocardiographic studies. Histologic, ultrastructural and immunohistochemical studies were made of endomyocardial biopsy specimens from 10 of these patients with chronic Chagasic cardiomyopathy. Antibodies to laminin were detected in 50% of the patients in each of the three groups. However analysis of the data did not allow us to determine any significant correlation among the severity of the different clinical and non-invasive studies and the level of circulating antibodies to laminin. The highest titers of antilaminin antibodies were detected in the group with severe cardiological alterations (37% of the patients). Histological and electron microscopic observation of myocardial biopsies disclosed marked thickening of the basement membranes of the myocytes, endothelial cells and vascular smooth muscle cells. Light (peroxidase-labeled antibodies) and electron (gold-conjugated antibody) microscopic immunohistochemical methods revealed a positive reaction for laminin in these thickened basement membranes. This thickening may develop as a consequence of: a) an immunologic reaction which is triggered by the presence of a laminin-like molecule on the surfaces of T. cruzi amastigotes and trypomastigotes; b) an immunologic response to direct injury of basement membranes causing some of their components to become antigenic; c) myocardial fibrosis, with synthesis of new connective tissue components, and d) a combination of the preceding factors. The relationship of these changes to antilaminin antibodies remains unclear. From these results, it is not possible to assure a physiopathogenic role for antibodies to laminin in chronic Chagas' cardiomyopathy.