PRESENCE OF ANTIHEART AND ANTISKELETAL MUSCLE GLYCOLIPID AUTOANTIBODIES IN THE SERA OF PATIENTS WITH CHAGASIC CARDIOPATHY

Objective: To characterize biochemically and isolate the skeletal and heart muscle cell epitope recognized by the autoantibodies present in the serum of chronically infected Trypanosoma cruzi patients. Secondly , to use that epitope in an immunoenzymatic assay for determining diff erences in antibody titre among Chagas' and other protozoan and heart diseases and between asymptomatic and cardiopathic chagasic patients. Design: Isolated human skeletal and heart muscle cells were treated wi th organic solvents, pronase, neuraminidase and sodium metaperiodate b efore immunofluorescence assay. Glycolipids were extracted from human skeletal muscle for ELISA. Patients: Sera were collected from 155 pati ents with positive serology for T cruzi infection; 44 healthy blood ba nk donors; and from patients after heart transplantation (16 patients) , during the first month after cardiac infarction (eight) or cardiotom y (10), dilated myocardiopathy (21), leishmaniasis (12), acute toxopla smosis (four) and hyperthyroid ophthalmopathy (five). Main Results: Im munofluorescence assay revealed that the chagasic sera recognized epit opes that appeared to be glycolipid in nature. ELISA showed that the c hagasic sera contained a higher titre of antiskeletal muscle glycolipi d antibodies than the control sera and that, in the chagasic populatio n, antibody titre was significantly higher in patients with heart fail ure than in asymptomatic subjects or in those presenting only electroc ardiographic abnormalities. Conclusions: The skeletal and heart muscle epitope recognized by antibodies present in the sera of chagasic pati ents has the characteristics of a glycolipid. ELISA with glycolipids e xtracted from human skeletal muscle indicated that chagasic patients p resented a higher antibody titre and that patients with heart failure showed a titre significantly higher than those who were asymptomatic o r with electrocardiographic abnormalities, suggesting that those antib odies could be immunological markers and even predictors of heart fail ure in Chagas' disease.