ANTIADRENERGIC AND MUSCARINIC RECEPTOR ANTIBODIES IN CHAGAS CARDIOMYOPATHY

Evidence accumulated over the last decade gives adequate proof for the existence of circulating antibodies in Chagas' disease which bind to beta adrenergic and muscarinic cholinergic receptors of myocardium. Th e interaction of antibodies with cardiac neurotransmitter receptors be having as an agonist, triggers intracellular signal transductions in t he cells that alter the physiological behaviour of the heart. These ev ents convert the normal to pathologically active cells. The interactio n of antibodies against heart beta adrenergic and cholinergic receptor s triggers physiologic, morphologic, enzymatic and molecular alteratio ns, leading to cardiac damage. The analysis of the prevalence and dist ribution of these antibodies shows a strong association with seroposit ive asymptomatic patients with autonomic dysfunction in comparison wit h those asymptomatic without alteration of the heart autonomic disorde rs. The presence of these antibodies may thus partially explain the ca rdiomyoneuropathy of Chagas' disease, in which the sympathetic and par asympathetic systems are affected. The deposit of autoantibodies on th e myocardial neurotransmitter receptors, behaving like an agonist, ind uced desensitization and/or down regulation of the receptors. This in turn, could lead to a progressive blockade of myocardium neurotransmit ter receptors, with sympathetic and parasympathetic dennervation, a ph enomenon that has been described in the course of Chagas cardioneuropa thy.