Antibodies with cholinergic activity in chagasic patients with dysautonomic syndrome

GOIN, J.C.; STORINO, R.; MILEI, J.; STERIN-BORDA, L.

Budapest, Hungría

Congreso; 8th International Congress of Immunology; 1992

Hungarian Society for Immunology/International Union of Immunological Societies (IUIS)

The pathogenesis of the autonomic dysfunction in Chagas’ disease has not been elucidated. Autonomic alterations could be observed in absence of cardiac manifestations. Different populations of neurotransmitter receptor-specific antibodies may co-occur in chagasic individuals, which has variety of functional consequences for heart muscle. The interaction of the IgG from chagasic patients (ch-IgG) with cardiac muscarinic cholinergic receptors (mACh-R) was characterized by studying the action of the ch-IgG on the specific mACh-R radioligand binding to cardiac membranes and the production of mACh-R, mediated transmembrane signals. Ch-IgG inhibited the binding of specific mACh-R radioligand and modified all the muscarinic cholinergic effects triggered by the activation of mACh-R: decrement in atria contractility, decrement of cAMP and increment of cGMP. The prevalence of antibodies with cholinergic activity was higher in serum from chagasic patients with heart dysautonomic syndrome (94%) than in those without heart dysautonomic alterations (48%). Results indicate the existence of circulating IgG in chagasic patients, which is able to interact with mACh-R of myocardium and modulates their activity. The presence of this antibody could be associated with alterations in cardiac function.