Anti-M2 muscarinic receptor autoantibodies in Trypanosoma cruzi-infected pediatric patients treated with benznidazole

Abstract

The presence of autoantibodies with adrenergic and cholinergic activity, capable of triggering neurotransmitter receptor-mediated effects, has been associated to pathogenesis in T. cruzi-infected hosts. We determined the presence of anti-M2 muscarinic receptor IgG autoantibodies in 14 pediatric patients with Chagas disease and 18 non-infected infants. T. cruzi-infected children showed a higher frequency and a 6.2 ± 1.8-fold increase in the level of autoantibodies to cardiac receptors when compared to controls. Patients were monitored since the initiation of specific treatment with benznidazole (Bz). Along the follow-up, we verified a significant linear decreasing trend in autoantibody reactivity. Remarkably, when treated children became seronegative for T. cruzi as direct consequence of parasiticidal chemotherapy, they displayed autoantibody titers similar to those detected in healthy subjects. We conclude that, in pediatric patients, the M2 muscarinic receptor autoantibody response is elicited early in the course of T. cruzi infection and decreases after specific treatment, implying that specific Bz treatment eliminates the parasite and reduces potentially pathogenic autoimmune responses.