[Chronic Chagas' disease: effects of treatment nn the levels of antibodies to crude and partially purified Trypanosoma cruzi antigens].

The specific therapy in Chagas' disease is useful in acute and neonatal infection and in children under three years old. The results of antiparasitic treatment during chronic infection are still controversial. It will be interesting to analyze the serological behavior in patients treated during chronic infection, to advance in the search of evolutive markers and markers of therapeutic efficacy. In the present work we have measured the antibody response by conventional serology and the response to partially purified T. cruzi antigens in chagasic patients who received nifurtimox or benznidazol 2 to 20 years before. The results showed that, by indirect immunofluorescence in 29% of treated patients the antibody levels were below the established cut off (1:32). By indirect hemagglutination 55% of treated patients showed this serological behavior. In this group a high number of discordant results was observed. By immunoenzimatic assay it was possible to detect a significative decrease of serologic reactivity to a partially purified acidic antigen (F IV) and to exoantigen of T. cruzi. It will be interesting to perform longitudinal surveys employing these antigens, to go further in the knowledge of possible immunological evolutive markers in Chagas' disease.