Tissue-reacting antibodies (EVI antibodies) in nifurtimox-treated patients with Chagas's disease.

Antibodies reacting against endothelial cells, vascular structures, and heart and skeletal muscle cells (EVI antibodies) were studied in 10 patients (one to 14 years of age) treated with Nifurtimox. The patients were observed for several months to two years after the onset of symptoms of acute infection with Trypanosoma cruzi. Although these 10 patients were selected because after treatment their sera became negative for antibodies to T. cruzi as detected by the immunofluorescence test, sera from six patients remained positive for EVI antibodies. It is suggested that EVI antibodies may be self-perpetuated in the absence of infection. Further studies are needed to determine the pathogenic significance of EVI antibodies.