Humoral nitric oxide levels and antibody immune response of symptomatic and indeterminate Chagas' disease patients to commercial and autochthonous Trypanosoma cruzi antigen.

We report here the evaluation of chagasic patients for the presence and/or severity of the disease, antibody to Trypanosoma cruzi, and nitric oxide (NO) serum levels. Serum samples tested by ELISA with autochthonous and commercial antigen revealed that 10% and 7.5% of the individuals were anti-T. cruzi antibody-positive, respectively. Ten of 21 seropositive individuals had no clinical signs, the other 11 cases presented cardiomyopathy and/or mega-gastrointestinal syndromes, and three patients presented a combined form. A statistical difference (P < 0.001) in antibody titer between asymptomatic and symptomatic patients with autochthonous antigen was detected, and serum NO levels was found to be three times higher in cases than in controls. These results suggest that it is recommended to use a sole source of antigen (autochthonous) for the serodiagnosis of Chagas' disease, and that the pathogenic role of NO in this disease should be evaluated.