[Cysteine-dependent protease in Trypanosoma cruzi useful for the diagnosis of Chagas disease].

An immunoenzymatic system on solid phase for the detection of IgG antibodies in serum from chronic Chagasic patients was standardized. A protease from Trypanosoma cruzi (GP57/51KDa) was used as an antigen. The sensitivity, specificity and predictive values of the procedure were calculated taking into account the results obtained from conventional serology (CS), indirect immunofluorescence (IIF), indirect hemagglutination (IHA) and complement-mediated lysis test (CML) for the detection of anti-Trypanosoma cruzi antibodies in serum. Except one, the positive samples obtained by those techniques were also positive by our method. These results show that GP 57/51 is useful in the serodiagnosis of Chagas disease.