Trypanosoma cruzi: detection of a circulating antigen in urine of chagasic patients sharing common epitopes with an immunodominant repetitive antigen.

A monospecific antiserum raised to a Trypanosoma cruzi recombinant antigen, with tandem repeat of 68 amino acids, was used to screen urine samples of chagasic and nonchagasic patients. The antiserum detected a specific 150-160 kDa antigen in urine of 60% of chronic chagasic patients, but not in urine samples from nonchagasic patients and healthy control individuals. The reactivity to 150-160 kDa urinary antigen could be abolished by adsorption with the recombinant repetitive antigen. These results suggest that 150-160 kDa urinary antigen is a T. cruzi-derived antigen and specific for Chagas' disease.