Using the Dot-ELISA technique, two antigenic preparations of Trypanosoma cruzi epimastigote forms have been compared for the diagnosis of Chagas' disease: (1) The citoplasmic fraction (citoplasmic antigen) and (2) whole fixed epimastigotes (integral antigen). There was been used sera from 95 chagasic patients with chronic cadiomyopathy, positive conventional serology and either positive or negative xenodiagnosis; 74 subjects with negative conventional serology, and either clinically normal or presenting cardiomyopathy; 74 patients with different diseases including siphilis,toxoplasmosis, leisjmaniasis or autoantibodies such as rheumatoid factor and antinuclear antibodies. By defining the diagnostic titers (cut Off): 1:512 for citoplasmatic antigen and 1:128 for the integral antigen, a sensitivity of 100% has been obtained with both antigenic preparations, being the specificity of 96% for the former and 100% for the latter when leishmaniasis sera were not included. A comparative study with conventional serology was carried out using 147 sera from a Laboratory of Chagas' diagnosis; Dot-ELISA with citoplasmic antigen showed co-positivity index of 1.0, co-negativity 0.989 and efficiency of 0.993, and Dot-ELISA with integral antigen 1.0, 0.979 and 0.986 respectively. According to this evaluation, Dot-ELISA using whole formalin fixed epimastigotes might be a practical alternative for the serological diagnosis of Chagas' disease.
immunoserology; Dot-ELISA; Trypanosoma cruzi antigenic preparations