A HIGHLY SENSITIVE AND SPECIFIC CHEMILUMINESCENT ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR DIAGNOSIS OF ACTIVE TRYPANOSOMA-CRUZI INFECTION

BACKGROUND: Chagas' disease is transmitted to man either by the bite o f insects harboring Trypanosoma cruzi or by the transfusion of blood f rom infected donors. The conventional serologic testing as presently u sed in blood banks in South America is unsatisfactory, because of a hi gh number of inconclusive and false-positive results. Other methods su ch as polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) with recombinant antigens have been proposed, but inherent dif ficulties have so far precluded their adoption in the large-scale scre ening required by blood banks. STUDY DESIGN AND METHODS: A highly sens itive and specific chemiluminescent ELISA using a purified trypomastig ote glycoconjugate antigen and a complex epimastigote antigen was devi sed for the diagnosis of active T. cruzi infection. RESULTS: Chemilumi nescent ELISA was 100-percent sensitive in the diagnosis of 100 cases of confirmed Chagas' disease. Inconclusive results and false-positive reactions were eliminated in a panel of 115 sera. The specificity of t he chemiluminescent ELISA was 100 percent with a purified trypomastigo te glycoconjugate antigen and 99.7 percent wiih a complex epimastigote antigen when applied to 1000 normal human sera and 288 heterologous s era from patients with other infections, including leishmaniasis, and vaccinated individuals. CONCLUSION: The chemiluminescent ELISAs provid e a test that is highly sensitive (purified trypomastigote glycoconjug ate and complex epimastigote antigens) and specific (purified trypomas tigote glycoconjugate antigen) for Chagas' disease diagnosis. It can b e used in blood bank screening and to monitor the treatment of patient s undergoing chemotherapy.