Process of preparation and use of trypanosoma cruzi antigens and assay for the diagnosis of Chagas disease

摘要

A chemiluminescent (CL)-ELISA method with purified and complex antigens of Trypanosoma cruzi is proposed for the specific and sensitive diagnosis of Chagas' disease in patients and blood bank samples. A trypomastigote specific antigen (A&T) together with an epimastigote extract (EpEx), used as a control of sensitivity, are the preparations used. The high sensitivity of the CL-ELISA method permits the use of extremely small amounts of antigen and allows a serum dilution in routine tests as high as 1:2000, thus reducing the nonspecific or false-positive reactions to a minimum. The use of the A&T purified antigen eliminates cross-reactivities with other infectious agents, detects active infection, and serves to monitor chemotherapy in chronic patients. The use of the EpEx antigenic preparation not only confirms the positive results with A&T but also, in case of discrepancy, suggests other infections such as leishmaniasis. In comparison with current tests used in major blood banks, the CL-ELISA method with A&T and EpEx antigens, tested in parallel, proved to be clearly superior either by eliminating indeterminate results or by increasing the statistics of diagnosed positive samples.