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Resultados inconclusos en un tamizaje serológico convencional para la enfermedad de Chagas en bancos de sangre: evaluación de las respuestas celulares y humorales.
Author(s) -
Furuchó Celia Regina,
Umezawa Eufrozina S.,
Almeida Igor,
Freitas Vera L.,
Bezerra Rita,
Nunes Elisabete V.,
Sanches Maria C.,
Guastini Cristina M.,
Teixeira Antonio R.,
ShikanaiYasuda Maria A.
Publication year - 2008
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.2008.02172.x
Subject(s) - serology , chagas disease , trypanosoma cruzi , immunology , antibody , antigen , trypanosomiasis , western blot , virology , immunofluorescence , biology , medicine , hemagglutination , parasite hosting , biochemistry , world wide web , computer science , gene
Summary Objective To find the most reliable screening method for Trypanosoma cruzi infection in blood banks. Material and methods Epidemiological data, lymphoproliferation assay, parasitological, conventional serological tests: immunofluorescence, haemagglutination, ELISA with epimastigote and trypomastigote antigens and reference serological tests: trypomastigote excreted‐secreted antigens (TESA) blot and chemiluminescent ELISA assay with mucine from trypomastigote forms were applied to individuals with inconclusive serology, non‐chagasic individuals and chronic chagasic patients. Results TESA blot had the best performance when used as a single test in all the groups. In the inconclusive group 20.5% of individuals were positive for TESA blot, 23.3% for either lymphoproliferation or TESA blot, and 17.8% for lymphoproliferation only. Positive lymphoproliferation without detectable antibodies was observed in 5.47% of all inconclusive serology cases. Analysis of six parameters (three serological assays, at least one parasitological test, one lymphoproliferation assay and epidemiological data) in the inconclusive group showed that diagnosis of Chagas’ disease was probable in 15 patients who were positive by two or more serological tests or for whom three of those six parameters were positive. Conclusion TESA blot is a good confirmatory test for Chagas’ disease in the inconclusive group. Although lymphoproliferation suggests the diagnosis of Chagas’ disease in the absence of antibodies when associated with a high epidemiological risk of acquiring Chagas’ disease, the data from this study and the characteristics of the lymphoproliferation assay (which is both laborious and time‐consuming) do not support its use as a confirmatory test in blood‐bank screening. However, our findings underscore the need to develop alternative methods that are not based on antibody detection to improve the diagnosis when serological tests are inconclusive.