Screening and confirmation in Chagas disease serology - a contribution

Oelemann, Walter; Teixeira, M. G. M.; Peralta, José Mauro

doi:10.1590/s0074-02761999000700057

Cited by 4 publications

(5 citation statements)

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“…The serologic diagnosis of Chagas' disease remains problematic, although various kits available show a high degree of precision (1,4,10). Differences in the developmental stage of the parasite and in the procedures used for extraction and purification of antigenic components, as well as in the assay protocol itself, present a permanent source variation for the final product, leading to difficulties in the industrial production of reproducible lots.…”

Section: Discussionmentioning

confidence: 99%

“…With the development of the techniques of molecular biology, various proteins were isolated and sequenced, and their corresponding genes were cloned and subsequently used to produce recombinant proteins. Their applicability in diagnosis as well as in our understanding of the host-parasite interactions leading to new ways of vaccine development has been widely reported (7,9,10,11,14,16). Among the synthetic peptides that have been evaluated, TcD and PEP2 are outstanding.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, parasite culture conditions and antigen purification protocols are difficult to standardize and therefore lead often to variations between different lots. In an attempt to improve the serological diagnosis of Chagas' disease and to avoid the problems of assay specificity and antigen obtainment, molecular techniques, such as gene cloning and expression, and the in vitro synthesis of the corresponding peptides allowed the identification and evaluation of a series of antigens that may be useful in diagnosis and vaccine development (10,14). Recent studies employing mixtures of synthetic peptides and/or recombinant antigens demonstrated an increase in assay sensitivity (11,14,16).…”

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confidence: 99%

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Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

et al. 2001

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Serological tests to detect Trypanosoma cruzi antibodies have been used for screening blood donors, for epidemic studies, and for diagnosis of probably infected persons. Among different tests, the enzyme-linked immunosorbent assay (ELISA) with total, semipurified, or synthetic antigens has been widely used, mainly due to its easy automation. Aiming to improve serological studies concerning Chagas' disease, we have developed and evaluated a new test, the TcF-ELISA, using an artificially engineered recombinant antigen, which contains tandem sequences of different T. cruzi-specific peptides. The sensibility of the TcF-ELISA was determined with 101 serum samples from chagasic patients well-defined by clinical and epidemiological criteria. The specificity was determined with 39 serum samples from leishmaniasis or kala-azar patients and 150 serum samples from nonchagasic blood donors from Sao Paulo, Brazil. The TcF-ELISA showed 100% sensitivity and 98.94% of specificity. Compared with conventional ELISA (with semipurified T. cruzi epimastigote antigens), the TcF-ELISA showed advantages; for example, it distinguishes better between reagent and nonreagent serum and provides better precision and a lower occurrence of leishmaniasis cross-reactions. Our studies demonstrate high reproducibility between two different lots of the TcF ELISA and its applicability for the serological diagnosis of Chagas' disease.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

et al. 2001

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“…INNO-LIA Chagas (Innogenetics N.V., Ghent, Belgium) is a commercially available immunoblot assay consisting of seven recombinant and synthetic antigens: CRA, FRA, Tc-24, SAPA, MAP, TcD and Ag39, which are coated at separate locations onto a single nylon membrane strip. While offering high diagnostic performance, results can be difficult to interpret, and this platform remains expensive [28][29][30][31]. Until 2015 and 2017, respectively, HBK 740 Immunoblot Linhas anti-T. cruzi and TESA-blot were routinely used for confirmatory testing [32]; however, commercial productions have since been discontinued, leaving a gap in the performance of confirmatory chronic CD diagnosis.…”

Section: Introductionmentioning

confidence: 99%

Western blot using Trypanosoma cruzi chimeric recombinant proteins for the serodiagnosis of chronic Chagas disease: A proof-of-concept study

et al. 2022

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Background Chagas disease (CD) is caused by Trypanosoma cruzi. The chronic phase of CD is characterized by the presence of IgG anti-T. cruzi antibodies; and diagnosis is performed by serological methods. Because there is no realible test that can be used as a reference test, WHO recommends the parallel use of two different tests for CD serodiagnosis. If results are inconclusive, samples should be subjected to a confirmatory test, e.g., Western blot (WB) or PCR. PCR offers low sensitivity in the chronic phase, whereas few confirmatory tests based on the WB method are commercially available worldwide. Therefore, new diagnostic tools should be evaluated to fill the gap in confirmatory tests CD. In recent years, four chimeric recombinant antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) have been evaluated in phase I, II and III studies using ELISA, liquid microarray and immunochromatography with 95–100% accuracy. Given the high diagnostic performance of these antigens, the present study investigated the ability of these molecules to diagnose chronic CD using a WB testing platform. Methodology/Principal findings In this study, we analyzed the diagnostic potential of four chimeric antigens using 40 T. cruzi-positive, 24-negative, and three additional samples positive for visceral leishmaniasis (i.e., potentially cross-reactive) using WB as the diagnostic platform. Checkerboard titration with different dilutions of antigens, conjugated antigens, and serum samples was performed to standardize all assays. All IBMP antigens achieved 100% sensitivity, specificity, and accuracy, with the exception of IBMP-8.3, which had 100% specificity despite lack of significance, but lower sensitivity (95%) and accuracy (96.9%). No cross-reactivity was observed in samples positive for leishmaniasis. Conclusions/Significance The present phase I (proof-of-concept) study demonstrated the high diagnostic potential of these four IBMP antigens to discriminate between T. cruzi-positive and -negative samples, making them candidates for phase II and confirmatory testing with WB.

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“…Excepto los liofilizados de plasma y los hemoderivados, todos los componentes de la sangre son infectantes (5)(6)(7). Se estima que el riesgo de adquirir la enfermedad de Chagas al recibir una unidad infectada oscila entre 20% y 40%, cifras que pueden incrementarse, entre otras causas, por la elevada prevalencia en la población, por el largo tiempo de latencia de la infección, que para el caso de Chagas puede ser de varios años, la elevada prevalencia en donantes de sangre, la baja cobertura del tamizaje de las unidades de sangre donadas, el número de unidades de sangre transfundidas, la larga supervivencia del parásito en las unidades de sangre almacenadas en refrigeración, la falta de canalización y confirmación de donantes reactivos sospechosos de estar infectados, y la deficiencia en los controles de calidad durante el procesamiento de la sangre y sus componentes (8,9). Sin embargo, la seguridad de las transfusiones sanguíneas en el país ha mejorado considerablemente en los últimos años, debido a la implementación de estrategias como las siguientes: 1) la obligatoriedad del tamizaje para anti-T.cruzi en todas las unidades de sangre para transfusión desde 1995; 2) la inclusión en la encuesta de selección del donante de preguntas relacionadas con el posible contacto que tenga el individuo con la enfermedad o con el vector, por ejemplo: "¿Conoce o ha sido picado por un insecto llamado pito, chupasangre, tábano, chipo, rondador, vinchuco o chinche besador o picudo?…”

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Control de la infección por Trypanosoma cruzi en donantes de sangre de Colombia, 2003.

Beltrán¹,

Bermúdez²,

Forero³

et al. 2005

biomedica

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Introducción. La enfermedad de Chagas es un problema de salud pública en Latinoamérica. Después de la vectorial, la segunda fuente de transmisión es la transfusional; en Colombia el tamizaje para este marcador es obligatorio en los bancos de sangre desde 1995. Objetivo. Evaluar el comportamiento de algunas estrategias de control de la infección en donantes y estimar el riesgo transfusional por enfermedad de Chagas. Materiales y métodos. Se analizaron los datos de cobertura de tamizaje y reactividad para anticuerpos anti-Trypanosoma cruzi; los resultados de los bancos de sangre en el Programa de Evaluación Externa del Desempeño de Serología (PEED) y los reportes de los Laboratorios de Salud Pública sobre pruebas confirmatorias de serología en donantes. Resultados. En 2003, los bancos de sangre del país captaron 482.371 unidades, 99,91% fueron analizadas para anti-T.cruzi, resultando reactivas 0,42%. Casanare presentó la mayor reactividad con 107/1.487 (7,2%), de los cuales se confirmaron como positivos 75. En el PEED participaron 45,5% bancos, la totalidad de los cuales utilizó ELISA para tamizaje; se hallaron 1,1% resultados falsos positivos y ningún falso negativo. En 12 departamentos que analizaron 338.563 unidades para anti-T.cruzi, 1.298 casos fueron notificados como reactivos y 1.108 (85,4%) se confirmaron por la prueba de IFI, registrando una positividad de 0,33%. Conclusiones. Aunque la cobertura del tamizaje llegó a 99,91%, existe aún riesgo de infección por T.cruzi. Los casos de T.cruzi en donantes oscilan entre 0 y 50 por cada mil, y como ya se mencionó, Casanare es el departamento con mayor riesgo de adquirir Chagas transfusional. Los bancos participantes en el PEED no mostraron resultados falsos negativos.Palabras clave: bancos de sangre, Trypanosoma cruzi, enfermedad de Chagas, Colombia, control de calidad. Control of infection for the Trypanosoma cruzi in blood donorsIntroduction. Chagas disease is a public health problem in Latin America. Whereas the primary source of transmission is the insect vector, the second is by blood transfusion. Consequently, in Colombia, screening for trypanosomiasis has been obligatory for blood donors since 1995. Objective. The effectiveness ot current strategies for infection control in donors was evaluated in order to estimate the risk of blood stock contamination with Chagas disease. The screening data came from the blood banks in the Program of External Evaluation in the Performance of Serology and the reports of the Laboratories of Public Health on confirming donor serology tests. Results. In 2003, 482,371 units of blood were collected in all of Colombia Of these, 99.9% were analyzed for anti-T.cruzi reactivity, with a positives of 0.42% detected. The Casanare Province presented the biggest number of reactive donors 107/1,487 (7.2%), with 75 confirmed positive. In the Program of External Evaluation in the Performance of Serology, 45.5% of all banks participated-all used ELISA for screening of anti-T.cruzi. 1.1% false positives and nofalse negatives were indicated ...

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Screening and confirmation in Chagas disease serology - a contribution

Cited by 4 publications

References 3 publications

Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

Enzyme-Linked Immunosorbent Assay for Serological Diagnosis of Chagas' Disease Employing a Trypanosoma cruzi Recombinant Antigen That Consists of Four Different Peptides

Western blot using Trypanosoma cruzi chimeric recombinant proteins for the serodiagnosis of chronic Chagas disease: A proof-of-concept study

Control de la infección por Trypanosoma cruzi en donantes de sangre de Colombia, 2003.

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