RESUMO
INTRODUCTION: Serological cross-reactivity between leishmaniasis and Chagas disease, especially at low titers, leads to difficulties of the seroepidemiological interpretation. METHODS: We have studied the ability of urea as a chaotrope to select high-avidity antibodies in IgG ELISA, thus reducing low-avidity IgG cross-reactivity in serologically positive samples in both assays. RESULTS: Using 0.5M urea for diluting the sample efficiently defined leishmaniasis or double infections in high-avidity IgG ELISA and eliminated false-positive results. CONCLUSIONS: The use of a chaotropic diluting agent is useful for improving the specificity of Chagas disease and leishmaniasis immunoassays.
Assuntos
Anticorpos Antiprotozoários/sangue , Afinidade de Anticorpos/imunologia , Doença de Chagas/imunologia , Reações Cruzadas/imunologia , Imunoglobulina G/sangue , Leishmaniose/imunologia , Ureia/farmacologia , Biomarcadores/química , Brasil/epidemiologia , Doença de Chagas/complicações , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Ensaio de Imunoadsorção Enzimática , Humanos , Leishmaniose/complicações , Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Vigilância da População , Sensibilidade e Especificidade , Ureia/químicaRESUMO
Abstract INTRODUCTION: Serological cross-reactivity between leishmaniasis and Chagas disease, especially at low titers, leads to difficulties of the seroepidemiological interpretation. METHODS: We have studied the ability of urea as a chaotrope to select high-avidity antibodies in IgG ELISA, thus reducing low-avidity IgG cross-reactivity in serologically positive samples in both assays. RESULTS: Using 0.5M urea for diluting the sample efficiently defined leishmaniasis or double infections in high-avidity IgG ELISA and eliminated false-positive results. CONCLUSIONS: The use of a chaotropic diluting agent is useful for improving the specificity of Chagas disease and leishmaniasis immunoassays.
