Comparación de técnicas serológicas convencionales y no convencionales para el diagnóstico de la enfermedad de Chagas importada en España / Comparison of conventional and non-conventional serological tests for the diagnosis of imported Chagas disease in Spain

RESUMEN

Introducción En España, la infección por Trypanosoma cruzi constituye una importante parasitosis importada debido al incremento de población procedente de área endémica. Como el diagnóstico de laboratorio de la fase crónica de la enfermedad se basa en la detección de anticuerpos IgG anti-T. cruzi, nuestros objetivos fueron los siguientes: i) comparar 10 técnicas de determinación de anticuerpos anti-T. cruzi; ii) evaluar su reactividad cruzada frente a enfermedades relacionadas, y iii) valorar el enzimoinmunoanálisis (ELISA)-rk39 y la inmunofluorescencia indirecta (IFI)-Leishmania para el diagnóstico diferencial de la leishmaniasis por Leishmania infantum.Material y Métodos Se analizaron 223 sueros: 40 caracterizados por la empresa Qpanel y 183 procedentes de la seroteca del Servicio de Parasitología, Centro Nacional de Microbiología (chagásicos=66, sanos=97, leishmaniasis visceral=30 y malaria=30). La pruebas utilizadas fueron IFI y ELISA in house, 5 ELISA comerciales (Certest/Abbot Laboratories, BiosChile; Ortho® Clinical Diagnostics; BLK Diagnostic; bioMérieux, y Biokit), la prueba de aglutinación en gel y 2 pruebas inmunocromatográficas (Operon y CTK Biotech). Los últimos 4 ensayos utilizaban antígenos recombinantes (pruebas no convencionales).Resultados La IFI y los ensayos de ELISA presentaron una sensibilidad entre el 97 y el 100%. Las pruebas inmunocromatográficas presentaron menor sensibilidad (92–96%). Todas las pruebas no convencionales presentaron menor número de reacciones cruzadas. El ELISA-rk39-Leishmania no presentó reactividad cruzada con los sueros chagásicos.(..) (AU)

ABSTRACT

Introduction Trypanosoma cruzi infection is a major imported parasitic disease in Spain, because of the increase of immigrants from endemic areas. Since the laboratory diagnosis during the chronic phase is based on detection of anti-T. cruzi IgG antibodies, our aims were to compare 10 tests for determining anti-T. cruzi antibodies, to assess their cross-reactivity with related diseases, and to evaluate the rk39-ELISA and IFAT-Leishmania tests as tools for the differential diagnosis of leishmaniasis due to Leishmania infantum. Material and Methods A total of 223 sera were tested: 40 had been previously characterized by Qpanel, and 183 were obtained from the serum library of the Parasitology Department, Centro Nacional de Microbiología (66 chagasic, 97 healthy, 30 visceral leishmaniasis, and 30 malaria). Samples were examined using in-house IFAT and ELISA, 5 commercial ELISAs (Certest/Abbot Laboratories/BiosChile; Ortho® Clinical Diagnostics; BLK Diagnostic; bioMérieux; and Biokit), particle gel agglutination (ID-PaGIA), and two immunochromatographic assays (Operon and CTK Biotech). The last 4 tests are based in recombinant antigens (non-conventional tests).Results The IFAT and ELISAs showed a sensitivity of 97% to 100%. The immunochromatographic tests had somewhat lower sensitivity (92&%#x02013;96%). All non-conventional tests presented a smaller number of cross-reactions. Leishmania-Rk39-ELISA did not show cross-reactivity with chagasic sera. Conclusions In general, our results confirm the data obtained by other authors. The sensitivity of ELISA is higher than other tests; therefore, these techniques would be the most appropriate for screening of T. cruzi infection. A suitable approach is the combination of a test using total antigen with another based on either recombinant antigens or synthetic peptides (AU)