Resumen de The Type of Trypanosoma Cruzi Strain (Native or Non-Native) Used as Substrate for Immunoassays Influences the Ability of Screening Asymptomatic Blood Donors
Martha A. Ballinas Verdugo, Ana María Mejía Domínguez, Sergio Arturo Guerrero Sánchez, Claudia Lerma, Mariana Martínez Cruz, Elsa Álvarez Manilla-Toquero, Xochiquetzali Jiménez Díaz, Francelia Barrera Trujillo, Marisela del R. Ticante Cruz, Irving Omar Estévez-García, Luis Manuel Amezcua Guerra, Pedro A. Reyes López
Background: The origin (native or non-native) of Trypanosoma cruzi strains used as substrate for immunoassays may influence their performance. Objective: To assess the performance of an immunoassay based on a native T. cruzi strain compared to another based on non-native T. cruzi strains, in asymptomatic blood donors from Mexico. Methods: Serum samples from a tertiary referral center were tested by both ELISA-INC9 (native) and Chagatest (non-native) assays. All reactive serum samples were further analyzed by indirect immunofluorescence. Results: Sera from 1,098 asymptomatic blood donors were tested.
A 4.3 and 0.7% serum reactivity prevalence was observed using ELISA-INC9 and Chagatest, respectively (kappa = 0.13;
−0.11 to 0.38). Subsequently, indirect immunofluorescence analyses showed higher positivity in serum samples reactive by ELISA-INC9 compared to those reactive by Chagatest (79 vs. 62.5%; p < 0.001). Furthermore, out of the 47 positive samples by both ELISA-INC9 and indirect immunofluorescence, only four (8.5%) were reactive in Chagatest assay. Meanwhile, four (80%) out of the five positive samples by both Chagatest and indirect immunofluorescence were reactive using ELISA-INC9. Conclusion:
Immunoassays based on a native T. cruzi strain perform better than those based on non-native strains, highlighting the need to develop and validate screening assays in accordance to endemic T. cruzi strains. (REV INVES CLIN. 2016;68:286-91)
