Performance of TcI/TcVI/TcII Chagas-Flow ATE-IgG2a for universal and genotype-specific serodiagnosis of Trypanosoma cruzi infection.
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2017
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Abstract
Distinct Trypanosoma cruzi genotypes have been considered relevant for patient management
and therapeutic response of Chagas disease. However, typing strategies for genotype-
specific serodiagnosis of Chagas disease are still unavailable and requires
standardization for practical application. In this study, an innovative TcI/TcVI/TcII Chagas
Flow ATE-IgG2a technique was developed with applicability for universal and genotypespecific
diagnosis of T. cruzi infection. For this purpose, the reactivity of serum samples
(percentage of positive fluorescent parasites-PPFP) obtained from mice chronically infected
with TcI/Colombiana, TcVI/CL or TcII/Y strain as well as non-infected controls were determined
using amastigote-AMA, trypomastigote-TRYPO and epimastigote-EPI in parallel
batches of TcI, TcVI and TcII target antigens. Data demonstrated that ªα-TcII-TRYPO/
1:500, cut-off/PPFP = 20%º presented an excellent performance for universal diagnosis of
T. cruzi infection (AUC = 1.0, Se and Sp = 100%). The combined set of attributes ªα-TcITRYPO/
1:4,000, cut-off/PPFP = 50%º, ªα-TcII-AMA/1:1,000, cut-off/PPFP = 40%º and ªα-
TcVI-EPI/1:1,000, cut-off/PPFP = 45%º showed good performance to segregate infections
with TcI/Colombiana, TcVI/CL or TcII/Y strain. Overall, hosts infected with TcI/Colombiana
and TcII/Y strains displayed opposite patterns of reactivity with ªα-TcI TRYPOº and ªα-TcII
AMAº. Hosts infected with TcVI/CL strain showed a typical interweaved distribution pattern.
The method presented a good performance for genotype-specific diagnosis, with global
accuracy of 69% when the population/prototype scenario include TcI, TcVI and TcII infections
and 94% when comprise only TcI and TcII infections. This study also proposes a
receiver operating reactivity panel, providing a feasible tool to classify serum samples from hosts infected with distinct T. cruzi genotypes, supporting the potential of this method for
universal and genotype-specific diagnosis of T. cruzi infection.
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ALESSIO, G. D. et al. Performance of TcI/TcVI/TcII Chagas-Flow ATE-IgG2a for universal and genotype-specific serodiagnosis of Trypanosoma cruzi infection. PLoS Neglected Tropical Diseases, v. 11, p. e0005444-24, 2017. Disponível em: <http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0005444>. Acesso em: 29 ago. 2017.