Human Chagas-Flow ATE-IgG1 for advanced universal and Trypanosoma cruzi Discrete Typing Units-specific serodiagnosis of Chagas disease

Abstract

The molecular and serological methods available for Discrete Typing Units (DTU)-specific diagnosis of Trypanosoma cruzi in chronic chagas disease present limitations. the study evaluated the performance of Human Chagas-Flow ATE-IgG1 for universal and DTU-specific diagnosis of Chagas disease. A total of 102 sera from Chagas disease patients (CH) chronically infected with TcI, TcVI or TcII DTUs were tested for IgG1 reactivity to amastigote/(A), trypomastigote/(T) and epimastigote/(E) antigens along the titration curve (1:250-1:32,000). The results demonstrated that "AI 250/40%", "EVI 250/30%", "AII 250/40%", "TII 250/40%" and "EII 250/30%" have outstanding accuracy (100%) to segregate CH from non-infected controls. The attributes "TI 4,000/50%", "EI 2,000/50%", "AVI 8,000/60%" and "TVI 4,000/50%" were selected for DTU-specific serotyping of Chagas disease. The isolated use of "EI 2,000/50%" provided the highest co-positivity for TcI patients (91%). The combined decision tree algorithms using the pre-defined sets of attributes showed outstanding full accuracy (92% and 97%) to discriminate "TcI vs TcVI vs TcII" and "TcI vs TcII" prototypes, respectively. The elevated performance of Human Chagas-Flow ATE-IgG1 qualifies its use for universal and TcI/TcVI/TcII-specific diagnosis of Chagas disease. These findings further support the application of this method in epidemiological surveys, post-therapeutic monitoring and clinical outcome follow-ups for Chagas disease. Chagas disease, caused by the parasite Trypanosoma cruzi, affects 8 million people worldwide mainly in Latin America 1. The short-term acute phase of the disease evolves to long-lasting chronic phase with distinct clinical manifestations ranging from asymptomatic to cardiac, digestive or cardiac/digestive clinical forms 2-4. Trypanosoma cruzi presents a remarkable genetic diversity and has been classified into at least six Discrete Typing Units (DTUs) and an emerging DTU named TcBat 5. Several studies have shown that besides selective

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“…Similarly, anti-epimastigote IgG1 has been able to distinguish between T. cruzi -infected and non-infected individuals [ 61 ]. Most recently, the Human Chagas-Flow ATE-IgG1 has been able to differentiate between TcI, TcVI and TcII lineages with high accuracy [ 62 ].…”

New insights into Trypanosoma cruzi genetic diversity, and its influence on parasite biology and clinical outcomes

“…The methodologies used for the genotype-specific diagnosis of Chagas disease to recognize T. cruzi DTUs have been developed, including biochemical and molecular methods ( 5 , 7 ) as well as serological tests ( 362 – 371 ). Considering the distinct geographic distribution of DTUs ( 7 ), genotype-specific diagnosis of Chagas disease is relevant for implementing epidemiological surveillance and more precise strategies for disease control in endemic areas.…”

“…Several innovative serological methods have been developed to overcome the limitations of molecular tests for genotype-specific diagnosis of Chagas disease, mainly during the chronic phase ( 362 – 371 , 421 ). The first serological marker to identify T. cruzi genotypes was the mucin trypomastigote small surface antigen (TSSA), a surface protein of the bloodstream trypomastigote, which initially appeared to correlate with the parasite lineages T. cruzi I (TcI) and T. cruzi II (TcII) ( 422 ).…”

“…Alessio et al. (2020) ( 371 ) evaluated the performance of Chagas-Flow ATE for DTU-specific diagnosis of Chagas disease using serum samples from patients with Chagas disease chronically infected with TcI, TcVI, or TcII DTUs of T. cruzi. The results obtained in this work demonstrated the high performance of the Chagas-Flow ATE technique for DTU-specific diagnosis of Chagas disease, with 92% global accuracy in discriminating “TcI vs. TcVI vs. TcII” and 97% global accuracy in segregating “TcI vs. TcII” T. cruzi infections.…”

“…The results obtained in this work demonstrated the high performance of the Chagas-Flow ATE technique for DTU-specific diagnosis of Chagas disease, with 92% global accuracy in discriminating “TcI vs. TcVI vs. TcII” and 97% global accuracy in segregating “TcI vs. TcII” T. cruzi infections. Earlier studies were pioneers in the development of a serological method by flow cytometry for the genotype-specific diagnosis of Chagas disease, with advantages such as the use of a wide range of antigenic preparations in a single flow cytometric platform ( 357 , 424 – 427 ), testing of a large number of samples, and evaluation of the reactivity of serum samples from single and mixed T. cruzi infections ( 367 , 368 , 371 ).…”