Chagas Working Group in Bolivia and Peru, ; (2018) Severity of Chagasic Cardiomyopathy Is Associated With Response To A Novel Rapid Diagnostic Test For Trypanosoma cruzi

Trypanosoma cruzi causes Chagas disease in the Americas. Outcome of infection ranges from lifelong asymptomatic status to severe disease. Understanding how history of T. cruzi lineage (TcI-TcVI) infection relates to clinical prognosis is challenging. We previously described peptide-based lineage-specific ELISA with Trypomastigote Small Surface Antigen (TSSA). A novel rapid diagnostic test (Chagas Sero K-SeT) incorporating a peptide corresponding to the TSSA-II/V/VI common epitope was developed, and validated by comparison with ELISA. Patients from Bolivia and Peru were then tested by Chagas Sero K-SeT, including individuals with varying cardiac pathology, and matched mothers and neonates. Chagas Sero K-SeT and ELISAs, with a Bolivian subset of cardiac patients, mothers and neonates, were in accord. In adult chronic infections (n = 121), comparison of severity class A (no evidence of Chagas cardiomyopathy) against classes B (ECG suggestive of Chagas cardiomyopathy) and C/D (moderate/severe Chagas cardiomyopathy) revealed statistically significant increase in Chagas Sero K-SeT reactivity with increasing severity (Chi Square for trend 7.39; p = 0.007). In Peru, where TcII/V/VI lineages are rarely reported, Chagas Sero K SeT detected sporadic infections. We develop a novel, low-cost, point-of-care, rapid test and demonstrate that it can replace ELISA for identification of lineage-specific TSSA II/V/VI IgG. Most importantly, we show that response to the TSSA II/V/VI epitope in this RDT is associated with severity of Chagas cardiomyopathy, and thus may have prognostic value. Repeated challenge with T. cruzi infection may both exacerbate disease progression and boost the immune response to the TSSApep-II/V/VI epitope.