Abstract Body: INTRODUCTION: Chagas disease affects approximately 8 million people, with approximately 30% developing chronic Chagas cardiomyopathy (CCC). Yet, the molecular and immunological mechanisms underlying the progression of CCC remain inadequately characterized, highlighting the critical need for high-resolution molecular techniques to better understand the pathogenesis of this disease.

AIM: To identify the immunologic changes that characterize CCC progression and that discriminate CCC from other cardiomyopathies.

METHODS: We performed multimodal transcriptomics including 1) cross-sectional single-cell RNA sequencing (scRNAseq) of peripheral blood mononuclear cells from 30 CCC and non-CCC patients, 2) spatial transcriptomics of the left ventricular wall of 2 patients with advanced disease, and 3) longitudinal whole blood bulk RNA-sequencing of 102 patients with CCC prior to disease progression. All groups were matched by sex and age.

RESULTS: By scRNAseq, we identified alterations in B cells and central memory CD4+ T cell populations with worsening CCC stage and when compared to other cardiomyopathies. By spatial transcriptomics we show that these cell populations are spatially association with regions of cardiac fibrosis, as determined by expression of markers such as COLA1 and COL3A1, and matched H&E images. We also highlight various immunologic pathways and cell-cell interactions that are enriched in CCC. Finally, using our longitudinal analysis we identify various differentially expressed immune-associated genes that are altered before disease progression occurs.

CONCLUSION: In summary, transcriptomic analysis of blood cells from patients with Chagas disease can discriminate individuals at different stages of CCC and between CCC and other cardiomyopathies. Our findings may help guide the design of novel molecular strategies for monitoring the progression of CCC and guide the development of novel therapies for Chagas cardiomyopathy.