Single-cell TCR Profiling in Left Atria Identifies Complement Pathway Involvement in Atrial Fibrillation

However, the role of T cells in AF pathogenesis remains unclear. In this study, we aimed to characterize the detailed landscape and clonal expansion of T cells using single-cell TCR sequencing, and validate our findings via O-link proteomics in plasma.

Analysis of left atrial tissues from eight AF patients identified five CD4+ T cells, six CD8+ T cells, and gamma delta T cells based on canonical gene expression markers. Notably, we observed clonal expansion of resident memory and cytotoxic T cells. CellChat analysis highlighted complement signaling–mediated interactions between T cells and fibroblasts.