S100A8 and atrial fibrillation: The most abundant immune cells in atrium of AF and SR patients were DC, B cell, Monocyte, Macrophages, NK, Neutrophil, CD4_T, CD8_T, NKT, and Tgd (Supplementary Figure S4B).We further analyzed the relationship between immune cell abundance and the expression level of hub genes (Supplementary Figure S4C) and found that the monocyte abundance was significantly associated with S100A8/A9 expression.