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. This evidence concerns the gene IGKV1D-22 and atrial fibrillation.