CD4 and atrial fibrillation: Furthermore, the Spearman correlation between immune cells abundance and hub immune-related genes showed that 7 significantly upregulated immune-related genes (HLA-DRA, LCK, ITK, CD48, CD247, CD3D, and IL2RG) were predominantly favorably correlated with Tfh cells, CD4+T cells, iTreg cells, and Th2 cells infiltrations and primarily negatively correlated with Neutrophil cells, Th17 cells, and NKT cells infiltrations in DCM and AF patients.