CD4 and atrial fibrillation: There were significant associations between 8 immune cell phenotypes and AF via the IVW method, including IgD− CD38dim AC, CD4 + CD8dim AC, BAFF-R on IgD + CD38− naive, CD25 on IgD + CD38dim, CD27 on IgD− CD38br, CX3CR1 on CD14 + CD16− monocyte, CD64 on monocyte, and SSC-A on myeloid DC.