Association between immune cells and cardiovascular disease risk: a genome-wide association study in European populations

• Five immune cell phenotypes were causally associated with atrial fibrillation risk, including CD11c on monocytes and CX3CR1 on monocyte subsets. • Three immune phenotypes (CD19 on switched memory B cells, CD25++CD8+ T cells, and their absolute count) were protective against hypertension. • No significant heterogeneity or horizontal pleiotropy was detected in sensitivity analyses, supporting the robustness of the causal estimates. • The findings suggest that immune cell phenotypes may serve as potential targets for monitoring and treating atrial fibrillation and hypertension.