TNF and atrial fibrillation: Atrial fibrillation is clearly associated with increased levels of known inflammatory markers, and inflammation plays a role in the genesis and perpetuation of AF.18, 19, 20 TWEAK is a member of the tumour necrosis factor (TNF) pro‐inflammatory cytokine superfamily.3, 21 Consistent with leucocytes as a main cellular source of TWEAK, TWEAK is expressed broadly by human peripheral blood‐derived innate immune cells.22, 23 Thus,we examined the expression of TWEAK in PBMCs and found that TWEAK levels were increased in PBMCs from patients with AF.