Increased thrombin generation could theoretically be caused by enhanced intrinsic factor XI (FXI) activation due to increased binding to HK, as the latter protein is less bound to PKa in this scenario.16Elevated FXI levels are associated with an increased risk of arterial and venous thromboses.17, 18, 19, 20However,KLKB1−/−mice have similar FXI plasma levels compared with wild-type mice.13 Here, F11 is linked to thrombotic disease.