Altered levels of FXIIa-serpin complexes in systemic lupus erythematosus (SLE) patients with previous vascular disease (VD). The plasma levels of FXIIa-C1INH (A) and FXIIa-AT (B) were assessed by sandwich ELISA in plasma from SLE patients (n = 69) and healthy controls (n = 68). Patients without previous vascular disease (VD-) were compared with those with previous VD (VD+). The VD + group was further divided into three subgroups: myocardial infarction (MI), venous thrombosis (Venous thr), and arterial thrombosis (Arterial thr). Furthermore, patients with antiphospholipid antibody syndrome (APS+) were compared with those without (APS-). In several samples, the levels of FXIIa-C1INH were below the level of detection (0.01 nM), and these data points are not visible in the figure. The numbers of individuals in the various groups with such data are as follows: controls 11/68, VD- 14/38, VD + 24/31, MI 7/10, Venous thr 14/20, Arterial thr 12/13, APS- 25/49, and APS + 13/20. The lines represent the mean values, and statistical significance was determined with the non-parametric Kruskall-Wallis test with Dunn’s multiple comparison (differences when compared with the control are not shown).