Generation of FXIa-, FXIIa- and kallikrein-C1-inhibitor complexes on in vitro contact activation in plasma. EDTA plasma was activated with DXS (0.05 or 0.2 mg/mL, final concentration) or with kaolin (2.5 or 5 mg/mL), respectively. FXIa-, FXIIa-, and kallikrein-C1-inhibitor complexes were measured using specific ELISAs (see Materials and Methods). White bars (□) represent FXIa-C1-inhibitor complexes, shaded bars (▨) represent FXIIa-C1-inhibitor complexes, and black bars (▪) represent kallikrein-C1-inhibitor complexes.