ACTIVATION OF THE COMPLEMENT, COAGULATION, FIBRINOLYTIC AND KALLIKREIN-KININ SYSTEMS DURING ATTACKS OF HEREDITARY ANGIOEDEMA

Five patients with hereditary angioedema (HAE) were studied during attacks and remission as were healthy controls. The high levels of C1/C1-INH complexes, low C4 and high ratio C4 activation products (C4bc)/C4 also differed significantly during remission compared to controls.During attacks C4bc/C4 increased (922–2007; P=0.022, remission versus attacks, median values throughout), C2 and CH50 dropped (111–31%; P=0.043 and 110–36%; P=0.016, respectively), TCC (C5b-9) increased (0.88–1.23 AU/ml; P=0.028). Cleavage of HK increased to be almost complete during attacks (20–90%; P=0.009). While factor XIa/serpin-complexes did not increase, a more than twofold rise in thrombin/antithrombin-complexes (0.20–0.50 μg/l; P=0.009) and in plasmin/alpha-2-antiplasmin-complexes (7.3–17 nmol/l; P=0.028) was observed. For the first time cascade activation in HAE was studied simultaneously, and corroborates that attacks lead to activation of the kallikrein-kinin system, fibrinolysis and early part of the classical complement pathway. In addition, the authors present novel data of terminal complement and coagulation activation, the latter apparently not via FXIa.