Legend for Figure 1
Figure 1. Activation of the coagulation system in chronic urticaria. Mast cells release inflammatory mediators including histamine after degranulation leading to activation of endothelial cells and eosinophils. Activated endothelial cells and eosinophils express tissue factor initiating coagulation activation after binding to activated factor VII (FVIIa) generating thrombin. Thrombin induces activation of platelets, cleaves fibrinogen, recruits inflammatory cells, activates mast cells and endothelial cells by binding to and cleaving protease-activated receptor (PAR-1) leading to increased vascular permeability with extravascular spillover of inflammatory mediators. EOS, eosinophils; MC, mast cells; NEU, neutrophils; F1+2, prothrombin fragment 1+2; FDP, fibrin degradation products; PL, phospholipids.