Biphasic activation of complement and fibrinolysis during the human nasal allergic response

The interlinked pathways of complement activation, coagulation, fibrinolysis, and fibrosis contribute to numerous respiratory diseases.1-4 Multiple proteases, including mast cell tryptase released in the allergic reaction, have been documented to activate complement.5 In an extensive gene expression analysis, we recently observed changes in complement factors in mucosal curettage samples following nasal allergen challenge (NAC).6 Although complement activation has been reported in response to allergen,7 it has hitherto not been characterized as a detailed in vivo kinetic response.