Owing to the ability of sPLA2s to modulate vascular permeability (either by directly activating endothelial cells or by catalyzing the production/degradation of vasoactive molecules) (36), we have analyzed the enzymatic activity and biological function of sPLA2s present in plasma from C1-INH-HAE patients in symptom-free period and during attacks. The gene discussed is SERPING1; the disease is hereditary angioedema.