We aimed to investigate the presence of NG progenitors, the expression of adhesion molecules and cytokine receptors, the production of NG effector molecules/systems, such as MPO, neutrophil extracellular trap (NET), ELA2, proteinase 3 (PRTN3) and reactive oxidative species (ROS), intracellular Ca2+-mobilization in response to N-formylmethionyl-leucyl-phenylalanine (fMLP) and BK, and the comparison of adhesive characteristics to ECs in C1-INH-HAE patients and healthy controls. This evidence concerns the gene MPO and hereditary angioedema.