Human proteinase 3resistanceto inhibition extends to alpha‐2 macroglobulin

Polymorphonuclear neutrophils contain at least four serine endopeptidases, namely neutrophil elastase (NE), proteinase 3 (PR3), cathepsin G (CatG), and NSP4, which contribute to the regulation of infection and of inflammatory processes. In physiological conditions, endogenous inhibitors including α2‐macroglobulin (α2‐M), serpins [α1‐proteinase inhibitor (α1‐PI)], monocyte neutrophil elastase inhibitor (MNEI), α1‐antichymotrypsin, and locally...