Loss- and gain-of-function mechanisms proposed to play a role in α1-antitrypsin deficiency
| Loss-of-function | Gain-of-function |
| Excessive elastase activity, destruction of extracellular matrix, increased LTB4, increase in neutrophil chemotaxis, reduced bacterial killing capacity | ER overload, NF-κB signalling |
| Reduced fibroblast stimulation | IL-6, IL-8 expression |
| Reduced defence against caspase-3-mediated apoptosis | Chemotaxis, neutrophil binding and activation |
| Neutrophil degranulation |
LTB4: leukotriene B4; ER: endoplasmic reticulum; NF-κB: nuclear factor-κB; IL: interleukin.