AAT is also able to suppress infection of MDM with Mycobacterium abscessus suggesting a potential to prevent bacterial infection in the lungs by acting directly on the macrophage.50 Further work is needed to elucidate the full effects of exogenous AAT on macrophage function and particularly the role in clearance of bacteria relevant to COPD (see Figure 2). Here, SERPINA1 is linked to bacterial infectious disease.