Neutrophils make an enzyme called neutrophil elastase, a protease capable of breaking down elastin, which is an extracellular matrix protein that gives elasticity and strength to lung tissues.
So while these little guys can help fight off infection by breaking down proteins of the bacteria, it can also go on to break down that precious elastin.
They're made out of the protein elastin which allows them to stretch and recoil like rubber bands; they're found in places like your skin, lungs, and blood vessel walls.
Nicotine causes narrowing of the blood vessels in the outermost layers of the skin, while the chemicals in tobacco smoke damage collagen and elastin, fibres which give the skin its elasticity.
Without alpha-1 antitrypsin, the opposite happens - neutrophil elastase goes unchecked, and it damages the walls of the alveoli, and without that elastin, the alveoli loses its elasticity and structural integrity.