SERPINA1 and alpha 1-antitrypsin deficiency: Bergin et al found that in clinically stable ZZ patients, the neutrophils have increased levels of TACE activity on their membranes, leading to a higher chemotactic index.90 Post AAT augmentation therapy, the increase in plasma concentration of AAT resulted in normalized ZZ-AATD neutrophil chemotactic responses by inhibiting TACE activity and thereby preventing FcγRIIIB from being shed from the cell membrane, reducing it to that of healthy control levels.