• Activation of complement component 3 is associated with airways disease and pulmonary emphysema in alpha-1 antitrypsin deficiency.

      O'Brien, Michael E; Fee, Laura; Browne, Niall; Carroll, Tomás P; Meleady, Paula; Henry, Michael; McQuillan, Karen; Murphy, Mark P; Logan, Mark; McCarthy, Cormac; et al. (2020-01-20)
      Direct binding of complement C3 to AAT was identified in vivo and in vitro. Compared with healthy controls, a breakdown product of C3, C3d, was increased in AATD (0.04 µg/mL vs 1.96 µg/mL, p=0.0002), with a significant correlation between radiographic pulmonary emphysema and plasma levels of C3d (R2=0.37, p=0.001). In vivo, AAT augmentation therapy significantly reduced plasma levels of C3d in comparison to patients not receiving AAT therapy (0.15 µg/mL vs 2.18 µg/mL, respectively, p=0.001).