C3 and alpha 1-antitrypsin deficiency: Although C3 activation in HC plasma upon addition of 10 μg/mL (338 nM) NE was not apparent, with the addition of NE to AATD plasma, a 33 kDa band corresponding to the correct molecular mass of C3d was visible, indicating that NE may play a role in the increased plasma C3d levels observed in AATD individuals.