SERPINA1 and chronic obstructive pulmonary disease: Non AATD-related COPD patients had the highest AAT concentrations (149.3 mg/dL (SD: 23.8), p < 0.001) (Fig 2) (Table 2) as well as the highest absolute EIA (1.88 mg/mL (SD: 0.4) p < 0.001) compared to the AATD-related COPD group.