Introduction:

AATD-associated lung disease is caused by a protease/antiprotease imbalance due to low circulating levels of alpha-1 antitrypsin (AAT) or decreased EIA. The aim of this study was to verify the reliability of the measurement of EIA in patients with AATD and COPD.

Material and methods:

Cross-sectional study performed in patients diagnosed with COPD with or without AATD Pi*ZZ. A control group of healthy individuals was included. AAT levels and EIA of AAT in blood plasma were determined. Measurement of EIA was conducted by a semiautomated immunoassay technique.

Results:

A total of 87 individuals were included: 38 patients with COPD (43.7%), 19 patients with COPD and Pi*ZZ (21.8%) (11 in augmentation therapy (12.6%) and 8 without therapy (9.2%)) and a control group of 30 healthy individuals (34.5%). The mean age was 64.1 (12.3) years, 56.3% were men and the mean AAT levels were 124.4 (46.2) mg/dL. The mean absolute EIA was 1.46 (0.63) mg/ml, with higher levels observed in COPD patients (1.84 (0.48) mg/ml), followed by AATD patients on augmentation therapy (1.30 (0.81) mg/ml) and finally non-augmented AATD patients (0.24 (0.01) mg/ml, p<0.001). The control group showed EIA levels of 1.36 (0.24) mg/ml.

Conclusion:

COPD individuals presented higher levels of EIA than patients with AATD and healthy controls. As expected, the EIA was higher in augmented versus non-augmented AATD patients. Measurement of the EIA may be useful to assess the protease/antiprotease balance in patients with COPD and AATD.