Routine Blood Biomarkers and Lung Disease in Patients with Alpha-1 Antitrypsin Deficiency from the EARCO Registry

The aim of our study was to identify routine serum biomarkers that may be related to alpha-1 antitrypsin deficiency lung disease phenotypes and severity.

Observational, cross-sectional, multicentre study conducted in patients with a Pi*ZZ genotype. Serum biomarkers, including neutrophil/lymphocyte ratio (NLR), eosinophil/lymphocyte ratio (ELR) and platelet/lymphocyte ratio (PLR), were calculated. Data were analysed to establish possible associations between biomarkers and lung function and lung phenotypes.

Among the 897 patients included, 48.4% were men with a mean age of 53.9 (standard deviation 14.7) years. Patients with chronic obstructive pulmonary disease (COPD) (n = 337) had higher haemoglobin levels (15.3 mg/dL vs. 13.9 mg/dL, p < 0.001), gamma-glutamyl transferase (GGT) (50.1 IU/L vs. 35.7 IU/L, p < 0.001), eosinophils (0.22 109/L vs. 0.19 109/L, p < 0.001), NRL (2.55 vs. 1.86), PLR (132.6 vs. 119.8), and ELR (0.12 vs. 0.1) compared to those without COPD. In multivariate analysis, older age, male sex, higher haematocrit, elevated alanine transaminase and GGT levels, and a higher NRL and PLR were associated with a worse forced expiratory volume in the first second (FEV1) (%). A higher Charlson score, elevated haematocrit and white cell count, as well as increased levels of AAT, aspartate aminotransferase (AST), GGT, and PLR were associated with worse carbon monoxide transfer coefficient (KCO) (%). Exacerbations were associated with female sex, and a higher PLR.

Some blood biomarkers are increased in patients worse lung function. However, the correlations between these biomarkers and the different measures of lung function are weak, and thus, identifying a single routine biomarker that accurately predicts disease severity and progression is challenging.