Eosinophil Subtypes in Adults with Asthma and Adults with Chronic Obstructive Pulmonary Disease

• Published in: American journal of respiratory and critical care medicine Vol. 208; no. 2; pp. 155 - 162
• Main Authors: Cabrera López, Carlos, Sánchez Santos, Alejandra, Lemes Castellano, Angelina, Cazorla Rivero, Sara, Breña Atienza, Joaquín, González Dávila, Enrique, Celli, Bartolomé, Casanova Macario, Ciro
• Format: Journal Article
• Language: English
• Published: United States American Thoracic Society 15-07-2023
• Subjects: Adult; Animals; Asthma; Chronic obstructive pulmonary disease; Cohort analysis; Drug therapy; Eosinophils; Humans; Leukocyte Count; Leukocytes; Mice; Proteins; Pulmonary Disease, Chronic Obstructive - drug therapy; Sialic Acid Binding Immunoglobulin-like Lectins - therapeutic use; eosinophils; asthma; COPD; subtypes
• ISSN: 1073-449X; 1535-4970
• DOI: 10.1164/rccm.202301-0149OC

There is a differential response to eosinophilic modulation between patients with asthma and those with chronic obstructive pulmonary disease (COPD). There is also evidence of different subtypes of eosinophils in murine models. However, no study has compared eosinophil subtypes in individuals with COPD and in those with asthma.
Study the differences in eosinophils subtypes based in the surface protein expression in COPD patients and asthmatic patients.
We studied 10 stable subjects in each of four groups: subjects with COPD, subjects with asthma, smokers without COPD, and healthy volunteers. Subjects with COPD and those with asthma were matched by age, sex, and FEV
% predicted. The following variables were determined: anthropometrics, smoking, exacerbation history, medication use, lung function, and comorbidities. Using flow cytometry and confocal microscopy from blood samples, we determined differences in eosinophil surface proteins and classified them as
) resident eosinophils (Siglec-8
CD62L
IL-3R
) or
) inflammatory eosinophils (iEos; Siglec-8
CD62L
IL-3R
). IL-5 receptor was also determined. Findings were validated in 59 patients with COPD and in 17 patients with asthma.
Patients with asthma had a higher proportion of iEos (25 ± 15%) compared with those with COPD (0.5 ± 1%), smokers without COPD (0.14 ± 0.24%), and healthy volunteers (0.67 ± 1.72%). In patients with asthma, the proportion of iEos was independent of total eosinophil number. iEos had more IL-5 receptors than resident eosinophils (777.02 ± 124.55 vs. 598.35 ± 318.69;
 < 0.01). In patients with COPD, there was no relation between iEos number and inhaled corticosteroid use, disease severity, or exacerbations rate. The findings in patients with COPD and those with asthma were confirmed in validation cohorts.
There are differences in the subtypes of circulating eosinophils between patients with asthma and those with COPD. This could have clinical implications in the interpretation of eosinophil significance and the approach to therapy in these patients.