Comparison of eosinophilic COPD and eosinophilic bronchitis.
| Feature | Eosinophilic COPD | Eosinophilic bronchitis |
|---|---|---|
| Definition | COPD phenotype with eosinophilic inflammation in airways and/or blood | Chronic cough with eosinophilic airway inflammation, without airflow obstruction |
| Typical symptoms | Chronic cough, sputum production, exertional dyspnea, wheezing; frequent exacerbations | Isolated chronic non-productive cough |
| Lung function | Persistent airflow limitation | Normal lung function |
| Bronchodilator response | Sometimes shows a high response (FEV1 > 15% and > 400 mL) | No bronchodilator response |
| Airway hyperresponsiveness | May or may not be present | Absent |
| Exacerbation pattern | Frequent, especially non-bacterial | Rare to none |
| Inflammatory profile | T2-high: IL-5, IL-4, IL-13; ILC2s and Th2 cells in airway mucosa | T2-high inflammation localized to the airway without systemic involvement |
| Histopathology | Patchy eosinophil-rich lung areas; GATA3+ cells | Sputum eosinophilia; absence of tissue remodelling |
| Associated biomarkers | Elevated BEC (≥ 150–300 cells/μL or ≥ 2–3% leukocytes), FeNO, T2 cytokines | Sputum eosinophils; no consistent blood eosinophilia |
| Patient demographics | More common in men, ex-smokers, those with higher BMI and ischemic heart disease | Not clearly associated with specific demographics |
| Asthma relationship | Can occur with or without asthma; not necessarily ACO | Not associated with asthma |
| Microbiome | Distinct from neutrophilic COPD; non-Haemophilus dominant | Not well characterized |
ACO: asthma-COPD overlap; BEC: blood eosinophil count; BMI: body mass index; COPD: chronic obstructive pulmonary disease; FeNO: fractional exhaled nitric oxide; IL: interleukin; ILC2s: group 2 innate lymphoid cells; T2: type 2; Th2: T-helper 2.
MDG, GWC: Conceptualization, Supervision, Writing—review & editing. GMW, LD, VP: Conceptualization, Writing—original draft (wrote section Pathophysiology of eosinophils (correspondence to Garry Michael Walsh: g.m.walsh@abdn.ac.uk)). GP, AMP, CDV, PT, DK, F Buta, NL, JO, MMA, CSR: Conceptualization, Writing—original draft (wrote section Eosinophilic inflammation across the upper airways: mechanisms, biomarkers, and therapeutic advances (correspondence to Giovanni Paoletti: giovanni.paoletti@hunimed.eu)). AY, F Braido, NR, DB: Conceptualization, Writing—original draft (wrote section Eosinophils and asthma (correspondence to Arzu Yorgancıoğlu: arzuyo@hotmail.com)). MC, MM: Conceptualization, Writing—original draft (wrote section Eosinophilic COPD (correspondence to Mario Cazzola: mario.cazzola@uniroma2.it)). GG: Conceptualization, Writing—original draft (wrote section Eosinophilic granulomatosis with polyangiitis and allergic bronchopulmonary aspergillosis (correspondence to Giuseppe Guida: giuseppe.guida@gmail.com) and Hypereosinophilic syndromes (correspondence to Giuseppe Guida: giuseppe.guida@gmail.com)). FP, RGC: Conceptualization, Writing—original draft (wrote section Other eosinophilic lung diseases (correspondence to Francesco Puppo: puppof@unige.it)). GM: Conceptualization, Writing—original draft (wrote section Eosinophilic myocarditis (correspondence to Giuseppe Murdaca: giuseppe.murdaca@unige.it)). PC, GCP: Conceptualization, Writing—original draft (wrote section Psychological and psychopathological components of eosinophilic myocarditis and pneumonia, a disease (correspondence to Pasquale Caponnetto: pasquale.caponnetto@unict.it)). WvdV, ER, NRF: Conceptualization, Writing—original draft (wrote section Eosinophils in gastrointestinal diseases (correspondence to Willem van de Veen: willem.vandeveen@siaf.uzh.ch)). TZ FRW: Conceptualization, Writing—original draft (wrote section Eosinophils and urticaria (correspondence to Torsten Zuberbier: torsten.zuberbier@charite.de)). MR, ERG: Conceptualization, Writing—original draft (wrote section Eosinophils in anaphylaxis and DRESS (correspondence to Matija Rijavec: Matija.Rijavec@klinika-golnik.si)). All authors read and approved the submitted version.
Giorgio Walter Canonica is the Editor-in-Chief of Exploration of Asthma & Allergy; Mario Di Gioacchino is the Co Editor-in-Chief of Exploration of Asthma & Allergy; Diego Bagnasco, Pasquale Caponnetto, Willem Van de Veen, Linhong Deng, Nelson Rosario Filho, Eva Rebelo Gomes, Giuseppe Murdaca, Vincenzo Patella, Ana Margarida Pereira, Francesco Puppo, Erminia Ridolo, Matija Rijavec, Nikoletta Rovina, Franziska Roth-Walter, Pongsakorn Tantilipikorn, Arzu Yorgancıoğlu are Editorial Board Members of Exploration of Asthma & Allergy; Fulvio Braido, Mario Cazzola, Giuseppe Guida, Mauro Maniscalco, Mário A. Morais-Almeida, Giovanni Paoletti, Chae-Seo Rhee, Garry M. Walsh, Torsten Zuberbier are Associate Editors of Exploration of Asthma & Allergy. They all had no involvement in the decision-making or the review process of this manuscript. The other authors declare no conflicts of interest.
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All datasets generated for this study are included in the manuscript.
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