Presentation
COPD: pathobiological features supporting the case for a T2 trait
Speakers
Carlos Cabrera Lopez (Spain)
Eosinophils in COPD: Biomarker of Type 2 Inflammation or Misclassified Asthma?
The role of eosinophils in asthma is well established and has been recognised for more than a century. Early studies demonstrated that eosinophilia was closely associated with disease activity, steroid responsiveness, and exacerbation risk.1-3
In COPD, the evidence is more complex. Population-based data from the Copenhagen General Population Study showed that elevated blood eosinophils were linked to higher exacerbation risk, supporting the idea that eosinophilia may have prognostic relevance in COPD.4 However, normal reference ranges published recently remind us that eosinophil counts in the general population vary widely, complicating their interpretation in COPD.5 Clinical trials suggest that higher eosinophil counts may predict greater benefit from inhaled corticosteroids, yet biologics targeting type 2 pathways such as IL-5, IL-4/IL-13, or IL-33 have produced mixed or negative results.6-8 Moreover, the biology of eosinophils in COPD may not mirror that of asthma, and the concept of a distinct “eosinophilic COPD” endotype remains controversial.9
Diagnostic overlap: asthma or COPD?
A major challenge is the overlap between asthma and COPD. Smokers with asthma may meet inclusion criteria for COPD studies, while COPD patients with elevated eosinophils and FeNO may actually have undiagnosed asthma.10 This raises concerns that positive treatment signals in some COPD trials may be driven by misclassified asthma populations rather than a true eosinophilic COPD phenotype.
Taken together, the ERS debate on eosinophils in COPD, underscored that asthma and COPD are not interchangeable diseases. Eosinophils carry clear diagnostic and therapeutic implications in asthma, but their role in COPD is far less certain. Reliance on blood eosinophils as a single biomarker risks misclassification, and genuine precision medicine in COPD will likely require new and more reliable markers of airway biology.
Nicolai Krogh
Medical Science Liaison, Chiesi Nordic
References
- Bousquet J, Chanez P, Vignola AM, Lacoste JY, Michel FB. Eosinophil inflammation in asthma. Am J Respir Crit Care Med. 1994;150(5 Pt 2):S33-38.
- Brown HM. Treatment of chronic asthma with prednisolone; significance of eosinophils in the sputum. Lancet. 1958;2:1245-47.
- Horn BR, Robin ED, Theodore J, Van Kessel A. Total eosinophil counts in the management of bronchial asthma. N Engl J Med. 1975;292(22):1152-55.
- Vedel-Krogh S, Nielsen SF, Lange P, Vestbo J, Nordestgaard BG. Blood eosinophils and exacerbations in chronic obstructive pulmonary disease. The Copenhagen General Population Study. Am J Respir Crit Care Med. 2016;193(9):965-74.
- Lommatzsch M, Nair P, Virchow JC. Normal blood eosinophil counts in humans. Respiration. 2024;103(4):214-16.
- Bhatt SP, Rabe KF, Hanania NA, et al. Dupilumab for COPD with type 2 inflammation indicated by eosinophil counts. N Engl J Med. 2023;389:205-14.
- Bhatt SP, Rabe KF, Hanania NA, Vogelmeier CF, Bafadhel M, Christenson SA, et al. Dupilumab for COPD with blood eosinophil evidence of type 2 inflammation. N Engl J Med. 2024. doi:10.1056/NEJMoa2401304.
- Rabe KF, Celli BR, Wechsler ME, et al. Safety and efficacy of itepekimab in patients with moderate-to-severe COPD: a randomised, double-blind, phase 2a trial. Lancet Respir Med. 2021;9(11):1288-98.
- Virchow JC. Anti-interleukin-4 receptor therapy for COPD with dupilumab? Lancet Respir Med. 2024;12(10):e61-62.
- Couillard S, Laugerud A, Jabeen M, et al. Derivation of a prototype asthma attack risk scale centred on blood eosinophils and exhaled nitric oxide. Thorax. 2022;77(2):199-202.
17081-07.10.2025