The relationship between eosinophilia and airway remodelling in mild asthma

Clin Exp Allergy. 2013 Dec;43(12):1342-50. doi: 10.1111/cea.12156.


Background: Eosinophilia is a marker of corticosteroid responsiveness and risk of exacerbation in asthma; although it has been linked to submucosal matrix deposition, its relationship with other features of airway remodelling is less clear.

Objective: The aim of this study was to investigate the relationship between airway eosinophilia and airway remodelling.

Methods: Bronchial biopsies from subjects (n = 20 in each group) with mild steroid-naïve asthma, with either low (0-0.45 mm(-2)) ) or high submucosal eosinophil (23.43-46.28 mm(-2) ) counts and healthy controls were assessed for in vivo epithelial damage (using epidermal growth factor receptor staining), mucin expression, airway smooth muscle (ASM) hypertrophy and inflammatory cells within ASM.

Results: The proportion of in vivo damaged epithelium was significantly greater (P = 0.02) in the high-eosinophil (27.37%) than the low-eosinophil (4.14%) group. Mucin expression and goblet cell numbers were similar in the two eosinophil groups; however, MUC-2 expression was increased (P = 0.002) in the high-eosinophil group compared with controls. The proportion of submucosa occupied by ASM was higher in both asthma groups (P = 0.021 and P = 0.046) compared with controls. In the ASM, eosinophil and T-lymphocyte numbers were higher (P < 0.05) in the high-eosinophil group than both the low-eosinophil group and the controls, whereas the numbers of mast cells were increased in the high-eosinophil group (P = 0.01) compared with controls.

Conclusion: Submucosal eosinophilia is a marker (and possibly a cause) of epithelial damage and is related to infiltration of ASM with eosinophils and T lymphocytes, but is unrelated to mucus metaplasia or smooth muscle hypertrophy.

Keywords: asthma; eosinophil; epithelium; goblet cell; inflammation; remodelling; smooth muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Airway Remodeling*
  • Asthma / immunology*
  • Asthma / metabolism
  • Asthma / pathology*
  • Case-Control Studies
  • Eosinophilia / pathology*
  • Female
  • Goblet Cells / pathology
  • Humans
  • Hyperplasia
  • Male
  • Middle Aged
  • Mucins / metabolism
  • Muscle, Smooth / metabolism
  • Muscle, Smooth / pathology
  • Respiratory Mucosa / immunology
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / pathology
  • Young Adult


  • Mucins