Metalloproteinase-9 in induced sputum correlates with the severity of the late allergen-induced asthmatic response

Respiration. May-Jun 2004;71(3):216-24. doi: 10.1159/000077418.


Background: Asthma is characterized by airway inflammation and remodeling in which matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMP) play an important role. Allergen exposure activates the inflammatory/repair process in sensitized subjects. Induced-sputum analysis is a non-invasive method that allows the assessment of changes in inflammatory and remodeling mediators implicated in asthma.

Objectives: To evaluate the changes in MMP-9 and its principal inhibitor (TIMP-1) in sputum and plasma of mild allergic asthmatic subjects after whole-lung allergen challenge.

Methods: Induced sputum and blood samples were obtained at baseline, and 6 and 24 h after challenge. MMP-9 and TIMP-1 levels in sputum and plasma were measured by ELISA.

Results: Allergen challenge increased the percentage of sputum eosinophils and MMP-9 levels 6 and 24 h after the challenge compared to baseline levels, but TIMP-1 levels did not vary significantly. A significant correlation was observed between MMP-9 levels at 6 h and the maximum percent fall in FEV(1) during the late response. Throughout the study, MMP-9 levels correlated significantly with the number of neutrophils in sputum.

Conclusions: This study shows that analysis of induced sputum is a useful tool to study the variations in MMP-9 and TIMP-1 levels following allergen challenge, therefore allowing to evaluate their role in allergen-induced airway damage and repair.

MeSH terms

  • Adolescent
  • Adult
  • Allergens / adverse effects*
  • Asthma / immunology*
  • Female
  • Humans
  • Male
  • Matrix Metalloproteinase 9 / analysis*
  • Severity of Illness Index
  • Sputum / chemistry
  • Tissue Inhibitor of Metalloproteinase-1 / analysis


  • Allergens
  • Tissue Inhibitor of Metalloproteinase-1
  • Matrix Metalloproteinase 9