Important features of airway remodeling include subepithelial fibrosis and increased deposition of extracellular matrix (ECM). Matrix metalloproteinase (MMP)-9 is involved in the normal ECM turnover and found to increase in patients with severe asthma. TGF-β1, IL-11, and IL-17 are profibrotic cytokines involved in the formation of subepithelial fibrosis and also increased in patients with severe asthma. The purpose of this study was to compare the levels of these enzyme and cytokines in the plasma of children with persistent asthma and newly diagnosed asthma.

The asthmatic children aged from 1 to 5 years old who admitted with asthma attack were included. The patients who had more than three episodes of asthma attack in the past year or who have treated for moderate-to-severe persistent asthma for more than 6 months before admission were designated as group 1 (n=24). The patients who were diagnosed with asthma for the first time were designated as group 2 (n=18). The plasma levels of MMP-9, TGF-β1, IL-11, and IL-17 were measured by ELISA in patient groups and controls (n=15).

MMP-9 in group 1 was significantly greater than in group 2 (p<0.01) and controls (p<0.05). TGF-β1 in group 1 was significantly greater than in group 2 and controls (p<0.05, respectively). No significant difference was observed between group 2 and controls. IL-11 and IL-17 showed no significant difference among three groups.

These results showed increased plasma levels of MMP-9 and TGF-β1 in young children with persistent asthma and suggest a process of airway remodeling in these patients.