Similarly, mast cell chymase may exhibit both pro- and anti-inflammatory effects in the context of airway inflammation, as it has been shown that chymase can promote fibrosis by degradation of fibronectin and collagen [30] but can also reduce AHR [12, 13] and degrade various type 2 cytokines and chemokines [31, 32]. This evidence concerns the gene AHR and inflammatory response.