A comparison of bronchial biopsies from patients with asthma found that the thickness of tenascin and airway smooth muscle mass were significantly reduced after treatment with biologics targeting IL-5 or IL-5 receptor,[50], [53] associated with the reduction of TGF-β+ eosinophils, which is consistent with our finding that TGF-β production in eosinophils was elevated by IL-5 while decreased by mepolizumab. This evidence concerns the gene IL5 and asthma.