TGF-β is well-established in asthma pathophysiology for its role in fibroblast activation, myofibroblast differentiation, and ECM deposition [36], the induction of TGF-β in response to IL-5 might also contribute alongside with IL-5 in the ECM expression Notably, IL-5-induced IL-6 [37] and TGF-β [38] secretion could contribute to steroid resistance in severe asthma, explaining why airway remodelling — driven in part by fibroblasts that respond poorly to corticosteroids [39] — remains difficult to manage with conventional therapy [37, 38]. This evidence concerns the gene IL5 and asthma.