IL9 and idiopathic pulmonary fibrosis: In patients with IPF, patients with CF, and SiO2-induced silicosis mouse models, IL-9 expression levels were significantly elevated, and over-expression of IL-9 in mice can promote collagen and fibronectin (FN) deposition in the bronchial regions of the lungs (30), whereas administration of IL-9-neutralizing antibodies to reduce IL-9 levels in mice can significantly suppress the fibroblasts activation, as well as collagen and FN deposition in the lungs (30).