IL13 and idiopathic pulmonary fibrosis: In addition to TGF-β1, other important fibrogenic mediators with increased expression in IPF lung tissue were CTGF, PDGF, FGF-2, ET-1, ANGII, and cytokines such as IL-13, IL-6, and chemokine ligand 2, all of which have been implicated in the pathogenesis of this disease [2, 3].