IL13 and pulmonary fibrosis: Our previous studies demonstrate upregulation of multiple growth factors including TGFβ, IL-6, IL-13, amphiregulin and epiregulin in distinct mesenchymal cell subsets such as fibrocytes, lung resident fibroblasts and WT1-positive myofibroblasts during TGFα-induced pulmonary fibrosis (Madala et al., 2014c; Sontake et al., 2015, 2018).