TGFB1 and pulmonary fibrosis: IL-17A stimulates the production of Th2 and Treg cytokines such as TGF-β1 and IL-10 to create a suppressive immune microenvironment in fibrotic lung tissue, which may interfere with autophagic clearance of inflammatory inducers, which may sustain chronic inflammation and promote the progression of pulmonary fibrosis.