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. The gene discussed is IL17A; the disease is pulmonary fibrosis.