The antifibrotic property of pirfenidone is demonstrated to depend on its ability to inhibit the direct production of profibrotic cytokines and growth factors, such as TGF-β1, basic-fibroblast growth factor, platelet-derived growth factor, IL-1β, and TNF-α in experimental models of pulmonary fibrosis [17]. Here, TGFB1 is linked to pulmonary fibrosis.