TGFB1 and idiopathic pulmonary fibrosis: As shown in Fig. 2a & b, TGF-β1-induced proliferation of NHLFs and IPF lung fibroblasts was significantly reduced by IFN-γ (10–40 ng/ml) and PFD (300–500 μg/ml) in a dose-dependent manner after 1, 3 and 5 days (p = 0.0002, Fig. 2a & p = 0.014 Fig. 2b).