TGF-β increased the deposition of mature fibrillar collagen by non-IPF fibroblasts but not IPF fibroblasts, which was alleviated by the pan-LO inhibitor β-APN (Fig. 3D), but TGF-β did not affect collagen fibre maturity/thickness (Fig. 3E). Here, TGFB1 is linked to idiopathic pulmonary fibrosis.