TGFB1 and idiopathic pulmonary fibrosis: However, PMCs did not transform into myofibroblasts during single-dose bleomycin-induced injury (or adeno transforming growth factor beta1 (TGFβ1)-induced pulmonary fibrosis) [49], which might be because bleomycin-driven fibrosis is transient and lacks subpleural lesions that are similar to IPF.