TGFB1 and idiopathic pulmonary fibrosis: TGFβ1 transcript levels were found to be elevated in unstimulated IPF and SSc lung fibroblasts compared to NL fibroblasts, and addition of IGF-II led to a time-dependent decrease in TGFβ1 mRNA in NL, implying that IGF-II does not rely on induction of TGFβ1 transcript or require supplemental addition of TGFβ to mediate fibrosis.