TGFB1 and idiopathic pulmonary fibrosis: Despite studies using either rat or mouse AECII [13, 14] or immortalized cell lines [15] as well as isolated AECII from IPF patients [16], the direct mechanistic connection of the TGFβ pathway on trans-diffe rentiation and collagen metabolism in human, primary AECII remains to be elucidated.