TGFB1 and chronic obstructive pulmonary disease: The idea that the lung exhibits abnormal repair in COPD has become a subject of increasing interest, and it has been proposed that a fundamental cause of emphysema is a failure to repair smoke-induced damage (reviewed in [7]); more specifically it has been suggested that the inability of the parenchyma to repair may result from relative TGFβ insensitivity [7].