TGFA and pulmonary emphysema: Similarly, we found in lungs of mice after cigarette-smoke exposure that (i) emphysema and fibrosis may be present in the same lung; (ii) the development of the emphysematous lesions occur at earlier time points than that of the fibrotic foci, and (iii) a positive immunohistochemical reaction for neutrophil elastase is associated with a positive reaction for TGF-β and TGF-α two major fibrogenic cytokines (i.e. [31,32] in foci of cellular proliferation, and in areas of fibrosis.