TGFB1 and pulmonary fibrosis: COPD exacerbations have been associated with increased markers of inflammation acts in the airway,57 and inflammation acted as an important driver in the development of pulmonary fibrosis.58 In our study, TGF-β3 levels (6.23 ± 0.84) in mice of the 2nd Immunization group increased significantly, while the TGF-β1 and TGF-β2 levels did not change much (data not shown).