LGALS9 and pulmonary emphysema: Histological analysis on day 21 revealed that PPE-treated mice that were administered PBS (PPE-treated control mice) showed diffuse emphysema lesions, as indicated by alveolar wall destruction and marked enlargement of airspace compared with saline-treated mice (non-PPE-treated mice), but Gal-9 administration did not affect lung structure in non-PPE-treated mice (Fig 1A–1C).