Immunohistochemical staining for chemokine (CC motif) ligand-2 (CCL2) in lung sections. Shown is the immunohistochemical localisation of CCL2 in lung sections on day 14 of treatment with bleomycin (BLM) (A–C) and BLM + pirfenidone (D–F). Representative images from alveolar regions, respiratory bronchioles, and terminal bronchioles are shown. Increased immunoreactivity for CCL2 was observed on alveolar epithelial (AE) cells, terminal and respiratory bronchiolar epithelial cells (arrowheads), and macrophages (arrows) with BLM treatment (A–C). Treatment with pirfenidone attenuated this staining in each section (D–F). Magnification, ×10. PFD, pirfenidone.