Antifibrotic drugs in lung transplantation and chronic lung allograft dysfunction: a review

Overview of normal lungs, idiopathic pulmonary fibrosis (IPF), bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). a) Normal lungs: chest computed tomography (CT), axial pulmonary window: normal lung parenchyma. Haematoxylin and eosin (HE) staining illustrates normally preserved lung parenchyma. b) IPF: chest CT, axial pulmonary window: i) peripheral subpleural reticulation and traction bronchiectasis; ii) honeycombing (right lower lobe), diffuse areas of consolidation and bronchiectasis. HE staining illustrates prominent honeycombing, characterised by irregular cystic airspaces of varying size, partly filled with mucus and surrounded by fibrotic remodelling. c) BOS: chest CT, axial pulmonary window: i) air trapping; ii) bronchiectasis. HE staining with presence of a typical bronchiolitis obliterans lesion, characterised by concentric subepithelial fibrosis narrowing the airway lumen. d) RAS: chest CT, axial pulmonary window: i) bilateral opacification especially of the left upper lung lobe, volume loss of the left lung, traction bronchiectasis; ii) areas of ground-glass opacification and interlobular septal thickening. Elastica van Gieson stain highlights the presence of prominent pleural fibrosis and subpleural fibroelastosis, consistent with pleuroparenchymal fibroelastosis. Figure partially created with BioRender.com.