Fig. 3

Representative immunohistochemical findings for BAFF in lung sections. Tissue was obtained from a, b a 23-year-old female non-smoker as a control, (c–g) a 56-year-old female non-smoking patient with CTD-ILD, and (h, i) a 63-year-old male non-smoking patients with CFIP. Weakly positive alveolar macrophages were observed in the a) BAFF b) goat IgG control. Strong cytoplasmic positivity of BAFF was observed in c), h) peripheral airways macrophages and cells in the alveolar walls, d), i) lymphoid follicles, e) peripheral airways, f) vascular endothelial cell and g) fibroblasts. Scale bars = 50 μm. BAFF: B cell–activating factor belonging to the tumour necrosis factor family; CTD-ILD: interstitial lung disease associated with connective tissue disease; CFIP: chronic fibrosing interstitial lung disease