Figure 5

Increased number of alveolar CCL21- and D6-positive lymphatic vessels in patients with advanced COPD. (A) Percentage of CCL21-positive lymphatic vessels among all Prox1-positive lymphatics and (B) number of CCL21-positive lymphatic vessels in bronchiolar subepithelial tissue, adventitia of bronchiole-associated arteries and alveolar parenchyma in never smokers and patients with GOLD stage IV COPD. (C) Percentage of D6-positive lymphatic vessels among all Prox1-positive lymphatics and (D) number of D6-positive lymphatic vessels in similar lung compartments as for (A and B) in never smokers and patients with GOLD stage IV COPD. Mann–Whitney rank sum test was used for comparison between two groups. Horizontal lines indicate median value for each cohort. ** p < 0.01. (E and F) Immunohistochemical staining for CCL21 (red) and Prox1 (brown nuclei) and (G) immunohistochemical staining for D6 (red) and Prox1 (brown nuclei) in sections of patients with GOLD stage IV COPD. LA, lymphoid aggregate. Sections were counterstained with Mayer’s haematoxylin (blue stain). Scale bars: (E, G) 20 μm; (F) 30 μm.