Fig. 5

Confocal microscopy of M1 and M2 alveolar macrophages in lung tissue. iNOS (M1) and CD206 (M2) expression in clusters of alveolar macrophages in lung sections from a patient with severe COPD (panel a), a smoker without COPD (panel b) and a non-smoking subject (panel c). iNOS immunoreactivity appears as a red diffuse cytoplasmic granular pattern (panel a), while CD206 immunoreactivity appears as a green linear pattern around the cellular membrane. In the smoker with severe COPD, M1 and M2 markers were co-expressed in the same cluster of alveolar macrophages, while in the smoker without COPD only a reduced co-expression can be observed (panel b). The alveolar macrophages in the non-smoking subject were mostly negative for both M1 and M2 markers (panel c). Alveolar macrophages were stained with anti-iNOS (red) and anti-CD206 (green). Nuclei were stained with DRAQ5 (blue). Bars: 10 μm