Fig. 1

Reduced expression of C/EBPβ in asymptomatic smokers and elevated expression in advanced COPD. Light micrographs of the immunoreactivity to CCAAT/enhancer-binding protein (C/EBP)β in peripheral pulmonary tissue of a (a) never-smoker, (b) asymptomatic smoker, and (c) patient with very severe chronic obstructive pulmonary disease (COPD). Immunoreactivity was detected by DAB (brown). Sections were counterstained with Mayer’s Hematoxylin (blue). Scale bar indicates 100 μm. The epithelium (Ep) is denoted and an arrowhead indicates a positive cell in (a). Inlet of (c) shows immunoreactivity to C/EBPβ in a tertiary lymphoid follicle. d Immunoreactivity (defined as number of positive pixels/mm²) to C/EBPβ in peripheral lung epithelium of never-smokers, asymptomatic smokers and patients with mild-moderate (global initiative of COPD, GOLD I-II) and severe-very severe (GOLD III-IV) COPD. Horizontal lines indicate mean value. e Pearson correlation coefficient analysis of the immunoreactivity/mm² to C/EBPβ in peripheral lung epithelium and the forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) of smokers without COPD and patients with GOLD I-IV COPD. Clear circles: never smokers without airway obstruction; grey circles: asymptomatic smokers, triangles: GOLD I-II COPD; squares: GOLD III-IV COPD. n = 6-18. *p < 0.05