Small airway epithelial-C/EBPβ is increased in patients with advanced COPD.

The expression of CCAAT/enhancer-binding protein (C/EBP)β in the small airway epithelium of COPD is unknown. C/EBPβ was assessed in peripheral lung tissue of non-smoking/smoking controls and patients with GOLD I-IV COPD by quantitative immunohistochemistry. The expression of C/EBPβ was decreased in smokers compared to never smokers. Furthermore, C/EBPβ was significantly elevated in advanced COPD vs. asymptomatic smokers, and the expression correlated to lung function decline. As C/EBPβ exerts pro-inflammatory effects in the context of cigarette smoke, the elevated C/EBPβ in advanced COPD may be an indication of a breakdown of regulatory mechanisms and excessive inflammation.