Correlation Between Tumor Necrosis Factor-α and Interleukin-1β in Exhaled Breath Condensate and Pulmonary Function

Background: Exhaled breath condensate (EBC) has emerged as a noninvasive method for assessing inflammation in lung diseases. Our aim is to investigate the correlation between tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in EBC and in lung tissue, and between these values in EBC with pulmonary function tests in patients with chronic obstructive pulmonary disease (COPD).

Materials and methods: To ensure the availability of lung tissue, 60 patients undergoing resection for early lung cancer were divided into 3 groups: a COPD treatment group, a COPD control group and a non-COPD group. Patients in the COPD treatment group received what was termed "lung-protective treatment" including ambroxol, budesonide and ipratropium bromide in addition to chest physiotherapy. Patients underwent pulmonary function testing and EBC collection, and TNF-α and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA). TNF-α and IL-1β in lung tissues were evaluated by immunoflorescense. Correlations were analyzed by Pearson correlation coefficients.

Results: The TNF-α and IL-1β levels in EBC were significantly higher in the COPD groups compared with the non-COPD group before surgery (all P < 0.01), and the levels were significantly decreased after lung-protective treatment was received before surgery (all P < 0.01). TNF-α and IL-1β levels in EBC were significantly decreased in all patients after surgery with lung-protective treatment (P = 0.027, P = 0.004). TNF-α and IL-1β content in lung tissues was significantly higher in the COPD groups (all P < 0.05), and the histologic analysis showed similar results. Negative correlations between FEV1/FVC and expression of TNF-α and IL-1β were observed. There was a positive correlation between TNF-α and IL-1β in lung tissues and in EBC.

Conclusions: TNF-α and IL-1β in EBC are potential biomarkers for evaluating pulmonary function and inflammation in patients with COPD. Furthermore, lung-protective treatment is effective in reducing inflammation in patients with COPD.