Role of TNF-α, sTNF-R55 and sTNF-R75 in Inflammation of Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Backgrounds: Although some recent studies have demonstrated the important role of tumor necrosis factor-α (TNF-α) and soluble TNF receptors (sTNF-R) in inflammation of chronic obstructive pulmonary disease, the exact roles of TNF-α and sTNF-R as well as their interaction remained unclear. Objectives: To study changes in levels of systemic and airway local TNF-α and sTNF-R (sTNF-R55, sTNF-R75) in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD), and clarify the relationship between these mediators and airflow limitation in AECOPD patients. Methods: TNF-α, sTNF-R55 and sTNF-R75 levels in induced sputum and plasma as well as lung functions were examined in 48 AECOPD patients before and after treatment. Samples from 28 healthy volunteers served as controls. Results: Compared to healthycontrols, both pre- and posttreatment levels of TNF-α, sTNF-R55 and sTNF-R75 in induced sputum and plasma of COPD patients were higher. In patients with AECOPD, posttreatment TNF-α levels significantly decreased compared to pretreatment levels (0.6 ± 0.46 vs. 0.82 ± 0.35 μg/l in plasma, p 0.05). sTNF-R55 and sTNF-R75 levels in induced sputum were positively correlated with lung functions (p 1) and the ratio of FEV1 to FEV1 predicted value. Conclusions: Inflammatory and anti-inflammatory mediators were imbalanced in the airways of AECOPD patients. It was local inflammation but not systemic inflammation that was closely related to airflow limitation.