Elevated levels of transforming growth factor-β1 in serum of patients with stable bronchiectasis

Bronchiectasis is a chronic inflammatory and infective airway disease characterized by irreversible dilatation of the bronchi and persistent purulent sputum. Transforming growth factor-β1 (TGF-β1) has been found to be increased in the lungs or bronchoalveolar lavage fluid of patients with inflammatory lung diseases. However, little is known on the serum TGF-β1 levels in patients with bronchiectasis. We aimed to determine the serum TGF-β1 concentrations in 95 patients with stable bronchiectasis (63 women; mean±sd age, 58.9±14.1 years) and 68 control subjects (23 women; 48.9±12.8 years) by ELISA, and to correlate with clinical parameters. The serum TGF-β1 levels were significantly higher in bronchiectatic patients compared with control subjects (median [range], 1812.5 pg/ml [1226.4-4114.5 pg/ml] vs. 1342.4 pg/ml [940.3-2371.7 pg/ml]; P<0.001). There was, however, no correlation between serum TGF-β1 levels with FEV1 (% predicted), FVC (% predicted), 24 h sputum volume, the number of bronchiectatic lung lobes or total white blood cell count (P>0.05). Our findings support previous indications that TGF-β1 may contribute to bronchiectatic airway inflammation. Further studies on the potential mechanisms and pathogenesis implications of this elevation should also be pursued in future.