Background and aim of the work: Bronchoalveolar lavage (BAL) is useful in diagnosis and management of interstitial lung diseases. Glutathione (GSH) represents an important defence molecule against reactive oxygen species produced during inflammation, which underlies both idiopathic pulmonary fibrosis (IPF) and sarcoidosis. Nitric oxide has been suggested as a marker of airway inflammation. The aim of this study was to examine the content of GSH and NO stable metabolites, nitrite/nitrate, in the BAL of a group of patients with IPF and sarcoidosis.
Methods: BAL was performed in 13 patients with newly diagnosed IPF, 13 patients with sarcoidosis and 4 controls. Total GSH and nitrite/nitrate were measured. BAL was repeated, in 5 patients with IPF, after 6 and 12 months and GSH was measured again.
Results: IPF patients had significantly lower levels of total GSH compared to sarcoidosis patients or controls (129 +/- 22 vs. 324 +/- 40 and 383 +/- 23 mM; p < 0.001) in the epithelial lining fluid (ELF). In patients with IPF (n = 5), total GSH levels in the ELF increased after 6 and 12 months (T0 = 98 +/- 19; T6 = 219 +/- 22; T12 = 301 +/- 34 microM; p < 0.05) following therapy with immunosuppressive drugs such as corticosteroids, methotrexate, cyclosporin A. Levels of nitrite/nitrate were found significantly elevated in IPF (n = 8) and sarcoidosis (n = 10) patients compared to controls (230 +/- 37 and 216 +/- 36 vs. 86 +/- 11 microM; p < 0.05).
Conclusion: These observations support the role of inflammation and antioxidant defences in interstitial lung diseases and may provide insights into the pathogenesis of oxidant-induced interstitial disease and their therapy.