Comparison of cellular composition of induced sputum, bronchial washings and bronchoalveolar lavage fluid in sarcoidosis, hypersensitivity pneumonitis and COPD

This study compares the cellular profiles of induced sputum (IS), bronchial washing (BW), and BAL fluid (BAL) in newly diagnosed sarcoidosis (BBS) and hypersensitivity pneumonitis (HP) patients to COPD group, and examines whether inflammatory cell counts from IS correlated with inflammatory cell counts from BW and BAL in sarcoidosis and HP patients. We recruited 23 untreated patients with stage II pulmonary sarcoidosis, 15 untreated patients with HP and 17 COPD patients. Sputum was induced with hypertonic saline solution in all individuals. Bronchoscopy was performed on a different occasions in all patients. Mean lymphocyte counts in IS, BW, and BAL fluid from sarcoidosis and HP patients were significantly higher than in COPD subjects (8.9% and 13.8 vs 2.9%, p < 0.05; 11.9% and 30.5 vs 3.2%, p < 0.05; 21.5% and 56 vs 3.4%, p < 0.05, respectively). Moreover we found higher percentage of CD4+, CD3+ CD28+, CD3+ HLADRV+, and gamma delta T cells in IS, BW, and BAL fluid from both BBS and HP groups than in from COPD. Elevated CD4/CD8 ratio characterized IS, BW and BAL fluid in BBS group. Strong correlation IS/BAL and IS/BW of CD3+ CD28+, CD3+ HLADRV+, and CD4/CD8 ratio was found. We demonstrated that, although the relative proportion of inflammatory cells differed in the three samples, lymphocyte counts in IS were high. This finding suggests that IS could be used as a valuable alternative method to more conventional invasive techniques in clinical assessment of interstitial lung diseases patients.