Increased levels of Treg cells in bronchoalveolar lavage fluid and induced sputum of patients with active pulmonary sarcoidosis

OBJECTIVE: It has recently been described that circulatory and BAL regulatory T-cells (Tregs), defined as CD4+CD25highCD127low are increased in patients with active sarcoidosis compared with other interstitial lung diseases. MATERIALS AND METHODS: We studied prospectively 17 patients (10 women, 7 men) of median age 39 years (range 27-65) with active granulomatous lung diseases (GLD) (10 patients with sarcoidosis (BBS), and 7 with hypersensitivity pneumonitis (HP), and 9 healthy controls. Bronchoalveolar lavage fluid (BAL) and induced sputum Treg counts, CD4+, CD8+, CD25+ cells were quantified by flow cytometry. Disease activity was measured by ACE serum level. Pulmonary function tests were performed using an Elite DL Medgraphics body box. RESULTS: We found Treg cells count significantly elevated in induced sputum from active GLD (38.3% vs. 7.1% and 5.3% in BBS, HP, and control, respectively). A significantly higher percentage of Treg cells characterized BAL cells from HP patients (2.27%; 9.5%; 2.1%, in BBS, HP and control, respectively). There was a strong correlation with ACE serum level and Treg cell count in BAL fluid of BBS patients, with no such correlation within HP patient group, nor Treg cell count and pulmonary function tests. CONCLUSIONS: Our data suggest a potential role of CD4+CD25 high CD127 low induced sputum and BAL lymphocytes from patients with active granulomatous lung diseases and hypersensitivity pneumonitis. An increased number of Treg cells in active GLD may be involved in immune regulation in active granulomatous lung diseases. The results indicate that analysis of these cells could be useful as markers of disease activity in granulomatous lung diseases.