[Th17 and Treg cell levels in patients with sarcoidosis and their relation to disease activation]

To investigate the Th17 cell and Treg cell levels in patients with sarcoidosis, and their relation to disease activation and glucocorticoids treatment.

Twenty-three sarcoidosis patients admitted in Yinzhou People's Hospital from January 2009 to December 2013 and 25 healthy subjects (controls) were included in this study. The blood samples and bronchoalveolar lavage fluid (BALF) samples were collected in all patients before and after glucocorticoids treatment. The serum angiotensin converting enzyme (SACE) levels were detected. The percentages of Th17 cells and Treg cells in peripheral blood and BALF were determined by flow cytometry, the concentrations of cytokines in serum and supernatants of BALF were measured by enzyme-linked immunosorbent assay (ELISA). The levels of ROR-γt and Foxp3 mRNA transcripts in peripheral blood mononuclear cells (PBMC) were determined by real-time quantitative PCR. The potential correlation between the percentages of Th17 or Treg cells and SACE levels was evaluated.

Compared with healthy controls, significantly higher frequencies of Th17 cells (4.34%±0.89% vs 1.60% ± 0.42%), lower frequencies of Treg cells (1.28% ± 0.37% vs 3.39% ± 0.50%) in peripheral blood were observed. Higher level of ROR-γt mRNA (21.31 ± 3.55 vs 3.63 ± 1.00) and lower level of Foxp3 mRNA (1.60 ± 0.24 vs 3.12 ± 0.76) in peripheral blood were detected in sarcoidosis patients in active stage (before glucocorticoids treatment) (all P<0.01). After the treatment of glucocorticoids, these index in peripheral blood were significantly improved (Th17 cells 2.16% ± 0.68%，Treg cells 2.21% ± 0.42%, ROR-γt mRNA 10.15 ± 1.93, Foxp3 mRNA 2.44 ± 0.38) ( all P<0.05). The changing trends of Th17 and Treg cell cytokines levels in serum were consistent with two type cells. Meanwhile, the changing trends of above index in BALF of patients treated by glucocorticoids were consistent with those in sarcoidosis patients in active stage. The increased ratios of Th17 cells to Treg cells were positively correlated with the level of serum SACE (r= 0.781).

The imbalance of Th17 cells and Treg cells in peripheral blood and airway may be involved in the pathogenesis of sarcoidosis, which was associated with the activity of disease, and the treatment of glucocorticoids may achieve a therapeutic effect by correcting the immune imbalance.