Article Text

Download PDFPDF

Inflammation in lung injury: the key mediators
S49 Is the development of acute lung injury influenced by increased levels of IL17 as a result of Treg/TH17 imbalance?
  1. R C A Dancer1,
  2. V D'Souza1,
  3. L Jeffery1,
  4. D Sansom1,
  5. C R Bassford1,
  6. G Perkins2,
  7. D R Thickett1
  1. 1University of Birmingham, Birmingham, UK
  2. 2University of Warwick, Warwick, UK


Introduction Vitamin D is known to have profound effects on the immune system. We have shown that vitamin D is lower in patients with Acute Lung Injury (ALI) than in healthy or at risk controls and that in patients at risk of ALI post oesophagectomy, low vitamin D levels are associated with increased post-operative systemic inflammatory response and alveolar epithelial dysfunction. Studies have shown that when T cells are exposed to vitamin D, expression of IL17 decreases and regulatory capacity increases. We hypothesised that vitamin D deficiency may play a role in development of Acute Lung Injury (ALI) via changes in the balance between regulatory T cells (Treg) and pro-inflammatory Th17 cells.

Methods Plasma levels of 25-OH Vitamin D (Tandem mass spectrometry) and 1,25-OH Vitamin D (ELISA)were measured in samples from patients with ALI. Normal T cells were exposed to BAL from patients with ALI with or without addition of exogenous vitamin D and determined frequencies of Treg and Th17 cells using flow cytometry.

Results All samples tested had insufficient plasma levels of 25-OH vitamin D (<75 nmol/l, median 14.1 nmol/l). 1,25 vitamin D levels ranged from <20 to 176 pmol/l (reference range 43–144 pmol/l). 1,25 vitamin D levels were significantly related to both ITU survival (p=0.04) and survival at 90 days (p=0.04). Our initial findings suggest that BAL taken on day 0 of ARDS upregulated IL17 expression in normal T cells. This finding was blocked by exogenous 1,25-OH Vitamin D. By contrast, BAL taken on day 4 upregulated FoxP3 and CD25 expression, suggesting an increase in regulatory T cell activity.

Discussion These results suggest that in early ARDS an imbalance in T cells favouring expression of IL-17 may play a role in the inflammatory response to injury, and this may be attenuated by adequate vitamin D levels. Later in the course of the disease, Treg cells may predominate and play a role in resolution.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.