Severe asthma (SA) is a significant problem both clinically and economically, given its poor response to corticosteroids (CS). We recently reported a complex type 1–dominated (IFN-γ–dominated) immune response in more than 50% of severe asthmatics despite high-dose CS treatment. Also, IFN-γ was found to be critical for increased airway hyperreactivity (AHR) in our model of SA. The transcription factor IRF5 expressed in M1 macrophages can induce a Th1/Th17 response in cocultured human T cells. Here we show markedly higher expression of IRF5 in bronchoalveolar lavage (BAL) cells of severe asthmatics as compared with that in cells from milder asthmatics or healthy controls. Using our SA mouse model, we demonstrate that lack of IRF5 in lymph node migratory DCs severely limits their ability to stimulate the generation of IFN-γ– and IL-17–producing CD4+ T cells and
Timothy B. Oriss, Mahesh Raundhal, Christina Morse, Rachael E. Huff, Sudipta Das, Rachel Hannum, Marc C. Gauthier, Kathryn L. Scholl, Krishnendu Chakraborty, Seyed M. Nouraie, Sally E. Wenzel, Prabir Ray, Anuradha Ray
Upregulation of IRF5 expression in the airways of severe asthma patients and in an experimental model and its role in airway hyperresponsiveness and airway inflammation.