Asthma is more common in males until puberty but becomes more prevalent and more severe in females after puberty suggesting a protective action of male sex hormones. ILC2 have recently emerged as critical players in the initiation of allergic responses. The present team established that androgens, signaling through the nuclear receptor 3 C4 (NR3C4) androgen receptor (AR), negatively control ILC2 at steady state and during lung inflammation. Relevant to this application, females with asthma have more circulating ILC2 than males. The present hypothesis is that harnessing AR signaling in ILC2 may provide a new therapeutic approach to down regulate tissue resident ILC2. This project will analyze the sex bias in circulating ILC2 in female and male patients with moderate to severe asthma. In females with asthma, the team will purify circulating ILC2 from peripheral blood mononuclear cells (PBMC) and expand them in vitro using cytokines and stromal cells in the presence of AR antagonist or agonist ligands. Bulk ILC2 cultures at day 7 will used to measure the expression profile of various gene, including AR.