FFAR2 and allergic asthma: Furthermore, signaling of microbiota-derived short-chain fatty acid (SCFA) via free fatty acid receptor 2 (FFAR2) can induce colonic ILC3 proliferation and production of IL-22 to promote intestinal barrier immunity[84] while ILC2s are inhibited by the SCFA butyrate, leading to improvement of allergic asthma symptoms [85].