The Interleukin-17/Interleukin-22 Innate Axis in the Gut as a New Drug Target in Allergic-Inflammatory and Autoimmune Diseases. A Working Hypothesis

The innate lymphoid cells (ILCs) have been grouped into three main categories: ILC1s [T helper (h) 1-like cells], ILC2s (Th2-like cells) and ILC3s (Th17-like cells), respectively. In particular, ILC3s are responsible for the secretion of both interleukin (IL)-17 and IL-22, which play either protective (antimicrobial and repairing activities) or harmful (inflammation and tumor growth) roles into the host. Here, some putative interventional studies will be hypothesized, taking into account that activation of innate cell receptors, arylhydrocarbon receptor and gut microbiota, respectively, contribute to both differentiation and function of ILC3s. A series of biological and natural compounds may represent putative regulators of these cells in the gut. In this respect, the modulating effects of agonist and antagonists of Toll-like receptors and nucleotide binding oligomerization domain-like receptors, polyphenols and probiotics will be described in detail.