Regulatory Innate Lymphoid Cells Control Innate Intestinal Inflammation

An emerging family of innate lymphoid cells (termed ILCs) has an essential role in the initiation and regulation of inflammation. However, it is still unclear how ILCs are regulated in the duration of intestinal inflammation. Here, we identify a regulatory subpopulation of ILCs (called ILCregs) that exists in the gut and harbors a unique gene identity that is distinct from that of ILCs or regulatory T cells (Tregs). During inflammatory stimulation, ILCregs can be induced in the intestine and suppress the activation of ILC1s and ILC3s via secretion of IL-10, leading to protection against innate intestinal inflammation. Moreover, TGF-β1 is induced by ILCregs during the innate intestinal inflammation, and autocrine TGF-β1 sustains the maintenance and expansion of ILCregs. Therefore, ILCregs play an inhibitory role in the innate immune response, favoring the resolution of intestinal inflammation.