Cross-talk Between RORγt+ Innate Lymphoid Cells and Intestinal Macrophages Induces Mucosal IL-22 Production in Crohnʼs Disease

BackgroundInterleukin (IL)-22–producing RORγt+ innate lymphoid cells (ILCs) play a pivotal role in intestinal immunity. Recent reports demonstrated that ILCs contribute to mucosal protection and intestinal inflammation in mice. In humans, numbers of RORγt+ ILCs are significantly increased in the intestine of patients with Crohn's disease (CD), suggesting that ILCs may be associated with intestinal inflammation in CD. However, the mechanism by which ILCs are regulated in the intestine of patients with CD is poorly understood. This study aimed to determine the activation mechanism of intestinal ILCs in patients with CD.