The accumulation of Th17 cells and their associated cytokines (IL-17, IL-21, and IL-22) was observed in the inflammatory lesions of active IBD patients, higher levels of IL-17A and IL-17A mRNA were found in the serum and intestinal tissue of IBD patients when compared with healthy controls [14], and IL-17A could recruit a variety of immune cells by activating the NF-κB and MAPK pathways [15]. The gene discussed is IL21; the disease is inflammatory bowel disease.