Notably, the expression of inducible costimulatory molecules (ICOS) on CD4 + T cells is significantly increased in the inflammatory mucosa of IBD patients, and this overexpression promotes the production of inflammatory cytokines such as IL-5 in UC and IFN-γ in CD, suggesting that ICOS may serve as a potential therapeutic target for IBD [40]. Here, IL5 is linked to inflammatory bowel disease.