CD4 and inflammatory bowel disease: As a pivotal regulator of immune homeostasis, dysregulated IL-2 expression is implicated in multiple immune-related disorders.[27,28] Elevated frequencies of hiCD25+ cells are commonly observed in T cells from CD patients and macrophages in UC, both subtypes of IBD.[29] CD27 (TNFRSF7), is a transmembrane glycoprotein constitutively expressed on CD4+/CD8+ T cells, NK cells, and thymocytes, with induced expression upon B cell activation.