title: Interleukin-21 in immune and allergic diseases.
abstract: Interleukin-21 (IL-21), a cytokine produced by various subsets of activated CD4+ T cells, plays a major role in the control of innate and adaptive immune responses. IL-21 biological activity is mediated by binding of the cytokine to a heterodimeric receptor, composed of a specific subunit, termed IL-21 receptor (IL-21R), and the common γ-chain, that is shared with IL-2, IL-4, IL-7, IL-9 and IL-15 receptors. IL-21 stimulates the proliferation of CD4+ and CD8+ T lymphocytes and regulates the profile of cytokines secreted by these cells, drives the differentiation of B cells into memory cells and Ig-secreting plasma cells, and enhances the activity of natural killer cells. IL-21 controls also the activity of non-immune cells, such as epithelial cells and stromal cells. The demonstration that IL-21 is involved in the immune responses occurring in chronic inflammatory and allergic diseases suggests that either disrupting or enhancing IL-21 signalling may be useful in specific clinical settings.
authors.affiliation: Dipartimento di Medicina Interna, Università “Tor Vergata” of Rome, Rome, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Sarra
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Cupi
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
mesh_terms: D000818:Animals; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007154:Immune System Diseases / Q000276:immunology*; D007249:Inflammation / Q000276:immunology; D007378:Interleukins / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D053655:Receptors, Interleukin-21 / Q000276:immunology*; D000098546:Interleukin-21
chemical_list: D007378:Interleukins; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21