title: Interleukin-9 and T helper type 9 cells in rheumatic diseases.
abstract: Interleukin (IL)-9 is a 28-30 kDa monomeric glycosylated polypeptide belonging to the IL-7/IL-9 family of proteins that bind to a composite receptor consisting of the private receptor IL-9R and the IL-2 receptor, gamma (IL-2RG), a common gamma subunit shared by the receptors of many different cytokines. The IL-9R is expressed widely and IL-9 impacts a number of effector cells, such as effector T cells, B cells, innate lymphoid cells, mast cells, polymorphonuclear cells, epithelial cells and smooth muscle cells, playing an important role in regulating inflammatory immunity. The critical role of IL-9 in promoting cellular and humoral immune responses makes it an important focus of potential therapeutic interventions. Recently, a defined subset of T helper type cells, Th9 cells, has been identified by the potent production of IL-9. The involvement of the Th9 cell subset has been described in many types of inflammatory diseases, namely atopic diseases, helminth infections, experimental autoimmune encephalomyelitis and ulcerative colitis. In this review, we summarize the IL-9 biological activities, highlighting roles for IL-9 and Th9 cells in rheumatoid and psoriatic arthritis, systemic vasculitis, systemic lupus erythematosus and systemic sclerosis.
authors.affiliation: Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, University of Palermo, Palermo.
authors.forename: F
authors.initials: F
authors.lastname: Ciccia
authors.affiliation: Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, University of Palermo, Palermo.
authors.forename: G
authors.initials: G
authors.lastname: Guggino
authors.affiliation: Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, University of Palermo, Palermo.
authors.forename: A
authors.initials: A
authors.lastname: Ferrante
authors.affiliation: Dipartimento di Scienze Cliniche Applicate e Biotecnologiche, Sezione di Reumatologia, Università di L'Aquila, L'Aquila, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Cipriani
authors.affiliation: Dipartimento di Scienze Cliniche Applicate e Biotecnologiche, Sezione di Reumatologia, Università di L'Aquila, L'Aquila, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Giacomelli
authors.affiliation: Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, University of Palermo, Palermo.
authors.forename: G
authors.initials: G
authors.lastname: Triolo
mesh_terms: D000818:Animals; D015535:Arthritis, Psoriatic / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology; D001402:B-Lymphocytes; D006801:Humans; D056724:Immunity, Humoral; D020381:Interleukin-17 / Q000276:immunology; D016906:Interleukin-9 / Q000096:biosynthesis / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D012216:Rheumatic Diseases / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000276:immunology; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000145:classification / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: C508607:IL9 protein, human; D020381:Interleukin-17; D016906:Interleukin-9
keywords: IL-9; SLE; Th9 cells; psoriatic arthritis; rheumatoid arthritis; systemic sclerosis; vasculitis