title: Significance of serum Il-9 levels in inflammatory bowel disease.
abstract: IL-9, which may be an inflammatory or regulatory cytokine, can be experimentally produced in a Th17 or modified Th2 context in the presence of T cell receptor (TCR) stimulation. The primary aim of this study was to measure serum IL-9 levels in patients with inflammatory bowel disease (IBD), and evaluate their relationships with the patients' clinical characteristics. The secondary aim was to determine the levels of interferon-γ (IFN (interferon)-γ), Th2 cytokines (IL-4, IL-5 and IL-13), and IL-6 in order to clarify the context of detectable peripheral cytokines in which IL-9 is produced.Venous blood samples of 43 IBD patients (20 with Crohn's disease [CD] and 23 with ulcerative colitis [UC]) were analysed by means of quantitative enzyme-linked immunosorbent assays using purified anti-human IL-4, IL-5, IL-13, IFN-γ, IL-9 and IL-6 antibodies, and the laboratory findings were statistically correlated with their clinical expression.None of the patients showed the peripheral presence of IL-4, IL-5 and IL-13. Forty (93%) were positive for IFN-γ, thus confirming the presence of Th1 in both UC and CD, and IFN-γ levels correlated with disease activity (P = 0.045). Eighteen patients (41%) were positive for IL-9, which was associated with a severe prognosis (P <0.001), and 72.2% of the IL-9-positive patients were also IL-6 positive. There was a significant correlation between disease severity and IL-9 in the CD patients (P <0.001), but not in the UC patients (P = 0.1).Our findings confirm the presence of common Th1 cytokines in UC and CD. However the IL-9 positivity indicates the presence of an alternative population of T cells that respond to antigen stimulation and condition the prognosis of IBD. The fact that the same serum IL-9 levels were differentially associated with clinical measures of CD and UC activity suggest that the same cytokine can be produced in different contexts.
authors.affiliation: Laboratory Unit, Fatebenefratelli Hospital, Milan, Italy caterina.defendenti@fbf.milano.it.
authors.forename: Caterina
authors.initials: C
authors.lastname: Defendenti
authors.affiliation: Rheumatology Unit, L. Sacco University Hospital, Milan, Italy.
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Sarzi-Puttini
authors.affiliation: Division of Pathology and Gastroenterology, Guido Salvini Hospital, Rho (Milan), Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Saibeni
authors.affiliation: Divisions of Pathology and Gastroenterology, Fatebenefratelli Hospital, Milan, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Bollani
authors.affiliation: Divisions of Pathology and Gastroenterology, Fatebenefratelli Hospital, Milan, Italy.
authors.forename: Savino
authors.initials: S
authors.lastname: Bruno
authors.affiliation: GI & Liver Unit, DI.BI.M.I.S. University of Palermo Policlinico, Palermo, Italy.
authors.forename: Piero Luigi
authors.initials: PL
authors.lastname: Almasio
authors.affiliation: Laboratory Unit, Fatebenefratelli Hospital, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Declich
authors.affiliation: IRCCS Galeazzi Orthopedic Institute, Milan, Italy.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Atzeni
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000276:immunology*; D015850:Interleukin-6 / Q000097:blood; D016906:Interleukin-9 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D058504:Th17 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
chemical_list: C508600:IL6 protein, human; C508607:IL9 protein, human; D015850:Interleukin-6; D016906:Interleukin-9
keywords: inflammation; inflammatory bowel disease; interleukin; lymphocyte homing; lymphocytes; mucosal immunity