title: Allergen-induced interleukin-9 production in vitro: correlation with atopy in human adults and comparison with interleukin-5 and interleukin-13.
abstract: BACKGROUND
  The contribution of IL-9 to human atopy is supported by genetic studies. However, IL-9 production in response to allergen in vitro has been reported only in children.
  
  
  OBJECTIVE
  Study IL-9 induction by allergen in adults, compare it with IL-5 and IL-13 and evaluate its association with atopy.
  
  
  METHODS
  Peripheral blood mononuclear cell (PBMC) from control adults and from atopic patients were cultured with various allergens or phytohaemagglutinin (PHA) and secreted IL-5, IL-9 and IL-13 were measured by ELISA.
  
  
  RESULTS
  IL-9 was produced in response to Dermatophagoides pteronyssinus (Der p) by PBMC from Der p-hypersensitive adults at levels equivalent to those induced by PHA but with slower kinetics. The induction of IL-9 was allergen specific, reflecting donor RAST profile. In Der p-triggered reactions of non-atopic and atopic subjects, IL-9 showed the highest selectivity for atopics, IL-5 and IL-13 being produced more frequently in non-atopic donors. Significant correlations with specific IgE titres were found for IL-9 with all allergens tested (Der p and two peptides of Bet v 1 birch allergen). For IL-5 and IL-13, they were in the same range for Der p but more variable for birch allergens. Patterns of cytokine production by individual patients in response to allergen reflected these differences: for Der p, IL-5, IL-9 and IL-13 productions were strongly correlated but for birch IL-5 differed from the latter two. The in vitro production of IL-9 reflected clinical hypersensitivity profiles and was higher in individuals with asthma than in those with disease limited to rhinitis and/or conjunctivitis.
  
  
  CONCLUSIONS
  Allergen-triggered IL-9 production in vitro is an excellent marker for atopy in adults given its virtual absence in allergen-stimulated PBMC from non-atopic individuals and its correlation with allergen-specific IgE and asthma.
authors.affiliation: Neuroendocrine Immunology, Pharmacology Department, Medical School, Vrije Universiteit Brussel, Brussels, Belgium. sadevos@vub.ac.be
authors.forename: S
authors.initials: S
authors.lastname: Devos
authors.forename: F
authors.initials: F
authors.lastname: Cormont
authors.forename: S
authors.initials: S
authors.lastname: Vrtala
authors.forename: E
authors.initials: E
authors.lastname: Hooghe-Peters
authors.forename: F
authors.initials: F
authors.lastname: Pirson
authors.forename: J
authors.initials: J
authors.lastname: Snick
mesh_terms: D000328:Adult; D000485:Allergens / Q000494:pharmacology; D039741:Antigens, Dermatophagoides / Q000494:pharmacology; D052179:Antigens, Plant; D060829:Arthropod Proteins; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood; D018793:Interleukin-13 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D016906:Interleukin-9 / Q000032:analysis* / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D052179:Antigens, Plant; D060829:Arthropod Proteins; D015415:Biomarkers; D018793:Interleukin-13; D015848:Interleukin-5; D016906:Interleukin-9; D010835:Phytohemagglutinins; D007073:Immunoglobulin E; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1