IL-9 is a key component of memory TH cell peanut-specific responses from children with peanut allergy

Helen A Brough, David J Cousins, Alina Munteanu, Yuen Fei Wong, Asha Sudra, Kerry Makinson, Alick C Stephens, Matthew Arno, Liviu Ciortuz, Gideon Lack, Victor Turcanu

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)
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BACKGROUND: Differentiation between patients with peanut allergy (PA) and those with peanut sensitization (PS) who tolerate peanut but have peanut-specific IgE, positive skin prick test responses, or both represents a significant diagnostic difficulty. Previously, gene expression microarrays were successfully used to identify biomarkers and explore immune responses during PA immunotherapy.

OBJECTIVE: We aimed to characterize peanut-specific responses from patients with PA, subjects with PS, and atopic children without peanut allergy (NA children).

METHODS: A preliminary exploratory microarray investigation of gene expression in peanut-activated memory TH subsets from 3 children with PA and 3 NA children identified potential PA diagnostic biomarkers. Microarray findings were confirmed by using real-time quantitative PCR in 30 subjects (12 children with PA, 12 children with PS, and 6 NA children). Flow cytometry was used to identify the TH subsets involved.

RESULTS: Among 12,257 differentially expressed genes, IL9 showed the greatest difference between children with PA and NA children (45.59-fold change, P < .001), followed by IL5 and then IL13. Notably, IL9 allowed the most accurate classification of children with PA and NA children by using a machine-learning approach with recursive feature elimination and the random forest algorithm. Skin- and gut-homing TH cells from donors with PA expressed similar TH2- and TH9-associated genes. Real-time quantitative PCR confirmed that IL9 was the highest differentially expressed gene between children with PA and NA children (23.3-fold change, P < .01) and children with PS (18.5-fold change, P < .05). Intracellular cytokine staining showed that IL-9 and the TH2-specific cytokine IL-5 are produced by distinct TH populations.

CONCLUSION: In this study IL9 best differentiated between children with PA and children with PS (and atopic NA children). Mutually exclusive production of IL-9 and the TH2-specific cytokine IL-5 suggests that the IL-9-producing cells belong to the recently described TH9 subset.

Original languageEnglish
Pages (from-to)1329-1338.e10
JournalJournal of Allergy and Clinical Immunology
Issue number6
Early online date8 Aug 2014
Publication statusPublished - 1 Dec 2014


  • Adolescent
  • Arachis/adverse effects
  • Child
  • Child, Preschool
  • Cytokines/genetics
  • Double-Blind Method
  • Female
  • Gene Expression Profiling
  • Humans
  • Immunoglobulin E/immunology
  • Immunologic Memory
  • Infant
  • Leukocytes, Mononuclear/immunology
  • Male
  • Oligonucleotide Array Sequence Analysis
  • Peanut Hypersensitivity/diagnosis
  • Skin/cytology
  • Skin Tests
  • T-Lymphocytes, Helper-Inducer/immunology


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