title: Basophil expression of diamine oxidase: a novel biomarker of allergen immunotherapy response.
abstract: BACKGROUND
  Immunotherapy inhibits basophil histamine release, but the assay is cumbersome, and no one has studied the effects of immunotherapy withdrawal.
  
  
  OBJECTIVE
  Intracellular fluorochrome-labeled diamine oxidase (DAO) was used as a novel functional readout of basophil histamine release after immunotherapy. Results were compared with conventional basophil surface expression of activation markers.
  
  
  METHODS
  Subcutaneous immunotherapy (SCIT)-treated patients (n = 14), sublingual immunotherapy (SLIT)-treated patients (n = 12), participants who completed 3 years of treatment with grass pollen sublingual immunotherapy (the SLIT-TOL group; n = 6), patients with untreated seasonal allergic rhinitis (SAR; n = 24), and nonatopic control subjects (n = 12) were studied. Intracellularly labeled DAO(+) and surface expression of CD203c(bright), CD63(+), and CD107a(+) on chemoattractant receptor-homologous molecule expressed on TH2 lymphocytes (CRTh2)-positive basophils were measured by means of flow cytometry. Serum IgG4 levels and serum inhibitory activity for IgE-allergen complex binding to B cells (IgE-FAB) and basophil histamine release were also determined.
  
  
  RESULTS
  Proportions of allergen-stimulated DAO(+)CRTh2(+) basophils were higher in participants in the SCIT, SLIT, and SLIT-TOL groups (all P < .0001) compared with those in patients in the SAR group. Similarly, there were lower proportions of CRTh2(+) basophils expressing surface CD203c(bright) (all P < .001), CD63 (all P < .001), and CD107a (all P < .01). Rhinitis symptoms were lower in the SCIT, SLIT, and SLIT-TOL groups (P < .001) compared with those in the SAR group. Serum inhibitory activity for IgE-FAB and basophil histamine release were also significantly greater in all immunotherapy groups (P < .05) compared with the SAR group.
  
  
  CONCLUSIONS
  These results support long-term clinical and immunologic tolerance during and after grass pollen immunotherapy. Intracellularly labeled DAO expression by basophils merits further investigation as a surrogate biomarker for monitoring efficacy and tolerance after immunotherapy.
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom; Immunomodulation and Tolerance Group, Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Imperial College London, London, United Kingdom.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Shamji
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom; Immunomodulation and Tolerance Group, Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Imperial College London, London, United Kingdom.
authors.forename: Janice A
authors.initials: JA
authors.lastname: Layhadi
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom.
authors.forename: Guy W
authors.initials: GW
authors.lastname: Scadding
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom; Immunomodulation and Tolerance Group, Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Imperial College London, London, United Kingdom.
authors.forename: Delica K M
authors.initials: DKM
authors.lastname: Cheung
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom.
authors.forename: Moises A
authors.initials: MA
authors.lastname: Calderon
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, Mass.
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Turka
authors.affiliation: Immune Tolerance Network, Bethesda, Md.
authors.forename: Deborah
authors.initials: D
authors.lastname: Phippard
authors.affiliation: Allergy and Clinical Immunology Section, Department of Leukocyte Biology, Division of National Heart and Lung Institute, Imperial College London, and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom. Electronic address: s.durham@imperial.ac.uk.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Durham
mesh_terms: D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology; D006631:Amine Oxidase (Copper-Containing) / Q000235:genetics / Q000378:metabolism*; D017951:Antigen Presentation / Q000276:immunology; D001491:Basophils / Q000276:immunology* / Q000378:metabolism*; D015415:Biomarkers; D003231:Conjunctivitis / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism / Q000628:therapy; D003888:Desensitization, Immunologic / Q000379:methods; D005260:Female; D015870:Gene Expression; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D017455:Receptors, IgE / Q000378:metabolism; D012220:Rhinitis / Q000175:diagnosis / Q000276:immunology / Q000378:metabolism / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000485:Allergens; D015415:Biomarkers; D017455:Receptors, IgE; D007073:Immunoglobulin E; D006631:Amine Oxidase (Copper-Containing)
keywords: Diamine oxidase; allergen immunotherapy; basophil activation assay; basophils; histamine; subcutaneous immunotherapy; sublingual immunotherapy