title: Early decrease in nasal eosinophil proportion after nasal allergen challenge correlates with baseline bronchial reactivity to methacholine in children sensitized to house dust mites.
abstract: BACKGROUND
  Allergic rhinitis is induced by an IgE mediated inflammation after allergen exposure of the membranes lining the nose which, in predisposed individuals, may constitute a risk factor for the occurrence of asthma.
  
  
  OBJECTIVE
  To detect early changes in nasal inflammation after allergen exposure, 11 children [9.0 (7, 11) yrs], sensitized to house dust mites (HDM), with rhinoconjunctivitis and asthma and an age- and gender-matched control group (Ctr) were studied.
  
  
  METHODS
  The following parameters were evaluated: i) pulmonary function; ii) bronchial reactivity to methacholine (MCh), expressed as Pd20MCh; iii) nasal brushing (NB) 'at baseline' and, on a separate day, 30 min after nasal allergen challenge (NAC). On NBs, the following markers of inflammation were evaluated: a) neutrophil and eosinophil proportion, b) 'intact to degranulated eosinophil' ratio, and c) expression of intercellular adhesion molecule (ICAM)-1 and HLA-DR by nasal epithelial cells.
  
  
  RESULTS
  'At baseline', allergic children showed elevated nasal eosinophilia and increased ICAM-1 and HLA-DR expression (p<0.05), as compared to Ctr. In allergic children, nasal eosinophilia correlated with Pd20MCh (p=0.002). The significant decrease in nasal eosinophilia observed after NAC (p=0.002) was associated with a significant decrease in the 'intact to degranulated eosinophil' ratio (p=0.001). Interestingly, correlations were still present between Pd20MCh and 'post NAC' eosinophilia (p=0.004) or the NAC-induced decrease in eosinophilia (p=0.010).
  
  
  CONCLUSIONS
  In children sensitized to HDM, experimental allergen exposure is followed by an early depletion of nasal eosinophils. The correlation between allergen-induced changes in nasal eosinophilia and bronchial reactivity to MCh further supports the concept of a tight link between upper and lower respiratory tract involvement in respiratory allergy.
authors.affiliation: Pulmonary Dept, G Gaslini Institute, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Silvestri
authors.forename: E
authors.initials: E
authors.lastname: Battistini
authors.forename: A C
authors.initials: AC
authors.lastname: Defilippi
authors.forename: F
authors.initials: F
authors.lastname: Sabatini
authors.forename: R
authors.initials: R
authors.lastname: Sale
authors.forename: S
authors.initials: S
authors.lastname: Pecora
authors.forename: G A
authors.initials: GA
authors.lastname: Rossi
mesh_terms: D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000276:immunology* / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000276:immunology; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D016022:Case-Control Studies; D002648:Child; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007958:Leukocyte Count; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D009297:Nasal Mucosa / Q000276:immunology / Q000378:metabolism; D009299:Nasal Provocation Tests; D009504:Neutrophils / Q000276:immunology; D039981:Pyroglyphidae / Q000276:immunology*; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology*
chemical_list: D000485:Allergens; D016085:Bronchoconstrictor Agents; D006684:HLA-DR Antigens; D016210:Methacholine Chloride; D018799:Intercellular Adhesion Molecule-1; D007073:Immunoglobulin E