title: Antigens drive memory IgE responses in human allergy via the nasal mucosa.
abstract: BACKGROUND
  Natural allergen contact induces an increase of IgE levels and sensitivity but the mechanisms underlying the allergen-specific memory responses are poorly understood. Furthermore, it has not been studied whether allergen exposure affects the molecular reactivity profiles in patients. The aim of this study was to analyze the influence of nasal allergen encounter on the molecular profile and magnitude of memory IgE responses and on systemic sensitivity.
  
  
  METHODS
  We investigated allergen-specific IgE, IgG subclass and IgM responses to defined allergen molecules (grass pollen: Phl p 1, Phl p 2 and Phl p 5; birch pollen: Bet v 1 and Bet v 2) in allergic patients in response to natural as well as to controlled nasal and dermal allergen exposure. Changes in systemic sensitivity were monitored by skin prick testing and by basophil histamine release experiments.
  
  
  RESULTS
  Respiratory antigen exposure boosted IgE levels to a pre-established profile of allergen molecules without inducing significant IgM responses or new IgE specificities in allergic individuals. The importance of the route of allergen contact is demonstrated by an increase of systemic IgE levels and sensitivity after nasal exposure. In vitro sensitisation of basophils with pre- and post-seasonal serum samples suggests an allergen-induced elevation of specific IgE as a cause for the increased allergen-specific sensitivity.
  
  
  CONCLUSIONS
  The characteristics of the allergen-driven antibody responses indicate a direct activation of an established pool of IgE memory cells with defined specificities as an underlying mechanism. Our finding that nasal allergen contact is a major factor for the boosting of memory IgE and systemic sensitivity may open new therapeutic possibilities.
authors.affiliation: Department of Otorhinolaryngology, Center for Public Health, Medical University of Vienna, Vienna, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Niederberger
authors.forename: Johannes
authors.initials: J
authors.lastname: Ring
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rakoski
authors.forename: Siegfried
authors.initials: S
authors.lastname: Jager
authors.forename: Susanne
authors.initials: S
authors.lastname: Spitzauer
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
authors.forename: Friedrich
authors.initials: F
authors.lastname: Horak
authors.forename: Michael
authors.initials: M
authors.lastname: Kundi
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
mesh_terms: D000281:Administration, Intranasal; D000287:Administration, Topical; D000328:Adult; D000941:Antigens / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007156:Immunologic Memory; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D012867:Skin / Q000276:immunology; D012882:Skin Tests
chemical_list: D000941:Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007073:Immunoglobulin E