title: Are basophil histamine release and high affinity IgE receptor expression involved in asymptomatic skin sensitization?
abstract: BACKGROUND
  Immunoglobulin (Ig)E-sensitized persons with positive skin prick test, but no allergy symptoms, are classified as being asymptomatic skin sensitized (AS). The allergic type 1 disease is dependant on IgE binding to the high affinity IgE-receptor (FcepsilonRI) expressed on basophils and mast cells. However, a relationship between the AS status and FcepsilonRI has not been investigated. We aimed to characterize basophils from AS by looking at histamine release (HR) (sensitivity and reactivity) and the FcepsilonRI molecule, and compare it with nonatopic (NA) or allergic (A) persons.
  
  
  METHODS
  Blood was obtained from NA (n = 14), grass and/or birch A persons (n = 17) and mono-sensitized grass or birch pollen AS (n = 12). The basophil sensitivity and reactivity were examined by anti-IgE triggered HR. Surface expression of FcepsilonRI and IgE were measured by flow cytometry, FcepsilonRIalpha protein was identified using a radioimmunoassay and Western blot. mRNA coding for the classic FcepsilonRIbeta-chain and the truncated form (FcepsilonRIbetaT) were determined by real-time PCR.
  
  
  RESULTS
  The AS group was less reactive than NA or A persons when triggered by anti-IgE and had a significant higher number of nonresponders. However, there was no difference in sensitivity among the three groups and furthermore; the groups did not vary in FcepsilonRI- and IgE-surface expression, FcepsilonRIalpha-protein level or beta/betaT ratio.
  
  
  CONCLUSIONS
  Basophils from AS persons are less reactive and include more nonresponders than basophils from NA and A persons, but do not differ regarding the FcepsilonRI molecule.
authors.affiliation: Allergy Clinic, National University Hospital, Copenhagen, Denmark.
authors.forename: B M
authors.initials: BM
authors.lastname: Jensen
authors.forename: K
authors.initials: K
authors.lastname: Assing
authors.forename: L
authors.initials: L
authors.lastname: Hummelshoj
authors.forename: C
authors.initials: C
authors.lastname: Glue
authors.forename: P S
authors.initials: PS
authors.lastname: Skov
authors.forename: L K
authors.initials: LK
authors.lastname: Poulsen
mesh_terms: D000328:Adult; D001491:Basophils / Q000276:immunology; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D006636:Histamine Release / Q000276:immunology* / Q000502:physiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007114:Immunization; D008297:Male; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D011863:Radioimmunoassay; D017455:Receptors, IgE / Q000032:analysis* / Q000235:genetics; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D012882:Skin Tests; D018709:Statistics, Nonparametric
chemical_list: D012333:RNA, Messenger; D017455:Receptors, IgE