title: Evaluation of basophil allergen threshold sensitivity (CD-sens) to peanut and Ara h 8 in children IgE-sensitized to Ara h 8.
abstract: BACKGROUND
  Diagnosing peanut allergy properly is important and can be achieved by combining clinical history with various diagnostic methods such as IgE-antibody (IgE-ab) measurements, skin-prick test, basophil allergen threshold sensitivity (CD-sens) and food challenge. We aimed to evaluate CD-sens to peanut, Ara h 8 and Gly m 4 in relation to an oral peanut challenge in children IgE-sensitized to birch, peanut and Ara h 8 avoiding peanuts.
  
  
  METHODS
  Twenty children IgE-sensitized to birch pollen and Ara h 8, but not to Ara h 1, Ara h 2 or Ara h 3 were challenged orally with roasted peanuts. Blood samples were drawn for IgE-ab and CD-sens analysis. To measure CD-sens, basophils were stimulated in vitro with decreasing doses of allergens until threshold sensitivity was reached.
  
  
  RESULTS
  All children passed challenge without objective symptoms, but mild oral allergy syndrome (OAS) symptoms were reported in 6/20 children. Nineteen of twenty children were negative in CD-sens to peanut but 17/20 were positive to rAra h 8. Eleven of twenty children were positive in CD-sens to rGly m 4.
  
  
  CONCLUSIONS
  Positive CD-sens to rAra h 8 show that the Ara h 8 IgE-ab sensitized basophils can be activated by a rAra h 8 allergen and initiate an allergic inflammation despite a negative challenge. Hence, children sensitized to Ara h 8 but not to peanut storage proteins may be at risk for systemic allergic reaction when eating larger amounts of peanuts but most likely don't have to fear smaller amounts.
authors: Department of Clinical Science and Education, Södersjukhuset, Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden ; Sachs' Children and Youth Hospital, Södersjukhuset, 118 83 Stockholm, Sweden.
authors: Susanne
authors: S
authors: Glaumann
authors: Department of Clinical Science and Education, Södersjukhuset, Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden ; Sachs' Children and Youth Hospital, Södersjukhuset, 118 83 Stockholm, Sweden.
authors: Caroline
authors: C
authors: Nilsson
authors: Department of Medicine, Clinical Immunology and Allergy Unit, Karolinska Institutet and Hospital, Stockholm, Sweden.
authors: S G O
authors: SG
authors: Johansson
authors: Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden ; Department of Women's and Children's Health, Karolinska Institutet at Astrid Lindgren Children's Hospital, Stockholm, Sweden.
authors: Anna
authors: A
authors: Asarnoj
authors: Sachs' Children and Youth Hospital, Södersjukhuset, 118 83 Stockholm, Sweden ; Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors: Magnus
authors: M
authors: Wickman
authors: Thermo Fisher Scientific, Uppsala, Sweden ; Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors: Magnus P
authors: MP
authors: Borres
authors: Department of Medicine, Clinical Immunology and Allergy Unit, Karolinska Institutet and Hospital, Stockholm, Sweden.
authors: Anna
authors: A
authors: Nopp
keywords: Basophils; Birch pollen allergy; CD-sens; CD63; Children; Cross-reactivity; Flow cytometry; Peanut allergy; Pediatrics; rAra h 8