Modified oral food challenge used with sensitization biomarkers provides more real-life clinical thresholds for peanut allergy.
BACKGROUND
Threshold levels for peanut allergy determined by using oral challenges are important for the food industry with regard to allergen labeling. Moreover, the utility of biological markers in predicting threshold levels is uncertain.


OBJECTIVE
We sought to use a modified oral food challenge regimen that might determine threshold levels for peanut allergy mimicking a more real-life exposure and to correlate the eliciting dose (ED) and severity of clinical reaction in children with peanut allergy with B-cell, T-cell, and effector cell markers.


METHODS
A modified food challenge procedure with doses scheduled 2 hours apart was used in 63 children with peanut allergy. All children received a maximum of 8 semi-log increasing titration steps of roasted peanuts ranging from 3 to 4500 mg of peanut protein until objective allergic reactions occurred. Severity of symptoms was graded from I to V. Biological markers were measured before challenge.


RESULTS
Forty-five of 63 patients showed objective symptoms after greater than 30 minutes, with a median latency of clinical reaction of 55 minutes. By using a log-normal dose-distribution model, the ED5 was calculated to be 1.95 mg of peanut protein. The ED was significantly and inversely correlated with peanut- and Ara h 2-specific IgE levels, skin prick test responses, basophil activation, and TH2 cytokine production by PBMCs. Symptom severity did not correlate with any of the markers or the ED.


CONCLUSIONS
This modified food challenge procedure might better reflect threshold levels for peanut allergy than the standard procedure because most of the patients reacted at a time interval of greater than 30 minutes. By using this model, threshold levels, but not severity, could be correlated with biological markers.
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany. Electronic address: nina.bluemchen@charite.de.
Katharina
K
Blumchen
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Alena
A
Beder
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
John
J
Beschorner
Children's Hospital "Altona", Hamburg, Germany.
Frank
F
Ahrens
Department of Pediatrics, Technical University Munich, Munich, Germany.
Armin
A
Gruebl
Department of Pediatrics, Ruhr-University Bochum, Bochum, Germany.
Eckard
E
Hamelmann
Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.
Gesine
G
Hansen
Center for Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany.
Andrea
A
Heinzmann
Department of Pediatrics, University Hospital Carl Gustav Carus, Technical University of Dresden, Dresden, Germany.
Katja
K
Nemat
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Bodo
B
Niggemann
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Ulrich
U
Wahn
Department of Pediatric Pneumology and Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Kirsten
K
Beyer
D055516:2S Albumins, Plant / Q000097:blood* / Q000276:immunology; D000284:Administration, Oral; D000293:Adolescent; D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant / Q000097:blood* / Q000276:immunology; D010367:Arachis / Q000276:immunology*; D015549:Basophil Degranulation Test; D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D015550:Cell Degranulation / Q000187:drug effects / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006023:Glycoproteins / Q000097:blood* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008297:Male; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D010940:Plant Proteins / Q000008:administration & dosage* / Q000276:immunology; D012720:Severity of Illness Index; D012882:Skin Tests; D013997:Time Factors
D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D015415:Biomarkers; D016207:Cytokines; D006023:Glycoproteins; D010940:Plant Proteins; D007073:Immunoglobulin E
Ara h 2; Basophil activation; children; cytokines; food challenge; peanut allergy