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Medline ® Abstracts for References 12,16

of 'Oral food challenges for diagnosis and management of food allergies'

Impact of Allergic Reactions on Food-Specific IgE Concentrations and Skin Test Results.
Sicherer SH, Wood RA, Vickery BP, Perry TT, Jones SM, Leung DY, Blackwell B, Dawson P, Burks AW, Lindblad R, Sampson HA
J Allergy Clin Immunol Pract. 2016 Mar-Apr;4(2):239-245.e4. Epub 2015 Dec 21.
BACKGROUND: Although there is concern that food allergy reactions may negatively affect the natural history of food allergy, the impact of reactions on food-specific IgE (sIgE) levels or skin prick test (SPT) wheal size is unknown.
OBJECTIVE: To measure the effects of allergic reactions on SPT wheal size and sIgE concentrations to milk, egg, and peanut.
METHODS: Participants included 512 infants with likely milk or egg allergy enrolled in a multicenter observational study. Changes in sIgE level and SPT wheal size to milk, egg, and peanut were measured before and after oral food challenge (OFC) or accidental exposure for 377 participants.
RESULTS: The median age of the cohort at the time of analysis was 8.5 years (67% males). There were no statistically significant changes in sIgE level or SPT wheal size after positive OFC to milk, egg, or peanut (n = 20-27 for each food). Change in sIgE level and SPT wheal size was measured after 446 and 453 accidental exposure reactions, respectively. The median change in sIgE level was a decrease of 0.33 kUA/L (P<.01) after milk and 0.34 kUA/L (P<.01) after egg reactions, but no other statistically significant changes in sIgE level or SPT wheal size were observed for milk, egg, or peanut. When we limited the analysis to only those participants who had diagnostic testing done within 6 months of an accidental exposure reaction, we found that peanut SPT wheal size increased by 1.75 mm (P<.01), but a significant increase was not noted when all participants with testing done within 12 months were considered.
CONCLUSIONS: The results suggest that reactions from OFCs and accidental exposure are not associated with increases in sensitization among children allergic to milk, egg, or peanut.
Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY. Electronic address: scott.sicherer@mssm.edu.
Modified oral food challenge used with sensitization biomarkers provides more real-life clinical thresholds for peanut allergy.
Blumchen K, Beder A, Beschorner J, Ahrens F, Gruebl A, Hamelmann E, Hansen G, Heinzmann A, Nemat K, Niggemann B, Wahn U, Beyer K
J Allergy Clin Immunol. 2014 Aug;134(2):390-8. Epub 2014 May 13.
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.
CONCLUSION: 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.