Supplementary Material for: Oral Immunotherapy in Japanese Children with Anaphylactic Peanut Allergy

Background: Reports on oral immunotherapy (OIT) for anaphylactic food allergy are lacking. We investigated the efficacy and safety of peanut OIT for anaphylactic patients. Methods: We enrolled 22 peanut anaphylactic patients who underwent OIT between 2011 and 2013, all of whom demonstrated anaphylaxis during a baseline double-blind, placebo-controlled food challenge. After starting in-hospital OIT, participants gradually increased ingestion to 795 mg of peanut protein per day at home and then took a maintenance dose (795 mg) daily. After 3 asymptomatic months, participants underwent an oral food challenge (OFC) of 795 mg after 2 weeks of peanut avoidance to confirm sustained unresponsiveness. The historical control group consisted of 11 patients with anaphylaxis by OFC and underwent the second OFC after 2 years. Results: All patients (22/22) achieved desensitization by 8 months after starting OIT and completed the protocol within 2 years. Two years later, 15/22 patients (68.1%) in the OIT group achieved sustained unresponsiveness, whereas only 2 (18.1%) in the control group passed the second OFC. After 2 years, the median peanut-specific IgE had significantly decreased (from 38.5 to 12.4 kUA/L) in the OIT group, but not in the control group. Median peanut- and Ara h 2-specific IgG4 in the OIT group had significantly increased from baseline after 1 month. The adverse reaction rate per ingestion was 43% in hospital and 5% at home. Three patients received adrenaline at the hospital and 2 at home. Conclusions: These data suggest that for patients with peanut anaphylaxis, OIT can increase the threshold and support achieving sustained unresponsiveness with relative safety.