Oral Immunotherapy in Japanese Children with Anaphylactic Peanut Allergy

Reports on oral immunotherapy (OIT) for anaphylactic food allergy are lacking. We investigated the efficacy and safety of peanut OIT for anaphylactic patients.

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.

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.

These data suggest that for patients with peanut anaphylaxis, OIT can increase the threshold and support achieving sustained unresponsiveness with relative safety.