Oral Desensitization and Induction of Tolerance in Peanut-Allergic Children

RATIONALE: This pilot study aims to determine if peanut-allergic children can be orally desensitized to peanut protein and if this oral immunotherapy protocol will both protect them from reaction on accidental exposure to peanut and ultimately induce long-term immunologic tolerance to peanut. METHODS: Children diagnosed with peanut allergy with serum peanut-specific IgE > 15 kU/L and no history of an anaphylactic reaction to peanut are being enrolled. The subjects undergo an oral immunotherapy (OIT) protocol for peanut with three phases: modified rush, dosage escalation and maintenance. The peanut doses for the modified rush and dosage escalation visits occur under direct observation in the research unit. All other doses are taken at home. Two years after enrollment, subjects undergo double-blind-placebo-controlled peanut challenge. RESULTS: Seven subjects (mean age 4.4 years, SD 0.98 years) have been in the protocol for six months or more. During modified rush, 4/7 subjects required a single dose of antihistamine to treat symptoms. No subjects required epinephrine. All subjects tolerated the dosage escalation visits with either mild or no symptoms. The home dosing has been well-tolerated. The mean peanut-specific IgE and IgG at baseline were 139.5 kU/L (SEM 55.3) and 14.3 (SEM 4.0) kU/L respectively. At 6 months, there has been mean increase in the peanut-specific IgG of 2.3 fold (95%CI 1.8 to 3, p=0.0002). The mean change in peanut-specific IgE was 0.9 fold (95%CI 0.6 to 1.35, p=0.6) CONCLUSION: Oral desensitization to peanut protein in a controlled setting seems to be safe and well tolerated.