Oral peanut immunotherapy in children with peanut anaphylaxis

Background The only treatment option for peanut allergy is strict avoidance. Objective To investigate efficacy and safety of oral immunotherapy (OIT) in peanut allergy. Methods Twenty-three children (age, 3.2-14.3 years) with IgE-mediated peanut allergy confirmed by positive double-blind, placebo-controlled food challenge (DBPCFC) received OIT following a rush protocol with roasted peanut for 7 days. If a protective dose of at least 0.5 g peanut was not achieved, patients continued with a long-term buildup protocol using biweekly dose increases up to at least 0.5 g peanut. A maintenance phase for 8 weeks was followed by 2 weeks of peanut avoidance and a final DBPCFC. Immunologic parameters were determined. Results After OIT using the rush protocol, patients tolerated a median dose of only 0.15 g peanut. Twenty-two of 23 patients continued with the long-term protocol. After a median of 7 months, 14 patients reached the protective dose. At the final DBPCFC, patients tolerated a median of 1 g (range, 0.25-4 g) in comparison with 0.19 g peanut at the DBPCFC before OIT (range, 0.02-1 g). In 2.6% of 6137 total daily doses, mild to moderate side effects were observed; in 1.3%, symptoms of pulmonary obstruction were detected. OIT was discontinued in 4 of 22 patients because of adverse events. There was a significant increase in peanut-specific serum IgG 4 and a decrease in peanut-specific IL-5, IL-4, and IL-2 production by PBMCs after OIT. Conclusion Long-term OIT appears to be safe and of some benefit in many patients with peanut allergy. With an increase in threshold levels and a reduction of peanut-specific T H 2 cytokine production, the induction of tolerance may be feasible in some patients.