Sublingual immunotherapy (SLIT) for peanut allergy: Clinical and immunologic evidence of desensitization

January 31, 2011.  Kim EH, Bird JA, Kulis M et al.  The Journal of Allergy and Clinical Immunology. in press.

Background.  There are no treatments currently available for peanut allergy. Sublingual immunotherapy (SLIT) is a novel approach to the treatment of peanut allergy.  Objective.  We sought to investigate the safety, clinical effectiveness, and immunologic changes with SLIT in children with peanut allergy.  Methods. In this double-blind, placebo-controlled study subjects underwent 6 months of dose escalation and 6 months of maintenance dosing followed by a double-blind, placebo-controlled food challenge.  Results.  Eighteen children aged 1 to 11 years completed 12 months of dosing and the food challenge. Dosing side effects were primarily oropharyngeal and uncommonly required treatment. During the double-blind, placebo-controlled food challenge, the treatment group safely ingested 20 times more peanut protein than the placebo group (median, 1,710 vs 85 mg; P = .011). Mechanistic studies demonstrated a decrease in skin prick test wheal size (P = .020) and decreased basophil responsiveness after stimulation with 10−2 μg/mL (P = .009) and 10−3 μg/mL (P = .009) of peanut. Peanut-specific IgE levels increased over the initial 4 months (P = .002) and then steadily decreased over the remaining 8 months (P = .003), whereas peanut-specific IgG4 levels increased during the 12 months (P = .014). Lastly, IL-5 levels decreased after 12 months (P = .015). No statistically significant changes were found in IL-13 levels, the percentage of regulatory T cells, or IL-10 and IFN-γ production.  Conclusion.  Peanut SLIT is able to safely induce clinical desensitization in children with peanut allergy, with evidence of immunologic changes suggesting a significant change in the allergic response. Further study is required to determine whether continued peanut SLIT is able to induce long-term immune tolerance.

http://www.jacionline.org/article/S0091-6749(10)03043-5/abstract