Utility of component analyses in subjects undergoing sublingual immunotherapy for peanut allergy.

Abstract

Sublingual immunotherapy (SLIT) with peanut changes clinical and immune responses in most peanut-allergic individuals, but the response is highly variable. We sought to examine the component-specific effects of peanut SLIT and determine whether peanut component testing could predict the outcome of a double-blind, placebo-controlled food challenge (DBPCFC) after 12months of peanut SLIT. We included 33 subjects who underwent peanut SLIT with a DBPCFC of 2500mg of peanut protein performed after 12months of therapy. Plasma samples from baseline and after 12months of peanut SLIT were assayed using ImmunoCAP for IgE and IgG4 against whole peanut, Ara h 1, Ara h 2, Ara h 3, Ara h 8, and Ara h 9. Following 12months of SLIT, 10 subjects (30%) passed the DBPCFC without symptoms and were considered desensitized. Subjects that failed the DBPCFC tolerated a median of 460mg peanut protein (range: 10-1710mg). The desensitized group had significantly lower baseline levels of IgE against peanut (median 40.8 vs. 231kUA /L, P=0.0082), Ara h 2 (median 17 vs. 113kUA /L, P=0.0082), and Ara h 3 (median 0.3 vs. 8.5kUA /L, P=0.0396). ROC curves indicated that baseline IgE against peanut and Ara h 2 were equally effective at discriminating between the two groups (AUC=0.7957, P=0.007752 for both). In this cohort of subjects undergoing SLIT for peanut allergy, lower baseline levels of IgE against Ara h 2, Ara h 3, and peanut were associated with successful desensitization.