Scientific Study

Background: Our group previously described preschool peanut oral immunotherapy (P-OIT) in a real-world multi-center setting, suggesting this therapy is safe for the vast majority of preschoolers. Objectives: We examined the safety and tolerability of tree nut (TN)-OIT in preschoolers in the real-world. Methods: As part of a Canada-wide quality improvement project, TN-OIT (cashew/pistachio, walnut/pecan, hazelnut, almond, macadamia nut) was administered to preschool-aged children who had (1) skin prick test ≥ 3mm or specific IgE level ≥ 0.35kU/L and convincing objective IgE-mediated reaction or (2) no ingestion history and specific IgE level ≥ 5kU/L. Patients built-up every two to four weeks to a maintenance dose of 300mg TN protein. Symptoms were recorded and classified using a modified World Allergy Organization Subcutaneous Immunotherapy Reaction Grading System (1 mildest, 5 fatal). Results: Of 92 patients who started TN-OIT from 2018-2021, 79 (85.9%) underwent single-food TN-OIT and 13 (14.1%) underwent multi-food TN-OIT to two (10.8%) or three (3.3%) TNs. Eighty-nine (96.7%) patients reached maintenance, and 4 dropped out (4.3%). Sixty-five (70.7%) patients experienced reactions during build-up: 35 (38.0%) grade 1, 30 (32.6%) grade 2 reactions, no grade 3 or 4 reactions, and 2 (2.17%) received epinephrine. Conclusions: Preschool TN-OIT in a real-world, multicenter setting appears safe and tolerable, with results comparable to our previously reported P-OIT findings. https://doi.org/10.1016/j.jaip.2023.01.031