Oral immunotherapy (OIT), a novel therapeutic approach to food allergy, appears to be effective in increasing the threshold for clinical reactivity to food. The aim of the study is to assess the risk factors associated with rush OIT (ROIT) for treating anaphylaxis induced by allergy to hen’s egg (HE), cow’s milk (CM), wheat (W), or peanut (P).
Methods
HE, CM, and W anaphylaxis in our department confirmed by the positive double-blind, placebo-controlled food challenge test received following treatment with ROIT. Patients were treated with a combination of rush phase followed by a slow build-up of maintenance doses. patients who had ingested trial foods (HE, heated-whole egg [60 g]; CM, 200 ml; W, Udon noodle [200 g]; P, peanut powder [3 g]) without any symptoms for several months, then they underwent the final oral food challenge (OFC) after allergen avoidance for 2 weeks to confirm the development of clinical tolerance. Any changes in antigen specific IgE levels during OIT treatment were documented.
Results
A total of 224 subjects (HE, n = 70; CM, n = 87; W, n = 38; P, n = 29) with an average age of 9.1 years, who had been receiving ROIT for 1 & 1/2 year or more, were enrolled in the study. One and half year later, 75 subjects (33%) passed the final OFC (tentative tolerance group, HE, 33; CM, 17; W, 11; P, 14), whereas 149 subjects (67%) had reacted to the trial foods (Allergic group). After 1 & 1/2 year of ROIT, the median antigen-specific IgE levels (kU/L) were significantly decreased compared to the levels prior to OIT (egg white: 23.4 vs. 7.0; ovomucoid: 20.3 vs. 5.3; milk: 56.4 vs. 14.0; casein: 54.5 vs. 14.8; wheat: 213.0 vs. 43.8; omega-5 gliadin: 6.4 vs. 1.3; peanut: 33.2 vs. 12.5; Ara h 2: 27.4 vs. 10.8, p < 0.05), whereas antigen specific IgG4 increased significantly (0.9 vs. 43.7 for egg white; and 2.2 vs. 9.1 for casein; p < 0.05). In the tentative tolerant group of HE and CM-ROIT, the initial antigen-specific IgE levels were significantly lower than that of the allergic group (tentative tolerant group vs. allergic group, egg white: 18.3 vs. 32.6; ovomucoid: 14.3 vs. 31.8; milk: 26.1 vs. 57.3; casein: 24.2 vs. 62.5; p < 0.05). No significant differences were found in patients allergic to W and P.
Conclusions
In this study, ROIT induced a significant decrease in antigen specific IgE levels. For HE and CM anaphylaxis, the patients who had relatively low antigen-specific IgE at the beginning of ROIT appeared to respond better to ROIT within 1 & 1/2 year.