Methods: A girl who had experienced many episodes of anaphylaxis was diagnosed with erythritol allergy by skin prick test (SPT), basophil activation test (BAT) using CD203c expression, and oral food challenge (OFC). Stripping of surface IgE and pretreatment with wortmannin (PI3K-inhibitor) were performed before BAT.
Results: Results of SPT and BAT were positive to erythritol, and ingestion of 0.2g of erythritol in the OFC provoked multiple urticaria and runny nose in the patient. Surface IgE-stripped basophils showed reduced proportion of high CD203c-expressing cells, which was ameliorated by supplementation with autologous plasma. Pretreatment with wortmannin also reduced the proportion of high CD203c-expressing cells.We conducted OIT with a starting dose of 0.1g. After 1year of OIT, and the patient achieved a maintenance dose of 1.8g, but she occasionally experienced allergic reactions. After 2years, when she continued the maintenance dose without any symptoms over 4months, we performed OFC after 2weeks of complete avoidance of antigen. The result was positive with induction of systemic urticaria, and BAT results remained positive at this time.
Conclusions: Allergic reaction to erythritol was mediated in an IgE-dependent manner. It is possible that some other substances in the patient’s plasma also contributed to the reaction. Although desensitization was obtained after 2years of OIT, immunological tolerance was not achieved.