Basophil activation test with food additives in patients with chronic urticaria

Abstract

Background: Chronic urticaria (CU) is defined as the urticaria persisting for more than 6 weeks. However the etiology is frequently deemed as unclear, as most classical investigations failed to find the causes. Some patients with CU complain about aggravation of their symptoms after meal ingestion. However, it seems that clinically relevant allergies to food itself are thought to be rare (less than 10%) in patients with CU. Food additives are the substances artificially added in the food and a few of these are known to be implicated in allergic or allergy-like reactions. However, the role of food additives in CU is also still under investigation. Basophil activation test (BAT) is an in vitro diagnostic tool to identify the activation of basophil, and is now increasingly applied in various fields of allergic researches. We aimed to explore the association between food additives and CU using BAT. Methods: The BAT was performed with 15 common food additives in 15 patients with CU who had histories of recurrent aggravation after various food intakes without definite food-specific IgE. Results: Among the 15 patients studied, only two patients (13.3%) presented positive BAT to the food additives. One patient responded to monosodium glutamate, showing 18.7% of CD203c basophil expression. Another patient showed a positive BAT to sodium benzoate. Both patients had clinical correlations with the agents, which were partly proven by elimination diets. Conclusion: The present study suggested a potential role of the BAT with food additives in the evaluation of possible causes in CU.