Higher allergenicity of high molecular weight hydrolysed wheat protein in cosmetics for percutaneous sensitization

Background Wheat protein derivatives are used in a variety of products worldwide. Gluten is commercially used ‘as is' or with modifications such as hydrolysis, which is carried out to overcome its insolubility. Several cases of contact urticaria following exposure to hydrolysed wheat protein (HWP) in cosmetics or of anaphylaxis caused by deamidated gluten in food or non‐food products have been described. Objectives To evaluate the types of HWP that have higher allergenicity for percutaneous sensitization. Methods We enrolled 7 patients with wheat‐dependent exercise‐induced anaphylaxis who had been sensitized to HWP primarily through the percutaneous and/or the rhinoconjunctival route by using facial soap containing HWP. Reaction to wheat proteins was confirmed by IgE immunoblotting and basophil CD203c expression with six HWP variants. Results The IgE of all the patients reacted to HWPs composed of large polypeptide aggregates. High molecular weight (MW) HWPs were also found to induce significant enhancement of basophil CD203c expression. Conclusions HWPs composed of large polypeptide aggregates possibly induce sensitization to a greater degree than lower‐MW HWPs. Basophil surface CD203c expression is useful for evaluating the allergenicity of HWPs.