Identification of patatin as a novel allergen for children with positive skin prick test responses to raw potato

Background: Peeling of ram potatoes may cause allergic symptoms, such as sneezing, wheezing, and contact urticaria, for adults. For children, potatoes as food may cause various allergic reactions. However, the identity and molecular structure of the putative allergens in potato have remained unknown, Objective: The aim of our study was to identify possible major allergens in potato by using sera of atopic children suspected of having food allergy and having positive skin prick test responses to raw potato, Methods: Potato proteins were purified by standard methods of protein chemistry and characterized with amino-terminal sequencing and mass spectrometry, The IgE-binding ability of the purified proteins was verified by immunoblotting and ELISA with IgE antibodies from the sera of atopic children having positive skin prick test responses to raw potato. Results: Immunoblotting showed strong IgE binding to a 43-kd protein, identified as patatin, the main storage protein of potato tubers. In ELISA, 20 of 27 (74%) children with positive skin prick test responses to potato and none of the control subjects showed specific binding of IgE antibodies to purified patatin, A positive wheal-and-pare reaction was seen in 8 of 14 children prick tested with purified patatin, Conclusion: These results show that patatin in potatoes is a significant, previously unrecognized, IgE-binding protein for children with a positive skin prick test response to raw potato. Further studies are needed to confirm the clinical importance of potatoes, and especially patatin, as a food allergen.