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 sn eezing, wheezing, and contact urticaria, for adults. For children, potatoes as food may cause various allergic reactions. However, the identity and mo lecular 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 a nd having positive skin prick test responses to raw potato, Methods: Potato proteins were purified by standard methods of protein chemi stry and characterized with amino-terminal sequencing and mass spectrometry , The IgE-binding ability of the purified proteins was verified by immunobl otting and ELISA with IgE antibodies from the sera of atopic children havin g positive skin prick test responses to raw potato. Results: Immunoblotting showed strong IgE binding to a 43-kd protein, ident ified as patatin, the main storage protein of potato tubers. In ELISA, 20 o f 27 (74%) children with positive skin prick test responses to potato and n one of the control subjects showed specific binding of IgE antibodies to pu rified patatin, A positive wheal-and-pare reaction was seen in 8 of 14 chil dren prick tested with purified patatin, Conclusion: These results show that patatin in potatoes is a significant, p reviously unrecognized, IgE-binding protein for children with a positive sk in prick test response to raw potato. Further studies are needed to confirm the clinical importance of potatoes, and especially patatin, as a food all ergen.