Identification of patatin as a novel allergen for children with positive skin prick test responses to raw potato.
BACKGROUND
Peeling of raw 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-flare reaction was seen in 8 of 14 children prick tested with purified patatin.


CONCLUSIONS
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.
Seppälä
U
U
Institute of Biotechnology, University of Helsinki, Finland.
Alenius
H
H
Turjanmaa
K
K
Reunala
T
T
Palosuo
T
T
Kalkkinen
N
N
D000485:Allergens / Q000276:immunology*; D002265:Carboxylic Ester Hydrolases; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005512:Food Hypersensitivity / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000378:metabolism; D007223:Infant; D010940:Plant Proteins / Q000276:immunology* / Q000302:isolation & purification; D011485:Protein Binding; D012882:Skin Tests; D011198:Solanum tuberosum / Q000009:adverse effects* / Q000276:immunology
D000485:Allergens; D010940:Plant Proteins; C043222:patatin protein, Solanum tuberosum; D007073:Immunoglobulin E; D002265:Carboxylic Ester Hydrolases