The results of this study demonstrate that the prevalence of positive skin-prick tests to extracts from wild-type and GM potatoes was 5.7% in our population of adult allergy patients. Serum-specific IgE antibodies were detected among the positive responders. The 45-kDa allergenic band was the most frequently bound (>80%) by the two types of extract, and ELISA inhibition studies suggested that they had similar potencies. Recent investigations to evaluate the allergic risks of GM corn and soybean demonstrated that allergenicity did not increase after genetic manipulation of wild-type corn  and soybean . Similarly, our study showed that the genetic manipulation of potatoes, which are one of the most common sources of food allergens in Korea, did not enhance their allergenic risk, as evaluated using in vivo and in vitro methods.
GM crops currently on the market have been thoroughly assessed for safety according to the guidelines developed by the World Health Organization  and the Food and Agriculture Organization of the United Nations . In addition, the potential allergenicity of newly introduced proteins must be assessed in all foods produced through agricultural biotechnology, and the FAO  and WHO have developed a rigorous approach for this assessment. The NPTII gene introduced in the potato used in this study encodes an enzyme that confers resistance to aminoglycoside antibiotics and was isolated from the prokaryotic transposon Tn5 . The PAT gene was obtained from the aerobic soil bacterium Streptomyces viridochromogenes. If the gene source is bacterial, specific and targeted serum screenings are not necessary because bacterial proteins are rarely allergenic, due to the low exposure levels and lack of allergic sensitization to these proteins . Furthermore, previous studies have confirmed that ingestion of genetically engineered plants expressing NPTII does not pose any safety concerns [20, 21]. Herouet et al.  found that PAT proteins do not possess the characteristics associated with food toxins or allergens, i.e., they have no sequence homology with any known allergens or toxins. These findings suggest that an increase in the allergenic risk of a GM potato is unlikely.
A few studies have identified IgE-binding components within potato extracts. Wahl et al.  reported four (16, 30, 45, and 65) IgE-binding components, which were detected by immunoblotting using sera from 12 patients with IgE-mediated hypersensitivity reactions to potatoes. Four major potato allergens, Sol t 1 (43 kDa), 2 (21 kDa), 3 (21 kDa), and 4 (16 kDa), were identified in children [24, 25]. Furthermore, several studies have shown that allergy to natural rubber latex is associated with cross-reactivity to potatoes and tomatoes [7, 26]. In our study of the Korean population, only one allergenic protein (45 kDa) could be identified as the major allergen, and it was present in extracts from wild-type and GM potatoes. Moreover, this protein may be the same one identified in a previous investigation .
Proteolytic stability is a useful criterion in assessing the allergenic potential of food allergens. The FAO/WHO  decision-tree approach advocates the use of resistance to proteolysis with pepsin as a comparative measure of digestive stability for proteins introduced into food through agricultural biotechnology. In the current study, we demonstrated that SGF and heat treatment substantially suppressed the activity of IgE-binding components in wild-type and GM potato extracts, while minimal changes were noted with SIF treatment alone.