Atopic dermatitis (AD) is a chronic, relapsing, inflammatory skin disease. Children with AD tend to have a higher prevalence of food allergies. This study investigated the clinical significance of food sensitization in AD patients. A total of 266 AD patients participated in this study. The prevalence of food sensitization and clinically relevant sensitization were compared in the subjects according to their age and AD severity. Sera from all patients were analyzed for food-specific IgE levels using the Pharmacia CAP System FEIA. The serum specific IgE levels for egg, milk, peanut and soybean were measured. Patients were regarded as sensitized to the food if their food-specific IgE levels were above 0.35 kUA/L. Also the food-specific IgE levels, the so-called diagnostic decision point, which is recommended as the clinically relevant level, for clinical food allergy, as suggested by Sampson et al, was used as an alternative method. From the measurement of food-specific IgE antibodies of the four foods, egg was the most highly sensitized and the main causative allergenic food in children with AD. The positive rates of specific IgE to the four major food allergens, and the prevalences of clinically relevant food sensitization, were higher for all foods tested in the group less than 1 year of age, and were significantly higher in moderate to severe AD compared to mild AD in infants and young children. In summary, presence of food specific IgE is prevalent in infants and young children with AD, and clinically relevant food sensitization is important in Korean infants and children with moderate to severe AD.
Child, Preschool ; Dermatitis, Atopic/*immunology ; Egg Hypersensitivity/epidemiology ; Female ; Food Hypersensitivity/diagnosis/*epidemiology ; Humans ; Immunoglobulin E/blood ; Infant ; Male ; Milk Hypersensitivity/epidemiology ; Peanut Hypersensitivity/epidemiology ; Soybeans/immunology

Genetically modified (GM) soybean (carrying the EPSPS transgene) is the most common GM food in Korea. In order to assess whether genetic modification increases the allergenic risk of soybeans, the allergenicity and IgE-reactive components of wild-type and GM soybean extracts were compared in allergic adults who had been sensitized to soybeans. We enrolled 1,716 adult allergy patients and 40 healthy, non-atopic controls. Skin prick tests and IgE enzyme linked immunosorbent assays (ELISAs) were performed using wild-type and GM soybean extracts, along with other common inhaled allergens. The specificities of serum IgE antibodies from allergic patients and the identities of the IgE-reactive components of the soybean extracts were compared using ELISA inhibition testing, 2-dimensional gel electrophoresis, and IgE immunoblotting. To evaluate the effects of digestive enzymes and heat treatment, the soybean extracts were heated or pre- incubated with or without simulated gastric and intestinal fluids. The IgE sensitization rates to wild-type and GM soybeans were identical (3.8% of allergic adults), and circulating IgE antibodies specific for the two extracts were comparable. The results of the ELISA inhibition test, SDS-PAGE, and IgE immunoblotting showed a similar composition of IgE-binding components within the wild-type and GM extracts, which was confirmed using two-dimensional gel electrophoresis, IgE immunoblotting, and amino acid sequencing. None of the subjects had a positive response to purified EPSPS protein in the skin prick test, ELISA, or IgE immunoblot analysis. These findings suggest that the IgE sensitization rate to GM soybean extracts is identical to that of wild-type soybean extracts in adult allergy patients. In addition, based on both in vivo and in vitro methods, the allergenicity of wild type and GM soybean extracts was identical.
Soybeans/*immunology ; Skin Tests ; Protein Structure, Tertiary ; *Plants, Genetically Modified ; Middle Aged ; Immunoglobulin E/blood/chemistry ; Immunoblotting ; Humans ; Food Hypersensitivity/etiology/*immunology ; Food/*adverse effects ; Enzyme-Linked Immunosorbent Assay ; Electrophoresis, Gel, Two-Dimensional ; *Crops, Agricultural ; Allergens/*immunology ; Adult ; Adolescent

Skin Prick Test (SPT's) are performed to identify the causes of allergy. However, low diagnostic accuracy is a limitation to SPT, for which many possible causes have been suggested. The protein composition and allergenicity of crude allergen extracts from foods and commercial allergen extracts for SPT were analyzed. Clinical significances of SPT using crude allergen extracts from foods were compared with those using commercial allergen extracts. A total of 292 atopic dermatitis patients were involved in this study. Crude allergen extracts were prepared from milk, egg white, egg yolk, and soybean. The protein composition of food allergen extracts and commercial allergen extracts of milk, whole egg, white, egg yolk, and soybean were compared by SDS-PAGE. The allergenicity was tested by the immunoblotting method using immune sera. SPTs were performed using crude and commercial allergen. Double-blind placebo- controlled food challenge (DBPCFC) was performed to verify the SPT results and to compare the clinical significance of crude and commercial allergen extracts. Protein composition differed markedly between crude and commercial allergen extracts. By immunoblotting, crude and commercial allergen extracts showed different allergenicity. The SPT results using crude and commercial allergen extracts showed significant differences. The prevalence of milk, egg and soybean allergy was over 35% in atopic dermatitis. The accuracy of SPT using crude allergen extracts from foods was significantly higher than that using commercial allergen extracts. In the case of soybeans, the result of SPT using commercial allergen extract was clinically insignificant for the prediction of soybean allergy. The source of allergen extract was very important for the appropriate SPT in food allergy. The accuracy of SPT might be improved using the appropriate allergen source for food allergy.
Adolescent ; Adult ; Allergens/*immunology ; Child ; Child, Preschool ; Comparative Study ; Dermatitis, Atopic/*immunology ; Double-Blind Method ; Egg Hypersensitivity/*diagnosis ; Female ; Food Hypersensitivity/*diagnosis ; Human ; Male ; Milk Hypersensitivity/*diagnosis ; Placebos ; Skin Tests ; Soybeans/*immunology