Guidelines for the diagnosis and management of food allergy in the United States: summary of the NIAID-sponsored expert panel report

Exposure to food allergens through inflamed skin promotes intestinal food allergy through the thymic stromal lymphopoietin-basophil axis

BACKGROUND

Exposure to food allergens through a disrupted skin barrier has been recognized as a potential factor in the increasing prevalence of food allergy.

OBJECTIVE

We sought to test the immunologic mechanisms by which epicutaneous sensitization to food allergens predisposes to intestinal food allergy.

METHODS

Mice were epicutaneously sensitized with ovalbumin or peanut on an atopic dermatitis-like skin lesion, followed by intragastric antigen challenge. Antigen-specific serum IgE levels and T(H)2 cytokine responses were measured by ELISA. Expression of type 2 cytokines and mast cell proteases in the intestine were measured by using real-time PCR. Accumulation of basophils in the skin and mast cells in the intestine was examined by using flow cytometry. In vivo basophil depletion was achieved by using diphtheria toxin treatment of Baso-DTR mice. For cell-transfer studies, the basophil population was expanded in vivo by means of hydrodynamic tail vein injection of thymic stromal lymphopoietin (TSLP) cDNA plasmid.

RESULTS

Sensitization to food allergens through an atopic dermatitis-like skin lesion is associated with an expansion of TSLP-elicited basophils in the skin that promote antigen-specific T(H)2 cytokine responses, increased antigen-specific serum IgE levels, and accumulation of mast cells in the intestine, promoting the development of intestinal food allergy. Critically, disruption of TSLP responses or depletion of basophils reduced the susceptibility to intestinal food allergy, whereas transfer of TSLP-elicited basophils into intact skin promoted disease.

CONCLUSION

Epicutaneous sensitization on a disrupted skin barrier is associated with accumulation of TSLP-elicited basophils, which are necessary and sufficient to promote antigen-induced intestinal food allergy.

Limited role of allergy testing in patients with eosinophilic gastrointestinal disorders

BACKGROUND AND AIM

Allergies have been implicated in the pathogenesis of eosinophilic gastrointestinal disorders, although it remains unknown what type of allergen is closely associated with their development. The aim of this study is to investigate the possible involvement of food and/or aeroallergen factors in eosinophilic gastrointestinal disorders.

METHODS

Eighteen patients with eosinophilic esophagitis (EoE), 23 with eosinophilic gastroenteritis (EGE), and 28 healthy volunteers were enrolled. The levels of total serum immunoglobulin E (IgE) and 33 different allergen-specific IgE antibodies, including those for six foods used in a standard EoE elimination diet, were determined in each subject. Serum antigen-specific IgE levels were measured using a chemiluminescence enzyme immunoassay with a multiple antigen simultaneous test 33 (MAST33). The expression patterns of specific antigens were compared among the groups.

RESULTS

The mean level of total IgE antibodies was significantly higher in patients with EGE (553.6 ± 115.3 IU/mL) than the healthy volunteers (230.6 ± 87.1 IU/mL). Two thirds of all subjects had sensitivity to at least one inhaled antigen. In positive cases, allergies against multiple antigens were more frequently seen in the EoE and EGE patients. Japanese cedar and dust mite aeroallergens were more prevalent than food antigens.

CONCLUSIONS

Consistent with higher levels of serum total IgE antibodies, patients with EoE and EGE were frequently sensitized to several different allergens. Reactions to aeroallergens were more prevalent in these groups, although no particular antigen causing EoE and/or EGE was detected by measuring serum antigen-specific IgE antibodies.

Is It Possible to Predict the Iron Status from an Infant's Diet History?

PURPOSE

Iron deficiency remains a very common nutritional problem despite the improvement in nutrition and increased understanding of methods for its prevention. Thus, we try to create a new method for screening iron nutrition through infant nutrition history.

METHODS

Among the children who visited Inha University Hospital from March 2006 to July 2012, 181 children with iron deficiency anemia (IDA) and 52 children without IDA ranging from 6 to 36 months of age were reviewed in this study. We used the age when they began to wean food, the type of sort weaning foods, the time required for successful weaning, iron content in weaning foods, and the duration of breastfeeding for scoring infant nutrition history based on a questionnaire.

RESULTS

The mean score of the IDA group was 7.8±2.6 points, which was significantly higher than that of the control group (5.6±2.1) (p=0.000). If we set up the cutoff value at 6 points, this screening has 86.8% sensitivity and 36% specificity. In addition, as the IDA score increased, there was a falling trend of hemoglobin.

CONCLUSION

The IDA score does not have high specificity or high sensitivity. However, this study conveys that those patients who record a high score have low hemoglobin. Therefore, we suggest this score system for screening more IDA patients via nonpainful techniques.

Characterization of food allergies in patients with atopic dermatitis

We examined the characteristics of food allergy prevalence and suggested the basis of dietary guidelines for patients with food allergies and atopic dermatitis. A total of 2,417 patients were enrolled in this study. Each subject underwent a skin prick test as well as serum immunoglobulin E (IgE) measurement. A double-blind, placebo-controlled food challenge was conducted using milk, eggs, wheat, and soybeans, and an oral food challenge was performed using beef, pork, and chicken. Food allergy prevalence was found among 50.7% in patients with atopic dermatitis. Among patients with food allergies (n = 1,225), the prevalence of non-IgE-mediated food allergies, IgE-mediated food allergies, and mixed allergies was discovered in 94.9%, 2.2%, and 2.9% of the patients, respectively. Food allergy prevalence, according to food item, was as follows: eggs = 21.6%, milk = 20.9%, wheat = 11.8%, soybeans = 11.7%, chicken = 11.7%, pork = 8.9% and beef = 9.2%. The total number of reactions to different food items in each patient was also variable at 45.1%, 30.6%, 15.3%, 5.8%, 2.2%, and 1.0% for 1 to 6 reactions, respectively. The most commonly seen combination in patients with two food allergies was eggs and milk. The clinical severity of the reactions observed in the challenge test, in the order of most to least severe, were wheat, beef, soybeans, milk, pork, eggs, and chicken. The minimum and maximum onset times of food allergy reactions were 0.2-24 hrs for wheat, 0.5-48 hrs for beef, 1.0-24 hrs for soybeans, 0.7-24 hrs for milk, 3.0-24 hrs for pork, 0.01-72 hrs for eggs, and 3.0-72 hrs for chicken. In our study, we examined the characteristics of seven popular foods. It will be necessary, however, to study a broader range of foods for the establishment of a dietary guideline. Our results suggest that it may be helpful to identify food allergies in order to improve symptoms in patients with atopic dermatitis.

Nutirtion labelling of food and allergen in food

The new regulation introduced mandatory nutrition labelling and ordering food manufacturers provide information on energy and six nutrients: fat, saturated fatty acids, carbohydrates, sugars, protein and salt - in that order, and per 100 g or 100 ml. This information should be included in the nutritional table in one visual field (usually on the back cover), moreover, can also be expressed on per serving. It is important to realize that this regulation requires manufacturers indicate the nutritional value in one field of vision, usually on the "back cover" designation in the principal field (e.g. "on the front cover") remains voluntary. Food allergy is a significant public health issue worldwide. Regulatory risk management strategies for allergic consumers have focused on providing information about the presence of food allergens through label declarations. A number of countries and regulatory bodies have recognized the importance of providing this information by enacting laws, regulations or standards for food allergen labelling of ‘‘priority allergens. Increasing volume of the international food trade suggests that there would be value in supporting sensitive consumers by harmonizing (to the extent possible) these regulatory frameworks. As a first step toward this goal, an inventory of allergen labelling regulations was assembled and analyzed to identify commonalities, differences, and future needs.