Food allergy overview in children. Clin Rev Allergy Immunol. 2008;34:217-230. [PMID: 17990125 DOI: 10.1007/s12016-007-8034-1]

Characterisation of allergen-specific responses of IL-10-producing regulatory B cells (Br1) in Cow Milk Allergy

CD19+CD5+ regulatory B cells regulate immune responses by producing IL-10. IL-10-producing regulatory B cell (Br1) responses by allergen stimulation were investigated in human food allergy. Six milk allergy patients and eight milk-tolerant subjects were selected according to DBPCFC. PBMCs were stimulated by casein in vitro and stained for intracellular IL-10 and apoptosis. In response to allergen stimulation, Br1 decreased from 26.2+/-18.3 to 15.5+/-8.9% (p=0.031, n=6) in the milk allergy group and increased from 15.4+/-9.0 to 23.7+/-11.2% (p=0.023, n=8) in the milk-tolerant group. Apoptotic non-IL-10-producing regulatory B cells increased from 21.8+/-9.3 to 38.0+/-16.1% (p=0.031, n=6) in the milk allergy group and unchanged from 28.8+/-13.8 to 28.0+/-15.0% (p=0.844, n=8) in the milk-tolerant group. Br1 may be involved in the immune tolerance of food allergies by producing IL-10 and simultaneously undergoing apoptosis in humans. The exact roles for Br1 in immune tolerance needs to be further investigated.

[Allergen specific IgE measurement with Polycheck Allergy: comparison of three multiple allergen simultaneous tests]

BACKGROUND

The in vivo skin prick test (SPT) or in vitro detection of allergen specific IgE in serum is commonly used for the diagnosis of allergic disease. In this study, we evaluated the usefulness of a new multiple allergen simultaneous test (MAST) immunoblot assay, Polycheck Allergy (Biocheck GmbH, Germany).

METHODS

A total of 100 patients with clinical findings of allergic diseases were tested by SPT and three different MAST assays: Polycheck Allergy (Biocheck GmbH, Germany), MAST CLA allergy system (Hitachi Chemical Diagnostics, USA) and Allergy Screen (R-biopharm, Germany). The results of MAST assays were compared with those of SPT.

RESULTS

Concordance rates of MAST assays with SPT were 79-100% for Polycheck Allergy, 88.9-100% for MAST CLA and 72.7-98.3% for Allergy Screen. In ROC curve analysis, significant differences were observed in four of 25 allergens analysed: Alternaria, Birch, Hazelnut and D. farinae. For Alternaria and Birch, Polycheck Allergy (P<0.001) and Allergy Screen (P=0.0075) showed significantly larger AUC (area under the curve) than MAST CLA. For Hazelnut, Polycheck Allergy (P=0.0021), and for D. farinae, MAST CLA (P=0.015) showed significantly larger AUCs than the other two tests. The ROC analysis for overall 16 food allergens showed better results in Polycheck Allergy (P<0.001), and that for overall 21 inhalants did not show significant differences among three MAST assays (P>0.05).

CONCLUSIONS

Since Polycheck Allergy showed similar or superior result to the others, it can be used for the detection of allergen specific IgE antibodies.

Allergic status of schoolchildren with food allergy to eggs, milk or wheat in infancy

Although children allergic to eggs, milk or wheat in infancy tend to become tolerant by school age, the allergic status of these children at school age has not been well evaluated. To investigate the allergic status of schoolchildren who avoided eggs, milk or wheat because of an immediate-type allergic reaction at <1-yr-old (food avoiders in infancy), we conducted a large-scale questionnaire-based survey of schoolchildren. A questionnaire on allergic diseases was distributed to the parents of 14,669 schoolchildren aged 7 to 15 yr in 30 schools in Kyoto, Japan. Of these, 13,215 responded (response rate, 90.1%). The rate of 7-yr-old children who were food avoiders in infancy was 5.4%. This rate decreased as the current age of the children increased, down to 3% in 15-yr-old children, indicating that food allergy in infancy tended to become more prevalent over the past 8 yr. Although more than 80% became tolerant to these foods by school age, the prevalence of bronchial asthma, atopic dermatitis, allergic rhinitis and allergic conjunctivitis were significantly higher in this group. Moreover, avoidance of other foods (buckwheat, shellfish, fruits and others) at school age was seen at much higher frequencies than in non-food avoiders in infancy (adjusted odds ratio, 7.7; confidence interval, 5.9-10.2). This risk did not differ significantly between those who did and did not develop tolerance to eggs, milk and wheat by 3 yr old. In conclusion, food avoiders in infancy appear to have a higher risk of not only other allergic diseases ('atopic march') but also allergy to other foods ('food allergen march') at school age, indicating the need for continuous attention to food allergy.

Useful tools for the management of atopic dermatitis

Eczema, frequently named atopic dermatitis, is the most frequent chronic skin disease of early childhood, with a high prevalence in industrialized countries and a relapsing-remitting course that is responsible for a serious burden on affected children and their families. Even though most facets of this disease are nowadays well known and numerous guidelines are available, some confusion still exists regarding certain aspects. First, several names have been proposed for the disorder. We suggest that the name and definition adopted by the World Allergy Organization should be used: 'eczema,' divided into 'atopic,' when an allergic sensitization can be demonstrated, and 'non-atopic,' in the absence of sensitization. Several diagnostic criteria have been proposed, but at present the two most reliable are the 2003 revision by the American Academy of Dermatology of the Hanifin-Rajka criteria, and those by Williams revised in 2005. To date, 20 different clinical scores have been published to assess the severity; however, only the EASI (Eczema Area and Severity Index), the SCORAD (SCORing Atopic Dermatitis), and the POEM (Patient-Oriented Eczema Measure) seem to have been adequately validated and are recommended for use in clinical practice and trials. The diagnostic tests to identify associated allergy or sensitization include skin-prick tests, determination of the specific IgE in serum using different assays, and atopy patch tests; in the case of suspected food allergy, a food challenge may be necessary to define the diagnosis. To evaluate quality of life, tools exist that allow both the child's and family's impairment to be considered. In addition, several algorithms exist to help decide therapy on a step-wise basis. However, such guidelines and algorithms represent only an aid to the physician and not an obligatory directive, since the ultimate judgment regarding any therapy must be performed by the physician and tailored to individual needs. A clear and validated definition of eczema control would permit better monitoring of the disease, similar to the situation with asthma in recent years. Finally, the review examines the role of special textiles in diminishing Staphylococcus aureus skin superinfection, of house dust-mite avoidance measures, and of educational programs for patients and their families, which may all help improve eczema.

Wheat allergy

PURPOSE OF REVIEW

This review describes the diverse clinical manifestations of IgE-mediated allergy to ingested wheat and summarizes recent advances in characterization of clinically significant allergens and diagnostic workup.

RECENT FINDINGS

Recent population-based studies have shown the prevalence of wheat allergy and sensitization more precisely than past studies among small populations and in hospital settings. Intensive research has demonstrated the diverse profile of both water/salt-soluble and insoluble allergens involved in clinical types of wheat allergies determined depending on the patient age, the sensitization route, and the protein state during the exposure. Consequently, some new allergens, including nonspecific lipid transfer protein (Tri a 14), have been identified. For diagnosis, the role of water/salt-insoluble gliadins, particularly omega-5 gliadin, a major allergen of wheat-dependent, exercise-induced anaphylaxis, was assessed as compared with the results of oral challenges. The mechanisms of eliciting anaphylactic symptoms by exercise in wheat-dependent, exercise-induced anaphylaxis were speculated upon; one is the allergenicity strengthened by activated tissue transglutaminase and another is the increased absorption of allergens through the gastrointestinal tract.

SUMMARY

Findings of the recent studies show potential for more precise diagnosis in each clinical type of wheat allergies.

Gastrointestinal manifestations of food allergy

Gastrointestinal food allergies are not rare in infants and children. Symptoms include vomiting, reflux, abdominal pains, diarrhea and constipation. Clinical diagnosis requires the exclusion of nonimmunologic diseases that have similar gastrointestinal symptoms. In food allergy, the immune reactions involved can be immunoglobulin (Ig)E-mediated, cell-mediated or both. Symptoms in other target organs are common in cases of IgE-mediated disorders, but not in the cell-mediated disorders in which symptoms are usually localized to the gut. Diagnosis utilizes detailed medical history, clinical evaluation, skin testing, food-specific IgE antibodies, responses to elimination diet and oral food challenges. Endoscopic biopsies are essential in cell-mediated disorders and allergic eosinophilic gastropathies. Treatment includes avoidance of the offending food by a restriction diet in children and the use of hydrolyzed or amino acid-based formulas in young infants. Topical and/or systemic corticosteroids can also be used in eosinophilic esophagitis. Current research is aimed at improving the diagnostic tools and therapeutic options available to patients.

Therapeutic effects of a fermented soy product on peanut hypersensitivity is associated with modulation of T-helper type 1 and T-helper type 2 responses

BACKGROUND

ImmuBalance is a koji fungus (Aspergillus oryzae) and lactic acid fermented soybean product. This unique production process is believed to create a food supplement that helps to induce or maintain normal immune response.

OBJECTIVE

To assess possible therapeutic effects of ImmuBalance on peanut (PN) hypersensitivity using a murine model of peanut allergy (PNA).

METHODS

PN allergic C3H/HeJ mice were fed standard mouse chow containing 0.5% or 1.0% ImmuBalance (ImmuBalance 2X), radiation-inactivated 1.0% ImmuBalance (I-ImmuBalance 2X), or regular diet chow (sham) for 4 weeks, beginning 10 weeks after the initial PN sensitization, and then challenged with PN. Anaphylactic symptom scores, plasma histamine, serum PN specific-IgE levels and splenocyte cytokine profiles were determined.

RESULTS

While 100% of sham-treated PNA mice developed anaphylactic reactions with a median score of 3.3 following PN challenge, only 50% of ImmuBalance, 30% of ImmuBalance 2X and 40% of I-ImmuBalance 2X-treated mice developed allergic reactions with median scores of 1.0, 0.4 and 0.5 respectively, which were significantly less than that in the sham-treated mice (P<0.05). Plasma histamine and PN specific-IgE levels were also significantly less in all treated mice than in sham-treated mice (P<0.05). Furthermore, IL-4, IL-5 and IL-13 production by PN-stimulated splenocytes in vitro from ImmuBalance fed mice were markedly reduced compared with sham-treated mice, whereas IFN-gamma production was moderately increased. TGF-beta and TNF-alpha production were similar.

CONCLUSIONS

ImmuBalance protects against PN-induced anaphylaxis when administered as a food supplement in this model. Protection was associated with down-regulation of Th2 responses. This supplement may provide a potential novel therapy for PNA.

The diagnosis of food allergy in children

PURPOSE OF REVIEW

To give an update about the optimal diagnostic work-up for children with suspected food allergy.

RECENT FINDINGS

Food allergy has become a very severe health problem not only for many children and parents, but also for the entire medical and paramedical community. The financial and social costs related to these conditions are increasing, but, contemporarily, basic and clinical research are deeply involved in the search of possible solutions to facilitate the management of these patients.

SUMMARY

Food allergy is defined as an abnormal immunological reaction to food proteins, which causes an adverse clinical reaction. Over 90% of food allergies in childhood are caused by eight foods: cow's milk, hen's egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The evaluation of a child with suspected food allergy includes detailed medical history, physical examination, screening tests and response to elimination diet and to oral food challenge. None of the screening tests, alone or in combination, can definitely diagnose or exclude it. The main principle of food allergy management is avoidance of the offending antigen. An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child's nutritional status and growth.

Potential, pitfalls, and prospects of food allergy diagnostics with recombinant allergens or synthetic sequential epitopes

This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both. However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. IgE-binding tests merely indicate sensitization, whereas the final proof of clinical relevance still relies on family/case history, physical examinations, and provocation tests. Novel technologies promise superior diagnostics. Microarray technology permits simultaneous measurement of multiple IgE reactivities regarding specificity, abundance, reactivity, or interaction. Improved functional tests might enable reliable estimation of the clinical relevance of IgE sensitizations at justifiable expenses.