Food reactions during avoidance: Focus on peanut.

OBJECTIVE: Peanut allergy has historically been difficult to manage, with most cases persisting into adulthood. Novel therapies for peanut allergy treatment are on the horizon, yet allergists must maintain a robust understanding of the risks and benefits of the current standard of therapy, avoidance diet. DATA SOURCES: A comprehensive literature search using PubMed of reviews and clinical articles was performed. STUDY SELECTIONS: Articles discussing peanut or other food-related allergic reactions, accidental exposures or anaphylaxis pertinent to avoidance diet or comparative to oral immunotherapy trials were selected. RESULTS: Peanut remains a leading allergen associated with accidental ingestions responsible for food-related reactions, both mild and severe. Fatal reactions, however, are rare and measures such as anaphylaxis plans can significantly decrease the risk of accidental anaphylaxis. Patients may over estimate situations thought to increase risk for reactions to peanut, such as inhalation or contact through skin. In oral immunotherapy trials, the rate of anaphylaxis secondary to treatment was significantly higher than avoidance practices. CONCLUSION: Clinicians should continue to discuss avoidance as a viable option for long-term peanut allergy management and empower patients to differentiate relevant situations in which accidental reactions might occur.

Managing Nut Allergy: A Remaining Clinical Challenge.

Peanut and tree nut allergies have become a public health problem over the last 2 decades. The diagnostic procedure relies on a suggestive history, as well as on evidence of sensitization (skin prick testing and/or specific IgE blood testing), followed in selected cases by a food challenge. Standard IgE tests may be positive to more than 1 nut, due to cross-reactivity (allergens common to several nuts) or cosensitivity (frequently associated positive test results without cross-reactivity). Thus, many patients with a peanut or a tree nut allergy avoid all nuts, relying on positive test results without clinical evidence of reactivity. In addition, coexisting pollen sensitivity may add to diagnostic uncertainty due to potential cross-reactivity between pollens and nuts. In this article, we discuss challenges in diagnosis and clinical management of peanut and tree nut allergy related to cross-reactivity and cosensitization, as well as the avoidance of nuts tested positive to reduce the risk of reactions by cross-contamination. Studies to provide more accurate characterization of genuine clinically relevant cross-reactivity or cosensitivity to multiple nuts are needed.

Food allergy in breastfeeding babies. Hidden allergens in human milk.

BACKGORUND: Food allergy is a rare disorder among breastfeeding babies. OBJECTIVE: Our aim was to identify responsible allergens in human milk. METHODS: We studied babies developing allergic symptoms at the time they were breastfeeding. Skin prick tests (SPT) were performed with breast milk and food allergens. Specific IgE was assessed and IgE Immunoblotting experiments with breast milk were carried out to identify food allergens. Clinical evolution was evaluated after a maternal free diet. RESULTS: Five babies had confirmed breast milk allergy. Peanut, white egg and/or cow's milk were demonstrated as the hidden responsible allergens. No baby returned to develop symptoms once mother started a free diet. Three of these babies showed tolerance to other food allergens identified in human milk. CONCLUSION: A maternal free diet should be recommended only if food allergy is confirmed in breastfed babies.

The Complexities of Early Peanut Introduction for the Practicing Allergist.

Recommendations for the timing of introducing major food allergens, such as peanut, into the diet of at-risk infants have undergone major changes in the past decade. The most substantial modification has been a shift toward advice that delaying beyond 4 to 6 months does not prevent and might actually increase the risk of food allergy. The Learning Early About Peanut (LEAP) study published last year provided strong evidence that early peanut introduction with regular ingestion has a potentially dramatic benefit. Although there is little current doubt of the effectiveness of early peanut introduction, many unanswered questions remain. Previous guidelines defined infants at risk as those with a first-degree relative with allergic disease, whereas the LEAP study defined high risk as severe eczema or egg allergy. The LEAP study chose to screen infants but did not have a comparison group randomized without screening. In the following case-based discussion, we explore the complexities of LEAP implementation for the practicing allergist. These include nonuniformity in the literature for defining at-risk infants, difficulties in assessing eczema severity objectively, variable adherence to current guidelines, proposed peanut screening methods contrasting with existing food allergy guidelines to not routinely screen before ingestion, unclear interpretation of positive test results if screened, risks of screening extending to foods not studied in the LEAP study, and uncertainties about the optimal dose and duration of peanut once introduced.

Survey of peanut levels in selected Irish food products bearing peanut allergen advisory labels.

Peanut allergy affects up to 2% of consumers and is responsible for the majority of fatalities caused by food-induced anaphylaxis. Peanut-containing products must be clearly labelled. Manufacturers are not legally required to label peanut if its inclusion resulted from unintentional cross contact with foods manufactured in the same facility. However, the use of allergen advisory statements alerting consumers of the potential presence of peanut allergen has increased in recent years. In previous studies, the vast majority of foods with precautionary allergen statements did not contain detectable levels of peanut, but no data are available on Irish food products. Thirty-eight food products bearing peanut/nut allergen-related statements were purchased from multiple locations in the Republic of Ireland and analysed for the presence of peanut. Peanut was detected in at least one lot in 5.3% (2 of 38) of the products tested. The doses of peanut detected ranged from 0.14 mg to 0.52 mg per suggested serving size (0.035-0.13 mg peanut protein). No detectable levels of peanut were found in the products that indicated peanut/nuts as a minor ingredient. Quantitative risk assessment, based on the known distribution of individual threshold doses for peanut, indicates that only a very small percentage of the peanut-allergic population would be likely to experience an allergic reaction to those products while the majority of products with advisory labels appear safe for the peanut-allergic population. Food manufacturers should be encouraged to analyse products manufactured in shared facilities and even on shared equipment with peanuts for peanut residues to determine whether sufficient risk exists to warrant the use of advisory labelling. Although it appears that the majority of food products bearing advisory nut statements are in fact free of peanut contamination, advice to peanut allergy sufferers to avoid said foods should continue in Ireland and therefore in the wider European Union.

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.

[Allergy to cashew nuts and peanuts]. / Allergie voor cashewnoten en pinda's.

Anaphylaxis due to the ingestion of peanuts is a serious, common condition, known to both the general public and physicians. Recently, an increasing number ofpatients with an anaphylactic reaction after eating small amounts of cashew nuts have been reported. In three children, a boy aged 7 and two girls aged 9 and 10 years, respectively, with heterogeneous case histories involving allergic upper airway and conjunctival symptoms and constitutional eczema, allergy for cashew nuts was diagnosed in the first two and allergy for peanuts in the third. They were given dietary advice and an adrenaline auto-injector for emergencies. In most cases, a detailed food history, together with the demonstration of IgE against cashew nuts by means of serology or skin prick tests, are sufficient to establish the diagnosis. If the clinical relevance of a sensitisation to cashew nuts is unknown, a food provocation test may be necessary. The treatment consists of dietary intervention, and an adrenaline auto-injector is prescribed for a serious anaphylactic reaction. So far, three major allergens from the cashew nut (Anacardium occidentale) have been identified and purified.

Hypoallergenicity: a principle for the treatment of food allergy.

Food allergy is a common disease with the treatment of choice being complete avoidance of the incriminated food. In cow's milk allergy a hypoallergenic milk substitute is necessary during infancy and childhood. Hypoallergenic formulas are produced through enzymatic hydrolysis of different sources such as bovine casein or whey followed by further processing such as heat treatment and/or ultrafiltration. According to the degree of protein hydrolysis the resulting products have been classified into 'extensively' or 'partially' hydrolyzed. Reduction of allergenicity should be assessed in vitro and in vivo. Hypoallergenic formulas might also be based on amino acid mixtures. These elementary diets can be considered as nonallergenic. Several novel therapies are currently being explored in food allergy. One of the most promising approaches is the immunotherapy with mutated proteins. For this approach, alteration of the IgEbinding sites through single amino acid substitution is performed resulting in reduced to complete loss of IgE binding. For the major peanut allergens such mutations were introduced into the cDNA sequences and successfully expressed as hypoallergenic recombinant proteins. In peanut-sensitized mice, the use of these modified proteins co-administered with adjuvant such as heat-killed Escherichia coli showed promising results for future therapeutic approaches.