Allergy to pine nuts in a bird fancier

A patient is described with the bird-egg syndrome who experienced an anaphylactic reaction after eating some of her parrot's food (pine nuts: Pinus pinea ). Specific IgE against this nut and another pine nut ( P cembra ) was demonstrated by RAST. Cross-reactivity between these botanically related seeds was shown by RAST inhibition. Besides avian antigens, bird food antigens should be taken into consideration when symptoms of allergy occur on exposure to birds.     

Food allergen avoidance – the patient's viewpoint

The profile of potentially fatal food allergies has altered in recent years. The vigilance required for allergen avoidance when shopping or eating out depends on information which is often hidden or misleading. Families with allergic children suffer social exclusion and stress, made worse by a serious shortage of specialist patient care. Those who die are usually teenagers and young adults who suffer from severe allergic asthma or anaphylaxis after eating away from the home. A recognised manufacturing standard would endorse businesses seeking to remove the risk of allergen cross-contamination, whilst the integration of allergy into training for caterers and environmental health professionals would influence and inform foodservice businesses.     

Interpretation of tests for nut allergy in one thousand patients, in relation to allergy or tolerance

BACKGROUND: Peanut and tree nut allergy are common, increasing in prevalence and the commonest food cause of anaphylaxis. In the USA, 7.8% are sensitized (have nut-specific IgE), but not all those sensitized are allergic. Lack of data makes interpretation of tests for nut-specific IgE difficult. OBJECTIVES: This is the first study to investigate the clinical significance of test results for peanut and tree nut allergy in allergic or tolerant patients. Findings are related to the severity of the allergy. METHOD: An observational study of 1000 children and adults allergic to at least one nut. History of reactions (severity graded) or tolerance to up to five nuts was obtained and skin prick test (SPT)/serum-specific IgE (CAP) performed. RESULTS: There was no correlation between SPT size and graded severity of worst reaction for all nuts combined or for peanut, hazelnut, almond and walnut. For CAP, there was no correlation for all nuts. Where patients tolerated a nut, 43% had positive SPT of 3-7 mm and 3% > or = 8 mm. For CAP, 35% were positive (0.35-14.99 kU/L) and 5% > or = 15 kU/L. In SPT range 3-7 mm, 54% were allergic and 46% were tolerant. There was poor concordance between SPT and CAP (66%). Of patients with a clear nut-allergic history, only 0.5% had negative SPT, but 22% negative CAP. CONCLUSIONS: Magnitude of SPT or CAP does not predict clinical severity, with no difference between minor urticaria and anaphylaxis. SPT is more reliable than CAP in confirming allergy. Forty-six per cent of those tolerant to a nut have positive tests > or = 3 mm (sensitized but not allergic). One cannot predict clinical reactivity from results in a wide 'grey area' of SPT 3-7 mm; 22% of negative CAPs are falsely reassuring and 40% of positive CAPs are misleading. This emphasizes the importance of the history. Understanding this is essential for accurate diagnosis. Patients with SPT > or = 8 mm and CAP > or = 15 kU/L were rarely tolerant so these levels are almost always (in > or = 95%) diagnostic.     

Investigation of the stability of apple allergen extracts

To determine optimal conditions for allergen preservation, we investigated the influence of different stabilizing additives and of storage temperature on the allergen activity of apple protein preparations, obtained by extraction in phosphate buffer or by precipitation in diacetone alcohol and resolubilization in phosphate buffer in the presence or absence of enzyme inhibitors. For this purpose, the extracts were stored for 6 months either in frozen state at −20° C or in lyophilized state at −20° C, 4° C, or room temperature and were characterized by SDS-PAGE, immunoblot, ELISA inhibition, and prick test. The highest stability revealed the extracts that were prepared by precipitation in the organic solvent in the presence of enzyme inhibitors, lyophilized, and stored at −20° C. For storage of extract solutions at 4° C, PBS/glycerol and cysteine/sodium citrate/glycerol were found to be the most effective stabilizing additives.     

Boletus edulis: a digestion-resistant allergen may be relevant for food allergy

BACKGROUND: Fungal components can cause allergic symptoms either through inhalation, ingestion or contact. Whereas respiratory allergy is thought to be induced by spores, allergic reactions following ingestion are attributed to other parts of the mushroom. Reports of food-related allergic reactions due to the edible mushroom Boletus edulis have occasionally been reported. OBJECTIVE: The aim of the study was to investigate whether separate allergens may be detected in alimentary allergy to Boletus edulis. METHODS: Sera of two subjects, one with recurrent anaphylaxis and the other with a predominantly oral allergy syndrome following ingestion of Boletus edulis, have been analysed by a time-course digestion assay using simulated gastric fluid and by SDS-PAGE immunoblotting. Sera of four Boletus edulis skin prick test-negative subjects and all without clinical symptoms to ingested Boletus edulis served as controls. RESULTS: In lyophilized Boletus edulis extract, at least four water-soluble proteins were detected, the most reactive at 55 kDa and at 80 kDa. Following the time-course digestion assay, IgE binding was found to a 75-kDa protein, but only if the sera of the subject with recurrent anaphylaxis was used. CONCLUSION: The data indicate that Boletus edulis can cause an IgE-mediated food allergy due to a digestion-stabile protein at 75 kDa. No IgE immune response to this protein was detected in the serum of a subject with respiratory allergy and oral allergy syndrome to Boletus edulis nor in control sera.     

Serum basal tryptase may be a good marker for predicting the risk of anaphylaxis in children with food allergy

A relationship between serum basal tryptase (sBT) levels, anaphylactic reactions, and clonal mast cell diseases was shown recently in adults with venom allergy, but the relationship between sBT levels and IgE‐mediated food allergy and anaphylaxis is not known. In this study, children with food allergy (FA; n = 167) were analyzed in two groups according to the presence (FA+/A+; n = 79) or absence of anaphylaxis (FA+/A?; n = 88) and were compared with a control group (n = 113). Median sBT values in FA+/A+, FA+/A?, and control groups were 4.0 ng/ml (2.8–5.8), 3.6 (2.3–4.5), and 3.3 (2.4–4.4), respectively (P = 0.022). sBT measurements higher than the cutoff values of 5.7 and 14.5 were associated with 50% and 90% predicted probabilities, respectively, of moderate to severe anaphylaxis. Children with tree nuts/peanut allergies had significantly higher levels of sBT than children with milk and egg allergy (P = 0.022). Results suggest that sBT levels may predict moderate to severe anaphylaxis in children with food allergy, which may follow a particular pattern according to the food allergy phenotype.     

IL-12 and IL-23 in health and disease

Food allergy affects up to 6% of children and 3–4% of adults in Westernized countries, and is the most common cause of outpatient anaphylaxis in most studies. The mainstay of treatment is strict avoidance of the offending allergens and education regarding the use of emergency medication in cases of accidental ingestions or exposures. While these approaches are generally effective, there are no definitive treatments that cure or provide long-term remission from food allergy. However, with recent advances in characterizing food allergens and understanding humoral and cellular immune responses in food allergy, several therapeutic strategies are being investigated. Potential treatments include allergen-specific immunotherapy as well as allergen-nonspecific approaches to downregulate the overall allergic response in food-allergic individuals.     

Precautionary allergen labelling: perspectives from key stakeholder groups

Precautionary allergen labelling (PAL) was introduced by the food industry to help manage and communicate the possibility of reaction from the unintended presence of allergens in foods. However, in its current form, PAL is counterproductive for consumers with food allergies. This review aims to summarize the perspectives of all the key stakeholders (including clinicians, patients, food industry and regulators), with the aim of defining common health protection and risk minimization goals. The lack of agreed reference doses has resulted in inconsistent application of PAL by the food industry and in levels of contamination that prompt withdrawal action by enforcement officers. So there is a poor relationship between the presence or absence of PAL and actual reaction risk. This has led to a loss of trust in PAL, reducing the ability of consumers with food allergies to make informed choices. The result has been reduced avoidance, reduced quality of life and increased risk‐taking by consumers who often ignore PAL. All contributing stakeholders agree that PAL must reflect actual risk. PAL should be transparent and consistent with rules underpinning decision‐making process being communicated clearly to all stakeholders. The use of PAL should indicate the possible, unintended presence of an allergen in a consumed portion of a food product at or above any proposed action level. This will require combined work by all stakeholders to ensure everyone understands the approach and its limitations. Consumers with food allergy then need to be educated to undertake individualized risk assessments in relation to any PAL present.     

Oral allergy syndrome (OAS) in pollinosis patients after eating pistachio nuts

We describe two uncommon cases of oral allergy syndrome (OAS) after eating pistachio nuts (p.n.) in subjects (a 54-year-old man and a 3-year-old girl) with exclusive skin prick test (SPT) positivity to Parietaria (P.) and pistachio nut (p.n.) allergens. Serologic P.- and p.n.-specific IgE determinations were also carried out. A double-blind, placebo-controlled food challenge (DBPCFC) was performed, for ethical reasons, only in the adult patient, but we observed a positive intraoral reaction only after slight scratching of the oral mucosa. Since this patient had put three whole p.n. with their shells into his mouth, breaking them with his teeth, before the onset of symptoms, we suggest that slight injury of the oral mucosa may enhance the local response. Preliminary results with SDS-PAGE and immunoblotting demonstrate the occurrence of a slight degree of cross-reactivity between these allergens, but further studies are necessary to obtain a definite conclusion.     

Surimi and native codfish contain a common allergen identified as a 63-kDa protein

We have compared the allergenicity of codfish and surimi (prepared from codfish) by skin testing, specific IgE-RIA, and leukocyte histamine release (LHR) in six fish-allergic patients. Prick tests were positive for codfish and, to a lesser extent, surimi. The percentages of labeled anti-IgE bound to surimi-Sepharose were 1.55 ± 0.19% and 3-6% with control and patient sera, respectively. Inhibition of the surimi protein-Sepharose IgE-RIA was greatest (80%) at protein concentrations of 13.4 and 408.5 μg/ml for codfish and surimi extract, respectively. The allergenic protein was isolated by gel filtration and subjected to SDS-PAGE. The eluate from codfish contained several proteins ranging from 13 to 63 kDa, while the eluate from surimi contained a single 63-kDa protein. It was concluded that surimi contained a single allergenic protein.
Mata E, Favier C, Moneret-Vautrin DA, Nicolas JP, Han Ching L, Guéant JL. Surimi and native codfish contain a common allergen identified as a 63-kDa protein.     

Food allergen avoidance in primary prevention of food allergy

Approximately 5–10% of children suffer from allergy to one or more foods. Primary prevention through a hypoallergenic diet may reduce the prevalence of food allergy and associated co-morbidity, such as eczema and urticaria. Breastfeeding has many advantages and should be recommended for all children. Those with a history of atopy in the immediate family are at a higher risk and maternal diet during lactation, avoiding highly allergenic foods, may enhance the benefit. Cow's milk should be strictly avoided, and supplements, if required, should be with a hypoallergenic formula. Delayed introduction of egg, nuts, wheat and fish has also been suggested. Dietary restriction may have nutritional consequences for the mother and child and supervision by a dietician is essential. Maternal diet during pregnancy is not advisable as the benefit is minimal and there may be adverse effects on the foetal nutrition. In high risk infants, a combined approach, where breastfeeding with maternal avoidance of highly allergenic foods, supplemented by extensively hydrolysed formula during the first 6 months of life, in addition to the delayed introduction of solid foods, has been shown to reduce the development of food allergy in infants.     

Allergenicity and cross-reactivity of pine pollen

Background Pine pollen has long been considered a non-allergenic pollen. The large size of the grain and its low levels of proteins are the main reasons invoked to explain this low allergenicity. The aim of this study was to describe the main allergenic bands of Pinus radiata ( PR ) and its cross-reactivity with other pine species, other conifers and grass pollen.
Methods Sixty-five pine-pollen-allergic patients (51% also sensitized to grass pollen) were studied. Skin prick tests (SPT) to a battery of allergens including PR, Pinus pinea, Pinus sylvestris, Pinus nigra and Cupressus sempervirens pollens and specific IgE determination to PR and Pinus strobus were performed. IgE-immunoblotting to a PR extract and other pine pollens was also carried out. UniCAP inhibition and immunoblotting inhibition studies were performed to assess the cross-reactivity between different pollens.
Results The SPTs were positive with all the pine pollen extracts tested in 69% of the patients. Specific IgE was positive to PR or P. strobus in 77% of the patients, and to Lolium perenne in 51%. Nine different allergenic bands were detected. The two main allergens were a 42 kDa band recognized by 85% of the patients and a band of approximately 6–8 kDa recognized by 40%. A high degree of cross-reactivity was observed between different pine pollen species, but not between pines and C. sempervirens pollen. A partial cross-reactivity could be seen between pine and grass pollens only in patients also sensitized to L. perenne .
Conclusions Pine pollen should be considered as a potential allergenic pollen especially where this pollen is abundant. The detection of a high number of patients that were monosensitized to pine pollen suggests the possibility of treating these patients with specific immunotherapy.     

Optimization of apple allergen preparation for in vivo and in vitro diagnostics

The aim of our investigation was to obtain a well-characterized active apple extract suitable for both in vivo and in vitro diagnostics by a technically simple method. For this purpose, apple extracts were prepared by homogenization in potassium phosphate buffer or by precipitation in organic solvents and resolubilization in potassium phosphate buffer in the presence or in the absence of enzyme inhibitors. These extracts were comparatively investigated by means of SDS-PAGE, two-dimensional electrophoresis, immunoblotting, RAST inhibition, and prick test. The in vitro investigations indicated that extracts prepared by precipitation in organic solvents (diacetone alcohol) at -20°C have a higher allergen activity than those prepared by extraction in aqueous solutions. From the in vivo tests (prick test), it was concluded that application of inhibitors of cytoplasmic enzymes (phenol oxidases, peroxidases, proteases) already during extraction is an essential precondition for active prick test solutions. Correspondingly, the extract obtained by solvent precipitation in the presence of enzyme inhibitors appeared to be most suitable for clinical application.     

Allergen immunotherapy with heat-killed Listeria monocytogenes alleviates peanut and food-induced anaphylaxis in dogs

BACKGROUND: Heat-killed Listeria monocytogenes (HKL) potently stimulates interferon (IFN)-gamma production in CD4 T-lymphocytes, and when used as adjuvant for immunotherapy, reduces immunoglobulin (Ig)E production and reverses established allergen-induced airway hyperreactivity (AHR) in a murine model of asthma. We asked if such treatment could decrease established peanut-induced anaphylaxis or cow's milk-induced food allergy in highly food-allergic dogs. METHODS: We therefore studied four 4-year-old atopic colony dogs extremely allergic to peanut (Group I), as well as five 7-year-old dogs very allergic to wheat, milk and other foods (Group II). All dogs experienced marked allergic symptoms, including vomiting and diarrhea on oral challenge with the relevant foods. The dogs were then vaccinated once subcutaneously with peanut or milk and wheat with HKL emulsified in incomplete Freund's adjuvant. RESULTS: Following vaccination of the allergic dogs with HKL and allergen, oral challenges with peanut (Group I) or milk (Group II) elicited only minor or no symptoms. In addition, skin test end-point titrations showed marked reductions for >10 weeks after treatment, and levels of Ara h 1-specific IgE in serum of peanut sensitive dogs, as demonstrated by immunoblotting, were greatly reduced by treatment with HKL plus peanut allergen. CONCLUSIONS: Thus, HKL plus allergen treatment markedly improved established food allergic responses in dogs, suggesting that such an immunotherapy strategy in humans might greatly improve individuals with food allergy and anaphylaxis.