Three peanut-allergic/sensitized phenotypes with gender difference.

BACKGROUND: Peanut-allergic reactions are heterogeneous ranging from mild symptoms to anaphylaxis. OBJECTIVE: Identify peanut-allergic/sensitized phenotypes to personalize patient management. METHODS: A combined factor and cluster analysis was used to study the phenotypes of 696 patients diagnosed with peanut sensitization and enrolled in the MIRABEL survey. The method was first applied to the 247 patients with an oral food challenge (OFC). It was then applied to the 449 patients without OFC to confirm the findings in an independent population. RESULTS: Three independent clusters emerged from the OFC subgroup. Cluster 1, 'Severe peanut allergy with little allergic multi-morbidity' (123 subjects), had the highest proportion of patients with positive OFC (92%), a medium level of peanut protein inducing a positive OFC (235 mg), lower percentage of allergic multi-morbidity (2% asthma plus atopic dermatitis (A + AD), no cases of A + AD + multiple food allergies (MFA)). Cluster 2, 'Severe peanut allergy with frequent allergic multi-morbidity' (62 subjects), had a high proportion of patients with positive OFC (85%) with the lowest level of peanut protein inducing a positive OFC (112 mg), 89% allergic subjects, 100% with allergic multi-morbidity (A + AD) and 84% with A + AD + MFA. Cluster 3, 'Mild peanut-allergic/sensitized phenotype' (62 subjects), had the lowest mean age, the lowest proportion of patients with positive OFC (53%) with a high level of peanut protein inducing a positive OFC (770 mg), a low percentage of allergic multi-morbidity (48% A + AD + MFA). The two severe peanut-allergic phenotypes were more frequent in girls. The same clusters were found in the subgroup of patients without OFC. CONCLUSION & CLINICAL RELEVANCE: Besides the classic markers associated with lower threshold doses of OFC (such as SPT and rAra h 2), allergic multi-morbidity and female gender should also be taken into account to better adapt the progressive dosage of provocation tests.

Severe anaphylaxis to Propofol: first case of evidence of sensitization to soy oil.

The growing worldwide prevalence of food allergies is drawing attention to the risk of allergenic proteins found in intravenous medicinal products, particularly anaesthetics. Propofol induced anaphylaxis has been described. The presence of soybean oil and egg lecithins in the lipid emulsion highlights their suspected responsibility in certain cases. We report a case of anaphylaxis to propofol in an adult patient without food allergy to soy, but with a latent sensitization to soy. An IgE-dependent allergy to propofol was established by a basophil activation test. Here, we document for the first time the existence of specific IgEs to a 65kDa protein, found in soybean oil and soy flour. In the absence of data on the reactogenic threshold for allergenic food proteins injected intravenously, a risk appears to be established and leads us to recommend a systematic detection for proteins in the refined soybean oil used in the pharmaceutical industry for intravenous products.

Peanut-allergic patients in the MIRABEL survey: characteristics, allergists' dietary advice and lessons from real life.

BACKGROUND: The MIRABEL survey is an observational study on peanut allergy in France, Belgium and Luxemburg. The objectives are to provide data on a large population, to analyse the consumer behaviour, to study the presence of peanut traces in pre-packed foods with/without precautionary allergen labelling (PAL), and to combine these data to quantify allergic risk and produce a cost/benefit analysis. This paper reports a real-life observatory of 785 patients (< 16y: 86%): medical characteristics, eliciting doses (ED) in real life and in oral food challenges (OFC), factors associated with severe reactions, allergist dietary advice and patients' anxiety regarding their allergy. METHODS: Age and symptoms at diagnosis, route of exposure, comorbidities, allergy tests, ED (OFC/real life; mg peanut protein), dietary advice about PAL, and anxiety score were recorded. RESULTS: Median age was 3 years; 85% were declared allergic. Severe/potentially severe reactions were reported in 30% of the allergic patients: serious systemic reaction (15%), laryngeal angioedema (8%), shock (4%) and acute asthma (3%); 66% had atopic dermatitis, 58% asthma. Median ara h 2 sIgE level was 11.5 kUA/L. Of the 278 OFCs, 225 were positive (median ED: 67.3 mg). Real-life ED was < 100 mg in 44.3%. Severe reactions were significantly more frequent in teenagers and adults (P = 0.004), asthmatic patients (P = 0.033), and patients who reacted to inhalation (P < 0.001). No significant association was found for OFC ED or ara h 2 sIgE. Factors associated with strict avoidance advice including PAL were OFC ED < 100 mg (P < 0.001), but not severe reaction history (P = 0.051) or asthma (P = 0.34). Anxiety was significantly associated with strict avoidance (P < 0.001). CONCLUSION AND CLINICAL RELEVANCE: Severe/potentially severe reactions, allergic comorbidities, and low EDs in real life are frequent in peanut-allergic patients. Asthma, teenage/adulthood and reaction to inhalation are associated with severe symptoms. PAL and criteria guiding dietary advice need to be improved.

Cross-reactivity of a new food ingredient, dun pea, with legumes, and risk of anaphylaxis in legume allergic children.

BACKGROUND: Legume allergy is the fifth food allergy in Europe. The dun pea (Pisum sativum sativum var. arvense), a pea belonging to the same subspecies as green pea, has been recently introduced as an ingredient in the human food industry. The aims of this study were to evaluate the cross-reactivity between dun pea and other legumes and to search for modification of allergenicity induced by food technologies. METHODS: A series of 36 patients with legume and/or peanut allergy was studied. They underwent skin tests to peanut and a panel of legumes including dun pea. Specific IgE to dun pea and cross-reactivity to peanut allergens, particularly to Ara h 1, were evaluated by ELISA. Proteins and allergens of different pea extracts were studied by SDS-PAGE and immunoblots. RESULTS: In France and Belgium, 7.7% of severe food anaphylaxis cases were due to legumes. Patients with isolated legume allergy had positive prick tests to dun pea, whereas patients with isolated peanut allergy had negative prick tests. Cross-reactivity between sIgE to peanut and dun pea was observed, and more frequently than expected (96%) peanut-allergic patients with legume sensitization or allergy had sIgE to Ara h 1. Analysis of dun pea allergens suggested that protein epitopes were presented differently in dun pea seeds, isolate and flour. CONCLUSIONS: This study identifies, for the first time, a risk of dun pea allergy in legume-allergic patients and in a subset of peanut-allergic patients.

Mirabel: an integrated project for risk and cost/benefit analysis of peanut allergy.

Food allergy is a major public health issue. However, no regulatory measures exist when allergens are present at trace levels and the different risk components are poorly described. Thus, knowledge on exposure components such as the allergens present in foods and the consumption behaviour of allergic consumers and models to estimate the related risk need to be enriched. Mirabel proposes for the first time studying each risk component using an integrated approach in order to improve the quality of life of the allergic population. Field surveys were conducted in order to fill in the current gaps in unintentional allergen traces in food, allergic consumers' food behaviour, threshold doses of allergic reaction, allergy symptoms and severity. The aim is also to propose methodological and operational tools to quantify allergic risk, to test management scenarios and to produce a cost/benefit analysis. Medical data on the peanut allergies of 785 patients were collected in the MIRABEL survey and 443 patients answered the food consumption questionnaire. The population surveyed was mostly paediatric - 86% were children under 16 years of age, with a high percentage of males (60%). This project will generate tangible results on peanut allergen exposure and risk which could be used in future risk assessment work and particularly to provide science-based guidance to set up concentration limits for peanut traces on packages.

Anaphylaxis to diclofenac: nine cases reported to the Allergy Vigilance Network in France.

Nine cases of diclofenac hypersensitivity recorded by the Allergy Vigilance Network in France from 2002 to 2012 were studied. Data from history, symptoms, skin tests, basophil activation tests, and oral challenge (OC) were recorded. Grade 3 severe anaphylactic reactions occurred in seven cases of nine. IgE-dependent anaphylaxis was confirmed in six cases: positive intradermal tests (n = 4), a syndromic reaction during skin tests (n = 1), and one case with grade 1 reaction and negative skin tests had an anaphylactic shock to the OC. A nonimmune reaction was suspected in one case. An IgE-dependent mechanism may be the predominant cause of adverse reactions to diclofenac. Allergy skin tests must be carried out sequentially at the recommended concentrations. BATs may be helpful because they can support the diagnosis of anaphylaxis. Given the risks of a direct challenge to diclofenac, OC to aspirin should be performed first to exclude a nonimmunologic hypersensitivity to NSAIDs. Tests for specific IgEs to most frequently used NSAIDs such as diclofenac and ibuprofen are urgently needed.

Iatrogenic angioedema associated with ACEi, sitagliptin, and deficiency of 3 enzymes catabolizing bradykinin.

New concepts of idiopathic and iatrogenic angioedema underline the role of bradykinin, and the importance of catabolizing enzymes. A case is described of Angiotensin converting enzyme inhibitor (ACEi) and sitagliptin induced angioedema, where AO attacks decreased after the withdrawal of lisinopril but resolved only after the withdrawal of sitagliptin, an inhibitor of dipeptylpeptidase IV. ACE, aminopeptidase P and carboxypeptidase N were decreased down to 17%, 42%, 64% of median references values, and remained low one year after the interruption of these drugs: 56%, 28% and 50%, respectively. The combined deficiency of APP and CPN might enhance the inhibiting effect of the DPP IV inhibitor. The fact that this triple deficiency remained latent before and after the treatment indicates that searching for latent enzyme deficiencies should be carried out when there is intention to treat with a combination of drugs interfering with the bradykinin metabolism.

Severe drug-induced anaphylaxis: analysis of 333 cases recorded by the Allergy Vigilance Network from 2002 to 2010.

BACKGROUND: A few series of well-documented cases of severe drug-induced anaphylaxis (SDA) are available. METHODS: Cases collected by the Allergy Vigilance Network from 2002 to 2010 were analyzed for clinical signs, causative drugs, and efficacy of a stepwise approach to diagnosis, using skin tests, laboratory tests, and oral challenges. RESULTS: Three hundred and thirty-three cases concerned 300 adults (90.1%) and 33 children (9.9%): 206 females (61.9%) and 127 males (38.1%). Mean age was 42.7 ± 18 years. Anaphylactic shock (76.6%), severe systemic reactions (10.5%), acute laryngeal edema (9%), severe bronchospasm (2.1%), and six fatal cases (1.8%) were recorded. There were 270 cases (81.1%) of ambulatory anaphylaxis. Sixty-three cases (18.9%) occurred during anesthesia. Hospitalization was required in 94.8% of cases. 23.7% of patients were admitted to an intensive care unit. Epinephrine was used in 57.9% of cases. Eighty-four drugs were incriminated: antibiotics (49.6%), muscle relaxants, latex and anesthetics (15%), nonsteroidal anti-inflammatory drugs (10.2%), acetaminophen (3.9%), iodinated or magnetic resonance imaging contrast media (4.2%), immunotherapy and vaccines (3.9%), and other drugs (13%). Among antibiotics, amoxicillin (97 cases), other penicillins (four cases), cephalosporins (41 cases), quinolones (15 cases), and pristinamycin (seven cases) were the most common. The diagnosis of drug hypersensitivity was obtained by skin tests in 72.9%, laboratory tests only in 2.4% of cases, and oral challenges (OCs) only in 3.9% of cases. CONCLUSIONS: Three hundred and thirty-three case reports provided data on drugs involved in severe anaphylaxis. The efficacy of skin tests and poor use of laboratory tests are underlined. Further progress may depend on OCs.

How much does transgenesis affect wheat allergenicity?: Assessment in two GM lines over-expressing endogenous genes.

Wheat kernel albumins/globulins (A/G) and gluten proteins are responsible for baker's asthma and food allergy in atopic subjects. Although no commercial genetically modified wheats are currently being grown, they are under study and the allergenicity of GM products is a major concern. In order to establish the expected and unexpected effects of genetic transformation on allergenicity and also to carry out a safety assessment of genetic transformation, two GM wheat lines (bread and pasta wheat) transformed with endogenous genes were compared to their untransformed counterparts (wt), first by an allergenomic approach, and second, using ELISA with sera from patients suffering from food allergy to wheat and baker's asthma. The 2D immunoblots performed on sera from patients suffering from food allergy and baker's asthma on the A/G fraction of the four lines (two GM and two wt) revealed comparable IgE-binding profiles. A total of 109 IgE-binding spots were analyzed by mass spectrometry, and most of the proteins identified had already been described as allergens or potential allergens. Only two IgE-binding proteins were specific to one GM line. The concentration of specific IgE against the A/G fractions of GM wheat lines and their wt genotypes differed for some sera. BIOLOGICAL SIGNIFICANCE: The originality of our paper is to relate the transformation of wheat lines with their potential allergenicity using patient sera, such focus has never been done before in wheat and should be of interest to the researches working in this field. Another interesting point of this paper is the study of two types of allergies (respiratory and food) on two wheat genotypes and their GM which reveals that some allergens already known in respiratory allergy could be involved in children suffering from wheat food allergy. In this paper we used a classical 2D proteomic analysis and the protein identifications were performed by mass spectrometry after spot picking and in gel trypsin hydrolysis. Concerning the LC-MS/MS analyses classical software and parameters were used as described in Material and methods. We worked on wheat which is actually not fully sequenced that was a difficulty; we therefore searched against two databanks (proteins and ESTs) in order to compare the results. Moreover all proteins reported in our paper were identified with at least three unique peptides. The identified proteins were checked for their potential allergenicity. In order to have a best interpretation of protein identified in terms of potential allergens, BLAST alignments were performed by using an allergen databank (SDAP). This allows the determination of the cross-reactivity of these identified proteins with known allergens of other species and also the prediction of a potential allergenicity.

Allergy to deamidated gluten in patients tolerant to wheat: specific epitopes linked to deamidation.

BACKGROUND: Gluten proteins can be modified by deamidation to enhance their solubility and technological applications. However, severe allergic reactions have been reported after the consumption of food products containing deamidated gluten (DG) in subjects tolerant to wheat. This work aimed to characterize allergen profiles for these patients in comparison with those of patients allergic to wheat and to identify IgE-binding epitopes. METHODS: Sera were obtained from 15 patients allergic to DG and from nine patients allergic to wheat proteins (WP). IgE-binding profiles were characterized both in ELISA and in a humanized rat basophilic leukaemia (RBL) cell model. Epitopes were mapped on γ- and ω2-gliadin sequences by Pepscan, and effect of glutamine/glutamic acid substitutions was studied. RESULTS: Compared to the heterogeneous pattern of allergens detected by IgE from patients allergic to WP, responses of patients allergic to DG were homogeneous. In ELISA, all the sera displayed IgE binding to deamidated γ- and ω2-gliadins and deamidated total gliadins, frequently with high concentrations. These modified proteins induced RBL degranulation with most of the sera from DG-allergic patients. A consensus epitope was found on native γ- and ω2-gliadins (QPQQPFPQ); it was repeated several times in their sequences. The substitution of two or three glutamines of this epitope into glutamic acid at positions Q3 or Q4 and Q8 (QPEEPFPE) increased its recognition the best. CONCLUSION: Allergy to DG is a separate entity from wheat allergy. It can be evidenced by strong IgE binding to deamidated gliadins or peptides of the type QPEEPFPE.

Anaphylaxis to pork kidney is related to IgE antibodies specific for galactose-alpha-1,3-galactose.

BACKGROUND: Carbohydrate-specific IgE antibodies present on nonprimate mammalian proteins were incriminated recently in delayed meat anaphylaxis. The aim of this study was to explore whether anaphylaxis to mammalian kidney is also associated with galactose-α-1,3-galactose (αGal)-specific IgE. METHODS: Fourteen patients with anaphylaxis to pork or beef kidney underwent prick tests to meat and kidney. Some patients also underwent skin tests to Erbitux(®) (cetuximab). IgE antibodies to αGal, swine urine proteins, beef and pork meat, serum albumin proteins, cat, and rFel d 1 were measured by ImmunoCAP(®). The αGal levels were estimated in meats and kidney by ELISA inhibition assay. Cross-reactivity between αGal and pork kidney was studied with the ImmunoCAP(®) inhibition assay. RESULTS: Among the 14 patients, 12 presented with anaphylactic shock. Reactions occurred within 2 h from exposure in 67% of patients. Associated risk factors were observed in 10 cases, and alcohol was the main cofactor. Three patients underwent an oral challenge to pork kidney, and anaphylaxis occurred after ingestion of small quantities (1-2 g). Prick tests to kidney were positive in 54% of patients. All tested patients showed positive skin tests to Erbitux(®). All patients tested positive for IgE to αGal, with levels ranging from 0.4 to 294 kU/l. IgE binding to αGal was inhibited by raw pork kidney extract (mean, 77%; range, 55-87%), which showed a high amount of αGal determinants. CONCLUSIONS: Pork or beef kidney anaphylaxis is related to αGal IgE. Its peculiar severity could be due to an elevated content of αGal epitopes in kidney.

Prevalence of sensitisation to oilseed rape and maize pollens in France: a multi-center study carried out by the Allergo-Vigilance Network.

BACKGROUND: Oilseed rape and maize crops represent a large part of agriculture fields in European countries. OBJECTIVE: To establish the actual prevalence of sensitization to oilseed rape and maize pollen, and to determine if this is correlated to the amount of exposure as well as to the patient's history of atopy or asymptomatic atopy. METHODS: The study was conducted by 69 allergists belonging to the Allergo-Vigilance Network, in collaboration with the French Agency for Safety of food, and compiles the results of skin prick-tests using oilseed rape and maize pollens and seeds, as well as common aeroallergens. The patients were classified into 3 groups: nonatopic, asymptomatic atopy, and actual atopic diseases. RESULTS: Among the 5372 subjects studied (2515 children, 2857 adults), 62.3% had an atopic disease, 10.2% had an asymptomatic atopy, and 27.5% were non-atopic. The level of sensitization was higher in the subjects with atopic disease, as compared to those with asymptomatic atopy: oilseed rape pollen: 11.8% vs 8%, maize pollen, 26% vs 19%, oilseed rape seeds, 7.7% vs 6.9%, corn seeds: 8.3% vs 4.8% (p < 0.001). The rate of sensitization was significantly increased in those living in high crop density regions. The association of an atopic disease with a high rate of exposure yielded a higher rate of sensitization of 13.8% and 21.3% for rapeseed pollen, and 22.9% and 30.7% for maize pollen in both children and adults, respectively. CONCLUSIONS: The incidence of sensitisation to rapeseed and maize pollen is positively correlated to the level of exposure. This prevalence is higher in patients with actual atopic disease as compared to those with asymptomatic atopy. The frequency of sensitization confirms the allergenicity of these plants destined for food supply and demonstrates the importance of monitoring for respiratory allergies to these pollens, not only in workers exposed to these types of crops, but also in atopic patients living in regions that contain a high density of rapeseed and maize fields. Cross-reactivities between pollens and seeds could potentially elicit cross-reacting food allergies.

Specific IgG levels to wheat in wheat tolerant professional cyclists may depend on a homeostatic immune response to a high consumption of wheat.

BACKGROUND: Implication of IgG antibodies to wheat has been alleged in gastrointestinal symptoms. Precise data on the specific IgG levels in healthy subjects are lacking. Our objectives are to compare levels of IgG antibodies to wheat protein fractions in healthy non atopic or atopic subjects, and in healthy professional cyclist subjects, taking into account the quantitative consumption of wheat. METHODS: 24 control subjects and 26 professional cyclist subjects were selected. ELISA was performed to 2 wheat commercial solutions and to 3 wheat protein fractions. RESULTS: No significant difference was observed between non atopic and atopic subjects. For wheat flour extract, physiological norm determined was 3.27 mg/L sIgG concentration +/- 1.25 CI (95% confidence intervals) for the professional cyclists (vs 1.56 mg/L +/- 0.91 CI in control subjects, p-value: 0.040). For gluten solution, physiological norm was 1.42 mg/L +/- 0.60 CI (vs 0.50 +/- 0.24 CI in control subjects, p-value: 0.010). CONCLUSION: Atopic and non atopic healthy adults have a similar level of sIgG to wheat. Increased levels of sIgG are observed correlatively with an excessive consumption, and could contribute to homeostasis of tolerance. Studies searching for a pathogenic role of sIgG in certain pathologies should take into account the quantitative consumption.

Immunoglobulin-E-binding epitopes of wheat allergens in patients with food allergy to wheat and in mice experimentally sensitized to wheat proteins.

BACKGROUND: At present, B cell epitopes involved in food allergy to wheat are known only for a few allergens and a few categories of patients. OBJECTIVE: To characterize the epitopes of different wheat kernel allergens: α-, γ, ω2, and ω5-gliadin, a low-molecular-weight (LMW) glutenin subunit, and a lipid transfer protein (LTP1) recognized by allergic patients and by sensitized mice and provide further understanding of the role of structure in determining allergic response. METHODS: Sera were obtained from 39 patients suffering from food allergy to wheat. BALB/c mice were sensitized to gliadins or LTP1 by intraperitoneal immunizations. Continuous epitopes bound by IgE were delineated by the Pepscan technique. The response to reduced, alkylated LTP1 was compared with that of the native form to evaluate the importance of protein folding on IgE reactivity. RESULTS: Few continuous epitopes of LTP1 reacted with IgE from allergic patients and mice, but one of them was common to several patients and sensitized mice. The unfolded protein was not recognized by either patient or mouse IgE, emphasizing the major role of LTP1 folding and discontinuous epitopes in IgE-binding. In contrast, many continuous epitopes were detected by patient and mouse IgE especially for an ω5-gliadin, which is an unstructured protein, and to a lesser extent, for the other gliadins and a LMW-glutenin subunit. CONCLUSION AND CLINICAL RELEVANCE: The conformation of LTP1 appeared to have a strong impact on the type of IgE-binding epitopes elicited by this protein in both man and mouse. The responses in mice sensitized to gliadins or LTP1 were sufficiently comparable with the human response in terms of IgE-binding epitopes to provide support for the use of the mouse model in further investigations.

Assessment of allergenicity of diploid and hexaploid wheat genotypes: identification of allergens in the albumin/globulin fraction.

Wheat is an important part of the daily diet of millions of people. However, this staple food is also responsible for food allergies. Ancient cultivars of wheat are gaining interest today but nothing is known about their allergenicity. Many wheat proteins have been reported as causative food allergens, including some prolamin-type gluten proteins, and salt soluble proteins of the albumin/globulin (A/G) type. The objective of this work is to obtain information about the allergenicity of the salt soluble A/G fraction of an ancient diploid cultivar compared with a standard hexaploid bread wheat cultivar using 20 sera from patients with wheat allergy. Differences in the IgE reactivity of sera towards the two genotypes were quantified by ELISA. Qualitative differences in IgE-binding proteins were searched after 1D or 2D electrophoresis. For most of the sera, the concentration in A/G specific IgE was higher for the hexaploid T. aestivum (cv Récital) than for the diploid T. monococcum (cv Engrain). The analysis of 2D spots revealed by immunoblotting leads to the identification by mass spectrometry of 39 IgE-binding proteins, some of them unknown until now as wheat allergens. Numerous allergens were identified, differences observed between Engrain and Récital will be discussed.

A novel immunoassay using recombinant allergens simplifies peanut allergy diagnosis.

BACKGROUND: Double-blind placebo-controlled food challenge (DBPCFC) is currently considered the gold standard for peanut allergy diagnosis. However, this procedure that requires the hospitalization of patients, mostly children, in specialized centers for oral exposure to allergens may cause severe reactions requiring emergency measures. Thus, a simpler and safer diagnosis procedure is needed. The aim of this study was to evaluate the diagnostic performance of a new set of in vitro blood tests for peanut allergy. METHODS: The levels of IgE directed towards peanut extract and recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7, and Ara h 8 were measured in 3 groups of patients enrolled at 2 independent centers: patients with proven peanut allergy (n=166); pollen-sensitized subjects without peanut allergy (n=61), and control subjects without allergic disease (n=10). RESULTS: Seventy-nine percent of the pollen-sensitized patients showed IgE binding to peanut, despite their tolerance to peanut. In contrast, combining the results of specific IgE to peanut extract and to recombinant Ara h 2 and Ara h 6 yielded a peanut allergy diagnosis with a 98% sensitivity and an 85% specificity at a positivity threshold of 0.10 kU/l. Use of a threshold of 0.23 kU/l for recombinant Ara h 2 increased specificity (96%) at the cost of sensitivity (93%). CONCLUSION: A simple blood test can be used to diagnose peanut allergy with a high level of precision. However, DBPCFC will remain useful for the few cases where immunological and clinical observations yield conflicting results.