M. Morisset

Epidemiology of life‐threatening and lethal anaphylaxis: a review

Severe anaphylaxis is a systemic reaction affecting two or more organs or systems and is due to the release of active mediators from mast cells and basophils. A four‐grade classification routinely places ‘severe’ anaphylaxis in grades 3 and 4 (death could be graded as grade 5). Studies are underway to determine the prevalence of severe and lethal anaphylaxis in different populations and the relative frequencies of food, drug, latex and Hymenoptera anaphylaxis. These studies will also analyse the risk arising from the lack of preventive measures applied in schools (personalized management protocols) and from the insufficient use of self‐injected adrenalin. Allergy‐related conditions may account for 0.2–1% of emergency consultations. Severe anaphylaxis affects 1–3 per 10 000 people, but for the United States and Australia figures are even higher. It is estimated to cause death in 0.65–2% of patients, i.e. 1–3 per million people. An increased prevalence has been revealed by monitoring hospitalized populations by reference to the international classification of disease (ICD) codes. The relative frequency of aetiological factors of allergy (food, drugs, insects and latex) varies in different studies. Food, drug and Hymenoptera allergies are potentially lethal. The risk of food‐mediated anaphylaxis can be assessed from the number of personalized management protocols in French schools: 0.065%. Another means of assessment may be the rate of adrenalin prescriptions. However, an overestimation of the anaphylaxis risk may result from this method (0.95% of Canadian children). Data from the literature leads to several possibilities. First, a definition of severe anaphylaxis should be agreed. Secondly, prospective, multicentre enquiries, using ICD codes, should be implemented. Moreover, the high number of anaphylaxis cases for which the aetiology is not identified, and the variation in aetiology in the published series, indicate that a closer cooperation between emergency specialists and allergists is essential.

Thresholds of clinical reactivity to milk, egg, peanut and sesame in immunoglobulin E‐dependent allergies: evaluation by double‐blind or single‐blind placebo‐controlled oral challenges

Background The prevalence of food anaphylaxis due to masked allergens has increased within the last 10 years. Contamination of manufactured products by food allergens is a key concern for food industries.

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.

Identification of oleosins as major allergens in sesame seed allergic patients.

Background:  The prevalence of sesame allergy is increasing in European countries. Cases of severe allergy lack any evidence of specific immunoglobulin (Ig)Es by prick tests and CAPSystem‐FEIA. The reasons for this negativity are unknown.

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

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.

Food anaphylaxis in schools: evaluation of the management plan and the efficiency of the emergency kit.

Background: Children with severe food allergies can benefit from a personalized care project (PCP) in schools. The usefulness of the PCP and the residual risk of allergic emergencies are poorly appreciated. The objective was to evaluate the efficiency of the management plan and the training in the use of the emergency kit.

Identification of enolases and aldolases as important fish allergens in cod, salmon and tuna: component resolved diagnosis using parvalbumin and the new allergens.

The majority of fish‐allergic patients are sensitized to parvalbumin, known to be the cause of important IgE cross‐reactivity among fish species. Little is known about the importance of fish allergens other than parvalbumin.

Prospective study of mustard allergy: first study with double-blind placebo-controlled food challenge trials (24 cases)

Background: Mustard allergy accounts for 1.1% of food allergies in children. However, double‐blind placebo‐controlled food challenge trials (DB PCFCs) have not yet been proposed.

Peanut Allergy Diagnosis in the Context of Grass Pollen Sensitization for 125 Patients: Roles of Peanut and Cross-Reactive Carbohydrate Determinants Specific IgE

Background: In vitro testing for food allergy may yield clinically irrelevant results due to cross-reactive carbohydrate determinants (CCD) specific immunoglobulin E (sIgE) induced by pollen exposure. The performances of 2 in vitro methods were evaluated for peanut sIgE measurement in patients allergic to grass pollen with or without subsequent allergy to peanuts. The correlation between clinically irrelevant peanut sIgE and the presence of CCD sIgE was investigated. Methods: In vitro measurement of peanut sIgE was performed using the Pharmacia ImmunoCap™ system Radio Immuno Assay (RIA) and the Immulite ® 2000 3gAllergy™ system. Discrepancies between in vitro results and peanut allergy diagnosis were evaluated by measurement of CCD sIgE using bromelain and ascorbic acid oxydase (AAO). Results: The sensitivity was 100% with both systems for the diagnosis of allergy to peanut (58 patients), nevertheless the specificity obtained with Immulite (73%) was better than that obtained using ImmunoCap (46%) in patients who were not allergic to peanuts, but who had a grass pollen allergy (n = 41). In 22 out of 41 patients who presented clinically irrelevant peanut sIgE results using ImmunoCAP, CCD sIgE was detected in 72% of the cases by bromelain and in 86% by AAO. In 11 patients out of 41 who presented irrelevant peanut sIgE results using Immulite, CCD sIgE was detected in 81% of the cases by bromelain and in 100% by AAO. Conclusion: The Immulite 2000 system had better specificity than the ImmunoCap system for accurate diagnosis of peanut allergy in patients allergic to grass pollen. CCD sIgE was identified in most of the false-positive peanut sIgE results.

Probiotics may be unsafe in infants allergic to cow's milk.

Differences in the intestinal microflora of atopic and nonatopic infants have been shown; atopic children have fewer bifidobacteria and lactobacilli (1–3). Beneficial immunoregulatory effects of probiotic flora have been confirmed by preventive and therapeutic studies with probiotics in infants at high risk of atopy and in those presenting with cow’s milk allergy (CMA) and atopic eczema/dermatitis syndrome (AEDS) (3, 4). We report a case supporting the hypothesis that residual milk proteins at risk of reactogenicity may be present in different probiotic brands that are marketed as health supplement products. A 11-month-old infant, with AEDS and CMA was fed an aminoacid formula (Neocate ; SHS International Ltd, Liverpool, UK). He presented with Escherichia coli colitis, so a probiotic (Bacilor ; Lab Lyocentre, Aurillac, France) was prescribed. Within 15 min, he presented with generalized erythema and laryngeal discomfort. A prick-test to Bacilor was positive, as was a prick-test to milk (Table 1). Three other children, aged from 3 to 10 years, with persistent milk allergy were tested to three probiotic brands: Bacilor , Imgalt (Lab Jaldes, Gigean, France) and Ditopy (Lab Ducray, Boulogne, France). The prick-tests were positive to Bacilor and Imgalt (Table 1). Bacilor contains only Lactobacillus casei, of the rhamnosus variety, Imgalt also has L. rhamnosus, L. acidophilus, Bifidobacterium bifidum and B. longum, Ditopy contains L. rhamnosus and L. acidophilus. The manufacturers of these preparations were questioned about the medium used for the growth of these strains: the medium used for Bacilor and Imgalt flora includes lactoserum proteins and casein. No control tests for residual milk proteins are carried out on thesemedicinal products. The culture medium of Ditopy flora is hydrolyzed soy protein. The immediate clinical reaction in the infant, as well as positive-prick tests in these four children, support the hypothesis of residual milk proteins, the level of contamination being clinically relevant in somemilk allergic infants, at risk of anaphylaxis (5). Despite previous encouraging results, therapeutic results of probiotics were not particularly marked in a recent study (6, 7). No information was provided about the culture medium. In the event of marked allergy to milk proteins, ingestion of probiotics containing small amounts of residual milk proteins could explain sustained AEDS.