First evidence of occupational asthma to argan powder in a cosmetic factory.

BACKGROUND: Argan is used worldwide in numerous cosmetic products, as this fruit is supposed to have many beneficial properties on health. New cases of allergy can be expected with the growing use of argan. We investigated all workers (9) employed by a cosmetic factory and exposed to argan powder to identify possible allergies related to exposure to argan powder. METHODS: Patients were investigated in the occupational disease department and, according to their symptoms, underwent pulmonary function testing, methacholine challenge, specific inhalation challenge to argan powder, skin prick tests, and immunoblotting analysis. RESULTS: We report three cases of occupational asthma to argan powder and a probable case of rhinitis. Fifteen argan proteins were recognized by the patients' IgE. Identification of proteins, cross-reactions to nuts, and ELISA inhibition tests suggested that some argan allergens can cross-react in vitro with hazelnut allergens, including 11S globulin and vicilin. CONCLUSION: High-level exposure to argan powder should be considered to be a potential cause of IgE-mediated allergy, and workers handling argan powder should be carefully investigated.

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.

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.

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.

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.

Interest of ImmunoCAP system to recombinant omega-5 gliadin for the diagnosis of exercise-induced wheat allergy.

BACKGROUND: omega-5 gliadin is a major allergen in exercise-induced wheat allergy (EIWA), but it is also implicated in immediate-type reactions to wheat. An ImmunoCAP assay to measure omega-5 gliadin-specific IgE has become available. This study aimed to evaluate this new biological test in wheat allergy diagnosis and to also determine if it was able to discriminate EIWA from other types of wheat allergy. METHODS: Sixty-one patients with wheat allergy were divided into 3 groups as a function of their symptoms (EIWA, immediate-type reactions and atopic dermatitis). These patients underwent skin prick tests with purified omega gliadins and ImmunoCAP to wheat flour, gluten and recombinant omega-5 gliadin. RESULTS: The experimental data showed that 78% of EIWA patients had a positive skin prick test to natural omega-5 gliadin and the same proportion had detectable specific IgE to recombinant omega-5 gliadin, indicating that omega-5 gliadin is the main allergen, but not the only one, in our population. Additionally, we showed that this detection was not EIWA specific since omega-5 gliadin-specific IgE was detected in 30% of other patients who had a wheat allergy. These results lead to a positive predictive value of 37.5% and to a negative predictive value of 91%. CONCLUSIONS: Although not specific to EIWA, the new ImmunoCAP omega-5 gliadin is an important biological test because of its negative predictive value. In case of food-dependent exercise-induced allergy, the absence of omega-5 gliadin-specific IgE will almost completely exclude the implication of wheat.

A murine model of cow's milk protein-induced allergic reaction: use for safety assessment of hidden milk allergens.

BACKGROUND: Masked allergens in processed food products can lead to severe allergic reactions following unintentional ingestion. We sought to develop a murine model for the detection of hidden cow's milk proteins (CMP). This study aimed to induce cow's milk allergy in mice, to characterize the anaphylaxis induced by CMP in this model, and to validate its reliability using three margarines manufactured with (A) or without (B, C) milk, sharing the same production line. MATERIALS AND METHODS: Three-week-old BALB/c mice were sensitized intragastrically with CMP plus cholera toxin and boosted 6 times at weekly intervals. CMP-sensitization status was monitored by skin tests, and measurement of CMP-specific IgE and IgG1 levels. On day 44, the minimal threshold of clinical reactivity to CMP in terms of anaphylaxis was determined by performing a dose response of intraperitoneal CMP challenge. Under the same conditions, anaphylaxis was evaluated in CMP-sensitized mice after challenge with protein extracts of margarines A, B or C. RESULTS: Sensitization to CMP was demonstrated by positive skin tests and increased CMP-specific IgE and IgG1. The minimal clinical reactivity threshold corresponding to 0.1 mg CMP elicited detectable anaphylaxis evidenced by clinical symptoms, a decrease in breathing frequency, and increased plasma histamine upon challenge. Similarly, challenges with margarine A containing CMP demonstrated anaphylaxis, whereas those with B or C did not elicit any detectable allergic reaction. CONCLUSION: This study shows that our murine model of CMP-induced anaphylaxis is useful for investigating the allergenic activity and the assessment of margarines with respect to milk.

Wheat grain allergies: an update on wheat allergens.

Wheat grain is a major staple of our diet. However, proteins derived from wheat grain have been implicated in both respiratory and food allergies, as well as in contact hypersensitivity. Numerous wheat allergens are present in the different fractions of wheat grain: a-amylase/trypsin inhibitor and lipid transfer protein are found in the water/salt soluble fraction, and omega5-gliadins and LMW-glutenins have been detected in the gluten fraction. This review discusses what is currently known about wheat grain proteins and allergens. The type of IgE-binding profiles (allergens or even epitopes) in patients with wheat food allergy as a function of age, symptoms, or genetic variability of wheat cultivars provides interesting and useful data for developing hypoallergenic foods as well as new tools for diagnostic and therapeutic methods.

Conserved stem-loop structures in the HIV-1 RNA region containing the A3 3' splice site and its cis-regulatory element: possible involvement in RNA splicing.

The HIV-1 transcript is alternatively spliced to over 30 different mRNAs. Whether RNA secondary structure can influence HIV-1 RNA alternative splicing has not previously been examined. Here we have determined the secondary structure of the HIV-1/BRU RNA segment, containing the alternative A3, A4a, A4b, A4c and A5 3' splice sites. Site A3, required for tat mRNA production, is contained in the terminal loop of a stem-loop structure (SLS2), which is highly conserved in HIV-1 and related SIVcpz strains. The exon splicing silencer (ESS2) acting on site A3 is located in a long irregular stem-loop structure (SLS3). Two SLS3 domains were protected by nuclear components under splicing condition assays. One contains the A4c branch points and a putative SR protein binding site. The other one is adjacent to ESS2. Unexpectedly, only the 3' A residue of ESS2 was protected. The suboptimal A3 polypyrimidine tract (PPT) is base paired. Using site-directed mutagenesis and transfection of a mini-HIV-1 cDNA into HeLa cells, we found that, in a wild-type PPT context, a mutation of the A3 downstream sequence that reinforced SLS2 stability decreased site A3 utilization. This was not the case with an optimized PPT. Hence, sequence and secondary structure of the PPT may cooperate in limiting site A3 utilization.

[Anaphylactic shock due to recombinant human insulin: follow-up of a desensitization protocol by basophil activation test]. / Choc anaphylactique à l'insuline humaine recombinante: suivi d'un protocole d'accoutumance par tests d'activation des basophiles.

INTRODUCTION: Despite the occurrence of a severe allergic reaction including an anaphylactic shock, a drug may remain essential and impossible to replace. This may be the case of insulin in a diabetic patient. We describe the case of an anaphylactic shock to human insulin in whom a desensitization protocol was successfully achieved. CASE REPORT: A 50-year-old type 2 diabetic man presented one year after initiation of the insulin therapy an anaphylactic shock following the subcutaneous administration of a human insulin containing protamine (Insulatard®). A desensitization protocol to human insulin was performed and allowed to use two human insulin analogues containing no protamine (asparte and glargine), with a two-year event-free follow-up. Positive skin tests with insulin and protamine, and the presence of insulin specific IgE were evidenced of an IgE-mediated mechanism. Desensitization was monitored by skin tests, Maunsell's test, measurement of specific IgE and IgG4, and the basophil activation test. The decrease of basophil sensitivity to insulin is an early marker for tolerance induction. CONCLUSION: The effectiveness of the desensitization to human insulin underlines the importance to define the modalities of such desensitization protocol and of the monitoring of the tolerance induction.

A second exon splicing silencer within human immunodeficiency virus type 1 tat exon 2 represses splicing of Tat mRNA and binds protein hnRNP H.

An equilibrium between spliced and unspliced primary transcripts is essential for retrovirus multiplication. This equilibrium is maintained by the presence of inefficient splice sites. The A3 3'-splice site of human immunodeficiency virus type I (HIV-1) is required for Tat mRNA production. The infrequent utilization of this splice site has been attributed to the presence of a suboptimal polypyrimidine tract and an exonic splicing silencer (ESS2) in tat exon 2 approximately 60 nucleotides downstream of 3'-splice site A3. Here, using site-directed mutagenesis followed by analysis of splicing in vitro and in HeLa cells, we show that the 5' extremity of tat exon 2 contains a second exonic splicing silencer (ESS2p), which acts to repress splice site A3. The inhibitory property of this exonic silencer was active when inserted downstream of another HIV-1 3'-splice site (A2). Protein hnRNP H binds to this inhibitory element, and two U-to-C substitutions within the ESS2p element cause a decreased hnRNP H affinity with a concomitant increase in splicing efficiency at 3'-splice site A3. This suggests that hnRNP H is directly involved in splicing inhibition. We propose that hnRNP H binds to the HIV-1 ESS2p element and competes with U2AF(35) for binding to the exon sequence flanking 3'-splice site A3. This binding results in the inhibition of splicing at 3'-splice site A3.