Andrea Vereda

Peanut allergy: Clinical and immunologic differences among patients from 3 different geographic regions

BACKGROUND Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens. OBJECTIVE We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach. METHODS Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed. RESULTS American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age. CONCLUSIONS Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.

Differences among Pollen-Allergic Patients with and without Plant Food Allergy

Background: A considerable number of pollen-allergic patients develops allergy to plant foods, which has been attributed to cross-reactivity between food and pollen allergens. The aim of this study was to analyze the differences among pollen-allergic patients with and without plant food allergy. Methods: Eight hundred and six patients were recruited from 8 different hospitals. Each clinical research group included 100 patients (50 plant food-allergic patients and 50 pollen-allergic patients). Diagnosis of pollen allergy was based on typical case history of pollen allergy and positive skin prick tests. Diagnosis of plant-food allergy was based on clear history of plant-food allergy, skin prick tests and/or plant-food challenge tests. A panel of 28 purified allergens from pollens and/or plant foods was used to quantify specific IgE (ADVIA-Centaur® platform). Results: Six hundred and sixty eight patients (83%) of the 806 evaluated had pollen allergy: 396 patients with pollen allergy alone and 272 patients with associated food and pollen allergies. A comparison of both groups showed a statistically significant increase in the food and pollen allergy subgroup in frequency of: (1) asthma (47 vs. 59%; p < 0.001); (2) positive skin test results to several pollens: Plantago,Platanus,Artemisia,Betula,Parietaria and Salsola (p < 0.001); (3) sensitization to purified allergens: Pru p 3, profilin, Pla a 1 – Pla a 2, Sal k 1, PR-10 proteins and Len c 1. Conclusion: Results showed relevant and significant differences between both groups of pollen-allergic patients depending on whether or not they suffered from plant-derived food allergy.

Isolation and identification of an 11S globulin as a new major allergen in mustard seeds

BACKGROUND Although mustard seed allergy has been largely reported during the preceding 20 years, currently only 2 allergens, Sin a 1 and Bra j 1, have been identified. OBJECTIVE To improve the characterization of the allergenic profile of yellow mustard seeds by reporting the identification and biochemical characterization of an 11S globulin as a new major allergen. METHODS Mustard seed proteins were separated using size exclusion and ion-exchange chromatographic columns, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 2-dimensional polyacrylamide gel electrophoresis. Separation of different polypeptide chains was achieved by reverse-phase high-performance liquid chromatography. Mass spectrometry after tryptic digestion and Edman degradation were used to determine amino acid sequences of peptides. IgE binding assays were performed with 13 serum samples from mustard allergic patients in immunoblotting and enzyme-linked immunosorbent inhibition assays. RESULTS A protein of 51 kDa was recognized as a major allergen by patients allergic to mustard and called Sin a 2. The allergen was dissociated in 2 chains of 36 and 23 kDa, which also bound IgE. N-terminal end and internal amino acid sequences allowed identification of the new allergen as a seed storage 11S globulin belonging to the Cupin super family. Purified allergen was able to inhibit the IgE binding of sera from allergic patients to mustard seeds extract in up to 55% of the responses. CONCLUSIONS An 11S globulin storage protein has been isolated and identified as a novel major allergen of mustard seeds.

nsLTP and profilin are allergens in mustard seeds: cloning, sequencing and recombinant production of Sin a 3 and Sin a 4.

Background Patients allergic to mustard are frequently sensitized to peach.

Identification of IgE sequential epitopes of lentil (Len c 1) by means of peptide microarray immunoassay.

BACKGROUND Lentils are often responsible for allergic reactions to legumes in Mediterranean children. Although the primary sequence of the major allergen Len c 1 is known, the location of the IgE-binding epitopes remains undefined. OBJECTIVE We sought to identify IgE-binding epitopes of Len c 1 and relate epitope binding to clinical characteristics. METHODS One hundred thirty-five peptides corresponding to the primary sequence of Len c 1 were probed with sera from 33 patients with lentil allergy and 15 nonatopic control subjects by means of microarray immunoassay. Lentil-specific IgE levels, skin prick test responses, and clinical reactions to lentil were determined. Epitopes were defined as overlapping signal above interslide and intraslide cutoffs and confirmed by using inhibition assays with a peptide from the respective region. Hierarchic clustering of microarray data was used to correlate binding patterns with clinical findings. RESULTS The patients with lentil allergy specifically recognized IgE-binding epitopes located in the C-terminal region between peptides 107 and 135. Inhibition experiments confirmed the specificity of IgE binding in this region, identifying different epitopes. Linkage of cluster results with clinical data and lentil-specific IgE levels displayed a positive correlation between lentil-specific IgE levels, epitope recognition, and respiratory symptoms. Modeling based on the 3-dimensional structure of a homologous soy vicilin suggests that the Len c 1 epitopes identified are exposed on the surface of the molecule. CONCLUSION Several IgE-binding sequential epitopes of Len c 1 have been identified. Epitopes are located in the C-terminal region and are predicted to be exposed on the surface of the protein. Epitope diversity is positively correlated with IgE levels, pointing to a more polyclonal IgE response.

The 11S globulin Sin a 2 from yellow mustard seeds shows IgE cross-reactivity with homologous counterparts from tree nuts and peanut

BackgroundThe 11S globulin Sin a 2 is a marker to predict severity of symptoms in mustard allergic patients. The potential implication of Sin a 2 in cross-reactivity with tree nuts and peanut has not been investigated so far. In this work, we studied at the IgG and IgE level the involvement of the 11S globulin Sin a 2 in cross-reactivity among mustard, tree nuts and peanut.MethodsEleven well-characterized mustard-allergic patients sensitized to Sin a 2 were included in the study. A specific anti-Sin a 2 serum was obtained in rabbit. Skin prick tests (SPT), enzyme-linked immunosorbent assay (ELISA), immunoblotting and IgG or IgE-inhibition immunoblotting experiments using purified Sin a 2, Sin a 1, Sin a 3, mustard, almond, hazelnut, pistachio, walnut or peanut extracts were performed.ResultsThe rabbit anti-Sin a 2 serum showed high affinity and specificity to Sin a 2, which allowed us to demonstrate that Sin a 2 shares IgG epitopes with allergenic 11S globulins from tree nuts (almond, hazelnut, pistachio and walnut) but not from peanut. All the patients included in the study had positive skin prick test to tree nuts and/or peanut and we subdivided them into two different groups according to their clinical symptoms after ingestion of such allergenic sources. We showed that 11S globulins contain conserved IgE epitopes involved in cross-reactivity among mustard, tree nuts and peanut as well as species-specific IgE epitopes.ConclusionsThe allergenic 11S globulin Sin a 2 from mustard is involved in cross-reactivity at the IgE level with tree nuts and peanut. Although the clinical relevance of the cross-reactive IgE epitopes present in 11S globulins needs to be investigated in further detail, our results contribute to improve the diagnosis and management of mustard allergic patients sensitized to Sin a 2.

Heating does not decrease immunogenicity of goat's and ewe's milk

URE 1. A, SDS-PAGE (A-1) and Western blot analysis (A-2) with u , and EM allergies and milk-tolerant negative control showed high an d (A-3). ALA, a-Lactalbumin; BLG, b-lactoglobulin; CC, cow’s che ecular weight; SA, serum albumin. extensive amino acid sequence identity of milk proteins (85%100%; see Tables E1 and E2 in this article’s Online Repository at www.jaci-inpractice.org) and similar proteome profiles that imply similarity of protein functions. However, selective GM and ewe’s milk (EM) allergy without CMA (GEMA) have been reported, including anaphylaxis to cheeses from GM and EM in CM-tolerant children. GEMA implies existence of unique GM and EM-allergenic epitopes that are different from CMallergenic epitopes. Among children with CMA, >70% can tolerate extensively heated CM in baked products. We sought to determine the effects of heating on the immunogenicity of GM and EM proteins in children with GEMA. We recruited 17 subjects with milk allergy from Spain, Greece, and the United States; 13 were males; median age was 7.2 years, and 25% to 75% interquartile range (IQR) was 4.0 to 9.9 years. The study was approved by the Institutional Review Boards at The Mount Sinai School of Medicine, Pediatric Hospital “P & A Kiriakou,” and Hospital Infantil Universitario Nino Jesus; informed consent was obtained from the subjects. Eight subjects with CM allergy tolerated extensively heated oral milk challenge but reacted to unheated milk challenge. Nine subjects had history of convincing, immediate allergic symptoms on ingestion of GM or EM or both (Table I). The 8

The lipid interaction capacity of Sin a 2 and Ara h 1, major mustard and peanut allergens of the cupin superfamily, endorses allergenicity.

Sin a 2 (11S globulin) and Ara h 1 (7S globulin) are major allergens from yellow mustard seeds and peanut, respectively. The ability of these two allergens to interact with lipid components remains unknown.