Jug r 6 is the allergenic vicilin present in walnut responsible for IgE cross-reactivities to other tree nuts and seeds

Poppy Seed Allergy: Molecular Diagnosis and Cross-Reactivity With Tree Nuts

BACKGROUND

Poppy seed (PS) can be a cause of severe allergic reactions, especially in individuals with concurrent allergy to tree nuts and other seeds, but diagnostic criteria and sensitization patterns are lacking.

OBJECTIVE

To assess the role of PS extract and individual allergens in diagnosing PS allergy and their cross-reactivities with tree nuts and buckwheat.

METHODS

Our retrospective study included 36 PS-sensitized patients; 10 with a positive and 26 with a negative oral food challenge (OFC). We identified individual PS allergens and compared the diagnostic performance of specific IgE (sIgE) to PS extract with its allergens. Cross-reactivities between PS and related allergens from other seeds were assessed by a competitive enzyme-linked immunosorbent assay.

RESULTS

We identified 4 novel PS allergens: Pap s 1 (vicilin), Pap s 1 (27-424) (α-hairpinin), Pap s 2 (legumin), and Pap s 3 (small hydrophilic seed protein). A positive OFC correlated with higher PS-sIgE levels and elevated sIgE levels for the PS allergens, except for Pap s 3. PS and α-hairpinin-sIgE effectively differentiated allergic from tolerant patients, with area under the curve values of 0.95 and 0.94. PS-sIgE >10.00 kUA/L exhibited 90% sensitivity and 73% specificity, whereas α-hairpinin-sIgE >2.60 kUA/L showed 100% sensitivity and 77% specificity. PS vicilin and legumin highly cross-reacted with hazelnut and buckwheat homologs, whereas α-hairpinin-sIgE cross-reacted with the related almond allergen.

CONCLUSIONS

This is the most extensive study on PS allergy to date. PS and α-hairpinin-sIgE are highly sensitive indicators of clinical reactivity to PS, whereas vicilin and legumin-sIgE contribute to concurrent sensitization to hazelnut and buckwheat.

A systematic review of allergen cross-reactivity: Translating basic concepts into clinical relevance

Access to the molecular culprits of allergic reactions allows for the leveraging of molecular allergology as a new precision medicine approach-one built on interdisciplinary, basic, and clinical knowledge. Molecular allergology relies on the use of allergen molecules as in vitro tools for the diagnosis and management of allergic patients. It complements the conventional approach based on skin and in vitro allergen extract testing. Major applications of molecular allergology comprise accurate identification of the offending allergen thanks to discrimination between genuine sensitization and allergen cross-reactivity, evaluation of potential severity, patient-tailored choice of the adequate allergen immunotherapy, and prediction of its expected efficacy and safety. Allergen cross-reactivity, defined as the recognition of 2 or more allergen molecules by antibodies or T cells of the same specificity, frequently interferes with allergen extract testing. At the mechanistic level, allergen cross-reactivity depends on the allergen, the host's immune response, and the context of their interaction. The multiplicity of allergen molecules and families adds further difficulty. Understanding allergen cross-reactivity at the immunologic level and translating it into a daily tool for the management of allergic patients is further complicated by the ever-increasing number of characterized allergenic molecules, the lack of dedicated resources, and the need for a personalized, patient-centered approach. Conversely, knowledge sharing paves the way for improved clinical use, innovative diagnostic tools, and further interdisciplinary research. Here, we aimed to provide a comprehensive and unbiased state-of-the art systematic review on allergen cross-reactivity. To optimize learning, we enhanced the review with basic, translational, and clinical definitions, clinical vignettes, and an overview of online allergen databases.

Prospects for developing allergen-depleted food crops

In addition to the challenge of meeting global demand for food production, there are increasing concerns about food safety and the need to protect consumer health from the negative effects of foodborne allergies. Certain bio-molecules (usually proteins) present in food can act as allergens that trigger unusual immunological reactions, with potentially life-threatening consequences. The relentless working lifestyles of the modern era often incorporate poor eating habits that include readymade prepackaged and processed foods, which contain additives such as peanuts, tree nuts, wheat, and soy-based products, rather than traditional home cooking. Of the predominant allergenic foods (soybean, wheat, fish, peanut, shellfish, tree nuts, eggs, and milk), peanuts (Arachis hypogaea) are the best characterized source of allergens, followed by tree nuts (Juglans regia, Prunus amygdalus, Corylus avellana, Carya illinoinensis, Anacardium occidentale, Pistacia vera, Bertholletia excels), wheat (Triticum aestivum), soybeans (Glycine max), and kidney beans (Phaseolus vulgaris). The prevalence of food allergies has risen significantly in recent years including chance of accidental exposure to such foods. In contrast, the standards of detection, diagnosis, and cure have not kept pace and unfortunately are often suboptimal. In this review, we mainly focus on the prevalence of allergies associated with peanut, tree nuts, wheat, soybean, and kidney bean, highlighting their physiological properties and functions as well as considering research directions for tailoring allergen gene expression. In particular, we discuss how recent advances in molecular breeding, genetic engineering, and genome editing can be used to develop potential low allergen food crops that protect consumer health.

Sesame allergy in children: New insights into diagnosis and management

Sesame is a potentially potent allergen that can trigger skin, gastrointestinal, and respiratory tract symptoms, and anaphylaxis. Only 20% to 30% of sesame-allergic children develop tolerance. The prevalence of sesame allergy depends on local diets and ranges from 0.1% to 0.9%. A high risk of accidental exposure to sesame has resulted in mandatory food labeling in many countries. More than half of patients with sesame allergy are also allergic to peanut/tree nuts. Serum-specific IgE testing with a quantitative Ses i 1 component can be performed safely and has higher clinical specificity and better positive predictive value for oral food challenge (OFC) than whole sesame extract or skin prick testing (SPT). Compared with SPT or OFC, in vitro Ses i 1 testing requires no special techniques and carries no risk of reactions. Diagnosis of suspected sesame allergy begins with a thorough history and physical examination. A positive sesame extract test (≥0.1 kUA /L) should prompt further testing. In patients with a high probability of reacting, results of component testing may facilitate a decision about performing an OFC. In a Japanese study of OFC and Ses i 1, there was a 5% probability of a positive OFC with Ses i 1 sIgE levels <0.13 kUA /L, and a 50% probability of a positive OFC with levels >32.0 kUA /L. Most patients could safely consume sesame if sIgE levels were <0.13 kUA /L. Ses i 1 testing can be used to guide appropriate management (avoidance, emergency medication, and oral immunotherapy).

Food Allergens of Plant Origin

This review presents an update on the physical, chemical, and biological properties of food allergens in plant sources, focusing on the few protein families that contribute to multiple food allergens from different species and protein families recently found to contain food allergens. The structures and structural components of the food allergens in the allergen families may provide further directions for discovering new food allergens. Answers as to what makes some food proteins allergens are still elusive. Factors to be considered in mitigating food allergens include the abundance of the protein in a food, the property of short stretches of the sequence of the protein that may constitute linear IgE binding epitopes, the structural properties of the protein, its stability to heat and digestion, the food matrix the protein is in, and the antimicrobial activity to the microbial flora of the human gastrointestinal tract. Additionally, recent data suggest that widely used techniques for mapping linear IgE binding epitopes need to be improved by incorporating positive controls, and methodologies for mapping conformational IgE binding epitopes need to be developed.

Natural History of Hazelnut Allergy and Current Approach to Its Diagnosis and Treatment

Hazelnut allergy is the most prevalent type of nut allergy in Europe, with symptoms that can range from mild, such as hives and itching, to severe, such as anaphylaxis, particularly in patients who are sensitized to highly stable allergens, such as storage proteins. Compared to other types of food allergies, allergies to tree nuts, including hazelnuts, tend to persist throughout life. Although symptoms can appear in early childhood, they often continue into adulthood, with a minority of cases improving during adolescence. Currently, there is no curative treatment available for hazelnut allergy, and patients must adhere to a restrictive diet and carry autoinjective epinephrine. However, oral allergen immunotherapy (AIT) is a promising treatment option. Patients can be categorized based on their risk for severe reactions using various clinical, in vivo, and in vitro tests, including component-resolved diagnosis and oral food challenge. This review aims to provide an overview of the current knowledge of the natural history of hazelnut allergy and new approaches for its diagnosis and management.

Sesame as a source of food allergens: clinical relevance, molecular characterization, cross-reactivity, stability toward processing and detection strategies

Sesame is an allergenic food with an increasing allergy prevalence among the European/USA population. Sesame allergy is generally life-persisting, being the cause of severe/systemic adverse immune responses in sesame-allergic individuals. Herein, clinical data about sesame allergy, including prevalence, diagnosis, relevance, and treatments are described, with focus on the molecular characterization of sesame allergens, their cross-reactivity and co-sensitization phenomena. The influence of food processing and digestibility on the stability/immunoreactivity of sesame allergens is critically discussed and the analytical approaches available for their detection in foodstuffs. Cross-reactivity between sesame and tree nuts or peanuts is frequent because of the high similarities among proteins of the same family. However, cross-reactivity phenomena are not always correlated with true clinical allergy in sensitized patients. Data suggest that sesame allergens are resistant to heat treatments and digestibility, with little effect on their immunoreactivity. Nevertheless, data are scarce, evidencing the need for more research to understand the effect of food processing on sesame allergenicity modulation. The demands for identifying trace amounts of sesame in foods have prompted the development of analytical methods, which have targeted both protein and DNA markers, providing reliable, specific, and sensitive tools, crucial for the effective management of sesame as an allergenic food.

Sesame allergy: mechanisms, prevalence, allergens, residue detection, effects of processing and cross-reactivity

Sesame allergy is a serious public health problem and is mainly induced by IgE-mediated reactions, whose prevalence is distributed all over the world. Sesame has been included on the priority allergic food list in many countries. This review summarizes the mechanism and prevalence of sesame allergy. The characteristics, structures and epitopes of sesame allergens (Ses i 1 to Ses i 7) are included. Moreover, the detection methods for sesame allergens are evaluated, including nucleic-acid, immunoassays, mass spectrometry, and biosensors. Various processing techniques for reducing sesame allergenicity are discussed. Additionally, the potential cross-reactivity of sesame with other plant foods is assessed. It is found that the allergenicity of sesame is related to the structures and epitopes of sesame allergens. Immunoassays and mass spectrometry are the major analytical tools for detecting and quantifying sesame allergens in food. Limited technologies have been successfully used to reduce the antigenicity of sesame, involving microwave heating, high hydrostatic pressure, salt and pH treatment. More technologies for reducing the allergenicity of sesame should be widely investigated in future studies. The reduction of allergenicity in processed sesames should be ultimately confirmed by clinical studies. What's more, sesame may exhibit cross-reactivity with peanut and tree nuts.

Multiplex component-based allergen macroarray test is useful to predict clinical reactivity to tree nuts in children

BACKGROUND

In tree nut (TN) allergy, singleplex tests showed the diagnostic utility of rAna o 3, rCor a 14/nCor a 9, and nJug r 1/nJug r 4 for cashew/pistachio, hazelnut, and walnut allergies, respectively. However, disadvantages of the tests include high costs and excessive blood sampling in multi-sensitized patients, and a limited number of components. We investigated the utility of a multiplex macroarray (i.e., the ALEX² test) in TN allergy.

METHODS

In 169 children, skin prick test, the component- and extract-specific IgEs of TNs were investigated for clinical reactivity and tolerance.

RESULTS

The predictors (AUC = 0.962-0.749) of clinical reactivity to cashew, pistachio, hazelnut, and walnut were rPis v 1/rAna o 3, rPis v 1/rAna o 3/nPis v 2/nPis v 3, rCor a 14/nCor a 11/nCor a 9, and nJug r 1/nJug r 2/nJug r 6/nJug r 4, respectively. More than 93% of the patients with clinical reactivity to pistachio/cashew, hazelnut and walnut had positivity of (≥0.3 kU_A/L) rPis v 1/rAna o 3, rCor a 14 and nJug r 1/nJug r 2, respectively. The highest accuracies of clinical reactivity to culprit nut were obtained with combination of rPis v 1, sIgE and SPT positivities for cashew/pistachio, rPis v 1 ≥ 1.0 kU_A/L for pistachio, rCor a 14 ≥ 1.0 kU_A/L for hazelnut and combination of nJug r 1 and nJug r 2 positivities for walnut, respectively. Also, higher concentrations of rPis v 1 (≥15.0 kU_A/L), rCor a 14 (≥5.0 kU_A/L) and nJug r 1/nJug r 2 (≥15.0 kU_A/L) had %100 specificity and PPV in predicting clinical reactivity to cashew, hazelnut and walnut, respectively.

CONCLUSIONS

Multiplex macroarray test is useful and reliable in the diagnosis of TN allergy in children, confirms and expands existing knowledge, and can be used as a stand-alone tool in the bottom-up diagnostic approach.

Food Allergies: Immunosensors and Management

Food allergies (FA) are commonly depicted as immune responses. The mechanism of allergic reactions involves immunoglobulin E (IgE) and non-immunoglobulin E (non-IgE)-related responses caused by contact with specific foods. FAs can be fatal, have negative effects and have become the subject of fanaticism in recent years. In terms of food safety, allergic compounds have become a problem. The immune response to allergens is different to that from food intolerance, pharmacological reactions, and poisoning. The most important allergenic foods are soybeans, milk, eggs, groundnuts, shellfishes, tree nuts, cereals and fish, which together are known as the “Big Eight”. This review will introduce and discuss FAs in milk, peanuts, nuts, shellfishes, eggs and wheat and their detections and potential treatments will also be provided. We believe that this review may provide important information regarding food-induced allergies for children who have allergic reactions and help them avoid the allergenic food in the future.

Characteristics of patients with spontaneous resolution of sesame allergy

BACKGROUND

The prevalence of sesame allergy is increasing; strict avoidance is the mainstay of therapy. Lately, sesame oral immunotherapy was presented as an alternative treatment, with a high rate of success. Therefore, data on the natural history and the clinical characteristics of patients with persistent sesame allergy are important for the management of patients with sesame allergy.

OBJECTIVE

To describe the natural history of patients with sesame allergy and the clinical characteristics of patients with spontaneous resolution of sesame allergy compared with patients with persistent sesame allergy.

METHODS

In our retrospective study, electronic health records of patients with sesame allergy diagnosis were reviewed for demographic and clinical data. Statistical analysis of clinical characteristics of patients with spontaneous resolution compared with persistent sesame allergy was performed.

RESULTS

A total of 190 patients with sesame allergy were followed for 3.86 ±4.43 years. Of these patients, 61 (32.1%) had spontaneous resolution of sesame allergy. Patients with mild, early (before the age of 10 months) first sesame allergic reaction, with smaller than 7-mm skin prick test and without concomitant tree nut allergy had better resolution rate (56.1%).

CONCLUSION

Sesame allergy spontaneously resolved in approximately one-third of our patients and in more than half of the patients with mild first reaction (grade 1) at a young age (<10 months), with small skin prick test (<7 mm) and no concomitant tree nut allergy. Larger prospective studies with longer follow-up period are needed to better characterize the sesame allergic patients with persistent allergy who may need oral immunotherapy.

Scientific Opinion on development needs for the allergenicity and protein safety assessment of food and feed products derived from biotechnology

This Scientific Opinion addresses the formulation of specific development needs, including research requirements for allergenicity assessment and protein safety, in general, which is urgently needed in a world that demands more sustainable food systems. Current allergenicity risk assessment strategies are based on the principles and guidelines of the Codex Alimentarius for the safety assessment of foods derived from 'modern' biotechnology initially published in 2003. The core approach for the safety assessment is based on a 'weight-of-evidence' approach because no single piece of information or experimental method provides sufficient evidence to predict allergenicity. Although the Codex Alimentarius and EFSA guidance documents successfully addressed allergenicity assessments of single/stacked event GM applications, experience gained and new developments in the field call for a modernisation of some key elements of the risk assessment. These should include the consideration of clinical relevance, route of exposure and potential threshold values of food allergens, the update of in silico tools used with more targeted databases and better integration and standardisation of test materials and in vitro/in vivo protocols. Furthermore, more complex future products will likely challenge the overall practical implementation of current guidelines, which were mainly targeted to assess a few newly expressed proteins. Therefore, it is timely to review and clarify the main purpose of the allergenicity risk assessment and the vital role it plays in protecting consumers' health. A roadmap to (re)define the allergenicity safety objectives and risk assessment needs will be required to inform a series of key questions for risk assessors and risk managers such as 'what is the purpose of the allergenicity risk assessment?' or 'what level of confidence is necessary for the predictions?'.

From Allergen Molecules to Molecular Immunotherapy of Nut Allergy: A Hard Nut to Crack

Peanuts and tree nuts are two of the most common elicitors of immunoglobulin E (IgE)-mediated food allergy. Nut allergy is frequently associated with systemic reactions and can lead to potentially life-threatening respiratory and circulatory symptoms. Furthermore, nut allergy usually persists throughout life. Whether sensitized patients exhibit severe and life-threatening reactions (e.g., anaphylaxis), mild and/or local reactions (e.g., pollen-food allergy syndrome) or no relevant symptoms depends much on IgE recognition of digestion-resistant class I food allergens, IgE cross-reactivity of class II food allergens with respiratory allergens and clinically not relevant plant-derived carbohydrate epitopes, respectively. Accordingly, molecular allergy diagnosis based on the measurement of allergen-specific IgE levels to allergen molecules provides important information in addition to provocation testing in the diagnosis of food allergy. Molecular allergy diagnosis helps identifying the genuinely sensitizing nuts, it determines IgE sensitization to class I and II food allergen molecules and hence provides a basis for personalized forms of treatment such as precise prescription of diet and allergen-specific immunotherapy (AIT). Currently available forms of nut-specific AIT are based only on allergen extracts, have been mainly developed for peanut but not for other nuts and, unlike AIT for respiratory allergies which utilize often subcutaneous administration, are given preferentially by the oral route. Here we review prevalence of allergy to peanut and tree nuts in different populations of the world, summarize knowledge regarding the involved nut allergen molecules and current AIT approaches for nut allergy. We argue that nut-specific AIT may benefit from molecular subcutaneous AIT (SCIT) approaches but identify also possible hurdles for such an approach and explain why molecular SCIT may be a hard nut to crack.

Shotgun proteomics of Brassica rapa seed proteins identifies vicilin as a major seed storage protein in the mature seed

Proteins make up a large percentage of the Brassica seed and are second only to the oil in economic importance with uses for both animal and human nutrition. The most abundant proteins reported in the seeds of Brassica are the seed storage proteins cruciferin and napin, belonging to the 12S globulin and 2S albumin families of proteins, respectively. To gain insight into the Brassica rapa seed proteome and to confirm the presence and relative quantity of proteins encoded by candidate seed storage genes in the mature seed, shotgun proteomics was carried out on protein extracts from seeds of B. rapa inbred line R-o-18. Following liquid chromatography tandem mass spectrometry, a total of 34016 spectra were mapped to 323 proteins, where 233 proteins were identified in 3 out of 4 biological replicates by at least 2 unique peptides. 2S albumin like napin seed storage proteins (SSPs), 11/12S globulin like cruciferin SSPs and 7S globulin like vicilin SSPs were identified in the samples, along with other notable proteins including oil body proteins, namely ten oleosins and two oil body-associated proteins. The identification of vicilin like proteins in the mature B. rapa seed represents the first account of these proteins in the Brassicaceae and analysis indicates high conservation of sequence motifs to other 7S vicilin-like allergenic proteins as well as conservation of major allergenic epitopes in the proteins. This study enriches our existing knowledge on rapeseed seed proteins and provides a robust foundation and rational basis for plant bioengineering of seed storage proteins.

IgE-Binding Epitopes of Pis v 1, Pis v 2 and Pis v 3, the Pistachio (Pistacia vera) Seed Allergens

Sequential IgE-binding epitopes were identified on the molecular surface of the Pis v 1 (2S albumin), Pis v 2 (11S globulin/legumin) and Pis v 3 (7S globulin/vicilin)—major allergens from pistachio (Pistacia vera) seeds—using the Spot technique. They essentially consist of hydrophilic and electropositively charged residues well exposed on the surface of the allergens. Most of the epitopic regions identified on Pis v 1 and Pis v 3 do not coincide with the putative N-glycosylation sites and thus are not considered as glycotopes. Surface analysis of these epitopic regions indicates a high degree of conformational similarity with the previously identified epitopic regions of the corresponding allergens Ana o 1 (vicilin), Ana o 2 (legumin) and Ana o 3 (2S albumin) from the cashew (Anacardium occidentale) nut. These results offer a molecular basis for the IgE-binding cross-reactivity often observed between pistachio and cashew nut. They support the recommendation for prescribing pistachio avoidance in cashew allergic patients. Other conformational similarities were identified with the corresponding allergens Ses i 1 (2S albumin), Ses i 3 (vicilin) and Ses i 6 (legumin) from sesame (Sesamum indicum), and Jug r 1 (2S albumin), Jug r 2 (vicilin) and Jug r 4 (legumin) from walnut (Juglans regia). Conversely, conformation of most of the epitopic regions of the pistachio allergens often differs from that of epitopes occurring on the molecular surface of the corresponding Ara h 1 (vicilin), Ara h 2 (2S albumin) and Ara h 3 (legumin) allergens from peanut (Arachis hypogaea).

Cloning, expression and immunological characterisation of Coc n 1, the first major allergen from Coconut pollen

Coconut pollen has been documented to be a major contributor to the aeroallergen load in India, causing respiratory allergy in a large cohort of susceptible individuals. Here, we report the identification of the first major allergen from Coconut pollen, Coc n 1. The full-length sequence of the allergen was determined from previously identified peptides and overexpressed in E. coli. Recombinant Coc n 1 folded into a trimer and was found to possess allergenicity equivalent to its natural counterpart. Proteolytic processing of Coc n 1 led to the formation of an immunodominant ∼20 kDa C-terminal subunit and the site of cleavage was determined by amino acid microsequencing. Five linear IgE binding epitopes were predicted and mapped on the homology modelled structure of Coc n 1. Amongst three immunodominant epitopes, two were present towards the C-terminal end. Coc n 1 was found to belong to the highly diverse cupin superfamily and mimics its structure with known 7S globulin or vicilin allergens but lacks sequence similarity. Using sequence similarity networks, Coc n 1 clustered as a separate group containing unannotated cupin domain proteins and did not include known vicilin allergens except Gly m Bd 28 kDa, a Soybean major allergen. 7S globulins are major storage proteins and food allergens, but presence of such protein in pollen grains is reported for the first time. Further study on Coc n 1 may provide insights into its function in pollen grains and also in the development of immunotherapy to Coconut pollen allergy.

Advances and novel developments in molecular allergology

The continuous search for new allergens and the design of allergen derivatives improves the understanding of their allergenicity and aids the design of novel diagnostic and immunotherapy approaches. This article discusses the recent developments in allergen and epitope discovery, allergy diagnostics and immunotherapy. Structural information is crucial for the elucidation of cross-reactivity of marker allergens such as the walnut Jug r 6 or that of nonhomologous allergens, as shown for the peanut allergens Ara h 1 and 2. High-throughput sequencing, liposomal nanoallergen display, bead-based assays, and protein chimeras have been used in epitope discovery. The binding of natural ligands by the birch pollen allergen Bet v 1 or the mold allergen Alt a 1 increased the stability of these allergens, which is directly linked to their allergenicity. We also report recent findings on the use of component-resolved approaches, basophil activation test, and novel technologies for improvement of diagnostics. New strategies in allergen-specific immunotherapy have also emerged, such as the use of virus-like particles, biologics or novel adjuvants. The identification of dectin-1 as a key player in allergy to tropomyosins and the formyl peptide receptor 3 in allergy to lipocalins are outstanding examples of research into the mechanism of allergic sensitization.

Identification and characterization of major IgE binding of purified allergenic protein (11 kDa) from Buchanania lanzan

Tree nut along with peanut are among the most potent food allergens, responsible for frequently inducing the IgE-mediated hypersensitivity reaction. Our aim was identification, purification of Buchanania lanzan (Bl-11 kDa) protein along with characterization and assessment of allergenic potential of clinically relevant allergen. Further study was executed in clinical samples of sensitive patients, BALB/c mice, and in-vitro. A major IgE binding 11-kDa protein from Buchanania lanzan was purified by anion exchange chromatography, reverse phase high pressure liquid chromatography (RP-HPLC) and characterized using peptide mass fingerprinting (PMF). Buchanania lanzan (Bl-11 kDa) protein shows the pepsin resistance and depicts IgE interacting capacity to Buchanania lanzan allergic patient's sera as well as sensitized mice sera. It also showed increase in the allergic mediator's like IgE, IgG1, histamine levels in sensitized mice sera. Further study was carried out in-vitro (RBL-2H3 cells) and increased release mast cell degranulation mediators such as β-hexosaminidase, histamine, CysL and PGD2 in the culture supernatant was found. The activation of Th2 cytokines/transcription factors and expression of molecular markers in the downstream of mast cell signaling were up-regulated while the Th1 transcriptional factor (T-bet) was decreased in Bl-11 kDa protein treated mice. Conclusively, our study demonstrates Buchanania lanzan purified protein to be potential allergen that may generate an allergic reaction in sensitized individuals, and one of the most important IgE binding protein responsible for its allergenicity.

Delineation of the Olive Pollen Proteome and Its Allergenome Unmasks Cyclophilin as a Relevant Cross-Reactive Allergen

Olive pollen is a major allergenic source worldwide due to its extensive cultivation. We have combined available genomics data with a comprehensive proteomics approach to get the annotated olive tree (Olea europaea L.) pollen proteome and define its complex allergenome. A total of 1907 proteins were identified by LC-MS/MS using predicted protein sequences from its genome. Most proteins (60%) were predicted to possess catalytic activity and be involved in metabolic processes. In total, 203 proteins belonging to 47 allergen families were found in olive pollen. A peptidyl-prolyl cis-trans isomerase, cyclophilin, produced in Escherichia coli, was found as a new olive pollen allergen (Ole e 15). Most Ole e 15-sensitized patients were children (63%) and showed strong IgE recognition to the allergen. Ole e 15 shared high sequence identity with other plant, animal, and fungal cyclophilins and presented high IgE cross-reactivity with pollen, plant food, and animal extracts.

Allergen Recognition Patterns in Walnut Allergy Are Age Dependent and Correlate with the Severity of Allergic Reactions

BACKGROUND

Walnut is an important elicitor of food allergy in children and adults with a high rate of severe reactions. Multicenter studies using a common clinical protocol and a comprehensive allergen are lacking.

OBJECTIVE

To investigate potential correlations between molecular sensitization patterns and clinical characteristics of walnut-allergic patients.

METHODS

A total of 91 walnut-allergic subjects and 24 tolerant controls from Switzerland, Germany, and Spain were included. Walnut allergy was established by food challenge in all but anaphylactic subjects. Specific IgE (sIgE) to walnut extract, rJug r 1 (2S albumin), rJug r 3 (nonspecific lipid transfer protein 1), nJug r 4 (11S globulin), rJug r 5 (PR-10 protein), 2 vicilin fractions, profiling, and cross-reactive carbohydrate determinant was determined by ImmunoCAP. A threshold of 0.10 kU_A/L was used for positivity.

RESULTS

Sensitivity of sIgE to walnut extract was 87% and increased to 96% for the sum of all walnut components. sIgE to walnut extract and all walnut components, except rJug r 5, was significantly higher in patients younger than 14 years at inclusion. Stratification by age at onset of walnut allergy led to similar results. All patients younger than 14 years had severe reactions, whereas 38% of patients 14 years or older were mild reactors. Severe reactors (n = 70) had higher sIgE levels than did mild reactors (n = 21) to walnut extract (P < .0001), rJug r 1 (P < .0001), nJug r 4 (P = .0003), and both vicilin fractions (P < .0001), but not to Jug r 3 and Jug r 5.

CONCLUSIONS

Sensitization to walnut storage proteins is acquired in childhood and correlates with severe reactions. sIgE levels to storage proteins Jug r 1 and Jug r 4 and vicilin fractions, but not to nonspecific lipid transfer protein and PR-10 proteins, correlate with systemic reactions to walnut.