Wheat-dependent exercise-induced anaphylaxis caused by a lipid transfer protein and not by ω-5 gliadin

Exertional Stress-induced Pathogenic Luminal Content Translocation - Friend or Foe?

The incidence of perturbed gastrointestinal integrity, as well as resulting systemic immune responses and gastrointestinal symptoms, otherwise known as exercised-induced gastrointestinal syndrome (EIGS), is common among individuals who partake in prolonged exercise. EIGS may cause the translocation of pathogenic material, including whole bacteria and bacterial endotoxins, from the lumen into circulation, which may progress into clinical consequences such as sepsis, and potentially subsequent fatality. However, further investigation is warranted to assess the possibility of food allergen and/or digestive enzyme luminal to circulatory translocation in response to exercise, and the clinical consequences. Findings from this narrative literature review demonstrate evidence that whole bacteria and bacterial endotoxins translocation from the gastrointestinal lumen to systemic circulation occurs in response to exercise stress, with a greater propensity of translocation occurring with accompanying heat exposure. It has also been demonstrated that food allergens can translocate from the lumen to systemic circulation in response to exercise stress and initiate anaphylaxis. To date, no research investigating the effect of exercise on the translocation of digestive enzymes from the lumen into systemic circulation exists. It is evident that EIGS and consequential pathogenic translocation presents life-threatening clinical implications, warranting the development and implementation of effective management strategies in at-risk populations.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Diagnostic management of patients reporting symptoms after wheat ingestion

Many patients report symptoms after wheat ingestion experiencing a wide spectrum of clinical manifestations. Three possible diagnoses have been recognized: celiac disease (CD), wheat allergy (WA), and non-celiac (gluten) wheat sensitivity (NCGS/NCWS). CD is a chronic immune-mediated disease of the small bowel caused by exposure to dietary gluten in genetically predisposed individuals, with a prevalence of approximately 1%. It is characterized by mucosal inflammation and atrophy following exposure to gluten and improvement after gluten withdrawal. Food allergies are immunological responses to a food antigen. WA is the expression of an immunologically mediated process that can be immunoglobulin E (IgE) or non-IgE mediated; its many symptoms include urticaria/angioedema, asthma, rhinitis, and anaphylaxis. NCGS/NCWS is characterized by gastrointestinal and/or extra-intestinal symptoms after ingestion of gluten-containing food in subjects not affected by CD or WA. The aim of this review is to help physicians and nutritionists diagnose the cause of symptoms reported after wheat ingestion, thus avoiding patient frustration, inappropriate testing, and incorrect or missed diagnoses. An algorithm for the diagnostic approach in these patients is provided, to help to diagnose CD, WA, NCGS/NCWS or to identify possible functional disorders as the wheat-sensitive irritable bowel syndrome. A personalized approach, regular follow-up, and the help of a skilled healthcare professional are mandatory for patients with symptoms following wheat ingestion is provided. A gluten-free-diet is often recommended for patients with self-reported gluten/wheat-dependent symptoms; for patients with symptoms similar to those of functional diseases while there is evidence that a low-FODMAP diet could be the first option.

Food-Dependent Exercise-Induced Wheals, Angioedema, and Anaphylaxis: A Systematic Review

BACKGROUND

Food-dependent exercise-induced wheals, angioedema, and anaphylaxis remain insufficiently characterized.

OBJECTIVE

We systematically reviewed the literature on clinical manifestations, laboratory investigations, culprit foods, triggering exercise, comorbidities, and treatment outcomes.

METHODS

Using predefined search terms and Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) recommendations, we searched 3 electronic databases to identify relevant literature published before July 2021.

RESULTS

Of 722 patients (median age 25 years; 55.4% male) from 231 studies (43 cohort studies, 15 cases series, and 173 case reports), 79.6% and 3.7% had anaphylaxis with and without wheals and/or angioedema, respectively. The remaining 16.6% had wheals and/or angioedema without anaphylaxis. The duration from eating to exercising and from exercising to symptom onset ranged from 5 minutes to 6 hours (median 1 hour) and from 5 minutes to 5 hours (median 30 minutes), respectively, and virtually all patients exercised within 4 hours after eating and developed symptoms within 1 hour after exercising. Wheat was the most common culprit food. Running was the most common trigger exercise. Most patients were atopic, and 1 in 3 had a history of urticaria. Aspirin and wheat-based products were the most frequent augmenting factors. On-demand antihistamines, corticosteroids, and epinephrine were commonly used and reported to be effective. Patients who stopped eating culprit foods before exercise no longer developed food-dependent exercise-induced allergic reactions.

CONCLUSIONS

Food-dependent exercise-induced allergic reactions are heterogeneous in their clinical manifestations, triggers, and response to treatment. Patients benefit from avoidance of culprit foods before exercise, which highlights the need for allergological diagnostic workup and guidance.

Critical structural elements for the antigenicity of wheat allergen LTP1 (Tri a 14) revealed by site-directed mutagenesis

Lipid transfer proteins (LTPs) were identified as allergens in a large variety of pollens and foods, including cereals. LTPs belong to the prolamin superfamily and display an α-helical fold, with a bundle of four α-helices held together by four disulfide bonds. Wheat LTP1 is involved in allergic reactions to food. To identify critical structural elements of antibody binding to wheat LTP1, we used site-directed mutagenesis on wheat recombinant LTP1 to target: (i) sequence conservation and/or structure flexibility or (ii) each disulfide bond. We evaluated the modifications induced by these mutations on LTP1 secondary structure by synchrotron radiation circular dichroism and on its antigenicity with patient's sera and with mouse monoclonal antibodies. Disruption of the C28-C73 disulfide bond significantly affected IgE-binding and caused protein denaturation, while removing C13-C27 bond decreased LTP1 antigenicity and slightly modified LTP1 overall folding. In addition, we showed Lys72 to be a key residue; the K72A mutation did not affect global folding but modified the local 3D structure of LTP1 and strongly reduced IgE-binding. This work revealed a cluster of residues (C13, C27, C28, C73 and K72), four of which embedded in disulfide bonds, which play a critical role in LTP1 antigenicity.

Adult anaphylaxis: A state-of-the-art review

Anaphylaxis is the most severe among acute allergic diseases and potentially life threatening. Despite its increasing frequency and related burden, it remains often underdiagnosed and improperly managed. Its multisystemic involvement, protean clinical manifestations and its rapid onset are contributory factors. In recent years new acquisitions have shed light into its pathogenesis pathways (and related biomarkers), triggers, factors increasing its severity, along with peculiar clinical manifestations. These breakthrough discoveries have contributed to phenotyping and endotyping this disease, possibly paving the way to a personalized approach which is not available at present. Moreover, to disseminate awareness and standardize diagnostic criteria and management practices, several guidelines and consensus reports, albeit mainly intended for specialist care, have been issued. We here discuss the latest issues in the field of anaphylaxis from the perspective of the emergency and/or internal medicine physician, so to improve its early recognition and treatment in the acute setting and favor allergology referral to implement therapeutical and preventive strategies, such as allergen identification in unclear cases and desensitizing therapies when available (e.g., for Hymenoptera venom allergy).

Rosaceae food allergy: a review

This review provides a global overview on Rosaceae allergy and details the particularities of each fruit allergy induced by ten Rosaceae species: almond/peach/cherry/apricot/plum (Amygdaleae), apple/pear (Maleae), and raspberry/blackberry/strawberry (Rosoideae). Data on clinical symptoms, prevalence, diagnosis, and immunotherapies for the treatment of Rosaceae allergy are herein stated. Allergen molecular characterization, cross-reactivity/co-sensitization phenomena, the impact of food processing and digestibility, and the methods currently available for the Rosaceae detection/quantification in foods are also described. Rosaceae allergy has a major impact in context to pollen-food allergy syndrome (PFAS) and lipid transfer protein (LTP) allergies, being greatly influenced by geography, environment, and presence of cofactors. Peach, apple, and almond allergies are probably the ones most affecting the quality of life of the allergic-patients, although allergies to other Rosaceae fruits cannot be overlooked. From patients' perspective, self-allergy management and an efficient avoidance of multiple fruits are often difficult to achieve, which might raise the risk for cross-reactivity and co-sensitization phenomena and increase the severity of the induced allergic responses with time. At this point, the absence of effective allergy diagnosis (lack of specific molecular markers) and studies advancing potential immunotherapies are some gaps that certainly will prompt the progress on novel strategies to manage Rosaceae food allergies.

Basophil Activation to Gluten and Non-Gluten Proteins in Wheat-Dependent Exercise-Induced Anaphylaxis

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a cofactor-induced wheat allergy. Gluten proteins, especially ω5-gliadins, are known as major allergens, but partially hydrolyzed wheat proteins (HWPs) also play a role. Our study investigated the link between the molecular composition of gluten or HWP and allergenicity. Saline extracts of gluten (G), gluten with reduced content of ω5-gliadins (G-ω5), slightly treated HWPs (sHWPs), and extensively treated HWPs (eHWPs) were prepared as allergen test solutions and their allergenicity assessed using the skin prick test and basophil activation test (BAT) on twelve patients with WDEIA and ten controls. Complementary sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), high-performance liquid chromatography (HPLC), and mass spectrometry (MS) analyses revealed that non-gluten proteins, mainly α-amylase/trypsin inhibitors (ATIs), were predominant in the allergen test solutions of G, G-ω5, and sHWPs. Only eHWPs contained gliadins and glutenins as major fraction. All allergen test solutions induced significantly higher %CD63⁺ basophils/anti-FcεRI ratios in patients compared with controls. BAT using sHWPs yielded 100% sensitivity and 83% specificity at optimal cut-off and may be useful as another tool in WDEIA diagnosis. Our findings indicate that non-gluten proteins carrying yet unidentified allergenic epitopes appear to be relevant in WDEIA. Further research is needed to clarify the role of nutritional ATIs in WDEIA and identify specific mechanisms of immune activation.

Lipid transfer protein allergy: A review of current controversies

Sensitization to lipid transfer protein (LTP), the most frequent cause of food allergy in southern Europe, still shows several controversial, but also intriguing, aspects. Some of these include the degree of cross-reactivity between LTPs from botanically distant sources, the definition of risk factors, the role of some cofactors, clinical outcomes, geographical differences and the identification of the primary sensitizer in different areas. This review article tries to analyse and comment on these aspects point by point suggesting some explanatory hypotheses with the final scope to stimulate critical thoughts and elicit the scientific discussion about this issue in the readership.

The diagnosis and management of allergic reactions in patients sensitized to non-specific lipid transfer proteins

Sensitization to one or more non-specific lipid transfer proteins (nsLTPs), initially thought to exist mainly in southern Europe, is becoming accepted as a cause of allergic reactions to plant foods across Europe and beyond. The peach nsLTP allergen Pru p 3 is a dominant sensitizing allergen and peaches a common food trigger, although multiple foods can be involved. A frequent feature of reactions is the requirement for a cofactor (exercise, alcohol, non-steroidal anti-inflammatory drugs, Cannabis sativa) to be present for a food to elicit a reaction. The variability in the food and cofactor triggers makes it essential to include an allergy-focused diet and clinical history in the diagnostic workup. Testing on suspected food triggers should also establish whether sensitization to nsLTP is present, using purified or recombinant nsLTP allergens such as Pru p 3. The avoidance of known trigger foods and advice on cofactors is currently the main management for this condition. Studies on immunotherapy are promising, but it is unknown whether such treatments will be useful in populations where Pru p 3 is not the primary sensitizing allergen. Future research should focus on the mechanisms of cofactors, improving diagnostic accuracy and establishing the efficacy of immunotherapy.

Non-specific lipid-transfer proteins: Allergen structure and function, cross-reactivity, sensitization, and epidemiology

Background

Discovered and described 40 years ago, non‐specific lipid transfer proteins (nsLTP) are present in many plant species and play an important role protecting plants from stressors such as heat or drought. In the last 20 years, sensitization to nsLTP and consequent reactions to plant foods has become an increasing concern.

Aim

The aim of this paper is to review the evidence for the structure and function of nsLTP allergens, and cross‐reactivity, sensitization, and epidemiology of nsLTP allergy.

Materials and Methods

A Task Force, supported by the European Academy of Allergy & Clinical Immunology (EAACI), reviewed current evidence and provide a signpost for future research. The search terms for this paper were “Non‐specific Lipid Transfer Proteins”, “LTP syndrome”, “Pru p 3”, “plant food allergy”, “pollen‐food syndrome”.

Results

Most nsLTP allergens have a highly conserved structure stabilised by 4‐disulphide bridges. Studies on the peach nsLTP, Pru p 3, demonstrate that nsLTPs are very cross‐reactive, with the four major IgE epitopes of Pru p 3 being shared by nsLTP from other botanically related fruits. These nsLTP allergens are to varying degrees resistant to heat and digestion, and sensitization may occur through the oral, inhaled or cutaneous routes. In some populations, Pru p 3 is the primary and sole sensitizing allergen, but many are poly‐sensitised both to botanically un‐related nsLTP in foods, and non‐food sources of nsLTP such as Cannabis sativa, Platanus acerifolia, (plane tree), Ambrosia artemisiifolia (ragweed) and Artemisia vulgaris (mugwort). Initially, nsLTP sensitization appeared to be limited to Mediterranean countries, however more recent studies suggest clinically relevant sensitization occurs in North Atlantic regions and also countries in Northern Europe, with nsLTP sensitisation profiles being broadly similar.

Discussion

These robust allergens have the potential to sensitize and provoke symptoms to a large number of plant foods, including those which are raw, cooked or processed. It is unknown why some sensitized individuals develop clinical symptoms to foods whereas others do not, or indeed what other allergens besides Pru p 3 may be primary sensitising allergens. It is clear that these allergens are also relevant in non‐Mediterranean populations and there needs to be more recognition of this.

Conclusion

Non‐specific LTP allergens, present in a wide variety of plant foods and pollens, are structurally robust and so may be present in both raw and cooked foods. More studies are needed to understand routes of sensitization and the world‐wide prevalence of clinical symptoms associated with sensitization to these complex allergens.

Evaluation of Diagnosis and Management of Omega-5-Gliadin Allergy: A Retrospective Survey

Background

Allergy to the omega-5-gliadin component of gluten (O-5-G allergy) often manifests when wheat ingestion is followed by a co-factor, usually exercise. There is no established best approach to management.

Objective

We sought to identify the beneficial effects, firstly of establishing a firm diagnosis, and secondly of stringent management, either by avoiding gluten ingestion altogether or separating it temporally from exercise by at least 4 hours. We also determined how frequently patients adhered to their physicians' clinical recommendations.

Methods

We undertook a survey of individuals diagnosed with O-5-G allergy at our institution over 8 years, who had a consistent clinical history and confirmatory laboratory evidence.

Results

Of 80 eligible individuals, 43 responded (54%). Symptoms began in adulthood for all bar one, and concurrent asthma and eczema was uncommon (9% prevalence, respectively). Median time to diagnosis was 2 years. Achieving a diagnosis reduced the rate of reactions (0.35 per month vs 1.085 reactions per month, p=0.029). Many patients (10/43) did not adhere to the recommended stringent approach, to either avoid wheat/gluten or separate food and exercise by 4 hours. However, those adopting a stringent approach had a substantially lower risk of recurrent allergic reaction (0.22 per month vs 0.74 per month, p=0.004).

Conclusion

The epidemiology of O-5-G allergy implies pathogenic mechanisms potentially distinct from those of childhood-onset food allergy. Accurate diagnosis improves the clinical trajectory, primarily through the adoption of a stringent management approach.

Component-resolved diagnosis in adult patients with food-dependent anaphylaxis

Food anaphylaxis is a severe, potentially life-threatening, systemic hypersensitivity reaction. Within a retrospective study we applied ImmunoCAP-ISAC in a heterogenous cohort of 54 food anaphylactic patients and compared its performance to conventional in vitro (ELISA, ImmunoCAP) and in vivo (skin prick test, oral food challenge) diagnosis. Comparing clinical diagnosis with results obtained by ImmunoCAP-ISAC we obtained moderate agreement (kappa 0.524, p < 0.05). The comparison between SPT and ImmunoCAP vs ImmunoCAP-ISAC indicates a good sensitivity of microarray testing. Among the 54 tested sera, 36 and 41 were in substantial agreement with results obtained by SPT (69%, kappa 0.667, p < 0.05) and ImmunoCAP-ISAC (76%, kappa 0.759, p < 0.05), respectively. Within this adult anaphylaxis cohort, plant food allergens were identified as the predominant IgE-binding proteins, with PR10 proteins, ω-5-gliadin and nsLTPs as the most frequent ones. In summary, microarray based IgE testing may help to unravel the elicitating food in anaphylaxis in particular when the elicitor is so far unknown.

Idiopathic Anaphylaxis: a Perplexing Diagnostic Challenge for Allergists

PURPOSE OF REVIEW

The aim of this systematic review is to present the proposed theories of pathogenesis for idiopathic anaphylaxis (IA), to discuss its classification, its diagnostic approach, and management.

RECENT FINDINGS

IA represents a major diagnostic challenge and is diagnosed when excluding the possible identifiable triggers of anaphylaxis. The current research, however, revealed that certain conditions including mastocytosis, mast cell activation syndromes, and hereditary alpha tryptasemia can masquerade and overlap with its symptomatology. Also, newly identified galactose-alpha-1,3-galactose mammalian red meat allergy has recently been recognized as underlying cause of anaphylaxis in some cases that were previously considered as IA. IA comprises a heterogenous group of conditions where, in some cases, inherently dysfunctional mast cells play a role in pathogenesis. The standard trigger avoidance strategies are ineffective, and episodes are unpredictable. Therefore, prompt recognition and treatment as well as prophylaxis are critical. The patients should always carry an epinephrine autoinjector.

LTP allergy/sensitization in a pediatric population

Plant lipid transfer proteins (LTPs) are widespread plant food allergens, highly resistant to food processing and to the gastrointestinal environment, which have been described as the most common food allergens in the Mediterranean area. LTP allergy is widely described in adults, but it represents an emerging allergen also in the pediatric population. Little is known about the real prevalence and the clinical features of this allergy in children and it still often remains underdiagnosed in these patients. An early identification and a deeper knowledge of this allergy in childhood can avoid severe systemic reactions and improve the child's quality of life. Pediatricians should always consider the possibility of LTP involvement in cases of plant-derived food allergy.

Novel insights regarding anaphylaxis in children - With a focus on prevalence, diagnosis, and treatment

Anaphylaxis is a serious allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction often leads to difficulty in breathing and can result in death. The estimated prevalence of anaphylaxis is 0.05%-2%, which is reported to be increasing in children. Although drugs and venom are the most common causes of anaphylaxis in adults, food is the most common cause of anaphylaxis in children. An interesting association between food-dependent exercise-induced anaphylaxis (FDEIA) and oral immunotherapy (OIT) has recently been reported. A provocation test to determine the diagnostic and augmenting factors of FDEIA has been reported in recent years. Remarkably, several articles showed allergic symptoms without exercise in children with FDEIA and in those with FDEIA development after OIT. Regarding OIT, full-dose OIT poses a risk of adverse reactions, including anaphylaxis. Recent trials have shown the efficacy and safety of low-dose OIT in patients with food-induced anaphylaxis. In this review, we summarized the novel insights regarding anaphylaxis in the pediatric population.

Exercise-induced allergic reactions on desensitization to wheat after rush oral immunotherapy

BACKGROUND

The effect of oral immunotherapy (OIT) on wheat allergy is promising in terms of the potential to obtain desensitization; however, the frequency of exercise-induced allergic reactions on desensitization (EIARDs) and the associated risk factors remain to be determined.

METHODS

Twenty-five patients underwent rush OIT for wheat allergy, and 21 achieved the full-dose intake of wheat products (5 g of wheat protein). Exercise-provocation tests were repeatedly performed after the ingestion of a full-dose wheat product. The time-course of the levels of the specific IgEs (sIgE) to wheat extract, total gliadin, deamidated gliadin, recombinant gliadin components (α/β-, γ- and ω-5-), and glutenin (high and low molecular weight) components was analyzed using ImmunoCAP^® , ELISA, or IgE immunoblotting.

RESULTS

Fourteen patients (66.7%) were diagnosed as EIARD+, which remained 5 years after rush OIT in 11 patients (52.4%). There were no differences in the clinical backgrounds of the EIARD+ and EIARD- patients. However, EIARD+ patients showed significantly higher sIgE levels to all gliadin and glutenin components than EIARD- patients before OIT. The sIgE levels to each component decreased equally after 1 and 2 years of OIT. On IgE immunoblotting, sera from all patients reacted to the multiple gluten bands, and some reacted to the water-soluble bands. The intensity of all IgE-reactive bands also became equally lighter after OIT.

CONCLUSIONS

EIARDs were frequently observed and remained for a long period after successful OIT for wheat allergy. None of the specific wheat components were found to contribute to EIARDs.

A WAO - ARIA - GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

Precision allergy molecular diagnostic applications (PAMD@) is increasingly entering routine care. Currently, more than 130 allergenic molecules from more than 50 allergy sources are commercially available for in vitro specific immunoglobulin E (sIgE) testing. Since the last publication of this consensus document, a great deal of new information has become available regarding this topic, with over 100 publications in the last year alone. It thus seems quite reasonable to publish an update. It is imperative that clinicians and immunologists specifically trained in allergology keep abreast of the new and rapidly evolving evidence available for PAMD@.

PAMD@ may initially appear complex to interpret; however, with increasing experience, the information gained provides relevant information for the allergist. This is especially true for food allergy, Hymenoptera allergy, and for the selection of allergen immunotherapy. Nevertheless, all sIgE tests, including PAMD@, should be evaluated within the framework of a patient's clinical history, because allergen sensitization does not necessarily imply clinical relevant allergies.

How to manage food dependent exercise induced anaphylaxis (FDEIA)

PURPOSE OF REVIEW

In recent years, the number of reports on food-dependent exercise-induced anaphylaxis (FDEIA) has been increasing. This review aims to describe the standard management of FDEIA including provocation tests and identify the issues that remain unclear.

RECENT FINDINGS

Provocation tests with aspirin for FDEIA enable us to confirm the definitive diagnosis and to make differential diagnosis. In some cases, FDEIA symptoms can be induced by aspirin and the causative food without exercise. Exercise may only be an augmenting factor of FDEIA, similar to aspirin or alcohol.

SUMMARY

The mechanisms of FDEIA development remain unclear. It has been suggested that in FDEIA, exercise lowers the threshold of a food allergy. Further research is needed to elucidate the mechanism of FDEIA and to establish strategies for effective disease management.

Identification and molecular characterization of allergenic non-specific lipid-transfer protein from durum wheat (Triticum turgidum)

BACKGROUND

Common wheat (Triticum aestivum) and durum wheat (T. turgidum) are both involved in Baker's asthma (BA) and food allergy (FA) including wheat-dependent exercise-induced asthma (WDEIA). However, allergens in durum wheat have not been described, and the over-expression of T. turgidum non-specific lipid-transfer protein (nsLTPs) is considered to increase resistance to phytopathogens.

OBJECTIVE

To identify and assess the allergenicity of nsLTP from T. turgidum.

METHODS

Recombinant T. turgidum nsLTP Tri tu 14 was generated and tested for structural integrity (circular dichroism-spectroscopy) and purity (SDS-PAGE). Thirty-two wheat allergic patients were enrolled: 20 Spanish patients (BA) with positive bronchial challenge to wheat flour, and 12 Italian patients (wheat FA/WDEIA) with positive double-blind placebo-controlled food challenge/open food challenge (OFC) to pasta. IgE values to wheat, Tri tu 14, Tri a 14 (T. aestivum) and Pru p 3 (P. persica) were determined by ImmunoCAP testing. Allergenic potency (in vitro mediator release) and IgE cross-reactivity were investigated.

RESULTS

Tri tu 14 was found to share 49% and 52% amino acid identity with Tri a 14 and Pru p 3, respectively. Among 25 Tri a 14 CAP positive sera, 23 (92%) were reactive to wheat extract, 22 (88%) to Tri tu 14 and 20 (80%) to Pru p 3. The correlation between Tri a 14 and Tri tu 14 specific IgE levels was r = 0.97 (BA) and r = 0.93 (FA/WDEIA), respectively. FA/WDEIA patients showed higher specific IgE values to Tri tu 14 and Pru p 3 than BA patients. Tri tu 14 displayed allergenic activity by mediator release from effector cells and IgE cross-reactivity with Pru p 3. The degree of IgE cross-reactivity between the two wheat nsLTPs varied between individual patients.

CONCLUSIONS AND CLINICAL RELEVANCE

Sensitization to Tri tu 14 likely appears to be more important in wheat FA/WDEIA than in BA. Over-expression of Tri tu 14 in wheat would represent a risk for patients with nsLTP-mediated FA.

Gluten sensitivities and the allergist: Threshing the grain from the husks

"Gluten sensitivity" has become commonplace among the public. Wheat allergy (WA) and celiac disease (CD) are well-defined entities, but are becoming a fraction of individuals following a gluten-free diet (GFD). Wheat allergy has a prevalence of <0.5%. Wheat, specifically its omega-5 gliadin fraction, is the most common allergen implicated in food-dependent, exercise-induced anaphylaxis. CD is a non-IgE hypersensitivity to certain cereal proteins: gluten in wheat, secalin in rye, hordein in barley, and to a lesser extent avenin in oat. It is a rare disease, with an estimated prevalence that varied widely geographically, being higher in Northern Europe and the African Saharawi region than in South-East Asia. In addition to suggestive symptoms, serologic testing has high diagnostic reliability and biopsy is a confirmatory procedure. Patients with CD have extra-intestinal autoimmune comorbid conditions more frequently than expected. A third entity is nonceliac gluten sensitivity, which has been created because of the increasing number of subjects who claim a better quality of life or improvement of their variety of symptoms on switching to a GFD. The phenomenon is being fueled by the media and exploited by the industry. The lack of a specific objective test has been raising substantial controversy about this entity. Allergists and gastroenterologists need to pay attention to the multitudes of individuals who elect to follow a GFD. Many such subjects might have WA, CD, or another illness. Providing them with appropriate evaluation and specific management would be of great advantages, medically and economically.

Mite-Induced Asthma and IgE Levels to Shrimp, Mite, Tropomyosin, Arginine Kinase, and Der p 10 Are the Most Relevant Risk Factors for Challenge-Proven Shrimp Allergy

BACKGROUND

Shrimp sensitization is common in the general population, but the presence of symptoms is only moderately related to sensitization. A point still at issue is which in vivo and/or in vitro tests (food challenge, component-resolved diagnosis, house dust mite [HDM] sensitization) can help in distinguishing shrimp-allergic subjects from subjects that are sensitized but tolerant.

METHODS

The aim of this study was to evaluate the role of IgE to the different shrimp and mite allergens in distinguishing shrimp challenge-positive from challenge-negative patients. Subjects with suspected hypersensitivity reactions to shrimp, positive skin prick tests (SPTs), and/or anti-shrimp IgE were submitted to open and double-blind placebo-controlled food challenges (DBPCFC). Specific IgE to shrimp, mites, and the recombinants rPen a 1, rDer p 1, 2, and 10 were tested using ImmunoCAP-FEIA. IgE immunoblotting was performed to identify the patients' allergenic profiles.

RESULTS

In total, 13 out of 51 (25.5%) patients with reported reactions to shrimp were truly shrimp allergic (7 DBPCFC positive and 6 with documented severe reactions). These patients had significantly higher skin test wheal diameters than nonallergic patients, as well as higher levels of IgE to rPen a 1 and rDer p 10. HDM-induced asthma and the simultaneous presence of anti-nDer p 1, 2, and 10 IgE levels increased the risk of true shrimp allergy.

CONCLUSION

Food challenge tests are mandatory for the diagnosis of shrimp allergy. Tropomyosin is associated with clinical reactivity. HDM-induced asthma and anti-mite IgE are risk factors for shrimp allergy.

Food-Dependent, Exercise-Induced Anaphylaxis: Diagnosis and Management in the Outpatient Setting

Food-dependent, exercise-induced anaphylaxis is a disorder in which anaphylaxis develops most predictably during exercise, when exercise takes place within a few hours of ingesting a specific food. IgE to that food should be demonstrable. It is the combination of the food and exercise that precipitates attacks, whereas the food and exercise are each tolerated independently. Recently, it was demonstrated that exercise is not essential for the development of symptoms, and that if enough of the culprit food is ingested, often with additional augmentation factors, such as alcohol or acetylsalicylic acid, symptoms can be induced at rest in the challenge setting. Thus, food-dependent, exercise-induced anaphylaxis appears to be more correctly characterized as a food allergy syndrome in which symptoms develop only in the presence of various augmentation factors, with exercise being the primary one. However, additional factors are not usually present when the patient exercises normally, so ongoing investigation is needed into the physiologic and cellular changes that occur during exercise to facilitate food-induced anaphylaxis.

Component-resolved diagnosis in anaphylaxis

PURPOSE OF REVIEW

Component-resolved diagnosis (CRD) is an advanced tool capable of aiding the clinician in fine tuning the diagnosis of the causal allergens of a reaction with the added value of providing information of severity risk, potential cross-reactivity, and subsequently, guiding management measures. This review will focus on the advantages of CRD of anaphylaxis in clinical practice.

RECENT FINDINGS

Research is continuously providing insight to which molecules are associated with genuine sensitization and/or potential severity risk for hymenoptera venom (Api m1, Ves v 1, Ves v 5, and Pol d 5), food allergy (seed storage proteins and nonspecific lipid transfer proteins), cofactor-enhanced food allergy (ω-5-gliadine, nonspecific lipid transfer proteins), red meat delayed anaphylaxis (α-gal), latex allergy (Hev b 1, Hev b 3, Hev b 5, and Hev b 6), and Anisakis allergy (Ani s 1, Ani s 4, Ani s 7, and Ani s 13); other molecules are primary associated with nonclinically relevant sensitizations, cross-reactivity, or mild reactions (carbohydrate determinants and profilins). New molecules, some minor allergens, are being identified as new potential biomarkers of severity.

SUMMARY

The usefulness of CRD in anaphylaxis is self-evident, since it improves the recognition of sensitization profiles associated with specific clinical outcomes and provides information to guide further management.

Cross-reactive LTP sensitization in food-dependent exercise-induced urticaria/anaphylaxis: a pilot study of a component-resolved and in vitro depletion approach

Background

Challenge tests for food-dependent exercise-induced anaphylaxis (FDEIA) carry some risk and have a high rate of false negatives. Our aim was to explore the usefulness of an in vitro immunodepletion assay and an allergen microarray test in the identification of IgE-mediated cross-reactive food allergens in patients with suspected FDEIA or food-dependent exercise-induced urticaria and panallergen sensitization.

Methods

Three patients with a history of food dependent exercise induced urticaria/anaphylaxis and food panallergen sensitization in whom a food-exercise challenge was not feasible were selected: a 25-year-old man with cholinergic urticaria who experienced generalized urticaria and angioedema during a soccer match after drinking a peach-based soft drink; a 19-year-old woman with allergic rhinitis and controlled asthma who experienced anaphylactic shock while playing soccer, having eaten walnuts in the previous 90 min; and a 57-year-old man with baker’s asthma who experienced four episodes of anaphylaxis during exercise after ingesting wheat-containing food. All individuals underwent a diagnostic work-up with skin prick tests, specific IgE (sIgE) and ImmunoCAP ISAC test. For the in vitro immunodepletion procedure, patients’ serum was pre-incubated with the suspected native allergen (peach, walnut, or wheat) in solid phase (ImmunoCAP). The eluted serum, containing unbound IgE, was collected and samples were re-tested using Immunocap ISAC 112 and compared with baseline results.

Results

All individuals were sensitized to lipid transfer proteins. The first patient was sensitized to Pru p 3, Cor a 8, Jug r 3, and Ara h 9; after pre-incubation with peach there was 100% depletion of sIgE to all components. The second patient was sensitized to Pru p 3, Cor a 8, Jug r 3, and Ara h 9; immunodepletion with walnut depleted sIgE to Ara h 9 by 67%, Pru p 3 and Pla a 3 (60%), Art v 3 (75%), Jug r 3 (88%), and Cor a 8 (100%). The third patient was sensitized to Pru p 3, Jug r 3, Ara h 9, and Tri a 14; immunodepletion with wheat depleted Tri a 14 only (100%).

Conclusions

In vitro immunodepletion might be a useful diagnostic tool in food dependent exercise induced urticaria/anaphylaxis with panallergen sensitization, particularly for identifying the culprit allergen and guiding dietary elimination recommendations.

Diagnosis of exercise-induced anaphylaxis: current insights

Exercise-induced anaphylaxis (EIAn) is defined as the occurrence of anaphylactic symptoms (skin, respiratory, gastrointestinal, and cardiovascular symptoms) after physical activity. In about a third of cases, cofactors, such as food intake, temperature (warm or cold), and drugs (especially nonsteroidal anti-inflammatory drugs) can be identified. When the associated cofactor is food ingestion, the correct diagnosis is food-dependent EIAn (FDEIAn). The literature describes numerous reports of FDEIAn after intake of very different foods, from vegetables and nuts to meats and seafood. One of the best-characterized types of FDEIAn is that due to ω5-gliadin of wheat, though cases of FDEIAn after wheat ingestion by sensitization to wheat lipid transfer protien (LTP) are described. Some pathophysiological mechanisms underlying EIAn have been hypothesized, such as increase/alteration in gastrointestinal permeability, alteration of tissue transglutaminase promoting IgE cross-linking, enhanced expression of cytokines, redistribution of blood during physical exercise leading to altered mast-cell degranulation, and also changes in the acid–base balance. Nevertheless, until now, none of these hypotheses has been validated. The diagnosis of EIAn and FDEIAn is achieved by means of a challenge, with physical exercise alone for EIAn, and with the assumption of the suspected food followed by physical exercise for FDEIAn; in cases of doubtful results, a double-blind placebo-controlled combined food–exercise challenge should be performed. The prevention of this particular kind of anaphylaxis is the avoidance of the specific trigger, ie, physical exercise for EIAn, the assumption of the culprit food before exercise for FDEIAn, and in general the avoidance of the recognized cofactors. Patients must be supplied with an epinephrine autoinjector, as epinephrine has been clearly recognized as the first-line intervention for anaphylaxis.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Common food allergens and their IgE-binding epitopes

Food allergy is an adverse immune response to certain kinds of food. Although any food can cause allergic reactions, chicken egg, cow's milk, wheat, shellfish, fruit, and buckwheat account for 75% of food allergies in Japan. Allergen-specific immunoglobulin E (IgE) antibodies play a pivotal role in the development of food allergy. Recent advances in molecular biological techniques have enabled the efficient analysis of food allergens. As a result, many food allergens have been identified, and their molecular structure and IgE-binding epitopes have also been identified. Studies of allergens have demonstrated that IgE antibodies specific to allergen components and/or the peptide epitopes are good indicators for the identification of patients with food allergy, prediction of clinical severity and development of tolerance. In this review, we summarize our current knowledge regarding the allergens and IgE epitopes in the well-researched allergies to chicken egg, cow's milk, wheat, shrimp, and peanut.

Diagnosis and treatment of pediatric food allergy: an update

The prevalence of pediatric food allergy and anaphylaxis has increased in the last decades, especially in westernized countries where this emerging phenomenon was marked as a "second wave" of the allergic epidemic. Over recent years great advances have been achieved in the field of in vitro allergy testing and component-resolved diagnosis has increasingly entered clinical practice. Testing for allergen components can contribute to a more precise diagnosis by discriminating primary from cross-reactive sensitizations and assessing the risk of severe allergic reactions.The basic concept of the management of food allergy in children is also changing. Avoidance of the offending food is still the mainstay for disease management, especially in primary health care settings, but it severely affects the patients' quality of life without reducing the risk of accidental allergic reactions. There is a growing body of evidence to show that specific oral tolerance induction can represent a promising treatment option for food allergic patients. In parallel, education of food allergic patients and their caregivers as well as physicians about anaphylaxis and its treatment is becoming recognized a fundamental need. International guidelines have recently integrated these new evidences and their broad application all over Europe represents the new challenge for food allergy specialists.

Anaphylaxis and sport

PURPOSE OF REVIEW

This article aims to review the most relevant studies on exercise-induced anaphylaxis, published in the last year, in order to provide comprehensive and updated evidence and hopefully contribute to a better definition of its pathophysiological mechanisms and treatment strategies.

RECENT FINDINGS

The search strategy was performed from 1/2/2013 to 31/1/2014 by scanning the principal electronic bibliographic database and by hand-searching the main scientific publications in Allergy and Clinical Immunology. Among the identified articles, 17 articles were selected to be part of the systematic review. Eligible studies included five experimental trials, eight case reports and four letters.

SUMMARY

The overall collected evidence was of very low quality. No randomized controlled trials were identified by the searching process. Most of the data derived from reports performed in small population samples or even in individual cases. Except for one article addressing issues related to the preventive management of exercise-induced anaphylaxis, all other articles focused on prevalence rates, causative triggers and pathogenetic mechanisms. More interesting findings were related to the influence of the IL-4-C590T polymorphism on the onset of wheat-dependent exercise-induced anaphylaxis and to the usefulness of the immuno solid-phase allergen chip technique in the allergic screening of polysensityzed athletes at risk of severe reactions.

Component resolved diagnosis: when should it be used?

The knowledge on molecular allergy diagnosis is continuously evolving. It is now time for the clinician to integrate this knowledge and use it when needed to improve the accuracy of diagnosis and thus provide more precise therapeutic and avoidance measures. This review does not intend to comprehensively analyze all the available allergen molecules, but to provide some practical clues on use and interpretation of molecular allergy diagnosis. The potential role of component resolved diagnosis in circumstances such as the indication of allergen immunotherapy, pollen polysensitization, food allergy, latex allergy or anaphylaxis, is assessed. Interpreting the information provided by molecular allergy diagnosis needs a structured approach. It is necessary to evaluate single positivities and negativities, but also to appraise "the big picture" with perspective.