Recent advances of in vitro tests for the diagnosis of food-dependent exercise-induced anaphylaxis

Detection of Sensitization Profiles with Cellular In Vitro Tests in Wheat Allergy Dependent on Augmentation Factors (WALDA)

Wheat allergy dependent on augmentation factors (WALDA) is the most common gluten allergy in adults. IgE-mediated sensitizations are directed towards ω5-gliadin but also to other wheat allergens. The value of the different in vitro cellular tests, namely the basophil activation test (BAT) and the active (aBHRA) and passive basophil histamine-release assays (pBHRA), in the detection of sensitization profiles beyond ω5-gliadin has not been compared. Therefore, 13 patients with challenge-confirmed, ω5-gliadin-positive WALDA and 11 healthy controls were enrolled. Specific IgE (sIgE), skin prick tests, BATs, aBHRA, and pBHRA were performed with allergen test solutions derived from wheat and other cereals, and results were analyzed and compared. This study reveals a distinct and highly individual reactivity of ω5-gliadin-positive WALDA patients to a range of wheat allergens beyond ω5-gliadin in cellular in vitro tests and SPT. In the BAT, for all tested allergens (gluten, high-molecular-weight glutenin subunits, α-amylase/trypsin inhibitors (ATIs), alcohol-free wheat beer, hydrolyzed wheat proteins (HWPs), rye gluten and secalins), basophil activation in patients was significantly higher than in controls (p = 0.004-p < 0.001). Similarly, significant histamine release was detected in the aBHRA for all test substances, exceeding the cut-off of 10 ng/mL in all tested allergens in 50% of patients. The dependency of tests on sIgE levels against ω5-gliadin differed; in the pBHRA, histamine release to any test substances could only be detected in patients with sIgE against ω5-gliadin ≥ 7.7 kU/L, whereas aBHRA also showed high reactivity in less sensitized patients. In most patients, reactivity to HWPs, ATIs, and rye allergens was observed. Additionally, alcohol-free wheat beer was first described as a promising test substance in ω5-gliadin-positive WALDA. Thus, BAT and aBHRA are valuable tools for the identification of sensitization profiles in WALDA.

Identification of RNAi hypoallergic bread wheat lines for wheat-dependent exercise-induced anaphylaxis patients

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is one of the most severe forms of wheat allergy. It occurs in patients when they exercise after ingesting wheat-containing foods. Nowadays, the only possible alternative for WDEIA patients is to avoid such foods. This study investigated the potential of six RNA of interference (RNAi) wheat lines with low-prolamin content as alternatives for WDEIA patients. For that purpose, a high performance-liquid chromatography (HPLC) analysis was performed to evaluate differences in gluten protein fractions among these lines. Next, western blots were conducted to measure the immunoglobulin E (IgE) reactivity to wheat proteins in sera from five WDEIA patients. Additionally, monoclonal antibodies (moAb) recognition sites and the IgE binding sites were searched in all peptides identified by LC-MS/MS after protein digestion. The results showed a 61.4%-81.2% reduction in the gliadin content of the RNAi lines, accompanied by an increase in their high-molecular weight (HMW) glutenin content compared to the wild type bread wheat line (WT). In all cases, the reduction in gliadin content correlated with a decrease in IgE reactivity observed in the sera of WDEIA patients, highlighting the E82 and H320 lines. These two RNAi lines exhibited a ≤90% reduction in IgE reactivity. This reduction could be attributed to an absence of IgE binding sites associated with α- and ω5-gliadins, which were present in the WT. Overall, these lines offer a potential alternative for foodstuff for individuals with WDEIA.

Genome-wide association study reveals an association between the HLA-DPB1∗02:01:02 allele and wheat-dependent exercise-induced anaphylaxis

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a life-threatening food allergy triggered by wheat in combination with the second factor such as exercise. The identification of potential genetic risk factors for this allergy might help high-risk individuals before consuming wheat-containing food. We aimed to identify genetic variants associated with WDEIA. A genome-wide association study was conducted in a discovery set of 77 individuals with WDEIA and 924 control subjects via three genetic models. The associations were confirmed in a replication set of 91 affected individuals and 435 control individuals. Summary statistics from the combined set were analyzed by meta-analysis with a random-effect model. In the discovery set, a locus on chromosome 6, rs9277630, was associated with WDEIA in the dominant model (OR = 3.95 [95% CI, 2.31-6.73], p = 7.87 × 10-8). The HLA-DPB1∗02:01:02 allele displayed the most significant association with WDEIA (OR = 4.51 [95% CI, 2.66-7.63], p = 2.28 × 10-9), as determined via HLA imputation following targeted sequencing. The association of the allele with WDEIA was confirmed in replication samples (OR = 3.82 [95% CI, 2.33-6.26], p = 3.03 × 10-8). A meta-analysis performed in the combined set revealed that the HLA-DPB1∗02:01:02 allele was significantly associated with an increased risk of WDEIA (OR = 4.13 [95% CI, 2.89-5.93], p = 1.06 × 10-14). Individuals carrying the HLA-DPB1∗02:01:02 allele have a significantly increased risk of WDEIA. Further validation of these findings in independent multiethnic cohorts is needed.

Identification of peroxidase-1 and beta-glucosidase as cross-reactive wheat allergens in grass pollen-related wheat allergy

BACKGROUND

Some patients with wheat-dependent exercise-induced anaphylaxis (WDEIA) or wheat allergy showed negative ω-5 gliadin-specific IgE test and high level of grass pollen-specific IgE. It was presumed that these patients developed allergic reaction upon cross-reaction of their IgE antibodies raised against grass pollen allergens to wheat allergens. This study aimed to clarify clinical characteristics and wheat allergens of this phenotype of WDEIA/wheat allergy, which were tentatively diagnosed as grass pollen-related wheat allergy (GPWA).

METHODS

A total of six patients with GPWA were enrolled, and controls were 17 patients with grass pollen allergy but no episode of wheat allergy, and 29 patients with other wheat allergies: 18 with conventional WDEIA and 11 with hydrolyzed wheat protein allergy. Sensitization to wheat proteins was determined by basophil activation test (BAT). IgE-binding proteins in wheat flour were identified by immunoblotting followed by mass spectrometry. Wheat allergen-specific IgE tests were established by CAP-FEIA system.

RESULTS

All the six patients with GPWA were sensitized to water-soluble wheat proteins in BAT and IgE-immunoblotting, and peroxidase-1 (35 kDa) and beta-glucosidase (60 kDa) were identified as specific IgE-binding wheat proteins. The binding of patient IgE to these proteins was inhibited by pre-incubation of patient sera with grass pollen. The peroxidase-1- and beta-glucosidase-specific IgE tests identified three and four of six patients with GPWA, respectively, but only two of 29 controls, indicating high specificity of these tests.

CONCLUSIONS

Peroxidase-1 and beta-glucosidase are specific wheat allergens for GPWA among grass pollen allergy and other types of wheat-induced food allergies.

Wheat-dependent exercise-induced anaphylaxis in Chinese people: a clinical research on 33 cases with antigenic analysis of wheat proteins

BACKGROUND

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a severe allergic condition in which wheat ingestion together followed by physical exercise induces anaphylaxis. For patients with WDEIA, omega-5 gliadin is considered to be one of the major allergens.

AIM

To analyse the clinical features and allergen spectrum of WDEIA and to investigate the relationship between WDEIA and serum levels of platelet-activating factor (PAF), interleukin (IL)-9 and IL-33.

METHODS

Medical histories and conditions of WDEIA cases were collected and summarized, with allergen tests of wheat proteins measured at the same visit. Of the 33 patients enrolled, 13 also had serum levels of PAF, IL-9 and IL-33 measured. The healthy control (HC) group consisted of 13 healthy individuals, who also underwent both the wheat-protein allergen tests and the inflammatory-mediator tests.

RESULTS

All patients experienced severe allergic reaction during exercise after wheat ingestion. Manifestations of WDEIA included facial oedema, generalized urticaria and respiratory symptoms. Unconsciousness was also observed in 21 cases. In the patient group, 57.6% were confirmed as hypersensitive to glyceraldehyde-3-phosphate dehydrogenase (GAPDH), while 54.5% were allergic to omega-5 gliadin. PAF concentration was significantly higher in patients with WDEIA compared with HCs, whereas there was no significant difference in IL-9 or IL-33 between the two groups.

CONCLUSIONS

WDEIA is a rare type of anaphylaxis. GAPDH and omega-5 gliadin may be the most common allergy-causing wheat proteins for Chinese people. PAF may be associated with the onset and development of WDEIA.

Diagnosis and prevention of food-dependent exercise-induced anaphylaxis

Introduction: Food-dependent, exercise-induced anaphylaxis (FDEIA) is a rare type of anaphylaxis with a growing incidence. Although the precise mechanism by which the patient reacts only in a combination of a culprit food and cofactors are not currently understood, many advances in diagnosis and management have been made since their first description. Areas covered: A literature search in PubMed was performed to review the diagnosis and management of FDEIA. Clinicians should have a high level of suspicion for identification of the culprit foods and the cofactors involved. Component-resolved diagnosis and more accurate provocation tests have revolutionized the diagnosis accuracy. Management is not easy and involves educating the patient to evict the combination of exposure to the culprit foods and the cofactors that elicit anaphylaxis, and how to act and treat if a reaction occurs. Expert opinion: FDEIA is currently misdiagnosed and the authors believe that there are many FDEIA patients labelled as idiopathic anaphylaxis with unnecessary evictions and with a poor quality of life because of the fear of an imminent reaction. Due to recent advances in diagnostic tools and the use of monoclonal antibodies for prophylaxis in persistent cases, FDEIA can have a better prognosis improving the quality of life of the patients and their families.

Gastrointestinal Conditions in the Female Athlete

Exercise can have significant effects on gastrointestinal diseases. Regular, moderate exercise can impart beneficial effects for the intestinal microbiome, irritable bowel syndrome symptoms, and inflammatory bowel disease. High-intensity training or prolonged endurance training, on the other hand, can have negative effects on these same entities. Female athletes report a higher prevalence of irritable bowel syndrome and celiac disease, and furthermore, have gastrointestinal symptoms modulated by the menstrual cycle. Management of gastrointestinal problems in the athletic population is widespread and includes training adjustments, dietary measures, and medicine management of symptoms.

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.

Wheat-dependent exercise-induced anaphylaxis

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a rare, but potentially severe food allergy exclusively occurring when wheat ingestion is accompanied by augmenting cofactors. It is clinically characterized by anaphylactic reactions ranging from urticaria and angioedema to dyspnoea, hypotension, collapse, and shock. WDEIA usually develops after ingestion of wheat products followed by physical exercise. Other cofactors are acetylsalicylic acid and other non-steroidal anti-inflammatory drugs, alcohol, and infections. The precise mechanisms of WDEIA remain unclear; exercise and other cofactors might increase gastrointestinal allergen permeability and osmolality, redistribute blood flow, or lower the threshold for IgE-mediated mast cell degranulation. Among wheat proteins, ω5-gliadin and high-molecular-weight glutenin subunits have been reported to be the major allergens. In some patients, WDEIA has been discussed to be caused by epicutaneous sensitization with hydrolysed wheat gluten included in cosmetics. Diagnosis is made based on the patient's history in combination with allergy skin testing, determination of wheat-specific IgE serum antibodies, basophil activation test, histamine release test, and/or exercise challenge test. Acute treatment includes application of adrenaline or antihistamines. The most reliable prophylaxis of WDEIA is a gluten-free diet. In less severe cases, a strict limitation of wheat ingestion before exercise and avoidance of other cofactors may be sufficient.

Clinical Characteristics of Inpatients with Anaphylaxis in China

OBJECTIVE

To analyze the clinical characteristics of inpatients with anaphylaxis and the factors that influenced those characteristics.

METHODS

Using the patient records from 1990 to 2013 from three highly ranked Chinese hospitals, we retrospectively analyzed the characteristics of 108 inpatients with anaphylaxis (not anaphylaxis admitted).

RESULTS

The mean patient age was 42 ± 20 years old and male-to-female ratio was 1 : 1.3. The number of patients with anaphylaxis increased gradually, and cases diagnosed after 2005 accounted for 68.5% of the 108 total cases. The most common trigger was medications. The most common clinical manifestations included cutaneous, nervous, respiratory, circulatory, and digestive signs and symptoms. Male patients were more likely to experience loss of consciousness. Multisystem involvement was more likely to develop in patients with low BP, whereas it was uncommon in those with anaphylaxis induced by antibiotics or anesthetics. Epinephrine was used as the first-line treatment for 56 cases.

CONCLUSIONS

Inpatient with anaphylaxis was more common in female patients and the number increased gradually during the study period. The most common trigger was medications. Patients with low BP were prone to having multisystem involvement, whereas the cases of anaphylaxis induced by antibiotics and anesthetics were less likely to involve multiple organ systems.

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.

Exercise-induced Anaphylaxis: the Role of Cofactors

Introduction:

Anaphylaxis is a dramatic clinical emergency. It is a very severe, life-threatening generalized or systemic hypersensitivity reaction. Based on immunologic mechanism the anaphylaxis is divided in IgE, IgG, complement, or immune complexes-mediated vs non allergic anaphylaxis. There are a lot of etiologic factors of anaphylaxis, but the three principal immunologic triggers are drugs, insect stings, and foods. Regarding the clinical severity there are several proposed grading systems. The diagnosis of anaphylaxis is mainly clinical.

Discussion:

The anaphylaxis markers measured in clinical laboratories are total tryptase and histamine. There are some conditions that modulate the onset of anaphylaxis, acting as co- or augmentation factors, which significantly lower the allergen dose necessary for triggering anaphylaxis. The well-documented cofactors of anaphylaxis are physical exercise, alcohol consumption, some foods, co-administration of nonsteroidal anti-inflammatory drugs (NSAID), and concomitant infectious diseases. Development of anaphylaxis depends on the sensitization pattern, the proportion of the involved immunoglobulin classes, characteristics of the allergen, the proportion of the involved immunoglobulin classes, the avidity and affinity of immunoglobulins to bind an allergen, the route of allergen application, and, last but not least, the presence of cofactors of anaphylaxis.

Conclusion:

Anaphylaxis remains a continuous challenge for the diagnosis and treatment. The adequate management of anaphylaxis requires rapid diagnosis, implementation of primary and secondary prevention measures, and immediate administration of subcutaneous epinephrine.

Wheat-dependent exercise-induced anaphylaxis: a retrospective case review from a tertiary hospital

BACKGROUND

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a specific form of wheat allergy caused by the combination of wheat ingestion and physical exercise and has been reported in other parts of Asia. At present, there are no published reports of WDEIA in Singapore. The objective of this study is to characterise the common local clinical and laboratory manifestations of WDEIA.

METHODS

This was a retrospective descriptive study of all WDEIA who presented to a tertiary Singaporean Hospital over a 5-year-period from 1 January 2009 to 30 June 2013.

RESULTS

Eight patients aged 9-41 years old were characterised. Six were males and the majority (5) was of Chinese ethnicity. An atopic history was found in four patients. The symptoms of anaphylaxis included cutaneous manifestations such as urticaria (n=7), angioedema (n=6), respiratory symptoms of dyspnoea and wheezing (n=5) and hypotension (n=5). The symptoms occurred 20-75 min after consumption of wheat-based products, often upon cessation of exercise [running (n=3), walking (n=4) and swimming (n=1)]. The WDEIA was recurrent in seven patients. The skin prick tests were positive to wheat in seven patients, and ω-5 gliadin test to wheat was positive in five patients.

CONCLUSIONS

With the emergence of wheat allergy in East Asian countries, WDEIA has become an important condition for physicians and Singapore is no exception. Under-recognition combined with life-threatening symptoms warrants better public awareness measures. In addition, further studies are necessary to identify possible unique genetic and environmental exposures that could explain the inter-regional differences of WDEIA.

Food-dependent exercise-induced anaphylaxis: is wheat unique?

This review draws comparisons between wheat-dependent exercise-induced anaphylaxis (WDEIA) and other food-dependent exercise-induced anaphylaxis (FDEIAs) and discusses the importance of co-factors in its pathophysiology. FDEIA remains an enigmatic condition since it was first described 30 years ago. The sporadic and unpredictable nature of its reactions has puzzled clinicians and scientists for decades, but recent studies on WDEIA have enlightened us about the pathophysiology of this condition. The identification of defined allergic epitopes such as Tri a 19, α-gliadin, β-gliadin and γ-gliadin in WDEIA enables it to become the perfect model for studying FDEIA, but WDEIA is by no means a unique condition. On a larger scale, FDEIA represents a crucial link between IgE-mediated and anaphylactoid reactions and provides supportive evidence for the concept of 'summation anaphylaxis' and the need to overcome the 'allergen threshold'. Future work should focus on identifying more of the FDEIA epitopes and understanding their distinct molecular properties. The development of a biomarker in order to identify patients susceptible to co-factor influences would be invaluable.