Food Allergy Diagnostics Research Articles

Differential diagnostics of food allergy as based on provocation tests and laboratory diagnostic assays.

Due to the scale of the phenomenon, food allergy constitute a significant health problem and significantly impair the quality of life of patients. Differential diagnostics, including skin tests, sIgE detection tests, basophil and mast cell activation tests as well as double-blind placebo-controlled food challenge tests, is the gold standard in the diagnosis of food allergy. Recently, increasing attention has been paid to the potential use of nasal provocation test in the diagnosis of food allergy. Allergen dose, protocol standardization, assessment of subjective complaints and objectivization of test results are important factors determining the applicability of provocation tests.

Bringing the Next Generation of Food Allergy Diagnostics Into the Clinic

Bringing the Next Generation of Food Allergy Diagnostics Into the Clinic

Bringing the Next Generation of Food Allergy Diagnostics Into the Clinic

Food allergy diagnosis has a massive impact on the lives of patients and their families. Despite recent developments with specific IgE to component allergens, a significant proportion of patients assessed for possible food allergy require oral food challenge to ensure an accurate diagnosis. More precise diagnostic methods are required to reduce the need for oral food challenges. Bead-based epitope assays and cellular tests, such as basophil activation and mast cell tests are the most novel and promising tests on the horizon. There is a pathway to pursue to enable their incorporation in clinical practice, including standardization, technical validation, clinical validation, external validation, overcoming practical and logistical issues, and regulatory approval. Valuable clinical application of these tests goes beyond diagnosis and includes risk assessment to identify allergic patients who are most sensitive and at risk for severe allergic reactions, and to define prognosis and assess clinical response to immunomodulatory treatments.

Algorithm of conducting oral provocation tests with milk in 1–3-year-old children: analysis of existing standards and own experience

Introduction. Food allergy is an urgent problem in modern pediatrics. Cow’s milk is the main food allergen in young children. By the age of one year, from 0.5 % to 3 % of children suffer from cow’s milk protein allergy. Aim. To analyze the existing standards of conducting oral provocation tests with milk in young children and suggest own algorithm of diagnostics. Materials and methods. Algorithm of diagnosing cow’s milk allergy was probated in 107 children aged from one to three years in Communal Municipal Children’s Clinical Hospital. To diagnose cow’s milk allergy, compilation of allergological anamnesis, examination, assessment of physical development, and determination of specific IgE to cow’s milk are performed. Then, different oral provocation tests are conducted based on the obtained results: at the allergist’s office on an outpatient basis, in a specialized inpatient department, in an intensive care unit. Results. Among 107 children, who were subjected to oral provocation test with milk, cow’s milk protein allergy was diagnosed in 67 (62.62 %). In children, who were diagnosed cow’s milk protein allergy (n = 67), skin (41.79 %) and gastrointestinal (28.36 %) symptoms prevailed. In the group of children with predictable low risk of allergy, diameter of a papule equaled 3.86 ± 0.62 mm2, the level of specific IgE to milk in blood serum was 0.58 [0.37–0.68], and in the group with medium risk – 5.51 ± 1.38 mm2 and 3.62 [0.86–9.66] kU/L, respectively. All 40 children, in whom cow’s milk protein allergy was not confirmed, constituted the group with predictable low risk of reaction development. Diameter of a papule during prick-test equaled 3.13 ± 0.24 mm2, the level of specific IgE to milk in blood serum was 0.36 [0.35–0.67] kU/L. In this group of children, complaints of gastrointestinal symptoms (82.5 %) prevailed. Conclusions. A complex diagnostic approach, in particular, study of anamnesis, examination, assessment of physical development, record of food diary, determination of specific IgE to milk, oral provocation tests enable to optimize diagnostics of food allergy and choose further therapeutic tactics. Algorithm of diagnosing cow’s milk protein allergy in 1–3-year-old children has been elaborated, which can be recommended for common application in clinical practice.

Can alternative epitope mapping approaches increase the impact of B-cell epitopes in food allergy diagnostics?

Summary In vitro allergy diagnostics are currently based on the detection of specific IgE binding on intact allergens or a mixture thereof. This approach has drawbacks as it may yield false‐negative and/or false‐positive results. Thus, we reviewed the impact of known B‐cell epitopes of food allergens to predict transience or persistence, tolerance or allergy and the severity of an allergic reaction and to examine new epitope mapping strategies meant to improve serum‐based allergy diagnostics. Recent epitope mapping approaches have been worthwhile in epitope identification and may increase the specificity of allergy diagnostics by using epitopes predominately recognized by allergic patients in some cases. However, these approaches did not lead to discrimination between clinically relevant and irrelevant epitopes so far, since the polyclonal serum IgE‐binding epitope spectrum seems to be too individual, independent of the disease status of the patients. New epitope mapping strategies are necessary to overcome these obstacles. The use of patient‐derived monoclonal antibodies instead of patient sera for functional characterization of clinically relevant and irrelevant epitope combinations, distinguished by their ability to induce degranulation, might be a promising approach to gain more insight into the allergic reaction and to improve serum‐based allergy diagnostics.

A Proof-of-Concept of Label-Free Biosensing System for Food Allergy Diagnostics in Biophotonic Sensing Cells: Performance Comparison with ImmunoCAP

Food allergy is a common disease worldwide with over 6% of the population (200–250 million people) suffering from any food allergy nowadays. The most dramatic increase seems to be happening in children and young people. Therefore, improvements in the diagnosis efficiency of these diseases are needed. Immunoglobulin type E (IgE) biomarker determination in human serum is a typical in vitro test for allergy identification. In this work, we used a novel biosensor based on label-free photonic transducers called BICELLs (Biophotonic Sensing Cells) for IgE detection. These BICELLs have a thin film of nitrocellulose over the sensing surface, they can be vertical optically interrogated, and are suitable for being integrated on a chip. The BICELLs sensing surface sizes used were 100 and 800 µm in diameter. We obtained calibration curves with IgE standards by immobilizating anti-IgE antibodies and identified with standard IgE calibrators in minute sample amounts (3 µL). The results, in similar assay format, were compared with commercially available ImmunoCAP®. The versatility of the interferometric nitrocellulose-based sensing surface was demonstrated since the limit of detections for BICELLs and ImmunoCAP® were 0.7 and 0.35 kU/L, respectively.

What is new in food allergy diagnostics? A practice-based approach

What is new in food allergy diagnostics? A practice-based approach

The possibility of food allergy diagnostics in Bukovyna

The possibility of food allergy diagnostics in Bukovyna

Food sensitisation patterns measured by ISAC multiplex assay in the Netherlands

Component-resolved diagnostics is increasingly used in food allergy diagnostics. In a Dutch tertiary patient population we determined the sensitization patterns and protein families involved in our population using the multiplex Immuno-Solid phase Allergen Chip (ISAC). Multiplex ISAC tests were performed in case of suspicion of (extensive) poly-sensitization in patients referred for food allergy and/or atopic eczema. Patient history of 40 random patients who have had an ISAC was analysed to determine the clinical value of the ISAC. Of 943 ISAC tests, 852 showed sensitization to at least one component and were included for further analysis. Mean age was 33,4 years. The majority of patients in our population was poly-sensitized, with 66% recognizing more than ten components. The most recognized component was Bet v 1 (70%). The top 10 food allergens were: apple (Mal d 1; 65%), peach (Pru p 1; 63%), hazelnut (Cor a 1.0401; 63%), peanut (Ara h 8; 56%, Ara h 6; 23%, Ara h 2; 15%), soy (Gly m 4; 39%), celery (Api g 1; 25%), kiwi (Act d 8; 20%) and walnut (Jug r 2; 15%). 84% showed sensitization to one or more food allergens. Within this group, 84% recognized at least one PR-10 component, followed by storage proteins (35%) and non-specific lipid transfer proteins (nsLTP; 12%). The prevalence of sensitization to cross-reactive carbohydrate determinants (CCD) within the entire population was 9%. Sensitization to at least one food components of animal origin (cow's milk/egg) was seen in 19% of all cases, with Bos d 8 recognized most frequently (8.1%). The ISAC seems to support clinical suspicion of food allergy in most cases, although sensitization together with a negative patient history is common. Bet v 1 is the allergen component recognized the most, followed closely by other PR-10 family proteins from plant foods. Sensitization to food components of animal origin was seen in 19% of the patients.

Molecular diagnosis of food allergy--do we know more?

Component-resolved diagnostics (CRD) is the research method that allows to determine the concentrations of specific immunoglobulin E against a particular allergenic components. The paper discusses the importance of CRD in the food allergy diagnosis to common animal and vegetable allergens. The capabilities of the method and its limitations in the application are presented. One of the main advantages of the CRD is to obtain information on the potential allergen cross-reactivity regarding inhalant allergens and food, which are exhibiting structural similarity within the epitopes. CRD explains on the molecular level allergens cross-reactivity. It allows to distinguish cross-reactions occurring after ingestion of food in patients with hypersensitivity that occurs primarily to pollen from the coexistence of inhaled and food allergies. It is also possible to use the method of the CRD for selected allergens to predict the severity of allergic reactions after ingestion of allergic food in patients with symptoms of food allergy. In addition, in small children component-resolved diagnostics can be helpful in predicting achieve in food tolerance to certain allergens. Due to the present limitations, practical conclusions and guidance should be drawn with a caution. This method does not replace clinical observation and double-blind placebo-controlled food challenge, which is still the gold standard in the diagnosis of food allergy. Due to the geographic diversity resulting in different exposure to pollen and dietary factors researches on allergen components in populations living in different climatic zones give different results. This allows to observe that the diagnostic and prognostic inference based on the analysis of CRD results is limited and should always be considered in the clinical context. Especially in situations of estimating the risk of severe allergic reactions. Despite these limitations, the CRD method is a modern tool to the current diagnosis of allergy deserving of its popularisation. It provides information on allergenic components at the molecular level, allowing better understanding of symptoms and patient adjusted procedures.

Difficulties and mistakes or how competent is diagnosis “Food allergy” (review with elements of own studies)

Actuality of the study of the food allergy (FA) in children is caused by it’s polisystemic and polispecific clinical symptoms. Food allergy – conception more pathophysiological, than clinical. There are several diseases in the international diseases classification that are associated with FA concept. All they have similarity – allergic inflammation in the basis, other are differences up to target-organ. These facts prove need to work up new diagnostic and treatment strategies for FA management. The aim of our work was to find out difficulties in FA diagnosis. Materials and methods . We had analyze indexes of the work of the allegrocenter in the Zaporizhia city multifield children hospital in 2011-2013 years. Case histories of the 67 children with FA were studied. All patients passed questionnaire about clinical symptoms and their manifestations. Results. In spite of the decrease in demographic indices allergological morbidity prolongs to grow. We founded out the next difficulties in the management of the FA patients. Most part of children are in the outpatient department. Frequently practitioners persistent skin elements diagnose as atopic dermatitis although it can be true food allergy or food intolerance or atopic exema. Each of these conditions require separate special treatment and further recommendations. Sometimes children with gastroenterological symptoms of the FA are treated against infections due to the similarity of clinical sighs to the intestinal infectious invasion. Questionnaire of the 67 children with food allergy and their parents showed that about 13% of them at least once had specific gastroenterological food allergy symptoms, that were caused by food intake and repeated in time periods after recurrent food intake. Conclusion. Conceptional and clinical difficulties associated with food allergy in children requires further studies of the mechanisms of it’s occurrence. This will allow to increase quality of the FA diagnostics and treatment.

Update: molecular diagnostics of allergies to vegetables and fruits

Most studies on the prevalence of food allergy report regional data. Pan-European multicenter cross-sectional studies on the prevalence of food allergies such as investigated within the framework of the EuroPrevall project are unfortunately not yet published. Based on published data, however, allergies to fruits and vegetables are among the most prevalent in food allergies in adolescence and adulthood. The current review on molecular diagnostics of fruit and vegetable allergies summarizes data on allergen component-based diagnosis gained primarily from patients with challenge-confirmed food allergies and focuses on the most frequent fruit and vegetable allergies, such as to carrot, celeriac, tomato, kiwifruit and peach, as the most important representative of the Rosaceae fruits. Such studies indicate the impact of component-specific diagnostics on the improvement of sensitivity and partially also specificity of in vitro diagnostics of food allergy. Furthermore, identification of marker allergens associated with a higher risk of developing severe systemic reactions will continuously improve the future management of patients with food allergy.

Advances in in vitro diagnostics in allergy, asthma, and immunology in 2012

Laboratory tests play an increasing role in risk assessment, diagnostics, and disease monitoring. Great advances have been achieved lately, particularly in the field of clinical immunology and allergy. These include neonatal screening of immunodeficiencies and asthma biomarkers and investigation into the role of recombinant allergens in in vitro testing. The latter area has implications for the diagnostics of food allergy, pollen-induced allergies, asthma, and insect allergies.

The IgE repertoire in patients with food allergy resolved at component level

Background Currently, more than 1200 purified allergens with defined structures are available. Some of them are used for food allergy diagnostics. We aimed to assess individual patientssensitizationtization profiles of food allergens by means of component resolved diagnosis. Methods Serum samples were analysed by microarray Immuno CAP ISAC (Phadia), which allows to detect specific IgE against more than 100 of molecular components. We have retrospectively analyzed 153 patients with proven food allergy, 96 of them being children under 18 years. We recorded occurence of early reactions including OAS and anaphylaxis and also delayed reactions (atopic eczema and eosinophilic gastrointestinal diseases). IgE antibodies against individual food alergens were divided to groups based on their origin and affiliation to any of panalergen families. With this approach, antibodies against ten groups of alergens were analyzed in indivi- dual age categories and diagnostic groups: cow' sm ilk allergens, hen's egg allergens, parvalbumins, lipid trans- fer proteins, flour allergens including gluten, vicilins, conglutins, cupin family allergens, 2S albumins and PR- 10 family proteins. Results As expected, in patients below age of 3 years, allergens to mild and egg occured most frequently. Suprisingly, however, we detected more than 40% of patients being sensitization against seed storage proteins (2 s albumins) and almost 30 % of patients have been sensitized by alergens of PR-10 group. In children allergic to peanut sensitization to proanafylactis alergens (Arah h 1, 2, 3) prevailed. In contrary, in older patients over 18 years we have found mainly sensitization to Ara h 8 from Bet v 1 family homologous proteins. Patients with eosinophilic gastrointestinal diseases, mainly eosinophilic esophagitis, demonstrated sensitization to Bet v 1 homologous pro- teins in more than 50% and almost 30% sensitization to allergens from seed storage protein families. Approxi- mately 20% of our patients had detectable antibodies against one or more of lipid transfer proteins. Conclusion CRD using microarray technics enables to detect IgE sen- sitisation profile not only in one patient, but also in a group of patients with defined age and diagnosis. This fact could contribute to optimalisation of diet according to possible cross-reactivity. Sensitization to proanaphylactic alergens, like LTPs and seed storage proteins, enables to detect individual risk of food induced anaphylaxis.

New approaches in diagnostics of food allergy and effectiveness of dietotherapy in infants

In the article the modern approaches to diagnostics of food allergy with the focus on other thenlgE-related forms of gastrointestinal hypersensitivity in infants are described. The results of the own study on efficacy assessment of new diagnostic system - immune-enzyme assay «Lactest» for specific IgE and IgG levels against food allergens as well as proteins from baby food estimation in sera of infants are presented. Dietotherapy for infants with food allergy based on immune-enzyme assay «Lactest» is described.

Food allergy

Food allergy is defined by a specific sensitization against food allergens which is associated with a clinical reaction. Immediate reactions are most common and the skin is most often involved in food allergy. Most food allergies are IgE-mediated although eczema reactions in atopic dermatitis and in hematogenous contact dermatitis to foods can be mediated by specific T-lymphocytes. Only few foods are responsible for the majority of most reactions in childhood. In adults up to 60% of all food allergic reactions are due to cross reactions between foods and inhalative allergens. A stepwise procedure which takes individual factors into account is necessary in the diagnostics of food allergy. The diagnostic algorithm in food allergy is not significantly different from that of other allergies. The oral provocation is the only method to prove food allergy in patients without a convincing history. A specific elimination diet is the only intervention which has been proven to be effective. Further therapeutic approaches are still under study and include specific immunotherapy, specific oral tolerance induction and treatment with anti-IgE antibodies.

Hauttestungen mit Nahrungsmittelallergenen

Skin tests have a central role in the diagnostics of food allergy. Particularly the prick test is established as a routine diagnostic tool. However, instable allergens and the lack of standardized extracts raise problems in the identification of sensitizations to food in suspected food allergy. Therefore, prick to prick tests with native foods are still recommended. The indications and contraindications do not differ with regard to common rules of skin testing in clinical allergology. We recommend a careful and restrictive application of skin tests in patients with a history of severe anaphylaxis to foods.

Potential, pitfalls, and prospects of food allergy diagnostics with recombinant allergens or synthetic sequential epitopes

This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both. However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. IgE-binding tests merely indicate sensitization, whereas the final proof of clinical relevance still relies on family/case history, physical examinations, and provocation tests. Novel technologies promise superior diagnostics. Microarray technology permits simultaneous measurement of multiple IgE reactivities regarding specificity, abundance, reactivity, or interaction. Improved functional tests might enable reliable estimation of the clinical relevance of IgE sensitizations at justifiable expenses.

Food allergy diagnostics: scientific and unproven procedures

Food allergy diagnostics: scientific and unproven procedures

Food allergy diagnostics: scientific and unproven procedures

The accurate diagnosis of food allergy is crucial not only for the right treatment but also for the avoidance of unnecessary diets. The diagnostic work-up of suspected food allergy includes the measurement of food-specific IgE antibodies using serologic assays, the skin prick test, elimination diets and oral provocation tests. In addition, some approaches are either under further rigorous investigation (the atopy patch test) or are already in widespread use, particularly by practitioners of alternative or complementary medicine, but are considered unproven. These diagnostic methods include specific IgG to foods, provocation/neutralization testing, kinesiology, cytotoxic tests and electrodermal testing. This review covers some of the most common scientifically validated and unproven approaches used in the diagnosis of food allergy. For specific serum IgE and the SPT, decision points have been established for some foods, allowing prediction of clinical relevance. The APT may be helpful, especially when considered in combination with defined levels of specific IgE. In regard to other approaches, most scientific studies do refute the usefulness of these approaches. In most patients, controlled oral food challenges remain the gold standard in the diagnostic work-up of suspected food allergy. The skin prick test and measurement of specific IgE antibodies to food extracts, individual allergens or allergenic peptides are helpful in the diagnostic approach. Food-specific IgG continues to be an unproven or experimental test. The other alternative and complementary techniques have no proven benefit and may endanger patients via misdiagnosis.