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Kirsten Beyer

Publications and source records attributed to Kirsten Beyer.

At least 19 recordsLinked to original sources
PubMed2007

IgE-mediated food allergy diagnosis: Current status and new perspectives.

In June 2005, the work of the EU Integrated Project EuroPrevall was started. EuroPrevall is the largest research project on food allergy ever performed in Europe. Major aims of the project are to generate for the first time reliable data on the prevalence of food allergies across Europe and on the natural course of food allergy development in infants. Improvement of in vitro diagnosis of food allergies is another important aim of the project. The present review summarizes current knowledge about the clinical presentation of food allergy and critically reviews available diagnostic tools at the beginning of the project period. A major problem in diagnosis is a relatively poor 'clinical specificity', i. e. both positive skin tests and in vitro tests for specific IgE are frequent in sensitized subjects without food allergy symptoms. So far, no in vitro test reliably predicts clinical food allergy. EuroPrevall aims at improving the predictive value of such tests by proceeding from diagnosis based on allergen extracts to purified allergen molecules, taking into account the affinity of the IgE-allergen interaction, and evaluating the potential of biological in vitro tests such as histamine release tests or basophil activation tests including assays performed with permanently growing cell lines.

Allergens↗
PubMed2006

The atopy patch test in the diagnostic workup of suspected food-related symptoms in children.

BACKGROUND: There is an increasing need to develop test instruments that make oral food challenges superfluous. OBJECTIVE: We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy. METHODS: We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed. RESULTS: We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge. CONCLUSION: Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. CLINICAL IMPLICATIONS: For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

Age Factors↗
PubMed2006

The potential allergenicity of two 2S albumins from soybean (Glycine max): a protein microarray approach.

BACKGROUND: The 2S albumins are a group of storage proteins that occur widely in seeds of dicotyledonous plants. The widespread distribution and stability to digestion of allergenic 2S albumins raise the question of why some members of this family present in important food sources, such as soybean, are not regarded as major allergens. METHODS: The pepsinolytic stability of two 2S albumins from soybean seed was determined using simulated gastric fluid. Using a new protein microarray system, IgE binding to these soybean 2S albumins was studied with the sera from 23 European individuals allergic to soybean. In order to validate the microarray result, two of the sera were selected and further tested using the micro-ELISA and UniCAP system. RESULTS: Both albumins exhibited high stability to digestion similar to other allergenic members of the 2S albumin, trypsin/amylase inhibitor and lipid transfer protein superfamily. None of the patients was found to have IgE specific to soybean 2S albumins by the microarray system, and this result was in agreement with the results from the micro-ELISA and UniCAP system. CONCLUSIONS: The results from microarray, micro-ELISA and UniCAP system suggested that the 2S albumins from soybean are not major allergens within the patient population analyzed.

Albumins↗
PubMed2005

Ana o 3, an important cashew nut (Anacardium occidentale L.) allergen of the 2S albumin family.

BACKGROUND: Cashew nut allergy is the second most commonly reported tree nut allergy in the United States. We have previously cloned and characterized major cashew allergens belonging to the vicilin and legumin families of seed storage proteins. OBJECTIVE: Here we set out to describe a third major cashew allergen, a 2S albumin. METHODS: The recombinant cashew 2S albumin was amplified from a cDNA library by means of PCR, sequenced, and expressed in Escherichia coli. Immunoblotting was used to screen for reactivity with patients' sera, and inhibition immunoblotting was used to identify the corresponding native cashew nut proteins. The mass of affinity-purified native allergen was determined by means of matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectroscopy. Patients' sera were used to probe solid-phase 2S albumin peptides to identify linear epitopes. RESULTS: The cloned allergen, designated Ana o 3, was identified as 2S albumin. MALDI-TOF mass spectroscopy of native Ana o 3 yielded a molecular mass of 12,598 d. Immunoblot analysis showed 21 (81%) of 26 sera from patients with cashew allergy were reactive. Three native Ana o 3 large-subunit isoforms with molecular weights ranging from approximately 6 to 10 kd were identified. Probing of overlapping synthetic Ana o 3 peptides with patients' sera identified 16 reactive peptides, 4 of which gave strong signals and one of which positionally overlaps linear epitopes in mustard and walnut allergenic 2S albumins. The overlapping cashew and walnut epitopes also share considerable homology. CONCLUSIONS: We conclude that this 2S albumin protein is a major allergen in cashew nut and demonstrates a possible basis for cross-reactivity with walnut 2S albumin.

Adolescent↗
PubMed2005

Food allergy diagnostics: scientific and unproven procedures.

PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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.

Complementary Therapies↗
PubMed2004

Microarray immunoassay: association of clinical history, in vitro IgE function, and heterogeneity of allergenic peanut epitopes.

BACKGROUND: IgE epitope mapping of food allergens is a prerequisite for engineering hypoallergenic immunotherapeutic agents and might reveal basic information regarding a patient's immune response. Mapping of large numbers of epitopes by using individual patient sera has been impractical with current techniques. OBJECTIVE: We sought to develop a peptide microarray-based immunoassay to map peanut epitopes by using microliter quantities of serum. METHODS: A set of 213 overlapping 20-residue peptides was synthesized corresponding to the primary sequences of Ara h 1, Ara h 2, and Ara h 3. These were arrayed in triplicate along with the corresponding recombinant proteins onto glass slides and used for immunolabeling. RESULTS: Seventy-seven patient and 15 control sera were analyzed. The majority of patients (97%) had specific IgE to at least one of the recombinant allergens, and 87% had detectable IgE to sequential epitopes. Microarray mapping correlated well with previous studies. However, the analysis of individual patients revealed remarkable heterogeneity in the number and patterns of epitope recognition. High epitope diversity was found in patients with a history of more severe allergic reactions. Also, sensitization of effector cells with more diverse IgE antibodies conferred greater reactivity to specific allergen. CONCLUSIONS: The protein microarray immunoassay confirmed that Ara h 1, Ara h 2, and Ara h 3 are major peanut allergens and allows for parallel epitope analysis. This has led to the discovery of an additional important epitope of Ara h 1 and the recognition of a high degree of patient heterogeneity. This qualitative difference in epitope diversity might provide prognostic information about the patient.

2S Albumins, Plant↗
PubMed2004

Determination of food specific IgE levels over time can predict the development of tolerance in cow's milk and hen's egg allergy.

BACKGROUND: The majority of children with cow's milk and hen's egg allergy develop clinical tolerance with time. However, there are no good indices to predict when and in whom this occurs. OBJECTIVE: The aim of this study was to determine if monitoring food specific IgE levels over time could be used as a predictor for determining when patients develop clinical tolerance. METHODS: Eighty-eight patients with hen's egg and 49 patients with cow's milk allergy who underwent repeated double-blind, placebo-controlled food challenges were included in the study. Using the Pharmacia CAP-System FEIA, specific IgE (sIgE) levels to cow's milk and hen's egg were retrospectively determined from stored serum samples obtained at the time of the food challenges. Logistic regression was used to evaluate the relationship between tolerance development and the decrease in sIgE levels over a specific time period between the two challenges. RESULTS: Twenty-eight of the 66 egg-allergic and 16 of the 33 milk-allergic patients lost their allergy over time. For egg, the decrease in sIgE levels (P=.0014) was significantly related to the probability of developing clinical tolerance, with the duration between challenges having an influence (P=.06). For milk there also was a significant relationship between the decrease in sIgE levels (P=.0175) and the probability of developing tolerance to milk but no significant contribution with regard to time. Stratification into 2 age groups, those below 4 years of age and those above 4 years of age at time of first challenge, had an effect, with the younger age group being more likely to develop clinical tolerance in relation to the rate of decrease in sIgE. The median food sIgE level at diagnosis was significantly less for the group developing "tolerance" to egg (P <.001), and a similar trend was seen for milk allergy (P=.06). Using these results, we developed a model for predicting the likelihood of developing tolerance in milk and egg allergy based on the decrease in food sIgE over time. CONCLUSION: We found that the rate of decrease in food sIgE levels over time was predictive for the likelihood of developing tolerance in milk and egg allergy. Using the likelihood estimates from this study could aid clinicians in providing prognostic information and in timing subsequent food challenges, thereby decreasing the number of premature and unnecessary double-blind, placebo-controlled food challenges.

Age Factors↗
PubMed2004

The potential use of Chinese herbal medicines in treating allergic asthma.

OBJECTIVE: To discuss the potential use of the Chinese herbal formula MSSM-002 in treating asthma based on its effects on a murine model of allergic asthma, immunoregulatory actions on T(H)2 cells in vitro, and the means of standardization for herbal formula quality control. DATA SOURCES: Information presented at the 2002 American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting International Symposium on Complementary Alternative Medicine in San Antonio, TX. STUDY SELECTION: All presentations from the ACAAI meeting that discussed MSSM-002 were considered for this review. RESULTS: The Chinese herbal formula MSSM-002 suppressed airway hyperreactivity and eosinophilic inflammation in a murine model of allergic asthma. These effects were comparable to dexamethasone but were not accompanied by the suppression of T(H)1 responses seen with dexamethasone. In vitro studies demonstrated that MSSM-002 significantly decreased antigen-induced T(H)2 cytokine secretion by murine T(H)2 polarized splenocytes and human mucosal T(H)2 cell lines, which in contrast to dexamethasone did not cause apoptosis and was not cytotoxic but was associated with decreased GATA-3 expression. Chromatographic fingerprints of MSSM-002 and evaluation of in vivo actions showed that the quality of several batches of MSSM-002 was consistent. CONCLUSION: MSSM-002 has a therapeutic effect on allergic asthma and immunoregulatory actions on established T(H)2 cells and may prove to be of potential clinical benefit to asthma patients.

Animals↗
PubMed2003

Mutational analysis of major, sequential IgE-binding epitopes in alpha s1-casein, a major cow's milk allergen.

BACKGROUND: Allergy to cow's milk is common in early childhood, and no therapy other than avoidance exists. In murine models of peanut allergy, immunotherapy with mutated, engineered, proteins appears promising. OBJECTIVE: We sought to identify the critical amino acids (AAs) for immunoglobulin E (IgE) binding within the major B-cell epitopes of alpha(s1)-casein, a major cow's milk allergen. This will provide the necessary information to alter the cDNA to encode a protein capable of activating milk-specific T cells, but with reduced IgE-binding capacity. METHODS: For mutational analysis of the IgE-binding epitopes, peptides of 10-14 AAs in length were synthesized on a derivatized cellulose membrane with single or multiple AA substitutions. Membranes were immunolabeled with pooled sera from 15 cow's-milk-allergic patients and with 8 individual sera. RESULTS: With the pooled sera, substitution of a single AA led to complete abrogation of IgE binding to 2 of 8 peptides and diminished binding in the remainder. Substitution of multiple AAs led to an abrogation of binding in the remaining peptides. In 4 of the 8 peptides, the critical AA identified with pooled sera did not result in significant reduction of IgE binding with 1 or more individual patients. For these patients, other critical AAs were identified, indicating a more heterogeneous pattern in IgE recognition. CONCLUSION: This study indicates that single or multiple AA substitutions within IgE-binding epitopes result in reduced binding of milk-specific IgE antibodies by patients' sera. However, for future immunotherapeutic interventions with mutated peptides, critical AAs should be evaluated with individual patient sera to determine B-cell-epitope heterogeneity.

Adolescent↗
PubMed2003

Measurement of peptide-specific IgE as an additional tool in identifying patients with clinical reactivity to peanuts.

BACKGROUND: Peanut allergy is one of the most common food allergies, often resulting in severe reactions. Diagnostic decision levels of food-specific IgE antibody concentrations have been described. However, many patients still need to undergo oral peanut challenges because their IgE levels are in the nondiagnostic level. OBJECTIVE: The aim of this study was to determine whether differences exist in IgE-binding epitope recognition between sensitized children with and without symptomatic peanut allergy. METHODS: Eight peptides representing the immunodominant sequential epitopes on Ara h 1, 2, and 3 were synthesized on SPOTs membranes. Individual patient labeling was performed with sera from 15 patients with symptomatic peanut allergy and 16 patients who were sensitized but tolerant. Ten of these 16 patients had "outgrown" their allergy. RESULTS: Regardless of their peanut-specific IgE levels, most patients with symptomatic peanut allergy showed IgE binding to the 3 immunodominant epitopes on Ara h 2. In contrast, each of these epitopes was recognized by < 10% of the tolerant patients. In addition, tolerant patients did not recognize 2 immunodominant epitopes on Ara h 1. At least 93% of symptomatic, but only 12.5% of tolerant patients, recognized 1 of these "predictive" epitopes on Ara h 1 or 2. Moreover, the cumulative IgE binding to the peanut peptides was significantly higher in patients with peanut allergy than in tolerant patients. With up to 50% of patients with peanut-specific IgE levels below diagnostic decision levels still being clinically reactive, oral food challenges could be avoided in ~90% of these patients through determination of peptide-specific IgE. CONCLUSIONS: Determination of epitope recognition provides an additional tool to diagnose symptomatic peanut allergy, especially in children with peanut-specific IgE below diagnostic decision levels.

2S Albumins, Plant↗
PubMed2003

Characterization of allergenic food proteins for improved diagnostic methods.

PURPOSE OF REVIEW: Diagnostic decision points for food allergen-specific serum IgE concentration and for skin prick test results have been established for several foods, reducing the requirement for food challenges in a number of patients. Many patients, however, still need to undergo oral food challenges because their food-specific IgE level is in the undefined range. In addition, diagnostic decision points could not be established for several foods. It appears that measurement of serum specific IgE concentrations to individual allergens is superior to determination of specific IgE to the crude food extract containing allergenic and nonallergenic proteins. This review will outline recent advantages in characterization of food allergens as well as the relevance of this knowledge for use in recently developed protein microarray technology. RECENT FINDINGS: Protein microarrays have been developed to profile allergen-specific IgE antibodies from human serum with the advantage of screening hundreds of allergens in parallel using minute amounts of blood. This technology, however, requires prior knowledge of the proteins to be studied. The identification and characterization of clinically relevant allergens have increased dramatically within the last several years. Relevant new allergens have been identified, especially in tree nuts and seeds. Interestingly, most of these allergens belong to the same family of seed storage proteins. In addition, known food allergens have been further characterized and IgE-binding sites have been determined. Moreover, 'informative' peptides shown to be predictive for the persistence of food allergy have been identified. SUMMARY: The combination of food allergen characterization and protein or peptide microarray technology will enable us to develop improved diagnostic tools in food allergy.

Allergens↗