Thomas Hawranek

Predictors of severe systemic anaphylactic reactions in patients with Hymenoptera venom allergy: Importance of baseline serum tryptase—a study of the European Academy of Allergology and Clinical Immunology Interest Group on Insect Venom Hypersensitivity

BACKGROUND Severe anaphylaxis to honeybee or vespid stings is associated with a variety of risk factors, which are poorly defined. OBJECTIVE Our aim was to evaluate the association of baseline serum tryptase concentrations and other variables routinely recorded during patient evaluation with the frequency of past severe anaphylaxis after a field sting. METHODS In this observational multicenter study, we enrolled 962 patients with established bee or vespid venom allergy who had a systemic reaction after a field sting. Data were collected on tryptase concentration, age, sex, culprit insect, cardiovascular medication, and the number of preceding minor systemic reactions before the index field sting. A severe reaction was defined as anaphylactic shock, loss of consciousness, or cardiopulmonary arrest. The index sting was defined as the hitherto first, most severe systemic field-sting reaction. Relative rates were calculated with generalized additive models. RESULTS Two hundred six (21.4%) patients had a severe anaphylactic reaction after a field sting. The frequency of this event increased significantly with higher tryptase concentrations (nonlinear association). Other factors significantly associated with severe reactions after a field sting were vespid venom allergy, older age, male sex, angiotensin-converting enzyme inhibitor medication, and 1 or more preceding field stings with a less severe systemic reaction. CONCLUSION In patients with honeybee or vespid venom allergy, baseline serum tryptase concentrations are associated with the risk for severe anaphylactic reactions. Preventive measures should include substitution of angiotensin-converting enzyme inhibitors.

Allergic cross‐reactivity: from gene to the clinic

A large number of allergenic proteins have now their complete cDNA sequences determined and in some cases also the 3D structures. It turned out that most allergens could be grouped into a small number of structural protein families, regardless of their biological source. Structural similarity among proteins from diverse sources is the molecular basis of allergic cross‐reactivity. The clinical relevance of immunoglobulin E (IgE) cross‐reactivity seems to be influenced by a number of factors including the immune response against the allergen, exposure and the allergen. As individuals are exposed to a variable number of allergenic sources bearing homologous molecules, the exact nature of the antigenic structure inducing the primary IgE immune response cannot be easily defined. In general, the ‘cross‐reactivity’ term should be limited to defined clinical manifestations showing reactivity to a source without previous exposure. ‘Co‐recognition’, including by definition ‘cross‐reactivity’, could be used to describe the large majority of the IgE reactivity where co‐exposure to a number of sources bearing homologous molecules do not allow unequivocal identification of the sensitizing molecule. The analysis of reactivity clusters in diagnosis allows the interpretation of the patients reactivity profile as a result of the sensitization process, which often begins with exposure to a single allergenic molecule.

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 Users 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.

Provoking allergens and treatment of anaphylaxis in children and adolescents--data from the anaphylaxis registry of German-speaking countries.

To cite this article: Hompes S, Köhli A, Nemat K, Scherer K, Lange L, Rueff F, Rietschel E, Reese T, Szepfalusi Z, Schwerk N, Beyer K, Hawranek T, Niggemann B, Worm M. Provoking allergens and treatment of anaphylaxis in children and adolescents – data from the anaphylaxis registry of German‐speaking countries. Pediatr Allergy Immunol 2011; 22: 568–574.

Predictors of side effects during the buildup phase of venom immunotherapy for Hymenoptera venom allergy: the importance of baseline serum tryptase.

BACKGROUND Severe side effects during venom immunotherapy (VIT) are associated with a variety of risk factors. OBJECTIVE Our aim was to evaluate the association of baseline serum tryptase concentration (BTC) and of other parameters, which are routinely recorded during patient evaluation, with the frequency of severe reactions requiring an emergency intervention during the buildup phase of VIT. METHODS In this observational prospective multicenter study, we enrolled 680 patients with established honeybee or vespid venom allergy who underwent VIT. Data were collected on tryptase concentration, age, sex, culprit insect, cardiovascular medication, degree of preceding sting reaction, preventive antiallergic medication before therapy, time between last preceding sting reaction and VIT, venom specific IgE concentration, and type of buildup procedure. Relative rates were calculated with generalized additive models. RESULTS Fifty-seven patients (8.4%) required an emergency intervention during buildup because of a severe systemic reaction. The frequency of interventions increased significantly with higher BTC (log-linear association; adjusted odds ratio, 1.56; 95% CI, 1.15-2.11; P < .005). The predictive power of BTC was markedly greater when VIT was performed for vespid venom allergy than for bee venom (for bee VIT, no significant association; for vespid VIT, log-linear association; adjusted odds ratio, 2.33; 95% CI, 1.28-4.26; P = .005). The most important other factor significantly associated with severe reactions during the buildup phase of VIT was bee venom allergy. CONCLUSION Before vespid VIT, measurement of baseline serum tryptase concentration should be used to identify patients with a high risk for side effects. Patients with bee venom allergy require a particularly high degree of surveillance during VIT.

Array-based profiling of ragweed and mugwort pollen allergens.

Background:  Ragweed (Ambrosia artemisiifolia) and mugwort (Artemisia vulgaris) pollen is the main cause of allergic reactions in late summer and autumn. The differential diagnosis between ragweed and mugwort pollen allergy is a frequent problem encountered by allergologists in areas where both plants are present due to shared antigenic structures and overlapping flowering seasons.

Triggers and treatment of anaphylaxis: an analysis of 4,000 cases from Germany, Austria and Switzerland.

BACKGROUND Anaphylaxis is the most severe manifestation of a mast cell-dependent immediate reaction and may be fatal. According to data from the Berlin region, its incidence is 2-3 cases per 100 000 persons per year. METHOD We evaluated data from the anaphylaxis registry of the German-speaking countries for 2006-2013 and data from the protocols of the ADAC air rescue service for 2010-2011 to study the triggers, clinical manifestations, and treatment of anaphylaxis. RESULTS The registry contained data on 4141 patients, and the ADAC air rescue protocols concerned 1123 patients. In the registry, the most common triggers for anaphylaxis were insect venom (n = 2074; 50.1%), foods (n = 1039; 25.1%), and drugs (n = 627; 15.1%). Within these groups, the most common triggers were wasp (n = 1460) and bee stings (n = 412), legumes (n = 241), animal proteins (n = 225), and analgesic drugs (n = 277). Food anaphylaxis was most frequently induced by peanuts, cow milk, and hens egg in children and by wheat and shellfish in adults. An analysis of the medical emergency cases revealed that epinephrine was given for grade 3 or 4 anaphylaxis to 14.5% and 43.9% (respectively) of the patients in the anaphylaxis registry and to 19% and 78% of the patients in the air rescue protocols. CONCLUSION Wasp and bee venom, legumes, animal proteins, and analgesic drugs were the commonest triggers of anaphylaxis. Their relative frequency was age-dependent. Epinephrine was given too rarely, as it is recommended in the guidelines for all cases of grade 2 and above.

Implementation of Anaphylaxis Management Guidelines: A Register-Based Study

Background Anaphylaxis management guidelines recommend the use of intramuscular adrenaline in severe reactions, complemented by antihistamines and corticoids; secondary prevention includes allergen avoidance and provision of self-applicable first aid drugs. Gaps between recommendations and their implementation have been reported, but only in confined settings. Hence, we analysed nation-wide data on the management of anaphylaxis, evaluating the implementation of guidelines. Methods Within the anaphylaxis registry, allergy referral centres across Germany, Austria and Switzerland provided data on severe anaphylaxis cases. Based on patient records, details on reaction circumstances, diagnostic workup and treatment were collected via online questionnaire. Report of anaphylaxis through emergency physicians allowed for validation of registry data. Results 2114 severe anaphylaxis patients from 58 centres were included. 8% received adrenaline intravenously, 4% intramuscularly; 50% antihistamines, and 51% corticoids. Validation data indicated moderate underreporting of first aid drugs in the Registry. 20% received specific instructions at the time of the reaction; 81% were provided with prophylactic first aid drugs at any time. Conclusion There is a distinct discrepancy between current anaphylaxis management guidelines and their implementation. To improve patient care, a revised approach for medical education and training on the management of severe anaphylaxis is warranted.

Detection of IgE to recombinant Api m 1 and rVes v 5 is valuable but not sufficient to distinguish bee from wasp venom allergy

To the Editor: Hofmann et al tackle an important problem in Hymenoptera venom allergy: the frequently observed (asymptomatic) double sensitization to bee andwasp venom, and the problemof identifying the relevant venom for immunotherapy. Component-resolved diagnosis is undoubtedly a major advancement in the diagnosis of Hymenoptera venom allergy. Nevertheless, the following aspects should be noted: Hofmann et al aswell asM€uller et al enrolled patients on the basis of a positive skin test response. However, some patients with a venom allergy have negative skin tests. Golden et al frequently observed negative skin tests in patients with allergy toHymenoptera venom, and a considerable number of these patients reacted to sting challenges. Particularly, a low total IgE level is linked to negative skin tests and nondetectable specific IgE (sIgE) but is associated with more severe reactions. Therefore, patients at high risk could bemissed. Second, the low frequency of sensitization to recombinant (r) Api m 1 compared with the bee venom extract is a cause for concern. Initially, a prevalence of sIgE to rApi m 1 of 97% with the ADVIA system (Siemens, Tarrytown, NY) was reported, but Hofmann et al registered a frequency of only 79% for the ImmunoCAP assay (Phadia, Uppsala, Sweden). We rechecked the sensitivity of sIgE to bee venom extract and rApi m1 in the same system. The data fromHofmann et al could be confirmed at 2Austrian centers,where positive skin testswereused as inclusion criterion. However, an even lower frequency of sensitization to rApi m 1 was registered at 1 Austrian center when all patients with systemic sting reactions in the past were included (Table I). Furthermore, regional differences in sensitization patterns have to be taken into account. In Europe, approximately two thirds of patients with allergy to Hymenoptera venom react towasp stings and only one third to bee stings. By contrast, IgE determination reveals double-positive results in up to 59%of patients. Thus, a diagnostic tool is urgently needed to exclude cross-reactivity via cross-reactive carbohydrate determinants. Because wasp venom allergies are more frequent, and bee venom bears more cross-reactive carbohydrate determinants, typically nonspecific cross-reactions to bee venom must be excluded. Is it adequate merely to determine Api m 1 for this purpose? In the worst case, 38 of 100 patients with bee venom allergy will not be diagnosed by sIgE to rApi m 1, as shown in Table I. Why is this so? Given the limited availability of the substances, we randomly analyzed 40 sera from the low-sensitivity group regarding sIgE to bee venom hyaluronidase (rApi m 2) andmelittin (native [n]Apim 4)with research prototype ImmunoCAPassays.All but 1 patient had detectable sIgE to beevenomextract, whereas 13 patients (32.5%) could not be diagnosed with rApi m 1 alone. After the use of rApi m 2 and nApi m 4, 6 additional patients could be diagnosed, and only 7 (17.5%) remained negative. In detail, 5 patients had detectable sIgE to rApi m 2 and 1 putatively to nApi m 4 only. Generally, 65.0% of patients were sensitized to rApi m 1, 52.2% to rApi m 2, and 42.5% to nApi m 4. From these data, it can be assumed that sensitization to multiple allergens might be common. Furthermore, we could again confirm the clinical relevance of Api m 2 beyond its carbohydrate epitopes. Therefore, these preliminary results indicate that a genuine bee venom sensitization can most likely be excluded in cases of negative sIgE test results to at least Api m 1 and 2.Nevertheless, addition of beevenomallergens likeApim3, 4, 5, 6, and 10would further increase diagnostic accuracy.A similar approach might be valid to exclude genuine wasp venom sensitization: because up to 13% of patients with wasp venom allergy could be missed, the combined determination of sIgE to Ves v 1 and 5 is essential. Taken together, the data indicate that the suggested approach of using rApi m 1 and rVes v 5 is insufficient and even fraught with risk for some patients because genuine sensitization to other major allergens might be missed. Gunter J. Sturm, MD Wolfgang Hemmer, PhD Thomas Hawranek, MD Roland Lang, PhD Markus Ollert, MD Edzard Spillner, PhD Simon Blank, PhD Danijela Bokanovic, MD Werner Aberer, MD

Proteomic profiling of birch (Betula verrucosa) pollen extracts from different origins

Pollen of the European white birch is a major source of spring pollinosis in Europe. Pollen‐allergy diagnosis and treatment by specific immunotherapy commonly rely on extracts of natural origin. To gain insight into the protein content and its variability, we evaluated the profile of allergenic and non‐allergenic proteins in extracts of pollen from different origins by MS‐based proteomics. Aqueous extracts prepared from commercially available Swedish birch pollen, pollen collected from Austrian trees and a commercial skin prick extract were analyzed by 1‐DE, 2‐DE, immunoblotting and mass spectrometry, resulting in a complete inventory of extractable, disease‐relevant pollen proteins. A main focus of this study was on the isoform distribution of Bet v 1, the major allergen of birch pollen. Using a combination of intact mass determination and peptide sequencing, five isoforms (a, b, d, f and j) were unequivocally identified in Swedish and Austrian birch pollen extracts, while the skin prick extract contained only isoforms a, b and d. Using the same methods as for Bet v 1, divergencies in the sequence of birch profilin (Bet v 2), a plant panallergen, were solved. The molecular characterization of pollen extracts is relevant for standardization and development of new reagents for specific immunotherapy.