Potential and limitations of epitope mapping and molecular targeting in Hymenoptera venom allergy

Hymenoptera venom (HV) allergy can lead to life threatening conditions by specific IgE (sIgE)-mediated anaphylactic reactions. The knowledge about major allergens from venom of different clinically relevant species increased in the last decades, allowing the development of component-resolved diagnostics in which sIgE to single allergens is analysed. Despite these advances, the precise regions of the allergens that bind to IgE are only known for few HV allergens. The detailed characterization of IgE epitopes may provide valuable information to improve immunodiagnostic tests and to develop new therapeutic strategies using allergen-derived peptides or other targeted approaches. Epitope-resolved analysis is challenging, since the identification of conformational epitopes present in many allergens demands complex technologies for molecular analyses. Furthermore, functional analysis of the epitopeś interaction with their respective ligands is needed to distinguish epitopes that can activate the allergic immune response, from those that are recognized by irrelevant antibodies or T cell receptors from non-effector cells. In this review, we focus on the use of mapping and molecular targeting approaches for characterization of the epitopes of the major venom allergens of clinically relevant Hymenoptera species. The screening of the most relevant allergen peptides by epitope mapping could be helpful for the development of molecules that target major and immunodominant epitopes blocking the allergen induced cellular reactions as novel approach for the treatment of HV allergy.

LAD2 mast cell activation test associates with the reaction severity and diagnoses BAT nonresponders in Hymenoptera venom allergy

BACKGROUND AND OBJECTIVE

The usefulness of the mast cell activation test (MAT) in diagnosing patients with uninterpretable basophil activation test (BAT) caused by nonresponding basophils has not yet been addressed. It should be further evaluated if the results of MAT are associated with the severity of the allergic reaction.

METHODS

We recruited 39 Hymenoptera venom allergic (HVA) patients, 22 non-sensitized controls, and 37 BAT nonresponding HVA patients. Specific IgE levels for honey bee venom (HBV), yellow jacket venom (YJV) and total IgEs were quantified using the Immulite system. BAT and MAT with LAD2 cells in response to HBV and YJV were performed.

RESULTS

We first optimized the susceptibility of LAD2 cells to IgE-mediated degranulation in HVA and showed that prestimulation with IL-33 and IL-6 significantly increased the LAD2 cells´ responsiveness to allergen stimulation (P<0.01). LAD2 MAT results correlated with BAT results, and patients with severe sting reactions (Mueller grades IV or III) had a median 2-fold higher LAD2 MAT than the patients with nonsevere sting reactions (Mueller grades II, I or LLR) (P<0.05). Further, LAD2 MAT provided conclusive results in 54.1% (20 of 37) of HVA patients with nonresponding basophils in the BAT.

CONCLUSION

The LAD2 MAT represents a new diagnostic tool for HVA patients with nonresponding basophils. Further, LAD2 MAT can identify patients at risk of severe sting reactions and thus can help guide recommendations for venom immunotherapy and improve the management of patients with HVA.

Revealing clinically relevant specific IgE sensitization patterns in Hymenoptera venom allergy with dimension reduction and clustering

Background

Immunoglobulin E (IgE) blood tests are used to detect sensitizations and potential allergies. Recent studies suggest that specific IgE sensitization patterns due to molecular interactions affect an individual's risk of developing allergic symptoms.

Objective

The aim of this study was to reveal specific IgE sensitization patterns and investigate their clinical implications in Hymenoptera venom allergy.

Methods

In this cross-sectional study, 257 hunters or fishers with self-filled surveys on previous Hymenoptera stings were analyzed. Blood samples were taken to determine Hymenoptera IgE sensitization levels. Using dimensionality reduction and clustering, specific IgE for 10 Hymenoptera venom allergens were evaluated for clinical relevance.

Results

Three clusters were unmasked using novel dimensionality reduction and clustering methods solely based on specific IgE levels to Hymenoptera venom allergens. These clusters show different characteristics regarding previous systemic reactions to Hymenoptera stings.

Conclusion

Our study was able to unmask non-linear sensitization patterns for specific IgE tests in Hymenoptera venom allergy. We were able to derive risk clusters for anaphylactic reactions following hymenoptera stings and pinpoint relevant allergens (rApi m 10, rVes v 1, whole bee, and wasp venom) for clustering.

Basophil Activation Test in Double-Sensitized Patients With Hymenoptera Venom Allergy: Additional Benefit of Component-Resolved Diagnostics

BACKGROUND

In Hymenoptera venom allergy serologically double-sensitized patients, it is often difficult to identify the culprit insect for venom immunotherapy (VIT).

OBJECTIVES

To evaluate if basophil activation tests (BATs) performed not only with venom extracts but additionally with single component-resolved diagnostics could differentiate between sensitized and allergic individuals and how the test results influenced the physicians' decision regarding VIT.

METHODS

BATs were performed with bee and wasp venom extracts and with single components (Api m 1, Api m 10, Ves v 1, and Ves v 5) in 31 serologically double-sensitized patients.

RESULTS

In 28 finally included individuals, 9 BATs were positive and 4 negative for both venoms. Fourteen of 28 BATs showed positive results for wasp venom alone. Two of 10 BATs positive for bee venom were only positive to Api m 1 and 1 of 28 BATs only to Api m 10, but not for whole bee venom extract. Five of 23 BATs positive for wasp venom were only positive for Ves v 5 but negative for wasp venom extract and Ves v 1. Finally, VIT with both insect venoms was recommended in 4 of 28 individuals, with wasp venom alone in 21 of 28 patients and with bee venom alone in 1 of 28. In 2 cases no VIT was recommended.

CONCLUSIONS

BATs with Ves v 5, followed by Api m 1 and Api m 10, were helpful for the decision for VIT with the clinically relevant insect in 8 of 28 (28.6%) patients. A BAT with components should therefore be additionally carried out in cases with equivocal results.

Stinging insect identification in children with Hymenoptera venom allergy and their parents

Introduction

The treatment of Hymenoptera venom allergy (HVA) is based among others on the proper identification of the culprit insect.

Aim

To assess the accuracy in identifying stinging insects by children with HVA and their parents.

Material and methods

Participants were recruited from a paediatric medical centre. The data on their demographics, sting history and ability of insect identification (based on pictures) were obtained using a questionnaire. The study sample consisted of 102 children with HVA and their parents as well as 98 children without HVA and their parents.

Results

The rates of subjects correctly identifying insects in the groups were 91.2%, 92.5%, 78.8%, 82.4%, respectively. When compared to children with HVA, those without HVA were less likely to correctly identify the bee, bumblebee and hoverfly. In this group, the correct identification of the wasp was more common among children living in the countryside. The correct identification of the bee and bumblebee by children without HVA was more common among children living in the city.

Conclusions

Some children with HVA and their parents cannot correctly identify stinging insects despite previous life-threatening allergic reactions. The ability to identify stinging insects may depend on the HVA diagnosis and place of residence.

Adverse reactions in venom immunotherapy protocols: conventional versus ultra-rush

BACKGROUND

Venom immunotherapy (VIT) is an effective treatment in the patients at high risk of anaphylaxis or life-threatening systemic reactions due to Hymenoptera venom allergy. But, systemic and large local reactions can be observed, especially during the build-up phase of VIT. We evaluated the safety of conventional and ultra-rush build-up protocols.

MATERIALS AND METHODS

Two protocols in 71 patients (39 conventional and 32 ultra-rush protocols) with honeybee and wasp venom allergy were evaluated retrospectively. Patients were diagnosed and selected for VIT according to the criteria established by the European Academy of Allergy and Clinical Immunology. The severity of systemic reactions was evaluated according to the criteria of Mueller.

RESULTS

Build-up phases were tolerated in 66.2% (n = 47) without any reaction. Allergic adverse reactions were observed in 33.8% (n = 24): large local reactions 22.5% (n = 16) and systemic reactions 11.3% (n = 8). There was no significant difference in the number of adverse reactions comparing patients receiving conventional and ultra-rush protocol. In addition, no association was found between allergic adverse reactions and the following factors: sex, previous systemic sting reactions, honeybee and wasp venom extract.

CONCLUSION

We found that both protocols were tolerated in patients with honeybee and wasp venom allergy. Ultra-rush protocol will be preferred for patients and clinicians because of its advantages in terms of time and costs.KEY MESSAGESVIT is the only curative treatment method that reduces the risk of severe reactions after a bee sting and improves the quality of life in patients with Hymenoptera venom allergy.Ultra-rush VIT protocol has advantages such as few injection and time savings.Both ultra-rush and conventional VIT are safe treatments to prevent potentially life-threatening reactions in patients with honeybee and wasp venom allergy.

Diagnosis of Hymenoptera Venom Allergy: State of the Art, Challenges, and Perspectives

Hymenoptera venom allergy is the most common cause of anaphylaxis in adults and the second-most frequent in children. The proper diagnosis of this life-threatening allergy remains a challenge. This review focuses on the current knowledge regarding diagnostics of Hymenoptera venom allergy. The paper includes a brief description of the representatives of Hymenoptera order and the composition of their venoms. Then, diagnostic tests for allergy to Hymenoptera venom are described. Common diagnostic problems, especially double positivity in tests for IgE antibodies specific to honeybee and wasp venom, are also discussed. Special attention is paid to the search for new diagnostic capabilities using modern methodologies. Multidimensional molecular analysis offers an opportunity to characterize changes in body fluids associated with Hymenoptera venom allergy and yields a unique insight into the cell status. Despite recent developments in the diagnostics of Hymenoptera venom allergy, new testing methodologies are still needed to answer questions and doubts we have.

The Lights And The Shadows Of Controlled Sting Challenge With Hymenoptera

Hymenoptera venom immunotherapy (VIT) is a treatment which has been shown to be effective in the protection of individuals with systemic allergic reactions caused by Hymenoptera stings. The need for a tool which shows the degree of protection afforded by VIT and the lack of useful biomarkers, has converted the Sting Challenge Test (SCT) into the gold standard for this disorder although its use has both lights and shadows. SCT with Hymenoptera is a test consisting of causing a real sting in a patient diagnosed with an allergy to the venom of the stinging insect and who normally is undergoing treatment with specific immunotherapy. In Spain, SCT is included in the list of services offered by some hospitals and forms part of their habitual clinical practice. This review aims to analyze the strengths and weaknesses of this test and describe the standardized procedure and necessary resources, based on the experience of a group of Spanish experts and a review of the literature.

Basophil activation test as alternative method to CAP-inhibition in patients with double sensitization to vespid venoms

Most patients with Hymenoptera venom allergy (HVA) to vespid venoms present double sensitization by specific IgE (sIgE)-mediated cross-reactivity. Thus, it is mandatory could discriminate between a true double and primary sensitization to implement an accurate venom-specific immunotherapy (VIT). To date, CAP-inhibition is the reference method in the diagnosis of cross-reactivity in double sensitized patients to vespid venoms, being the results obtained with the component resolved diagnostics (CRD) conflicting. For this, we have studied in a cohort of double sensitized patients to Vespula vulgaris (VV) and Polistes dominulus (PD) venoms (n = 40) the diagnostic accuracy of CRD using the CAP-inhibition as reference method, as well as to investigate whether basophil activation test (BAT) is an alternative method for inconclusive results obtained by CAP-inhibition. CAP-inhibition showed a sensitivity of 59.46 % in view of the indeterminate results; most patients had true double sensitization (54.5 %), followed by single sensitization to PD (27.27 %) and VV (18.18 %) venoms. CRD based on rVes v 5/rPol d 5 (or vice versa) ratio as well as whole extracts I3/I77 (or vice versa) ratio (specific IgE-I3 to VV/specific IgE-I77 to PD) showed a low diagnostic accuracy (AUC = 0.504, p = 0.974; AUC = 0.35, p = 0.235; respectively). BAT was determined in parallel with CAP-inhibition in 12 patients, presented higher sensitivity than CAP-inhibition (p = 0.021) and a positive agreement of 71.43 %. Likewise it was able to identify 100% of inconclusive results, showing a specificity of 83.3 %. Therefore, CRD is not a suitable method to distinguish monosensitization and BAT appears to be an appropriate method resolving indeterminate results from the gold standard method.

Allergen Content of Therapeutic Preparations for Allergen-Specific Immunotherapy of European Paper Wasp Venom Allergy

Allergy to Polistes dominula (European paper wasp) venom is of particular relevance in Southern Europe, potentially becoming a threat in other regions in the near future, and can be effectively cured by venom immunotherapy (VIT). As allergen content in extracts may vary and have an impact on diagnostic and therapeutic approaches, the aim was to compare five therapeutic preparations for VIT of P. dominula venom allergy available in Spain. Products from five different suppliers were analyzed by SDS-PAGE and LC-MS/MS and compared with a reference venom sample. Three products with P. dominula venom and one product with a venom mixture of American Polistes species showed a comparable band pattern in SDS-PAGE as the reference sample and the bands of the major allergens phospholipase A1 and antigen 5 were assignable. The other product, which consists of a mixture of American Polistes species, exhibited the typical band pattern in one, but not in another sample from a second batch. All annotated P. dominula allergens were detected at comparable levels in LC-MS/MS analysis of products containing P. dominula venom. Due to a lack of genomic information on the American Polistes species, the remaining products were not analyzed by this method. The major Polistes allergens were present in comparable amounts in the majority, but not in all investigated samples of venom preparations for VIT of P. dominula venom allergy.

Natural History of the Hymenoptera Venom Sensitivity Reactions in Adults: Study Design

Background: Allergic reactions to Hymenoptera stings can have varying levels of severity, according to the Müller grading system. Methods: By an epidemiological concept, this is a retrospective cohort study. The observed cohort was represented by patients referred to the University Clinic Golnik due to Hymenoptera allergic reaction in the period from 1997 to 2015. From the immunological database of the University Clinic Golnik, we obtained laboratory data (sIgE, skin tests and basophil activation test). The clinical characteristics of patients were obtained from BIRPIS. With the help of a questionnaire, which was sent to each patient in the period from May 2019 to April 2021, we obtained epidemiological data. For the assessment of the association between the severity of allergic reaction for the observed outcome, the severity of the first allergic reaction after Hymenoptera sting was used. Other variables were grouped according to risk factors. Discussion: We will identify the risk factors that could play an important role in a severe systemic reaction: the aetiology of the Hymenoptera sting, sex, age, history and severity of previous systemic reactions, being re-stung in an interval of two months, the frequency of re-stings, atopy, genetic predisposition, preventive medication use, other medication use, beekeeping or living next to beehives and why immunotherapy was not taken. Laboratory data will also be analysed to determine if there is any association with laboratory tests and the severity of the allergic reactions after Hymenoptera stings. Conclusions: Several new approaches are introduced in the study design. The most important is that the protocol covers epidemiological data gained from the questionnaire, as well as clinical data gained from the Immunological database and BIRPIS database. We expect to obtain significant results that will explain the risk factors for the natural history of Hymenoptera sting allergic reactions and will help allergologists, as well as general doctors, when facing those patients allergic to Hymenoptera venom without immunotherapy.

Unusual Reactions to Hymenoptera Stings: Current Knowledge and Unmet Needs in the Pediatric Population

Hymenoptera stings are generally well-tolerated and usually cause limited local reactions, characterized by self-resolving erythema and edema associated with pain. However, Hymenoptera stings can induce immediate and delayed hypersensitivity reactions. In addition to these manifestations, unusual reactions to Hymenoptera stings have been reported. The latter are defined as unusual because of their atypical characteristics. They may differ from classical hypersensitivity reactions due to the stings' particular localization and the unusual involvement of one or more specific organs. Although unusual reactions to Hymenoptera stings are infrequent, it is essential for clinicians to know the possible related clinical manifestations. Here, we review the available literature and propose a diagnostic and management algorithm. At present, there are no defined guidelines for most of the unusual reactions to Hymenoptera stings, which should be managed in a tailored way according to the specifical clinical manifestations presented by the patients. Further studies are needed to better define these conditions and the underlying pathogenetic mechanisms to improve the diagnostic and therapeutic approach.

[Allergen immunotherapy: FAQs and facts]

Die Allergenimmuntherapie (AIT) ist – neben der oft nicht suffizient durchzuführenden Allergenmeidung – die einzige kausale Therapie Ig(Immunglobulin)E-vermittelter Allergien gegen Aeroallergene und Hymenopterengifte. Sie kann je nach Allergen als subkutane Injektion (subkutane Immuntherapie [SCIT]) oder über eine sublinguale Applikation (sublinguale Immuntherapie [SLIT]) erfolgen, kürzlich wurde zudem auch ein Verfahren zur oralen Immuntherapie zur Behandlung der Nahrungsmittelallergie zugelassen. Neben der korrekten Indikationsstellung (positive Anamnese und Diagnostik einer IgE-vermittelten Allergie, Allergenkarenz nicht ausreichend möglich) sind mögliche Kontraindikationen und Risikofaktoren zu beachten. Zudem kann es unter einer AIT zu – potenziell auch lebensgefährlichen – Nebenwirkungen kommen. Im Folgenden sollen häufig gestellte Fragen und Fakten zur Entscheidungsfindung für die Durchführung und zum Risikomanagement der AIT beleuchtet und unter Berücksichtigung der aktuellen Datenlage diskutiert werden.

Characterization of New Allergens from the Venom of the European Paper Wasp Polistes dominula

Discriminating Polistes dominula and Vespula spp. venom allergy is of growing importance worldwide, as systemic reactions to either species’ sting can lead to severe outcomes. Administering the correct allergen-specific immunotherapy is therefore a prerequisite to ensure the safety and health of venom-allergic patients. Component-resolved diagnostics of Hymenoptera venom allergy might be improved by adding additional allergens to the diagnostic allergen panel. Therefore, three potential new allergens from P. dominula venom—immune responsive protein 30 (IRP30), vascular endothelial growth factor C (VEGF C) and phospholipase A2 (PLA2)—were cloned, recombinantly produced and biochemically characterized. Sera sIgE titers of Hymenoptera venom-allergic patients were measured in vitro to assess the allergenicity and potential cross-reactivity of the venom proteins. IRP30 and VEGF C were classified as minor allergens, as sensitization rates lay around 20–40%. About 50% of P. dominula venom-allergic patients had measurable sIgE titers directed against PLA2 from P. dominula venom. Interestingly, PLA2 was unable to activate basophils of allergic patients, questioning its role in the context of clinically relevant sensitization. Although the obtained results hint to a questionable benefit of the characterized P. dominula venom proteins for improved diagnosis of venom-allergic patients, they can contribute to a deeper understanding of the molecular mechanisms of Hymenoptera venoms and to the identification of factors that determine the allergenic potential of proteins.

Remission of a case of multiple Hymenoptera stings-associated chronic urticaria during venom immunotherapy

Hymenoptera stings mostly cause acute urticaria but we describe a case of CU after wasp stings which remitted during venom immunotherapy. IgE-mechanisms have not been fully clarified in CU, except for isolated circumstances. In our case immunotherapy has played a positive role reducing immune cells reactivity and improving urticaria symptoms.

Impact of specific immunotherapy and sting challenge on the quality of life in patients with hymenoptera venom allergy

Background

An experienced life-threating anaphylactic reaction to hymenoptera venom can sustainably impair patients’ quality of life (QoL). Besides carrying emergency medication, venom-specific immunotherapy (VIT) exists as a causal treatment of allergy.

Objective

This study aimed to examine QoL, anxiety, depression, and physical and mental health in patients allergic to hymenoptera venom before and during VIT and the impact of a tolerated sting challenge (SC).

Methods

Between July 2017 and August 2017, 142 patients with venom allergy were analyzed using validated questionnaires as the: Vespid Allergy Quality for Life Questionnaire" (VQLQ-d), the "Hospital Anxiety and Depression Scale" (HADS-D) and the "Short Form 36" (SF-36). To evaluate the impact of VIT and SC on the QoL, patients were divided into 3 groups: (A) VIT and tolerated SC (n = 45), (B) VIT before carrying out SC (n = 73), and (C) therapy-naïve before VIT (n = 20). Further parameters like gender, age, insect species, and severity of the anaphylactic reaction were assessed.

Results

A significant correlation between the health-related QoL and the parameters of gender and state of treatment was seen. Especially male patients, as well as patients allergic to yellow jacket venom, benefit from a SC in terms of a significant increase in their QoL. In the total study cohort, a clear trend was observed towards a higher QoL in patients under VIT who tolerated a SC. Overall, neither the patients’ age nor the insect species exerted a relevant influence on QoL, depression or anxiety. However, women showed a lower QoL combined with higher anxiety and depression scores than men.

Conclusion

Immunotherapy leads to an improved QoL, which can be further increased by a SC. A tolerated SC conceivably reassures the patients by objectifying the treatment success. Female patients appear to have a stronger impaired QoL per se. Taken together, a SC can be performed during VIT to strengthen the patients’ QoL.

New Biomarkers of Hymenoptera Venom Allergy in a Group of Inflammation Factors

Hymenoptera venom allergy significantly affects the quality of life. Due to the divergences in the results of the available test and clinical symptoms of patients, the current widely applied diagnostic methods are often insufficient to classify patients for venom immunotherapy (VIT). Therefore it is still needed to search for new, more precise, and accurate diagnostic methods. Hence, this research aimed to discover new biomarkers of Hymenoptera venom allergy in a group of inflammation factors using set of multi-marker Bioplex panel. The adoption of a novel methodology based on Luminex/xMAP enabled simultaneous determination of serum levels of 37 different inflammatory proteins in one experiment. The study involved 21 patients allergic to wasp and/or honey bee venom and 42 healthy participants. According to univariate and multivariate statistics, soluble CD30/tumor necrosis factor receptor superfamily, member 8 (sCD30/TNFRSF8), and the soluble tumor necrosis factor receptor 1 (sTNF-R1) may be considered as effective prognostic factors, their circulating levels were significantly decreased in the allergy group (p-value < 0.05; the Area Under the Curve (AUC) ~0.7; Variable Importance in Projection (VIP) scores >1.2). The obtained results shed new light on the allergic inflammatory response and may contribute to modification and improvement of the diagnostic and monitoring methods. Further, large-scale studies are still needed to explain mechanisms of action of studied compounds and to definitively prove their usefulness in clinical practice.

Simultaneous Influenza Vaccination and Hymenoptera Venom Immunotherapy Is Safe

Allergen immunotherapy (AIT) is a standard treatment for venom allergy. Our purpose was to determine if the administration of both allergen and protective vaccines during one visit is safe and if such a procedure does not deteriorate the tolerance of both vaccines. As current guidelines are based on theoretical assumptions, our aim was to establish the safety and tolerance of shortening the recommended interval between vaccinations. During two influenza seasons, 44 adult patients, with a history of systemic allergic reactions after a Hymenoptera sting, underwent 58 simultaneous allergen and seasonal influenza vaccinations (study group) while in the maintenance phase of venom immunotherapy (VIT). The control group consisted of 57 healthy adults who were vaccinated against influenza only. The conditions of the patients were monitored during hospital visits, and via telecommunication methods to evaluate the safety and tolerance of the procedure. Within the study group, there were no immediate or delayed allergic reactions after vaccinations. The presence of common, adverse influenza vaccine reactions among study group patients (29%) and control group patients (32%) did not differ significantly (p = 0.841). We did not observe a difference in the frequency of various adverse reactions in either group or a dependence of previous vaccinations against influenza on the occurrence of adverse reactions. The most frequent occurrences were local adverse reactions. All adverse reactions were resolved without treatment. These findings demonstrate the safety and tolerance of an influenza vaccination and Hymenoptera venom immunotherapy administration during one visit.

Bone Marrow Mastocytosis: A Diagnostic Challenge

Bone marrow mastocytosis (BMM) represents a provisional, indolent subvariant of systemic mastocytosis (SM). Utilizing WHO criteria, BMM requires bone marrow (BM) involvement and the absence of mastocytosis skin lesions. BMM is characterized by male sex prevalence, a slight increase of serum tryptase levels, low BM mast cells (MC) burden, and an indolent clinical course. BMM shows a strong correlation with severe anaphylaxis, mainly due to an IgE-mediated allergy to bee or wasp venom and, less frequently, to unexplained (idiopathic) anaphylaxis. Furthermore, BMM is often associated with osteoporosis which could be the only presenting symptom of the disease. BMM is an undervalued disease as serum tryptase levels are not routinely measured in the presence of unexplained osteoporosis or anaphylaxis. Moreover, BMM patients are often symptom-free except for severe allergic reactions. These factors, along with typical low BM MCs infiltration, may contribute to physicians overlooking BMM diagnosis, especially in medical centers that lack appropriately sensitive diagnostic techniques. This review highlights the need for a correct diagnostic pathway to diagnose BMM in patients with suspected symptoms but lacking typical skin lesions, even in the case of normal serum tryptase levels. Early diagnosis may prevent potential life-threatening anaphylaxis or severe skeletal complications.

Association between Venom Immunotherapy and Changes in Serum Protein-Peptide Patterns

Venom immunotherapy (VIT) is administered to allergic patients to reduce the risk of dangerous systemic reactions following an insect sting. To better understand the mechanism of this treatment and its impact on the human organism, we analysed serum proteomic patterns obtained at five time-points from Hymenoptera-venom-allergic patients undergoing VIT. For statistical analyses, patients were additionally divided into two groups (high responders and low responders) according to serum sIgG4 levels. VIT was found to be associated with changes in seven proteins: the fibrinogen alpha chain, complement C4-A, complement C3, filamin-B, kininogen-1, myosin-9 and inter-alpha-trypsin inhibitor heavy chain H1. The number of discriminative m/z (mass-to-charge ratio) features increased up to the 90th day of VIT, which may be associated with the development of immunity after the administration of increased venom doses. It may also suggest that during VIT, there may occur processes involved not only in protein synthesis but also in protein degradation (caused by proteolytic venom components). The results are consistent with measured serum sIgG4 levels, which increased from 2.04 mgA/I at baseline to 7.25 mgA/I at 90 days. Moreover, the major proteomic changes were detected separately in the high responder group. This may suggest that changes in protein–peptide profiles reflect the actual response to VIT.

Update on Insect Sting Anaphylaxis

PURPOSE OF REVIEW

This review describes improvement in diagnostic accuracy, prediction of outcomes, identifying high-risk factors, and refinements of treatment that continue to evolve over the past 5-10 years.

RECENT FINDINGS

The risk of anaphylaxis is relatively low (< 5%) in patients with previous large local reactions or strictly cutaneous systemic reactions, but much higher in those with moderate-to-severe anaphylaxis (40%-70%) or mastocytosis (> 90%). Use of recombinant venom allergens and basophil activation tests may improve diagnostic accuracy. Elevated serum tryptase (and possible mastocytosis) occurs in 10% of patients with insect sting allergy, and in 25% of those with hypotensive reactions. Rush VIT is proven safe and rapidly effective. There are known high-risk factors that justify treatment beyond 5 years. Diagnostic accuracy and prediction of risk have improved in recent years. There are still knowledge gaps related to prediction and management of risk with current diagnostic and therapeutic modalities.

Precision Medicine in Hymenoptera Venom Allergy: Diagnostics, Biomarkers, and Therapy of Different Endotypes and Phenotypes

Allergic reactions to stings of Hymenoptera species may be severe and are potentially fatal deviations of the immunological response observed in healthy individuals. However, venom-specific immunotherapy (VIT) is an immunomodulatory approach able to cure venom allergy in the majority of affected patients. An appropriate therapeutic intervention and the efficacy of VIT not only depend on a conclusive diagnosis, but might also be influenced by the patient-specific manifestation of the disease. As with other diseases, it should be borne in mind that there are different endotypes and phenotypes of venom allergy, each of which require a patient-tailored disease management and treatment scheme. Reviewed here are different endotypes of sting reactions such as IgE-mediated allergy, asymptomatic sensitization or a simultaneous presence of venom allergy and mast cell disorders including particular considerations for diagnosis and therapy. Additionally, phenotypical manifestations of venom allergy, as e.g. differences in age of onset and disease severity, multiple sensitization or patients unsusceptible to therapy, are described. Moreover, biomarkers and diagnostic strategies that might reflect the immunological status of the patient and their value for therapeutic guidance are discussed. Taken together, the increasing knowledge of different disease manifestations in venom hypersensitivity and the growing availability of diagnostic tools open new options for the classification of venom allergy and, hence, for personalized medical approaches and precision medicine in Hymenoptera venom allergy.

Hymenoptera venom allergy among children in Italy: time for pediatricians to take action

Hymenoptera venom allergy (HVA) is one of the most frequent causes of anaphylaxis following a bee, vespid or ant sting. Real-life data regarding the management of HVA in children are lacking. To address this unmet need, we carried out a survey defining the current management of HVA in children among pediatric allergists in Italy. Educational investments on the improvement of the management of pediatric patients with HVA are urgently needed, and our analysis represents a relevant instrument in targeting a roadmap with this aim. The time for pediatric allergists to take action has come, and a task force from the Rare Allergic Diseases Commission of the Italian Society of Pediatric Allergy and Immunology is working on the topic to improve pediatricians' knowledge and optimize the care of these patients.

Cross-Reactive Carbohydrate Determinant in Apis mellifera, Solenopsis invicta and Polybia paulista Venoms: Identification of Allergic Sensitization and Cross-Reactivity

Allergic reactions to Hymenoptera venom, which could lead to systemic and even fatal symptoms, is characterized by hypersensitivity reactions mediated by specific IgE (sIgE) driven to venom allergens. Patients multisensitized to sIgE usually recognize more than one allergen in different Hymenoptera species. However, the presence of sIgE directed against Cross-Reactive Carbohydrate Determinant (CCD), which occurs in some allergens from Hymenoptera venom, hampers the identification of the culprit insects. CCD is also present in plants, pollen, fruits, but not in mammals. Bromelain (Brl) extracted from pineapples is a glycoprotein commonly used for reference to sIgE-CCD detection and analysis. In sera of fifty-one Hymenoptera allergic patients with specific IgE ≥ 1.0 KU/L, we assessed by immunoblotting the reactivity of sIgE to the major allergens of Apis mellifera, Polybia paulista and Solenopsis invicta venoms. We also distinguished, using sera adsorption procedures, the cases of CCD cross-reaction using Brl as a marker and inhibitor of CCD epitopes. The presence of reactivity for bromelain (24–28 kDa) was obtained in 43% of the patients, in which 64% presented reactivity for more than one Hymenoptera venom in radioallergosorbent (RAST) tests, and 90% showed reactivity in immunoblot analysis to the major allergens of Apis mellifera, Polybia paulista and Solenopsis invicta venoms. Sera adsorption procedures with Brl lead to a significant reduction in patients’ sera reactivity to the Hymenoptera allergens. Immunoblotting assay using pre- and post-Brl adsorption sera from wasp-allergic patients blotted with non-glycosylated recombinant antigens (rPoly p1, rPoly p5) from Polybia paulista wasp venom showed no change in reactivity pattern of sIgE that recognize allergen peptide epitopes. Our results, using Brl as a marker and CCD inhibitor to test sIgE reactivity, suggest that it could complement diagnostic methods and help to differentiate specific reactivity to allergens’ peptide epitopes from cross-reactivity caused by CCD, which is extremely useful in clinical practice.

Comparison of the Safety Profiles of 3 Different Hymenoptera Venom Immunotherapy Protocols: A Retrospective 2-Center Study of 143 Patients

INTRODUCTION

Venom immunotherapy (VIT) is highly effective and the treatment of choice for patients with a history of systemic anaphylactic reactions to a Hymenoptera sting. It has been assumed that VIT protocols with a rapid dose increase during the induction phase are associated with a higher frequency of systemic reactions (SR); however, study data addressing this issue are conflicting.

OBJECTIVE

The aim of this study was to compare the safety of 3 different Hymenoptera VIT protocols (half-day ultra-rush, 3-day rush, 3-week cluster).

METHODS

This retrospective 2-center study included 143 Hymenoptera venom-allergic patients, who underwent 147 VIT procedures during the years 2015-2018. Twenty cluster, 75 rush, and 52 ultra-rush VIT protocols were performed with honeybee (54 protocols) and wasp (93 protocols) venom. All documented side effects were classified into large local and SR (Ring and Messmer classification).

RESULTS

SR were observed during 11 (7.5%) VIT procedures and did not exceed severity grade II. SR occurred more frequently in cluster compared to accelerated protocols. This result was observed for both honeybee (cluster: 25%, rush: 8.7%, and ultra-rush: 15.8%) and wasp VIT (cluster: 12.5%, rush: 0%, and ultra-rush: 6.1%), though the differences were statistically significant only in the wasp VIT subgroup. Honeybee venom elicited more SR than wasp venom (14.8 and 3.2%, respectively, p = 0.01). The risk for SR did not depend on age, sex, concomitant antihypertensive medication, hypertryptasemia, or severity of the index sting reaction.

CONCLUSION

Accelerated VIT protocols, namely, rush and ultra-rush protocols are safe therapeutic options for Hymenoptera venom-allergic patients and displayed fewer SR than cluster VIT protocols in our study.

Antigen 5 Allergens of Hymenoptera Venoms and Their Role in Diagnosis and Therapy of Venom Allergy

PURPOSE OF REVIEW

Stings of Hymenoptera of the superfamily Vespoidea such as yellow jackets, paper wasps or stinging ants are common triggers for severe and even fatal allergic reactions. Antigen 5 allergens are potent allergens in the majority of these venoms with major importance for diagnosis and therapy. Reviewed here are the characteristics of antigen 5 allergens, their role in component-resolved diagnostics as well as current limitations of the available diagnostics for proper therapeutic decisions.

RECENT FINDINGS

Antigens 5 are proteins of unknown function in Hymenoptera venoms with high allergenic potency. They represent key elements in component-resolved diagnosis to discriminate between honeybee and vespid venom allergy. However, due to their pronounced cross-reactivity, there are remaining diagnostic and therapeutic challenges that have to be addressed. Antigens 5 are highly relevant venom allergens of the Vespoidea superfamily. Although their use in component-resolved diagnosis facilitates dissection of cross-reactivity and primary allergy in double sensitization to honeybee and vespid venom, new diagnostic concepts are needed to discriminate between allergies to different vespid species.

Functional Profile of Antigen Specific CD4+ T Cells in the Immune Response to Phospholipase A1 Allergen from Polybia paulista Venom

Insect venom can cause systemic allergic reactions, including anaphylaxis. Improvements in diagnosis and venom immunotherapy (VIT) are based on a better understanding of an immunological response triggered by venom allergens. Previously, we demonstrated that the recombinant phospholipase A1 (rPoly p 1) from Polybia paulista wasp venom induces specific IgE and IgG antibodies in sensitized mice, which recognized the native allergen. Here, we addressed the T cell immune response of rPoly p 1-sensitized BALB/c mice. Cultures of splenocytes were stimulated with Polybia paulista venom extract and the proliferation of CD8⁺ and CD4⁺ T cells and the frequency of T regulatory cells (Tregs) populations were assessed by flow cytometry. Cytokines were quantified in cell culture supernatants in ELISA assays. The in vitro stimulation of T cells from sensitized mice induces a significant proliferation of CD4⁺ T cells, but not of CD8⁺ T cells. The cytokine pattern showed a high concentration of IFN-γ and IL-6, and no significant differences to IL-4, IL-1β and TGF-β1 production. In addition, the rPoly p 1 group showed a pronounced expansion of CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25^-FoxP3⁺ Tregs. rPoly p 1 sensitization induces a Th1/Treg profile in CD4⁺ T cell subset, suggesting its potential use in wasp venom immunotherapy.

Shedding Light on the Venom Proteomes of the Allergy-Relevant Hymenoptera Polistes dominula (European Paper Wasp) and Vespula spp. (Yellow Jacket)

Allergic reactions to stings of Hymenoptera species can have serious or even fatal consequences. If the identification of the culprit insect is possible, venom-specific immunotherapy effectively cures Hymenoptera venom allergies. Although component-resolved diagnostics has strongly evolved in recent years, the differentiation between allergies to closely related species such as Polistes dominula and Vespula spp. is still challenging. In order to generate the basis for new diagnostic and therapeutic strategies, this study aims at resolving the venom proteomes (venomes) of these species. The venoms of P. dominula and Vespula spp. (V. germanica, V. vulgaris) were analyzed by liquid chromatography-mass spectrometry. Resulting proteins were characterized regarding their function, localization and biochemical properties. The analyses yielded 157 proteins in Vespula spp. and 100 in P. dominula venom; 48 proteins, including annotated allergens, were found in both samples. In addition to a variety of venom trace molecules, new allergen candidates such as icarapin-like protein and phospholipase A2 were identified. This study elucidates the venomes of closely related allergy-eliciting Hymenoptera species. The data indicates that relying on marker allergens to differentiate between P. dominula and Vespula spp. venom allergy is probably insufficient and that strategies using cross-reactive major allergens could be more promising.

Efficacy and safety of honeybee and wasp tyrosine-adsorbed venom immunotherapy

Introduction

It is acknowledged that any claim of efficacy of allergen immunotherapy must be done for each specific product, and this remains true also for venom immunotherapy (VIT). Thus, we evaluated the efficacy and safety of a specific tyrosine-adsorbed VIT for vespula spp. and honeybee in real-life.

Methods

Consecutive patients diagnosed with hymenoptera allergy, and receiving VIT for either vespula or honeybee with a tyrosine-adsorbed preparation were observed to evaluate the grade of reaction (according to Muller) at the first field re-sting. A modified ultra-rush protocol was used.

Results

A total of 247 patients (73 female) were observed (102 honeybee, group H, 145 vespula, group V). Seventy-five patients in group H had a re-sting, and 74/75 had a lower grade reaction at re-sting as compared to the pre-VIT reaction. Considering systemic reactions, protection was achieved in 89% of patients. In group V 118 patients were re-stung, and 76/118 patients with previous grade III-IV reaction had no more systemic reaction under VIT. Overall, considering systemic reactions, protection was achieved in 92% of subjects. Of note, in both groups there was a clear inverse correlation between the severity of pre-VIT and during VIT reactions. The duration of VIT at the time of re-sting did not affect the efficacy. The safety was overall good, with 18% ad 15.4% local reactions in groups H and V, respectively.

Discussion

Modified extracts, including tyrosine-absorbed, have the aim of improving the safety of VIT still yet maintaining the efficacy. Field re-sting is the best way to assess the efficacy in real life. In this observational study we could confirm the protective efficacy of the tyrosine-adsorbed extract, with a good safety expecially in the build-up using a modified-rush protocol.

Conclusion

The tyrosine-adsorbed VIT used herein is a viable and advantageous form of treatment for hymenoptera allergy.

Large local reaction to Hymenoptera stings: Sound studies are needed to change a shared concept

The natural history of large local reactions to Hymenoptera stings allowed to estimate the risk to develop a systemic reaction after an initial large local reaction in about 4% of patients. A recently published study claimed that such risk concerns instead around one-fourth of patients. However, such study is flawed by serious imprecision, particularly the unreliable identification by patients of the culprit insect, as well as the dubious identification of the causative venom in multisensitized patients. Also, the authors criticized previous studied because of the limited number of patients, while they included in the study 662 patients. Indeed, when only patients clearly restung by the same insect according to their history data were considered, the number of patients fell to 35. These data are unable to change the current shared concept on the low risk of systemic reactions in patients with initial large local reaction.

Immunotherapy and biologicals for the treatment of allergy to Hymenoptera stings

Introduction: Venom immunotherapy (VIT) is an effective treatment for Hymenoptera venom allergy. The occurrence of severe reactions (SRs) to VIT, although infrequent, hampers the achievement of tolerance to insect stings. Risk factors for such reactions include allergy to honeybee venom, concomitant mast cell disorders, and the build-up phase of VIT. A role for omalizumab has come forward in recent years. Areas covered: This article reviews the available literature on the efficacy of omalizumab in preventing SRs and allowing the attainment of VIT maintenance doses. Pre- and co-treatments with omalizumab were evaluated, with positive overall results. Adding omalizumab to VIT in patients with SRs generally results in tolerance to VIT, thus restoring its precious preventive value. Expert opinion: VIT is effective for patients with Hymenoptera venom allergy and is recommended to prevent further (possibly fatal) reactions to stings. Omalizumab has shown efficacy in protecting patients from VIT-related SRs, particularly in those at high risk of SRs because of mast cell disorders and/or honeybee venom allergy. Notwithstanding, the accepted dose and time course of omalizumab for achieving tolerability and ensuring safety during VIT are not yet defined. In the future, other biologicals may play a role in preventing SRs during VIT.

Quality of life in parents of children and adolescents after systemic sting reactions

INTRODUCTION AND OBJECTIVES

The study aimed at evaluating the impact of Hymenoptera venom allergy (HVA) in children and adolescents, on their parents' QoL, taking into account their socio-demographic characteristics.

MATERIAL AND METHODS

The study sample consisted of 101 parents of children and adolescents aged 9-17 years, with a history of systemic reaction after insect sting who were referred for consultations in the tertiary level allergology department. The mean age of the parents was 39 years (SD=8.1; range 25-65 years); the majority were mothers (68%) and rural inhabitants (62%). QoL in parents of HVA children and adolescents was measured with the Parents of Children with Hymenoptera Venom Allergy Quality of Life Scale, a questionnaire covering 5 dimensions: anxiety, caution, limitations and discomfort, support provided to the child and feeling of safety, each measured on the scale ranging from 1 to 5. Independent predictors of QoL were estimated using the Generalized Linear Model.

RESULTS

Parents of urban children and adolescents treated with venom immunotherapy (VIT) up to 3 years (B=-1.37, 95CI= (-2.22;-0.53); p=0.001) and of rural children treated for more than 3 years (B=-0.94, 95CI=(-1.55;-0.33); p=0.003) reported lower anxiety than parents studied at diagnosis. In urban parents, individuals studied at VIT beginning reported a lower feeling of safety (B=-0.63, 95CI=(-1.11;-0.15); p=0.010); those studied up to 3 years of treatment reported a higher feeling of safety (B=0.64, 95CI=(0.11;1.16); p=0.018) than those studied at diagnosis. Contrariwise, in rural parents, those studied at the beginning of immunotherapy reported a higher feeling of safety than those studied at diagnosis (B=0.51, 95CI=(0.13;0.88); p=0.008).

CONCLUSIONS

The longest VIT duration in children and adolescents with HVA is related to the decreased anxiety of their parents. Parent's feeling of safety depends on the stage of treatment and place of residence.

Health-related quality of life in children and adolescents after systemic sting reaction

INTRODUCTION AND OBJECTIVES

Insect stings are the second trigger of anaphylaxis in children and adolescents, causing a potentially life-threatening reactions. Hence health-related quality of life (HRQoL) is an important issue for Hymenoptera venom allergy (HVA) patients. The aim of this cross-sectional study was to evaluate the impact of HVA on young patients' HRQoL, including their socio-demographic characteristics.

MATERIAL AND METHODS

The study sample included 102 patients aged 8-17 (Mean 12.5 years, SD=3.0), who were under diagnosis or venom immunotherapy due to systemic reaction after an insect sting in one of the tertiary referential centers in Poland. They were mostly boys (70%), and mainly from rural areas (63%). HRQoL of studied patients was measured with the Children's Hymenoptera Venom Allergy Quality of Life Scale, a questionnaire covering 6 dimensions: anxiety, caution, limitations, discomfort, support received from parents and a feeling of safety, each measured from 1 to 5. Independent predictors of HRQoL were estimated using the Generalized Linear Model.

RESULTS

In the group of children being dermal reactors, girls reported a higher level of anxiety (B=1.17, 95%CI=(0.30;2.03), p=0.008). In the group of children with grade 2 it was the girls who reported lower anxiety (B=-1.33, 95%CI=(-2.38;-0.29), p=0.013). Boys treated longer than 3 years had their level of anxiety significantly lower than those studied at diagnosis (B=-0.65, 95%CI=(-1.23;-0.07), p=0.028). The feeling of safety was higher in children living in villages than in those living in towns (B=0.30, 95%CI=(0.03;0.56), p=0.031).

CONCLUSIONS

The gender, treatment duration and stage of anaphylactic reaction influenced level of anxiety. The level of feeling of safety was related to the place of living.

Characterization of the honeybee venom proteins C1q-like protein and PVF1 and their allergenic potential

Honeybee (Apis mellifera) venom (HBV) represents an ideal model to study the role of particular venom components in allergic reactions in sensitized individuals as well as in the eusociality of Hymenoptera species. The aim of this study was to further characterize the HBV components C1q-like protein (C1q) and PDGF/VEGF-like factor 1 (PVF1). C1q and PVF1 were produced as recombinant proteins in insect cells. Their allergenic properties were examined by determining the level of specific IgE antibodies in the sera of HBV-allergic patients (n = 26) as well as by their capacity to activate patients' basophils (n = 11). Moreover, the transcript heterogeneity of PVF1 was analyzed. It could be demonstrated that at least three PVF1 variants are present in the venom gland, which all result from alternative splicing of one transcript. Additionally, recombinant C1q and PVF1 from Spodoptera frugiperda insect cells exhibited specific IgE reactivity with approximately 38.5% of sera of HBV-allergic patients. Interestingly, both proteins were unable to activate basophils of the patients, questioning their role in the context of clinically relevant sensitization. Recombinant C1q and PVF1 can build the basis for a deeper understanding of the molecular mechanisms of Hymenoptera venoms. Moreover, the conflicting results between IgE sensitization and lack of basophil activation, might in the future contribute to the identification of factors that determine the allergenic potential of proteins.

Clinical evaluation of reactions following stings, in patients qualified for venom immunotherapy

Introduction

Hymenoptera venom allergy (HVA) in some patients occurs with general symptoms involving respiratory and cardiovascular system with anaphylactic shock with constitutes a significant threat to life.

Aim

Assessment of the prevalence of HVA in our own material.

Material and methods

There were 498 patients after a general reaction to wasp and/or bee venom. The survey included questions: the type of stinging insect, body parts stung by insects, profession, frequency of stings by wasps and bees depending on professional activity, places of stings, clinical symptoms using the scale according to Muller, and the treatment following the sting. Among 498 patients, there were 281 women and 217 men.

Results

Wasp stings were more frequent and affected 382 (77%) persons, while bee stings affected 116 (23%) persons. Limbs constituted the most common area of the body stung by both wasps and bees. The sting was more frequent in rural areas and during summer rest. A severe systemic reaction (class III and IV according to Muller) occurred more often in people stung by bees. The most common medications included intravenous glucocorticosteroids, calcium preparations and antihistamines. Intramuscular Adrenaline injection was used in 48% of patients, while only 15% received its prescription as an emergency medication. Bee stings were the most common cause of severe systemic symptoms.

Conclusions

The treatment after the sting in a significant percentage of episodes still deviates from the recommendations of the guidelines, especially in the field of adrenaline recommendations for patients in case of a resting by an insect

EAACI guidelines on allergen immunotherapy: Hymenoptera venom allergy

Hymenoptera venom allergy is a potentially life-threatening allergic reaction following a honeybee, vespid, or ant sting. Systemic-allergic sting reactions have been reported in up to 7.5% of adults and up to 3.4% of children. They can be mild and restricted to the skin or moderate to severe with a risk of life-threatening anaphylaxis. Patients should carry an emergency kit containing an adrenaline autoinjector, H₁ -antihistamines, and corticosteroids depending on the severity of their previous sting reaction(s). The only treatment to prevent further systemic sting reactions is venom immunotherapy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Venom Immunotherapy as part of the EAACI Guidelines on Allergen Immunotherapy initiative. The guideline aims to provide evidence-based recommendations for the use of venom immunotherapy, has been informed by a formal systematic review and meta-analysis and produced using the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included representation from a range of stakeholders. Venom immunotherapy is indicated in venom-allergic children and adults to prevent further moderate-to-severe systemic sting reactions. Venom immunotherapy is also recommended in adults with only generalized skin reactions as it results in significant improvements in quality of life compared to carrying an adrenaline autoinjector. This guideline aims to give practical advice on performing venom immunotherapy. Key sections cover general considerations before initiating venom immunotherapy, evidence-based clinical recommendations, risk factors for adverse events and for relapse of systemic sting reaction, and a summary of gaps in the evidence.

Vespa crabro immunotherapy versus Vespula-venom immunotherapy in Vespa crabro allergy: a comparison study in field re-stings

Background

In ascertained allergic sensitization to Vespa crabro (VC) venom, the European guidelines still consider venom immunotherapy (VIT) with Vespula (VE) venom sufficient to achieve an adequate protection against VC. However, antigen 5 immunoblotting studies showed that a genuine sensitization to VC venom may exist. In such cases, a specific VC venom would be preferable for VIT treatment. Since in the last few years, VC venom extracts became available for diagnosis and desensitization, we assessed the efficacy and safety of VIT with a VC-VIT, compared to VE extract.

Methods

Patients stung by VC, and carefully diagnosed for specific sensitization and indication to VIT underwent a 5-year course of immunotherapy with either VE or VC extracts. The severity of reactions at the first sting (pre-VIT) and after field re-stings (during VIT) were compared.

Results

Eighty-three patients, treated with VE extract and 130 patients treated with VC extract completed the 5-year course of VIT. Only a fraction of those patients (43,8%) were field-re-stung by VC: 64 patients on VC VIT and 69 on VE VIT. In the VC VIT group, reactions at re-sting were: 50 negative, 12 large local reactions, 4 systemic reactions (Muller grade I). In this group the VC VIT efficacy was 93,8%. In the VE VIT treated group the reactions at VC re-sting were: 51 negative, 10 large local reactions and 9 systemic reactions (5 Muller I, 3 Mueller III, 1 Muller IV). In this group the overall efficacy of VIT was 87,0%. The difference in efficacy between the two groups was not statistically significant, as previously reported in literature. Nonetheless, field sting systemic reactions Muller III and IV were recorded only in those patients receiving VE VIT.

Conclusion

This observation suggests that in patients with ascertained VC-induced allergic reactions a specific VC VIT, where available, would be more adequate, at least concerning the safety profile.

A 13-year real-life study on efficacy, safety and biological effects of Vespula venom immunotherapy

Background

Hymenoptera venom immunotherapy (VIT) is a clinically effective treatment. However, little is known about its long-term clinical efficacy and biological effects. Several mechanisms have been proposed to account for VIT efficacy, including reduction of specific IgE and induction of allergen-specific IgG₄, but the overall picture remains elusive. We investigated Vespula VIT clinical efficacy up to 8 years after discontinuation and the kinetics of Vespula-specific IgE and IgG₄. Out of 686 consecutive patients we retrospectively selected and analysed a series of 23 patients with Vespula allergy that underwent a 5-year IT course, followed by a prolonged follow-up.

Methods

Clinical efficacy of VIT was assessed as number and severity of reactions to Vespula re-stinging events. The presence of Vespula-specific IgE and IgG₄ was also monitored over time.

Results

During the VIT treatment, patients were protected, reporting no reactions or mild reactions in occasion of re-stinging events. This protection was entirely maintained during the follow-up, up to 8 years. Skin reactivity (reflecting mast cell-bound Vespula-specific IgE) and circulating Vespula-specific IgE levels declined substantially during VIT. Notably, this reduction was maintained over time during the follow-up. Moreover, all the patients were analysed for IgG₄. A robust induction of Vespula-specific IgG₄ was observed during the VIT course, with a substantial decline during the follow-up.

Conclusions

We conclude that Vespula VIT is a clinically effective treatment, which induces long-term protection after discontinuation. The reduction of specific IgE, assessed by skin tests and RAST, closely matches the VIT- induced protection, while the IgG₄ induction seems not to be associated with VIT clinical efficacy in the long term.

Electronic supplementary material

The online version of this article (10.1186/s12948-017-0079-y) contains supplementary material, which is available to authorized users.

Venom immunotherapy in patients with allergic reactions to insect stings

INTRODUCTION

Allergy to Hymenoptera (Apis mellifera, Vespula species, Polistes species, Vespa crabro) venom can be safely and effectively treated by venom immunotherapy (VIT), which in the 40 years since its introduction has been able to prevent reactions to stings, and to treatment as well, though systemic reactions, occasionally severe, are possible. Areas covered: We reviewed the recent literature on VIT by searching in PubMed for the terms 'venom immunotherapy' and 'Hymenoptera venom immunotherapy' to highlight the current status of VIT and the likely development in the coming years. Expert commentary: VIT, provided the correct choice of the venom and adequate venom preparations and maintenance doses are used, is a treatment of great value in preventing systemic reactions to Hymenoptera stings. A 5-year duration ensures a prolonged tolerance to stings following VIT discontinuation, unless patients suffer from mastocytosis. In fact, due to reports of fatal reactions after stopping VIT, patients with mastocytosis, or with very severe reactions to stings, need an indefinite duration of treatment.

New trends in anaphylaxis

This review presents the current trends in anaphylaxis management discussed at the fourth International Network for Online-Registration of Anaphylaxis (NORA) conference held in Berlin in April 2017. Current data from the anaphylaxis registry show that Hymenoptera venom, foods, and pharmaceutical drugs are still among the most frequent triggers of anaphylaxis. Rare triggers include chicory, cardamom, asparagus, and goji berries. A meta-analysis on recent trends in insect venom anaphylaxis demonstrated for the first time that, although data on the efficacy of insect venom immunotherapy is limited, the occurrence of severe reactions upon repeated sting events can be prevented and patients’ quality of life improved. Molecular diagnostics of insect venom anaphylaxis have significantly improved diagnostic sensitivity and specificity. Self-treatment of anaphylaxis is of great importance. Recent data from the anaphylaxis registry show an increase (from 23% in 2012 to 29% in 2016) in the use of adrenaline as recommended in the guidelines. A survey on the implementation of guidelines conducted among the centers reporting to the anaphylaxis registry highlights the extent to which the guideline has been perceived and implemented. Reports on a variety of cases in the anaphylaxis registry illustrate the diversity of this potentially life-threatening reaction. Component-resolved diagnostics can help to specify sensitization profiles in anaphylaxis, particularly in terms of the risk for severe reactions. Recent studies on anaphylaxis awareness show that training methods are effective; nevertheless, target groups and learning methods need to undergo further scientific investigation in coming years.

Overcoming severe adverse reactions to venom immunotherapy using anti-IgE antibodies in combination with a high maintenance dose

BACKGROUND

An omalizumab treatment and a high maintenance venom dose may both help to prevent recurrent systemic allergic reactions (SAR) to venom immunotherapy (VIT). The effectiveness of this combination therapy, however, is unclear.

OBJECTIVE

We wanted to explore the possibility whether a temporary treatment with the anti-IgE antibody omalizumab combined with a VIT using an elevated maintenance dose of >100 μg venom may establish a permanent tolerance of maintenance VIT.

METHODS

For this retrospective case series, we scoured our institutional data base for patients who had had an insect venom allergy, and in whom it had not been possible to continue VIT because of repeated unstoppable SAR during maintenance VIT. Patients were divided into those who had received the combination therapy (omalizumab group) and those who had not received omalizumab because its costs could not be covered (controls). Guided by the total IgE level and by body weight, omalizumab had been given subcutaneously 5, 3 and 1 weeks before VIT had been restarted. Three to 6 months after an elevated maintenance dose (200-300 μg venom) had been reached, omalizumab had been stopped.

RESULTS

Between 2006 and 2011, 15 patients had qualified for an off-label use of omalizumab: 10 patients had received the combination therapy, and 5 patients had remained without such a therapy. The combination therapy leads to a durable tolerance of VIT in all patients even after omalizumab had been discontinued (median of follow-up time 5.8 years, IQR 2.7-8.6 years). Sting challenge tests were tolerated by all of the re-stung omalizumab patients (n = 8). In all controls, VIT had to be stopped permanently due to repeated SARs (P < .001 vs omalizumab group).

CONCLUSIONS AND CLINICAL RELEVANCE

Combining a temporary omalizumab therapy with an elevated maintenance dose seems a promising approach to achieve a tolerance of treatment in patients with a recurrent SAR to VIT.

Specific Immunotherapy in Hymenoptera Venom Allergy and Concomitant Malignancy: A Retrospective Follow-up Focusing on Effectiveness and Safety

BACKGROUND

Malignancies are often considered a contraindication for allergen-specific immunotherapy. Consequently, patients with severe Hymenoptera venom allergy and cancer require specific care. The aim of this retrospective study was to assess patients with Hymenoptera venom allergy and cancer undergoing venom immunotherapy (VIT).

METHODS

The study population comprised all patients referred for evaluation of Hymenoptera venom allergy or for a routine check-up during VIT from January 1, 2004 to December 31, 2008.

RESULTS

Of the patients assessed, 2% (51 of 2594) had a documented Hymenoptera venom allergy and cancer (25 female, 26 male; mean age 58 years). Of these, 42 patients received VIT (82%): 25 patients had a previously diagnosed malignancy, 16 were diagnosed with malignancy during VIT, and 1 patient was diagnosed with cancer after completion of VIT. The most frequent type of tumor was breast cancer in female patients (60%) and prostate cancer in male patients (39%). Systemic allergic reactions during VIT were recorded in 7% of patients. A total of 19 patients experienced a field sting or underwent a sting challenge test during VIT: 95% tolerated the sting well. VIT was halted definitively in 9 patients (new diagnosis of cancer in 7 patients, reactivation of cancer in 1, and progressive polyneuropathy in 1).

CONCLUSIONS

The effectiveness and adverse effects of VIT in patients with Hymenoptera venom allergy and cancer in remission are comparable to those of patients without malignancy. Our findings show that patients with Hymenoptera venom allergy and cancer are eligible for VIT.

Application of recombinant antigen 5 allergens from seven allergy-relevant Hymenoptera species in diagnostics

BACKGROUND

Hymenoptera stings can cause severe anaphylaxis in untreated venom-allergic patients. A correct diagnosis regarding the relevant species for immunotherapy is often hampered by clinically irrelevant cross-reactivity. In vespid venom allergy, cross-reactivity between venoms of different species can be a diagnostic challenge. To address immunological IgE cross-reactivity on molecular level, seven recombinant antigens 5 of the most important Vespoidea groups were assessed by different diagnostic setups.

METHODS

The antigens 5 of yellow jackets, hornets, European and American paper wasps, fire ants, white-faced hornets, and Polybia wasps were recombinantly produced in insect cells, immunologically and structurally characterized, and their sIgE reactivity assessed by ImmunoCAP, ELISA, cross-inhibition, and basophil activation test (BAT) in patients with yellow jacket or Polistes venom allergy of two European geographical areas.

RESULTS

All recombinant allergens were correctly folded and structural models and patient reactivity profiles suggested the presence of conserved and unique B-cell epitopes. All antigens 5 showed extensive cross-reactivity in sIgE analyses, inhibition assays, and BAT. This cross-reactivity was more pronounced in ImmunoCAP measurements with venom extracts than in sIgE analyses with recombinant antigens 5. Dose-response curves with the allergens in BAT allowed a differentiated individual dissection of relevant sensitization.

CONCLUSIONS

Due to extensive cross-reactivity in various diagnostic settings, antigens 5 are inappropriate markers for differential sIgE diagnostics in vespid venom allergy. However, the newly available antigens 5 from further vespid species and the combination of recombinant allergen-based sIgE measurements with BAT represents a practicable way to diagnose clinically relevant sensitization in vespid venom allergy.

Rush Venom Immunotherapy in Children

BACKGROUND

Rush venom immunotherapy (VIT) is highly effective in Hymenoptera venom allergy. Still, specific data regarding its safety and efficiency in children are rather sparse.

OBJECTIVES

The objective of this study was to better evaluate the safety and efficiency of rush VIT in this specific age group.

METHODS

Children younger than 16 years with systemic reaction to insect sting involving, at least, one body system other than skin and children aged 16-18 years with any kind of systemic reaction were offered conventional or rush VIT with a build-up phase that lasted 3 days.

RESULTS

Eighty-four of 127 children together with their caregivers chose to receive rush VIT. Seventy of them were allergic to bee venom only. There was no difference between the children receiving rush or conventional VIT in the incidence of systemic reactions during the build-up phase (19% and 23.2%, respectively), nor was there any difference in regard to the severity of these reactions. Efficiency was improved with rush VIT, as reflected by a higher number of patients achieving the 100 mcg maintenance dose with the primary protocol (83 of 84 patients, 98.8%, and 39 of 43, 90.7%, for rush and conventional, respectively, P = .04).

CONCLUSIONS

Rush VIT in children is as safe as and more efficient than conventional VIT.

Predominant Api m 10 sensitization as risk factor for treatment failure in honey bee venom immunotherapy

BACKGROUND

Component resolution recently identified distinct sensitization profiles in honey bee venom (HBV) allergy, some of which were dominated by specific IgE to Api m 3 and/or Api m 10, which have been reported to be underrepresented in therapeutic HBV preparations.

OBJECTIVE

We performed a retrospective analysis of component-resolved sensitization profiles in HBV-allergic patients and association with treatment outcome.

METHODS

HBV-allergic patients who had undergone controlled honey bee sting challenge after at least 6 months of HBV immunotherapy (n = 115) were included and classified as responder (n = 79) or treatment failure (n = 36) on the basis of absence or presence of systemic allergic reactions upon sting challenge. IgE reactivity to a panel of HBV allergens was analyzed in sera obtained before immunotherapy and before sting challenge.

RESULTS

No differences were observed between responders and nonresponders regarding levels of IgE sensitization to Api m 1, Api m 2, Api m 3, and Api m 5. In contrast, Api m 10 specific IgE was moderately but significantly increased in nonresponders. Predominant Api m 10 sensitization (>50% of specific IgE to HBV) was the best discriminator (specificity, 95%; sensitivity, 25%) with an odds ratio of 8.444 (2.127-33.53; P = .0013) for treatment failure. Some but not all therapeutic HBV preparations displayed a lack of Api m 10, whereas Api m 1 and Api m 3 immunoreactivity was comparable to that of crude HBV. In line with this, significant Api m 10 sIgG₄ induction was observed only in those patients who were treated with HBV in which Api m 10 was detectable.

CONCLUSIONS

Component-resolved sensitization profiles in HBV allergy suggest predominant IgE sensitization to Api m 10 as a risk factor for treatment failure in HBV immunotherapy.