Comparing the ability of molecular diagnosis and CAP-inhibition in identifying the really causative venom in patients with positive tests to Vespula and Polistes species

Hymenoptera venom allergy in children

From a taxonomic point of view, Hymenoptera are subclassified into families: Apidae, including honeybees (Apis mellifera) and bumblebees (Bombus), and Vespidae, which, in turn, are divided into the subfamilies of Vespinae (wasps, including hornets, vespules, dolichovespules) and Polistinae (paper wasp). Hypersensitivity to Hymenoptera venom can be linked to immunological (IgE-mediated or non-IgE-mediated) and non-immunological mechanisms. Reactions are classified into local reactions, large local reactions, systemic reactions, toxic reactions, and unusual reactions. In general, children sensitize less frequently and have less severe reactions than adults, probably due to less exposure to repeated stings and fewer comorbidities. There are risk factors for systemic reactions that should be discussed with patients and their parents as appropriate. A correct diagnosis of Hymenoptera venom allergy relies on a careful clinical history and the appropriate use of skin and in vitro tests. The in vitro tests include serum specific IgE toward venom extracts and toward allergenic molecules. In complex diagnoses, CAP-inhibition and the Basophil Activation Test can also be used. In the presence of a systemic reaction, the basal serum tryptase measurement should be performed to rule out mastocytosis. In case of allergic reactions to Hymenoptera stings, in the acute phase, according to the current guidelines, the treatment of signs and symptoms mainly includes the use of adrenaline as first-line treatment in case of anaphylaxis and antihistamines and corticosteroids as subsequent lines of treatment. Given the impossibility of avoiding a new sting with certainty, the treatment of choice in subjects with hypersensitivity to Hymenoptera venom who have experienced systemic reactions is based on venom immunotherapy (VIT), with the venom of the responsible stinging insect identified after an adequate allergological work-up. VIT is performed in a suitable environment and has proved to be safe and effective with various administration protocols, both accelerated and conventional. The prevention of Hymenoptera venom anaphylaxis in patients who have already developed a previous episode is crucial and must be supported by environmental protection interventions and early therapy. Places where one is more likely to encounter insects and risky behaviors should be avoided.

Bee/Vespula Venom-Specific IgE Ratio Greater Than 5:1 Indicates Culprit Insect in Double-Sensitized Patients

BACKGROUND

Venom-allergic patients are frequently double-sensitized to honeybee venom (BV) and Vespula venom (VV). Genuine double allergy is uncommon.

OBJECTIVES

To assess whether a quantitative comparison of BV- and VV-specific IgE levels permits an identification of the culprit venom in double-sensitized patients, and to evaluate whether independent sensitization to BV- and VV-specific components corresponds to an indication for double immunotherapy.

METHODS

This single-center observational study evaluated 1,069 consecutive patients; 490 nonallergic controls were available for statistical comparison. The diagnosis (BV allergy, VV allergy, or double allergy) was based on a comprehensive allergological workup including patient history, IgE serology, intradermal skin test, and, when required, basophil activation testing. Quantitative allergen-specific IgE to BV, VV, rApi m 1, and rVes v 5 was retrospectively compared with the final diagnosis. The ratio of BV/VV-specific IgE levels was considered in double-sensitized venom-allergic patients.

RESULTS

Sensitization to whole-venom preparations and components was frequent in patients and asymptomatic controls, with higher specific IgE levels in the patient group. At least 5:1 dominance of the specific IgE to either BV or VV was documented in 239 of 459 double-sensitized venom-allergic patients (52.1%). Of these patients 232 (97.1%) received a diagnosis of monoallergy to only the venom to which they were dominantly sensitized.

CONCLUSIONS

Dominant specific IgE at a ratio of 5:1 indicates the culprit venom in double-sensitized allergic patients. Additional component-resolved diagnostic testing can be restricted to cases with double sensitization to whole venom at a ratio of less than 5:1. Double sensitization to rApi m 1 and rVes v 5 per se does not justify double venom immunotherapy.

Unraveling wasp sensitization in a patient with systemic mastocytosis by CAP-inhibition assay

Systemic mastocytosis (SM) is a clonal mast cell disorder that can lead to potentially severe anaphylactic reactions. Hymenoptera sting is one of the most frequent triggers of anaphylaxis in these patients, and diagnosis of indolent SM (ISM) without skin involvement (ISMs) is not rare. In this subgroup of patients, venom immunotherapy (VIT) is an effective treatment decreasing subsequent systemic reactions, and lifelong administration is recommended. An individualized diagnosis is necessary to offer the most adequate VIT, and molecular diagnosis (MD) may be useful to discriminate between primary sensitization and cross-reactivity. Nevertheless, other techniques such as ImmunoCAP inhibition assays may be necessary to identify the genuine sensitization to offer the most suitable VIT. We present a male patient with an anaphylactic reaction following several wasp stings. The patient was diagnosed with ISM, and allergy to both Polistes dominula and Vespula sp venom was confirmed. In this scenario, MD did not discriminate between a genuine double sensitization and venom cross-reactivity between both vespids. Thus, CAP-inhibition assay was performed. This case indicated the importance of an accurate diagnosis of hymenoptera venom allergy (HVA). It also highlights the usefulness of CAP-inhibition assays when MD fails to distinguish between genuine double Polistes-Vespula sensitization and cross-reactivity.

Venom Component Allergen IgE Measurement in the Diagnosis and Management of Insect Sting Allergy

Accurate identification of allergy-eliciting stinging insect(s) is essential to ensuring effective management of Hymenoptera venom-allergic individuals with venom-specific immunotherapy. Diagnostic testing using whole-venom extracts with skin tests and serologic-based analyses remains the first level of discrimination for honeybee versus vespid venom sensitization in patients with a positive clinical history. As a second-level evaluation, serologic testing using molecular venom allergens can further discriminate genuine sensitization (honeybee venom: Api m 1, 3, 4, and 10 vs yellow jacket venom/Polistes dominula venom Ves v 1/Pol d 1 and Ves v 5/Pol d 5) from interspecies cross-reactivity (hyaluronidases [Api m 2, Ves v 2, and Pol d 2] and dipeptidyl peptidases IV [Api m 5, Ves v 3, and Pol d 3]). Clinical laboratories use a number of singleplex, oligoplex, and multiplex immunoassays that employ both extracted whole-venom and molecular venom allergens (highlighted earlier) for confirmation of allergic venom sensitization. Established quantitative singleplex autoanalyzers have general governmental regulatory clearance worldwide for venom-allergic patient testing with maximally achievable analytical sensitivity (0.1 kUA/L) and confirmed reproducibility (interassay coefficient of variation <10%). Emerging oligoplex and multiplex (fixed-panel) assays conserve on serum and are more cost-effective, but they need regulatory clearance in some countries and are prone to higher rates of detecting asymptomatic sensitization. Ultimately, the patient's clinical history, combined with proof of sensitization, is the final arbiter in the diagnosis of Hymenoptera venom allergy.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

The mitogenome of a medically important paper wasp, Polistes hebraeus (Hymenoptera, Vespidae)

Polistes hebraeus (Smith) is a common paper wasp species of subfamily Polistinae. The clinical potential allergic reaction after stings and valuable venom components of P. hebraeus make it a medical importance species. Here, the mitochondrial genome of P. hebraeus was analyzed. The mitogenome was 19,262 bp in length including 22 transfer RNAs (tRNA) and 2 ribosomal RNAs (rRNA). The protein coding gene (PCGs) number and order are consistent with existing records of Polistidae. The nucleotide composition is AT: 84.5% and CG: 15.5% which are largely similar with other complete Polistidae mitogenome (15.27 ∼ 19.16%). The available mitogenome resources of Polistidae species and P. hebraeus were used to construct the phylogenetic tree. It showed that the genus Polistes could clearly seperated from Parapolybia, and the relationship in Polistes was consistent with previous studies. This mitogenome resource can contribute to further phylogenetic and taxonomic study on paper wasp.

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.

Management of Double Sensitization to Vespids in Europe

Wasp allergy with a diagnostic profile of double sensitizations to vespid venom is a frequent clinical problem in areas where different genera of wasps are present. Identification of the insect responsible for serious reactions poses a diagnostic challenge as the only effective treatment to date is immunotherapy based on the specific venom. In southern Europe, the double sensitization to Vespula and Polistes venoms is highly frequent. It has been shown that the major allergenic proteins (Phospholipase A1 and Antigen 5) share sequences across the different genera and species, which would be the cause of cross-reactivity. Additionally, the minor allergens (Dipeptidyl-peptidases, Vitellogenins) have been found to share partial sequence identity. Furthermore, venom contains other homologous proteins whose allergenic nature still remains to be clarified. The traditional diagnostic tools available are insufficient to discriminate between allergy to Vespula and Polistes in a high number of cases. IgE inhibition is the technique that best identifies the cross-reactivity. When a double sensitization has indeed been shown to exist or great uncertainty surrounds the primary sensitization, therapy with two venoms is advisable to guarantee the safety of the patient. In this case, a strategy involving alternate administration that combines effectiveness with efficiency is possible.

Investigation on the Effect of Age and Gender on Hypersensitivity Reactions due to Allergens Injection in Iraqi Population

Hyperactivity of the immune system due to the insertion of allergens into the living body has been known as an allergic reaction. Some substances, such as pollen grains, insects' venom, house dust mite, foods, and medicines, can induce allergic responses. Therefore, this study was designed to shed light on the role of gender and age in allergic reactions resulting from some organic and chemical allergens. A total of 200 individuals participated in this study, including 70 males and 130 females. A skin test was performed by subcutaneously injecting allergens, namely amoxicillin, cefotaxine, gentamicin, Vespula spp., and Apis mellifera. All the chemicals were purchased from Sigma-Aldrich unless otherwise stated. The spot of injection was sterilized by ethyl alcohol (70%) and well dried; subsequently, 0.05 mL of each allergen (antigen) was injected via a 1-mL medical syringe. The results showed that 140 cases were allergic. Anti-cefotaxine occupied the highest percentage among the studied drug allergens. The highest percentage of males (37.5%) that were allergic was at the age range of 28-35 years, whereas the highest percentage of females (18.5%) that were allergic was at the age range of 17-27 years. Sensitivity to amoxicillin accounted for 12.5% of males at the age range of 28-37 years and 3.7% of females at the age range of 17-27 years. Gentamicin triggered the highest percentage of sensitivity in 12.5% and 7.4% of males and females aged 48-57 years and 17-27 years, respectively. The results showed that honey bees had the highest percentage of total sensitivity at 40%. The highest sensitivity rate stood at 37.5% in males at the age range of 28-37 years and 18.5% in females at the age range of 17-27 years. Wasps recorded a total sensitivity rate of 17.1%, with the highest percentage at 37.5% in males who were aged 17-27 years and 3.7% in females at the age ranges of 17-27 and 48-57 years. The results of the statistical analysis indicated that there were significant (P≤0.05) differences for all allergens that were studied regarding gender and age.

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.

Prevalence of Pol d 1 Sensitization in Polistes dominula Allergy and Its Diagnostic Role in Vespid Double-Positivity

BACKGROUND

Stings by Polistes species frequently cause allergic reactions. However, standard allergy diagnostics are often unable to differentiate between primary sensitization and cross-reactivity in case of Vespula/Polistes double-sensitization because antigen 5 is the only Polistes venom molecule currently available in diagnostics (Pol d 5).

OBJECTIVE

To evaluate the frequency of phospholipase A1 in Polistes venom allergy (Pol d 1) and its diagnostic role in vespid allergy.

METHODS

We performed component-resolved diagnostics in patients with vespid allergic reactions who were positive to Polistes venom. A prevalence analysis was performed and the diagnostic accuracy of Pol d 1 was evaluated to detect primary Polistes sensitization in double-sensitized patients.

RESULTS

Blood samples were collected from 132 patients. Pol d 1 was present in 97% to 100% of 128 Polistes-positive patients. It was frequently involved in case of positivity to a single Polistes molecule (48% in double- and 80% in mono-sensitized patients). Furthermore, Pol d 1 was positive in 95% of Pol d 5-negative subjects. The diagnostic accuracy of Pol d 1 was good (folded type: area under the curve = 87%; 82% sensitivity and 77% specificity at the best cutoff of 5.773), and even better when used combined with the whole extract ratio (area under the curve = 99%; 91% sensitivity and 100% specificity).

CONCLUSIONS

The study shows that Pol d 1 is the most frequent Polistes allergen in Italian patients. It can distinguish Polistes primary sensitizations with good diagnostic accuracy, which supports its use in clinical practice.

Personalized medicine for allergy treatment: Allergen immunotherapy still a unique and unmatched model

The introduction of personalized medicine (PM) has been a milestone in the history of medical therapy, because it has revolutionized the previous approach of treating the disease with that of treating the patient. It is known today that diseases can occur in different genetic variants, making specific treatments of proven efficacy necessary for a given endotype. Allergic diseases are particularly suitable for PM, because they meet the therapeutic success requirements, including a known molecular mechanism of the disease, a diagnostic tool for such disease, and a treatment blocking the mechanism. The stakes of PM in allergic patients are molecular diagnostics, to detect specific IgE to single-allergen molecules and to distinguish the causative molecules from those merely cross-reactive, pursuit of patient's treatable traits addressing genetic, phenotypic, and psychosocial features, and omics, such as proteomics, epi-genomics, metabolomics, and breathomics, to forecast patient's responsiveness to therapies, to detect biomarker and mediators, and to verify the disease control. This new approach has already improved the precision of allergy diagnosis and is likely to significantly increase, through the higher performance achieved with the personalized treatment, the effectiveness of allergen immunotherapy by enhancing its already known and unique characteristics of treatment that acts on the causes.

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.

The role of component-resolved diagnosis in Hymenoptera venom allergy

PURPOSE OF REVIEW

Component-resolved diagnostics (CRD) is a new tool aiming at detecting IgE-mediated sensitizations against individual, relevant allergens. Here, we discuss recent literature on molecular diagnosis in the field of Hymenoptera venom allergy (HVA) as well as CRD strengths and weaknesses.

RECENT FINDINGS

CRD, using single molecules or panels of allergens, may discriminate between primary sensitization and cross-reactivity in patients with double/multiple positivity in diagnostic tests with whole extracts, allowing the specialist to choose the most suitable venom for specific immunotherapy (VIT), avoiding unnecessary VIT and reducing the risk of side effects. Future availability of the cross-reactive recombinant pairs of allergens of different species may further increase the diagnostic performance. CRD may be useful in patients with negative allergy tests and a proven history of a previous systemic reaction, including those with mast cell disorders, who could benefit from VIT. In honeybee venom allergy, different sensitization profiles have been identified, which could be associated with a greater risk of VIT failure or treatment side effects.

SUMMARY

CRD is undoubtedly an innovative diagnostic method that leads to a more precise definition of the sensitization profile of the HVA patient. Together with a better knowledge of the molecular composition of different venom extracts, CRD may contribute to optimize patient-tailored therapy.

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.

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.

A WAO - ARIA - GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

Precision allergy molecular diagnostic applications (PAMD@) is increasingly entering routine care. Currently, more than 130 allergenic molecules from more than 50 allergy sources are commercially available for in vitro specific immunoglobulin E (sIgE) testing. Since the last publication of this consensus document, a great deal of new information has become available regarding this topic, with over 100 publications in the last year alone. It thus seems quite reasonable to publish an update. It is imperative that clinicians and immunologists specifically trained in allergology keep abreast of the new and rapidly evolving evidence available for PAMD@.

PAMD@ may initially appear complex to interpret; however, with increasing experience, the information gained provides relevant information for the allergist. This is especially true for food allergy, Hymenoptera allergy, and for the selection of allergen immunotherapy. Nevertheless, all sIgE tests, including PAMD@, should be evaluated within the framework of a patient's clinical history, because allergen sensitization does not necessarily imply clinical relevant allergies.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Immunology of Bee Venom

Bee venom is a blend of biochemicals ranging from small peptides and enzymes to biogenic amines. It is capable of triggering severe immunologic reactions owing to its allergenic fraction. Venom components are presented to the T cells by antigen-presenting cells within the skin. These Th2 type T cells then release IL-4 and IL-13 which subsequently direct B cells to class switch to production of IgE. Generating venom-specific IgE and crosslinking FcεR1(s) on the surface of mast cells complete the sensitizing stage in allergic individuals who are most likely to experience severe and even fatal allergic reactions after being stung. Specific IgE for bee venom is a double-edged sword as it is a powerful mediator in triggering allergic events but is also applied successfully in diagnosis of the venom allergic patient. The healing capacity of bee venom has been rediscovered under laboratory-controlled conditions using animal models and cell cultures. The potential role of enzymatic fraction of bee venom including phospholipase A2 in the initiation and development of immune responses also has been studied in numerous research settings. Undoubtedly, having insights into immunologic interactions between bee venom components and innate/specific immune cells both locally and systematically will contribute to the development of immunologic strategies in specific and epitope-based immunotherapy especially in individuals with Hymenoptera venom allergy.

Component-resolved diagnostics to direct in venom immunotherapy: Important steps towards precision medicine

Stings of Hymenoptera can induce IgE-mediated systemic and even fatal allergic reactions. Venom-specific immunotherapy (VIT) is the only disease-modifying and curative treatment of venom allergy. However, choosing the correct venom for VIT represents a necessary prerequisite for efficient protection against further anaphylactic sting reactions after VIT. In the past, therapeutic decisions based on the measurement of specific IgE (sIgE) levels to whole venom extracts were not always straightforward, especially when the patient was not able to identify the culprit insect. In the last years, the increasing knowledge about the molecular structure and relevance of important venom allergens and their availability as recombinant allergens, devoid of cross-reactive carbohydrate determinants, resulted in the development of an advanced component-resolved diagnostics (CRD) approach in venom allergy. Already to date, CRD has increased the sensitivity of sIgE detection and enabled the discrimination between primary sensitization and cross-reactivity, particularly in patients with sensitization to both honeybee and vespid venom. Hence, CRD in many patients improves the selection of the appropriate immunotherapeutic intervention. Moreover, the detailed knowledge about sensitization profiles on a molecular level might open new options to identify patients who are at increased risk of side-effects or not to respond to immunotherapy. Therefore, increasing potential of CRD becomes evident, to direct therapeutic decisions in a personalized and patient-tailored manner. Reviewed here are the state of the art options, recent developments and future perspectives of CRD of Hymenoptera venom allergy.

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.

Which immunotherapy product is better for patients allergic to Polistes venom? A laboratory and clinical study

BACKGROUND

Venom immunotherapy (VIT) is highly effective in preventing allergic reactions to insect stings, but the appropriate venom must be used to achieve clinical protection. In patients with multiple positive results to venoms, molecular allergy diagnostics or CAP-inhibition may identify the causative venom. Concerning allergy to venom from Polistes spp. it has been proposed that only the European species P. dominulus should be used for VIT. However, this recommendation is not present in any international guideline. Using both laboratory and clinical data, we aimed to evaluate the reliability of this proposal.

METHODS

We performed an in vitro study using CAP-inhibition to determine sensitization of 19 patients allergic to Polistes venom. The clinical study included 191 patients with positive tests to Polistes treated with VIT, 102 were treated with P. dominulus and 89 were treated with a mix of American Polistes (mAP).

RESULTS

The difference in % of inhibition was significant concerning inhibition of P. dominulus sIgE by P. dominulus venom (79.8%) compared with inhibition by mAP venom (64.2%) and not significant concerning the inhibition of mAP sIgE by P. dominulus venom (80.1%) and by mAP venom (73.6%). Instead, the clinical protection from stings was not statistically different between the two kinds of venom.

CONCLUSION

The data from CAP inhibition would suggest that the choice of either P. dominulus venom or mAP venom for VIT is appropriate in patients with CAP inhibition higher than 70%, but the clinical data show the same odds of protection from stings using for VIT P. dominulus or mAP venom.