Influence of total IgE levels on the severity of sting reactions in Hymenoptera venom allergy

Modified rush venom immunotherapy in dogs with Hymenoptera hypersensitivity

BACKGROUND

Hymenoptera envenomation occurs frequently in people and dogs and can trigger anaphylaxis. Venom immunotherapy (VIT) is the only preventive treatment for Hymenoptera hypersensitivity and is indicated for people with severe adverse reactions to insect stings. Rush VIT is an accelerated VIT protocol in people. This has not been reported in dogs.

OBJECTIVES

The objective of the study was to evaluate the safety of modified rush VIT.

ANIMALS

Twenty client-owned dogs with Hymenoptera hypersensitivity based on a history of adverse reactions to Hymenoptera envenomation and a positive intradermal test to honey bee and/or paper wasp venom.

MATERIALS AND METHODS

Dogs received incremental doses of venom via subcutaneous injection one day per week for three consecutive weeks until the maintenance dose was achieved. Vital signs were recorded every 30 min prior to venom administration. Adverse reactions were categorised as localised or grade I-IV systemic reactions.

RESULTS

Nineteen of 20 dogs (95%) completed rush VIT. One dog experienced a grade III systemic adverse reaction and was withdrawn from the study. No adverse reactions occurred in 10 of 20 dogs (50%). Localised and grade I-II systemic reactions occurred in nine of 20 dogs (45%), including nausea (n = 5), injection site pruritus (n = 3) and diarrhoea and lethargy (n = 1).

CONCLUSIONS AND CLINICAL RELEVANCE

Modified rush VIT in dogs was well-tolerated and should be considered for dogs with Hymenoptera hypersensitivity. Larger studies are needed to evaluate the efficacy of VIT in dogs for preventing hypersensitivity reactions to insect stings.

Intracutaneous Skin Tests and Serum IgE Levels Cannot Predict the Grade of Anaphylaxis in Patients with Insect Venom Allergies

Background

Allergies against Hymenoptera venoms are a major cause of severe anaphylaxis. Risk assessment for subjects with suspected allergy is difficult because there are currently no biomarkers that predict the likelihood of high-grade anaphylaxis other than several associated comorbidities.

Objective

We investigated the relationship between the severity of anaphylaxis and the results of intracutaneous skin tests (ICTs) together with serum levels of tryptase, total IgE, and venom-specific IgE, IgG, and IgG4.

Methods

We performed a retrospective evaluation of 194 patients who presented to a single medical center with allergies to bee venoms (Apis mellifera, Bombus spp.; n=24, 12.4%), vespid venoms (Vespula spp., Vespa spp., Polistes spp.; n=169, 87.1%), or both (n=1, 0.5%).

Results

Index bee stings occurred earlier in the year than vespid stings, although the latter were reported more frequently overall. On average, subjects who previously experienced grade IV anaphylaxis required higher dosages of venom to yield positive ICTs than those who exhibited lower grade responses. Patients diagnosed with grade IV anaphylaxis exhibited significantly lower levels of venom-specific IgE and IgG and trended toward elevated levels of tryptase. No significant differences in average levels of venom-specific IgG4 and total IgE were observed.

Conclusion

Our findings reveal that intracutaneous skin testing and levels of venom-specific IgE do not predict the degree of anaphylaxis that develops in patients with venom allergy. Furthermore, the month of the index sting is not a reliable means to differentiate bee from vespid stings in patients presenting with an uncertain history.

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.

Total serum IgE levels as predictor of the acquisition of tolerance in children with food allergy: Findings from a pilot study

BACKGROUND

The gold standard to diagnose food allergy (FA) is a double-blind, placebo-controlled food challenge (OFC), even if it shows potential risk of severe allergic reactions for the patient and is time-consuming. Therefore, easier, and less invasive methods are needed to diagnose FA and predict the tolerance, changing the clinical practice.

AIM

The main aim of this study was to assess whether the total IgE values at the diagnosis of FA were associated with the duration of the tolerance acquisition and thus of the food elimination diet.

METHODS

We retrospectively analyzed the medical records of 40 patients allergic to milk or egg who performed an OFC for the reintroduction of the causal food at the Pediatric Allergy and Respiratory Unit of the University of Chieti from January 2018 to December 2020.

RESULTS

We found a positive association of total serum IgE with the elimination diet duration (β = 0.152; CI, 95% 0.04-0.27) after adjusting for age, sex, and type of allergy (milk or egg). We also showed a significant correlation (r = 0.41 and p-value = 0.007) between the total IgE values and the duration of the elimination diet and a significant correlation between the casein specific IgE values at diagnosis of FA and the severity of the clinical presentation (r = 0.66; p-value 0.009).

CONCLUSION

Total serum IgE at baseline, along with the downward trend of food-specific IgE levels (to milk or egg), may be useful in the prognostication of natural tolerance acquisition.

Biomarkers of the Severity of Honeybee Sting Reactions and the Severity and Threshold of Systemic Adverse Events During Immunotherapy

BACKGROUND

A biomarker that could identify individuals at high risk for severe honeybee sting allergic reaction and/or systemic adverse events (SAEs) during venom immunotherapy (VIT) would improve the management of patients with honeybee (HB) venom allergy.

OBJECTIVE

To identify biomarkers for risk of severe sting reactions or SAEs during VIT.

METHODS

We recruited 332 patients undergoing HB VIT. We ascertained predictors of the severity of the field-sting reaction and the severity and threshold of SAEs during VIT. We assessed the use of cardiovascular medications; baseline serum tryptase (BST) levels; specific IgEs to HB venom, rApi m 1, and rApi m 10; and basophil activation test (BAT) response.

RESULTS

Significant and independent predictors of a severe HB field-sting reaction were age (P = .008), an absence of skin symptoms (P = .001), BST (P = .014), and BAT response at an HB venom concentration of 0.1 μg/mL (P = .001). Predictors of severe SAEs during HB VIT were age (P = .025), BST (P = .006), and BAT response (P = .001). BAT response was also an individual and significant predictor of any SAEs and SAEs at a low cumulative allergen dose (median, 55 μg) during VIT build-up (P < .001). The use of β-blockers and angiotensin-converting-enzyme inhibitors and specific IgE levels were not associated with the severity of HB field-sting reactions or VIT SAEs.

CONCLUSIONS

BST and basophil activation are independent risk factors for severe HB sting anaphylaxis and SAEs during HB VIT. BAT response was the best biomarker for any SAEs and a lower threshold of SAEs during HB VIT. These risk factors can help guide recommendations for VIT and overcome systemic reactions to HB VIT.

Wasp Venom Biochemical Components and Their Potential in Biological Applications and Nanotechnological Interventions

Wasps, members of the order Hymenoptera, are distributed in different parts of the world, including Brazil, Thailand, Japan, Korea, and Argentina. The lifestyles of the wasps are solitary and social. Social wasps use venom as a defensive measure to protect their colonies, whereas solitary wasps use their venom to capture prey. Chemically, wasp venom possesses a wide variety of enzymes, proteins, peptides, volatile compounds, and bioactive constituents, which include phospholipase A2, antigen 5, mastoparan, and decoralin. The bioactive constituents have anticancer, antimicrobial, and anti-inflammatory effects. However, the limited quantities of wasp venom and the scarcity of advanced strategies for the synthesis of wasp venom’s bioactive compounds remain a challenge facing the effective usage of wasp venom. Solid-phase peptide synthesis is currently used to prepare wasp venom peptides and their analogs such as mastoparan, anoplin, decoralin, polybia-CP, and polydim-I. The goal of the current review is to highlight the medicinal value of the wasp venom compounds, as well as limitations and possibilities. Wasp venom could be a potential and novel natural source to develop innovative pharmaceuticals and new agents for drug discovery.

Predictors of severe anaphylaxis in Hymenoptera venom allergy: The importance of absence of urticaria and angioedema

BACKGROUND

Severe anaphylaxis (SA) in Hymenoptera venom allergy has been associated with a number of risk factors. However, the effect of several of those risk factors on the severity of anaphylaxis is poorly defined.

OBJECTIVE

To evaluate risk factors for SA in Hymenoptera venom allergy.

METHODS

We evaluated data from 500 patients who were referred to our department for the diagnosis of Hymenoptera venom allergy during a period of 11 years to identify risk factors for SA.

RESULTS

Six significant risk factors for SA were identified (P < .05): short interval from sting to reaction, absence of urticaria or angioedema (U/A) during anaphylaxis, older age, male sex, elevation of baseline serum tryptase (BST) level, and diagnosis of systemic mastocytosis. Moreover, elevation in BST level was significantly associated with the absence of U/A and older age. No association could be established between SA and comorbidities, concurrent cardiovascular medication, or the severity of the systemic reaction during the initiation of venom immunotherapy.

CONCLUSION

Apart from BST and older age, male sex, short interval from sting to reaction, and absence of U/A are also risk factors for SA. The association between elevated BST level and SA was largely confined to those who had an absence of U/A after field sting, possibly because of the higher risk of concurrent systemic mastocytosis. Patients with an SA after a field sting do not have an elevated risk of systemic reactions during the initiation of venom immunotherapy compared with patients with mild anaphylaxis; therefore, additional preventive measures are not necessary.

Risk factors and indicators of severe systemic insect sting reactions

Hymenoptera venom allergy ranks among the top three causes of anaphylaxis worldwide, and approximately one-quarter of sting-induced reactions are classified as severe. Fatal sting reactions are exceedingly rare, but certain factors may entail a considerably higher risk. Delayed administration of epinephrine and upright posture are situational risk factors which may determine an unfavorable outcome of the acute anaphylactic episode and should be addressed during individual patient education. Systemic mastocytosis and senior age are major, unmodifiable long-term risk factors and thus reinforce the indication for venom immunotherapy. Vespid venom allergy and male sex likewise augment the risk of severe or even fatal reactions. Further studies are required to assess the impact of specific cardiovascular comorbidities. Available data regarding potential effects of beta-blockers and/or ACE inhibitors in coexisting venom allergy are inconclusive and do not justify recommendations to discontinue guideline-directed antihypertensive treatment. The absence of urticaria/angioedema during sting-induced anaphylaxis is indicative of a severe reaction, serum tryptase elevation, and mast cell clonality. Determination of basal serum tryptase levels is an established diagnostic tool for risk assessment in Hymenoptera venom-allergic patients. Measurement of platelet-activating factor acetylhydrolase activity represents a complementary approach but is not available for routine diagnostic use.

Risk factors for severe systemic sting reactions in wasp (Vespula spp.) and honeybee (Apis mellifera) venom allergic patients

Background

Hymenoptera stings are a major cause of anaphylaxis. Various risk factors are discussed in literature. This study aims to investigate potential risk factors for severe sting reactions in wasp (Vespula spp.) and honeybee (Apis mellifera) venom allergic patients and analyses the correlation between diagnostic test results and the severity of the allergic reaction.

Methods

480 patients suffering from wasp or honeybee venom allergy were included in this retrospective case series. Only individuals allergic to Vespula spp. but not to other vespids such as Polistes were considered. The severity of their systemic field sting reaction was analysed with regard to the amount of specific IgE antibodies to whole venom extracts and to major allergens of honeybee and/or wasp venom. Furthermore, the following potential risk factors for severe sting reactions were examined: age, sex, latency time, skin symptoms, baseline serum tryptase levels and the concentration of venom inducing a positive intracutaneous test.

Results

The two following indicators for severe systemic sting reactions in honeybee and wasp venom allergic patients have been identified: a short latency time and the absence of skin symptoms. The patient’s age and baseline serum tryptase levels have been found to positively correlate with the grade of the sting reaction only in individuals allergic to wasp venom. No correlation could be found between the degree of sensitisation and the severity of the allergic reaction. Neither the amount of specific IgE antibodies to whole venom extracts nor to major allergens were significantly associated with the severity of the sting reaction.

Conclusion

The clinical history is essential for the allergological workup and therapeutic decision on Hymenoptera venom allergies. A short latency time and the absence of skin symptoms are indicators for severe systemic sting reactions, followed by the patient’s age and baseline serum tryptase levels.

Large local reactions to Hymenoptera stings: Outcome of re-stings in real life

BACKGROUND

Large local reaction to Hymenoptera stings is usually defined as a swelling >10 cm which lasts longer than 24 hours, sometimes associated with erythema, pruritus and blisters. Currently, the risk of subsequent systemic reactions after re-stings is considered low (2%-15%). Therefore, a diagnostic workup in case of large local reaction is often judged unnecessary, as well as adrenaline auto-injector and venom immunotherapy prescription. The aim of this study was to prospectively evaluate the outcome of re-stings in a real-world setting, in patients with a history of one previous large local reaction.

METHODS

We consecutively enrolled patients who experienced their first large local reaction (as per EAACI definition), treated with antihistamine and steroids. They were followed for field re-stings and assessed for risk of subsequent systemic reactions.

RESULTS

We enrolled 662 patients. Out of the 225 re-stung subjects, 24% did not experience reactions, 52% reported a second large local reaction and 24% had systemic reactions. The risk of subsequent systemic reactions was higher in case of skin test reactivity to Apis mellifera or Vespula species (OR 2.1 and 3.8, respectively), in particular if positive at 0.001 µg/mL concentration (OR 13.4 and 16.5, respectively).

CONCLUSIONS

Systemic reactions, after a previous large local reaction, occur more frequently than that reported by literature. After analysing the predictive role of large local reactions for systemic reactions, we demonstrated that an accurate diagnostic workup may be considered, particularly skin tests. Further studies in different countries are needed to confirm these results and large local reaction management.

Risk prediction of severe reaction to oral challenge test of cow's milk

Cow's milk is one of the most common food allergens among children. Oral food challenge tests determine the threshold dose of allergens, but have not been standardized. To reduce the severe reactions, we developed a practical model of the test. We studied 111 high-risk patients who underwent a first milk oral food challenge on the risk-stratified dose between 2011 and 2017 for predicting the severe reaction risk. Severe reactions were defined as showing > 3 of Sampson's classification grade. Twenty-eight patients (25%) showed severe reactions without death. Prior to oral food challenge, severe reaction patients experienced milk avoidance (71% vs. 45%, p = 0.02) or bronchial asthma (61% vs. 28%, p = 0.003) more frequently and showed higher milk-specific IgE levels (median 28.3 vs. 7.7 U_A/mL, p < 0.0001) than non-severe reaction patients. Multivariate logistic regression analyses established a formula including severe reaction-associated factors; increased levels of milk-specific IgE (odds ratio 11.61, p = 0.001), milk avoidance (odds ratio 3.88, p = 0.02), and bronchial asthma (odds ratio 3.75, p = 0.02). This model had 86% sensitivity and 56% specificity (cut-off 0.25) for risk. Five patients with < 25% probability developed severe reactions, which started in > 3 grade dyspnea up to 20 mL of challenge.Conclusion: This model could effectively reduce the severe reaction development on the first milk oral food challenge test according to the individual needs. What is Known: •Higher levels of milk-specific IgE values, bronchial asthma, and complete milk avoidance are independent risk factors of severe reactions during the cow's milk oral food challenge. What is New: •Statistical analyses of our milk oral food challenge records for 111 patients helped us develop a model formula predicting severe reactions at the first test with high specificity and sensitivity. •This simple risk-stratified protocol is useful for minimizing the adverse events in the first milk challenge.

The pathophysiology of anaphylaxis

Anaphylaxis is a severe systemic hypersensitivity reaction that is rapid in onset; characterized by life-threatening airway, breathing, and/or circulatory problems; and usually associated with skin and mucosal changes. Because it can be triggered in some persons by minute amounts of antigen (eg, certain foods or single insect stings), anaphylaxis can be considered the most aberrant example of an imbalance between the cost and benefit of an immune response. This review will describe current understanding of the immunopathogenesis and pathophysiology of anaphylaxis, focusing on the roles of IgE and IgG antibodies, immune effector cells, and mediators thought to contribute to examples of the disorder. Evidence from studies of anaphylaxis in human subjects will be discussed, as well as insights gained from analyses of animal models, including mice genetically deficient in the antibodies, antibody receptors, effector cells, or mediators implicated in anaphylaxis and mice that have been "humanized" for some of these elements. We also review possible host factors that might influence the occurrence or severity of anaphylaxis. Finally, we will speculate about anaphylaxis from an evolutionary perspective and argue that, in the context of severe envenomation by arthropods or reptiles, anaphylaxis might even provide a survival advantage.

Improved recombinant Api m 1- and Ves v 5-based IgE testing to dissect bee and yellow jacket allergy and their correlation with the severity of the sting reaction

BACKGROUND

No study has assessed the diagnostic sensitivity of rApi m 1 and rVes v 5 on Immulite testing system.

OBJECTIVE

To compare the diagnostic sensitivity of commercially available venom recombinant allergens between the currently available immunoassays [ImmunoCAP (CAP) and Immulite (LITE)] and establish their correlation with the severity of the sting reaction.

METHODS

This study evaluated 95 bee venom and 110 yellow jacket venom-allergic subjects. We measured the levels of sIgE to rApi m 1, rVes v 5 (LITE and CAP), rApi m 2 (LITE), rVes v 1 (CAP) and total IgE (CAP). Forty-nine healthy subjects served as controls.

RESULTS

The diagnostic sensitivity of rApi m 1 and rVes v 5 was significantly higher with the LITE than with the CAP system (71% vs. 88% and 82% vs. 93%). The specificity of both assays for both allergens was between 94% and 98%. Twenty-nine patients that tested negative for rApi m 1 or rVes v 5 with CAP were positive with LITE, but none of the patients that tested negative with LITE were positive with CAP. The positive values of rApi m 1 and rVes v 5 were on average 2.7 and 2.3 times higher, with the LITE than with the CAP system. The combination of rApi m 1 and rApi m 2 (LITE) and the combination of rVes v 5 (LITE) and rVes v 1 (CAP) almost matched the sensitivity of native venoms (95% and 97%, respectively), whereas the diagnostic sensitivity of the combination of rVes v 5 and rVes v 1 (CAP) did not reach the sensitivity of rVes v 5 (LITE) alone (90% vs. 93%). IgE levels to venom recombinants and total IgE did not correlate with the severity of sting reaction.

CONCLUSIONS & CLINICAL RELEVANCE

The use of rApi m 1 and rVes v 5 with the LITE system significantly enhanced diagnostic utility of venom recombinants and should improve the dissection of bee and yellow jacket venom allergy.

Development of a prediction model of severe reaction in boiled egg challenges

BACKGROUND

We have proposed a new scoring system (Anaphylaxis SCoring Aichi: ASCA) for a quantitative evaluation of the anaphylactic reaction that is observed in an oral food challenge (OFC). Furthermore, the TS/Pro (Total Score of ASCA/cumulative protein dose) can be a marker to represent the overall severity of a food allergy. We aimed to develop a prediction model for a severe allergic reaction that is provoked in a boiled egg white challenge.

METHODS

We used two separate datasets to develop and validate the prediction model, respectively. The development dataset included 198 OFCs, that tested positive. The validation dataset prospectively included 140 consecutive OFCs, irrespective of the result. A 'severe reaction' was defined as a TS/Pro higher than 31 (the median score of the development dataset). A multivariate logistic regression analysis was performed to identify the factors associated with a severe reaction and develop the prediction model.

RESULTS

The following four factors were independently associated with a severe reaction: ovomucoid specific IgE class (OM-sIgE: 0-6), aged 5 years or over, a complete avoidance of egg, and a total IgE < 1000 IU/mL. Based on these factors, we made a simple scoring prediction model. The model showed good discrimination in a receiver operating characteristic analysis; area under the curve (AUC) = 0.84 in development dataset, AUC = 0.85 in validation dataset. The prediction model significantly improved the AUC in both datasets compared to OM-sIgE alone.

CONCLUSIONS

This simple scoring prediction model was useful for avoiding risky OFC.

IgE and mast cells in host defense against parasites and venoms

IgE-dependent mast cell activation is a major effector mechanism underlying the pathology associated with allergic disorders. The most dramatic of these IgE-associated disorders is the fatal anaphylaxis which can occur in some people who have developed IgE antibodies to otherwise innocuous antigens, such as those contained in certain foods and medicines. Why would such a highly "maladaptive" immune response develop in evolution and be retained to the present day? Host defense against parasites has long been considered the only beneficial function that might be conferred by IgE and mast cells. However, recent studies have provided evidence that, in addition to participating in host resistance to certain parasites, mast cells and IgE are critical components of innate (mast cells) and adaptive (mast cells and IgE) immune responses that can enhance host defense against the toxicity of certain arthropod and animal venoms, including enhancing the survival of mice injected with such venoms. Yet, in some people, developing IgE antibodies to insect or snake venoms puts them at risk for having a potentially fatal anaphylactic reaction upon subsequent exposure to such venoms. Delineating the mechanisms underlying beneficial versus detrimental innate and adaptive immune responses associated with mast cell activation and IgE is likely to enhance our ability to identify potential therapeutic targets in such settings, not only for reducing the pathology associated with allergic disorders but perhaps also for enhancing immune protection against pathogens and animal venoms.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Update on food allergy

Food allergies are a global health issue with increasing prevalence. Allergic reactions can range from mild local symptoms to severe anaphylactic reactions. Significant progress has been made in diagnostic tools such as component-resolved diagnostics and its impact on risk stratification as well as in therapeutic approaches including biologicals. However, a cure for food allergy has not yet been achieved and patients and their families are forced to alter eating habits and social engagements, impacting their quality of life. New technologies and improved in vitro and in vivo models will advance our knowledge of the pathogenesis of food allergies and multicenter-multinational cohort studies will elucidate interactions between genetic background, lifestyle, and environmental factors. This review focuses on new insights and developments in the field of food allergy and summarizes recently published articles.

IgE antibodies, FcεRIα, and IgE-mediated local anaphylaxis can limit snake venom toxicity

BACKGROUND

Type 2 cytokine-related immune responses associated with development of antigen-specific IgE antibodies can contribute to pathology in patients with allergic diseases and to fatal anaphylaxis. However, recent findings in mice indicate that IgE also can enhance defense against honeybee venom.

OBJECTIVE

We tested whether IgE antibodies, IgE-dependent effector mechanisms, and a local anaphylactic reaction to an unrelated antigen can enhance defense against Russell viper venom (RVV) and determined whether such responses can be influenced by immunization protocol or mouse strain.

METHODS

We compared the resistance of RVV-immunized wild-type, IgE-deficient, and Fcer1a-deficient mice after injection of a potentially lethal dose of RVV.

RESULTS

A single prior exposure to RVV enhanced the ability of wild-type mice, but not mice lacking IgE or functional FcεRI, to survive challenge with a potentially lethal amount of RVV. Moreover, IgE-dependent local passive cutaneous anaphylaxis in response to challenge with an antigen not naturally present in RVV significantly enhanced resistance to the venom. Finally, we observed different effects on resistance to RVV or honeybee venom in BALB/c versus C57BL/6 mice that had received a second exposure to that venom before challenge with a high dose of that venom.

CONCLUSION

These observations illustrate the potential benefit of IgE-dependent effector mechanisms in acquired host defense against venoms. The extent to which type 2 immune responses against venoms can decrease pathology associated with envenomation seems to be influenced by the type of venom, the frequency of venom exposure, and the genetic background of the host.

Total serum IgE level influences oral food challenge tests for IgE-mediated food allergies

Probability curves predicting oral food challenge test (OFC) results based on specific IgE levels are widely used to prevent serious allergic reactions. Although several confounding factors are known to affect probability curves, the main factors that affect OFC outcomes are currently unclear. We hypothesized that an increased total IgE level would reduce allergic reactivity. Medical records of 337 and 266 patients who underwent OFCs for 3.5 g boiled hen's egg white and 3.1 ml raw cow's milk, respectively, were examined retrospectively. We subdivided the patients into three groups based on total IgE levels and age by percentile (<25th, 25-75th, and >75th percentiles), and logistic regression analyses were performed on each group. Patients with higher total IgE levels were significantly less responsive. In addition, age did not significantly affect the OFC results. Therefore, total IgE levels should be taken into account when predicting OFC results based on food-specific IgE levels.

Clinical features of children with venom allergy and risk factors for severe systemic reactions

BACKGROUND

Severe systemic reactions (SRs) to insect venom are rare in childhood and there are few data on this study population. The aim of our study is to analyze the clinical features and to document the risk factors for severe SRs in children with insect venom allergy.

METHODS

Children with SRs after Hymenoptera sting were analyzed. The diagnosis was based on medical history, skin tests and/or specific IgE testing.

RESULTS

Seventy-six children were included [57 boys (75%), mean age 9.8 ± 3.4 years]. The mean age of children at the time of SR was 8.3 ± 3.4 years. Reactions were accounted for Vespula (wasp) venom in 58 (76%) and Apis mellifera (bee) venom in 18 (24%) patients. Twenty-six percent of patients had aeroallergen sensitization and 33% had atopic disease, whereas 66% had experienced previous stings. The upper limb was the most frequent area of sting (43%), and the cutaneous system (99%) was the most frequent involved system. SRs occurred in 59% of patients. Multivariate logistic regression analysis revealed eosinophilia (>5%) [odds ratio (OR) 12.6; confidence interval (CI) 1.5-109.7; p = 0.022], female sex (OR 6.4; CI 1.5-26.9; p = 0.011) and accompanying atopic disease (OR 3.4; CI 1.2-12.3; p = 0.016) as significant risk factors for severe SRs. Ninety-seven percent of patients were admitted to the emergency department; however, epinephrine was used in only 46% of patients.

CONCLUSIONS

There was a high frequency of hypersensitivity to wasp venom among the study population, and severe reactions were related to mild eosinophilia, female sex and concomitant atopic diseases. A better understanding of the risk factors may lead to effective utilization of health care sources in the future.

Primary school teachers' knowledge about and attitudes toward anaphylaxis

BACKGROUND

One in 10,000 children experiences an anaphylactic attack, every year. It has been demonstrated that 82% of these attacks occur in children of school age and that most of the attack-related deaths have occurred in schools. In this study, we aimed to investigate primary school teachers' knowledge about and attitudes toward anaphylaxis.

METHOD

A total of 237 teachers were questioned: 91 working in elementary state schools and 146 in private schools. A questionnaire was completed to obtain data on their knowledge of anaphylaxis and the availability of emergency treatment facilities in schools.

RESULTS

Fifty-two percent of the teachers knew which students had an allergic disease. When questioned about agents that can potentially cause anaphylaxis, the most significant causes were thought to be pollen by 54% of the teachers, food by 47%, mites by 40%, and drugs by 30%. Of foods, eggs (30.4%) and strawberries (25.3%) were thought to be the two leading causes. The teachers' responses on what would be their initial reaction in the event of an anaphylactic reaction were: he/she would give first aid in 24.3%, notify the school nurse in 39.7%, and call the emergency services in 19.8%. Only 10% were aware of an epinephrine autoinjector, and only 4% knew where to apply it. While 28% of the teachers reported that they had been informed about anaphylaxis previously, most had formed their ideas from brochures or the media. While 25% of the teachers knew all of the symptoms of anaphylaxis, 54% knew some, and 21% none. Only 6% of the teachers reported that there was a management plan for anaphylaxis in their schools.

CONCLUSION

This study shows that primary school teachers are not well informed about anaphylaxis. Teachers should be given training on the subject, and there should be a re-evaluation of school and health policies with a wider global perspective. There is an urgent need to inquire into the allergy management plans and policies in schools and to develop teacher education organizations on the subject.

Evaluation of a Novel Rapid Test System for the Detection of Specific IgE to Hymenoptera Venoms

Background. The Allergy Lateral Flow Assay (ALFA) is a novel rapid assay for the detection of sIgE to allergens. The objective of this study is the evaluation of ALFA for the detection of sIgE to bee venom (BV) and wasp venom (WV) in insect venom allergic patients. Methods. Specific IgE to BV and WV was analyzed by ALFA, ALLERG-O-LIQ, and ImmunoCAP in 80 insect venom allergic patients and 60 control sera. Sensitivity and specificity of ALFA and correlation of ALFA and ImmunoCAP results were calculated. Results. The sensitivity/specificity of ALFA to the diagnosis was 100%/83% for BV and 82%/97% for WV. For insect venom allergic patients, the Spearman correlation coefficient for ALFA versus ImmunoCAP was 0.79 for BV and 0.80 for WV. However, significant differences in the negative control groups were observed. Conclusion. ALFA represents a simple, robust, and reliable tool for the rapid detection of sIgE to insect venoms.

Risk factors for systemic reactions to bee venom in British beekeepers

BACKGROUND

There is a high incidence of systemic reactions (SRs) to bee stings in beekeepers, but the factors predisposing individuals to such responses are not well understood.

OBJECTIVES

To identify factors that predispose British beekeepers to SRs and to investigate how beekeepers access specialist services after SRs to bee venom.

METHODS

A link to an online survey was published in the bimonthly magazine and on the Web site of the British Beekeepers Association. The demographic results are presented using descriptive analysis, and a logistic regression model was used to determine risk factors for SRs.

RESULTS

There were 852 responses to the questionnaire of which 63% were from male beekeepers; the most common age range was 51 to 60 years. Twenty-eight percent of all responders had experienced a large local reaction and 21% had experienced a SR. Factors that predisposed beekeepers to SRs included female sex, having a family member with bee venom allergy, more than 2 years of beekeeping before a SR, and premedication with an antihistamine before attending the hives. A total of 44% of beekeepers with SRs attended the emergency department because of their symptoms, 16.6% were reviewed by an allergy specialist, and only 18% carried an adrenaline autoinjector.

CONCLUSIONS

Logistic regression analysis identified a number of novel factors to be associated with the development of SRs. Rates of attendance at the emergency department, allergy specialist review, and carriage of adrenaline were low, highlighting a need for education in the beekeeping community and among health care professionals.

Influence of total and specific IgE, serum tryptase, and age on severity of allergic reactions to Hymenoptera stings

BACKGROUND

  The aim of this study was to analyze the influence of total serum IgE and other potential risk factors on severity of systemic allergic Hymenoptera sting reactions.

METHODS

  In a retrospective analysis of one thousand and two patients referred for insect allergy over 5 years, 865 reported systemic allergic sting reactions, most often by honey bees and wasps. In 758, total IgE, venom-specific IgE, and baseline tryptase levels were available and analyzed together with atopy state, age, and sex in relation to severity of sting reactions according to H. L. Mueller.

RESULTS

  In a binary logistic regression model considering, besides IgE, also other risk factors for severity, an influence of total and specific IgE on severity of systemic allergic sting reactions could not be shown, while high severity of systemic allergic sting reactions was significantly more often reported in patients with a baseline tryptase of ≥11.4 μg/l (P < 0.0001) and higher age (P = 0.026). In a bivariate analysis, however, in patients with grade IV reactions total IgE (P = 0.003) and honey bee venom-specific IgE (P = 0.001) were significantly lower than in lower severity grades. Bee venom-specific mean IgE rank was significantly higher in bee than in Vespula venom allergic patients (P = 0.0001).

CONCLUSIONS

  Connection of high severity sting reactions with lower IgE is mainly because of older age, which is associated with lower total IgE, and moreover with cardiovascular disease and elevated baseline serum tryptase, which are both risk factors for severe reactions.

Cutaneous manifestations in Hymenoptera and Diptera anaphylaxis: relationship with basal serum tryptase

OBJECTIVES

To compare the clinical presentation of systemic anaphylaxis to Hymenoptera and Diptera with regard to basal serum tryptase (BT) and to evaluate mastocytosis in patients with elevated tryptase.

PATIENTS AND METHODS

The medical records of 140 patients with a history of a systemic reaction to venom were retrospectively reviewed. Symptoms and severity of anaphylaxis and BT were recorded. Most patients with elevated tryptase were screened for mastocytosis: a dermatological examination with a skin biopsy was performed in 19 cases and a bone marrow biopsy in 14 cases.

RESULTS

Tryptase was elevated in 23 patients. These patients reported fewer usual skin reactions (urticaria in 26.1% of cases with raised tryptase vs. 76.1% of cases with normal tryptase), more flushing (52.2% vs. 4.3%) and frequently did not present skin reaction (26.1% vs. 9.4%). They presented a more severe reaction (mean grade of severity: 3.48 vs. 2.69). Mastocytosis was diagnosed in seven patients with elevated tryptase: indolent systemic mastocytosis in six cases and cutaneous mastocytosis without systemic involvement in one case. In five cases, mastocytosis was previously undiagnosed. Lesions of cutaneous mastocytosis, diagnosed in five patients, consisted of urticaria pigmentosa in all cases and were often inconspicuous.

CONCLUSION

These results demonstrate particular clinical features of the allergic reaction in patients with elevated BT and the higher frequency of mastocytosis in this population. In patients with a severe anaphylactic reaction without urticaria, but with flushing, tryptase should be assayed and an underlying mastocytosis should be considered.