Single venom-based immunotherapy effectively protects patients with double positive tests to honey bee and Vespula venom

Hymenoptera venom immunotherapy: Safety and efficacy of an accelerated induction regimen with depot aluminum adsorbed extracts

Introduction: Hymenoptera venom immunotherapy (VIT) is the only therapy that protects patients with Hymenoptera venom allergy by preventing systemic reactions after a new sting. Various extracts for VIT are available and used. VIT administration consists of an induction phase and a maintenance phase. Depot preparations of Hymenoptera VIT extracts are typically used for cluster and conventional protocols, and the maintenance phase. Many patients with Hymenoptera allergy need to achieve tolerance quickly because of the high risk of re-sting and possible anaphylaxis. Objective: Our study aimed to show the safety and efficacy of an accelerated regimen with depot preparations on aluminum hydroxide by using relatively high starting doses in a heterogeneous group of patients. Methods: The research focused on a group of patients with a history of severe systemic reactions to Hymenoptera stings, with the necessity of swift immunization due to high occupational risks. Aluminum hydroxide depot extracts either of Vepula species or Apis mellifera extracts were used. Results: The induction protocol was started with the highest concentration of depot venom extract of 100,000 standard quality unit and was well tolerated by 19 of 20 patients. Onne patient presented with a mild systemic reaction during the accelerated induction schedule, which was promptly treated with intravenous steroids and intramuscular H1 antihistamine; when switched to a conventional induction protocol, he had a similar reaction but finally reached maintenance with an H1-antagonist premedication. Conclusion: If validated, the accelerated induction protocol by using depot aluminum adsorbed extracts with the highest concentration of venom from the beginning could offer a streamlined and accessible treatment modality for patients diagnosed with anaphylaxis from bee and wasp venoms in need of rapid desensitization.

Hymenoptera Venom Immunotherapy in Dogs: Safety and Clinical Efficacy

Hymenoptera allergens are the main triggers for anaphylaxis in susceptible dogs and humans. Hymenoptera venom specific immunotherapy (VIT), the only disease-modifying treatment, has the potential to prevent future life-threatening reactions in human patients. Prospective clinical data on VIT efficacy in dogs are currently lacking. Therefore, the aim of this study was to show that VIT is not only safe but also efficacious in preventing anaphylaxis in dogs allergic to Hymenoptera. This uncontrolled prospective clinical trial included 10 client-owned dogs with a history of anaphylaxis following repeated Hymenoptera stings. The sensitization to bee and wasp allergens was demonstrated by intradermal testing (IDT) and allergen-specific IgE serology. For VIT induction (induction phase), dogs received a shortened rush immunotherapy protocol with aqueous allergens, which was then followed by monthly injections of 100 µg of alum-precipitated allergen (maintenance phase). VIT efficacy was determined by observing patients' clinical reactions to re-stings. No systemic adverse events were seen during the induction and maintenance phases. From the seven re-stung dogs, only one developed a mild angioedema at the site of the sting; the remaining dogs were asymptomatic. These results show that VIT represents a safe and effective treatment option for Hymenoptera-allergic dogs.

Current practices in diagnosis of Hymenoptera venom allergy in Poland

Introduction

Hymenoptera venom allergy (HVA) is associated with a high risk of anaphylaxis. Effective treatment of HVA patients requires allergologists' familiarity with the latest HVA recommendations.

Aim

Evaluation of current practices in HVA diagnosis in Poland.

Material and methods

A survey questionnaire was conducted in 32 HVA centres in Poland.

Results

The response rate was 97%. There were 1829 patients evaluated due to HVA in 2015. Sixty six percent (n = 21) of the centres used skin prick tests, out which 90% (n = 19) used 100 µg/ml of the venom extract as the highest concentration. All the centres performed intradermal tests (IDT) and serum specific IgE (sIgE), an initial diagnostic tool in 91% (n = 29). The highest venom concentration in IDT was 1 µg/ml in 75% (n = 24), 0.1 µg/ml in 16% (n = 5), 0.01 µg/ml in 3% (n = 1) and 10 µg/ml in 6% (n = 2). Baseline serum tryptase was assessed in 84% of the centres (n = 27), out of which 53% (n = 17) tested all their patients, whereas 31% (n = 10) checked only those with life-threatening reactions. In case of negative IDT/sIgE, 59% of the centres (n = 19) performed components evaluation, while 19% (n = 6) did the basophil activation test. In case of no identification of the culprit insect and sensitization to both venoms, VIT employed venom with higher sIgE.

Conclusions

Most allergology centres in Poland follow HVA guidelines. We identified two inaccuracies in their HVA management including non-adequate venom concentration in IDT and a false belief in correspondence between sIgE concentration and severity of allergic reactions.

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.

Hymenoptera venom immunotherapy while maintaining cardiovascular medication: safe and effective

BACKGROUND

The hypothetical risks of cardiovascular medication during Hymenoptera venom immunotherapy (VIT) are still a matter of controversy.

OBJECTIVE

To assess the potential influence of β-blockers (BBs) and/or angiotensin-converting enzyme inhibitors (ACEIs) on the long-term safety and outcome of VIT.

METHODS

Data on the course of VIT maintenance phase, Hymenoptera re-stings, and concurrent medication were retrospectively derived from standardized questionnaires in a cohort of patients with significant cardiovascular comorbidity.

RESULTS

Of 225 patients, 125 (55.6%) were taking cardiovascular medication at the time of data collection: 71 (31.6%) took an ACEI, and 40 (17.8%) took a BB. A total of 3,397 months of maintenance VIT during intake of an ACEI and 1,418 months during BB therapy were evaluated. Cumulative VIT-related reaction rates, including subjective symptoms, were 9.1% per treatment cycle and 0.31% per injection, with objective reaction rates of 1.7% and 0.06%, respectively. The incidence of adverse events was significantly higher in patients with a previous history of systemic reactions at VIT buildup (P = .004). Surprisingly, reaction rates were lower in patients taking any kind of cardiovascular medication (P = .04) or an ACEI (P = .03). The overall reexposure rate to Hymenoptera stings was 42.7%, and the field sting-induced objective reaction rate was 7.3%. There was no evidence of an increase of field sting-related relapse or hospitalization rates by concurrent cardiovascular medication.

CONCLUSION

Cardiovascular medication does not impair the safety and/or the efficacy of Hymenoptera VIT.

[Cross reactions between Hymenoptera venoms from different families, genera and species]

Simultaneous reactivity with the venoms of different Hymenoptera is commonly seen in patients allergic to insect venoms. Strong, though individually variable, cross-reactivity occurs between the venoms of different Vespinae species (Vespula, Dolichovespula, Vespa). In Middle Europe, anaphylaxis after European hornet stings is nearly always due to cross-reactivity with Vespula venom. The identification of the primary venom in patients testing positive for Vespula and Polistes (paper wasps) is particularly important in Mediterranean areas. Component-resolved diagnosis with the marker allergens Ves v 5 and Pol d 5 may directly identify the causative venom in the majority of patients. There is substantial cross-reactivity between honeybee and bumblebee venom, sometimes causing allergic symptoms in patients allergic to honeybee venom after accidental bumblebee stings. However, subjects strongly exposed to bumblebees may show bumblebee-specific sensitization and require immunotherapy with bumblebee venom. More than half of all venom-allergic patients show double-positive test results to honeybee and vespid venoms. This may be due to true double sensitization or due to cross-reactivity between homologous allergens present in both venoms and sharing around 50 % sequence identity, i.e. hyaluronidases (Api m 2/Ves v 2), dipeptidyl peptidases (Api m 5/Ves v 3), and vitellogenins (Api m 12/Ves v 6). The clinical relevance of these cross-reactions is unknown. In up to 50 % the double-positivity is caused by clinically irrelevant IgE antibodies against CCDs. Many (though not all) patients with true double sensitization may be identified by means of the species-specific marker allergens Api m 1 and Ves v 1/5. Some Vespula venom-allergic patients may clinically cross-react to fire ant stings (Solenopsis), but otherwise allergen relationships with other ant species are not well studied.