Api m 6 and Api m 10 as Major Allergens in Patients With Honeybee Venom Allergy.

BACKGROUND: Component-resolved diagnosis plays a key role in the diagnosis and treatment of honeybee venom allergy (HVA). Our aim was to study whether any of the allergens not included in the usual diagnostic platforms are relevant in our population. MATERIAL AND METHODS: The allergenic sensitization profile of Spanish patients who experienced a systemic reaction after a honeybee sting and were diagnosed with HVA was studied by immunoblotting based on raw autochthonous Apis mellifera venom characterized using SDS-PAGE and mass spectrometry and a commercial assay (ImmunoCAP). RESULTS: Allergens in the International Union of Immunological Societies database were detected in the raw A mellifera venom extract used, except Api m 12. Sera from 51 patients with a median (IQR) age of 46.2 years (35.6-54.6) were analyzed. ImmunoCAP revealed Api m 1 and Api m 10 to be major allergens (88.2% and 74.5%, respectively). Moreover, Api m 6 (85.4%) was detected by immunoblotting. CONCLUSION: Api m 1, Api m 6, and Api m 10 are major A mellifera venom allergens in our population.

The Honeybee Venom Major Allergen Api m 10 (Icarapin) and Its Role in Diagnostics and Treatment of Hymenoptera Venom Allergy.

PURPOSE OF REVIEW: In Hymenoptera venom allergy, the research focus has moved from whole venoms to individual allergenic molecules. Api m 10 (icarapin) has been described as a major allergen of honeybee venom (HBV) with potentially high relevance for diagnostics and therapy of venom allergy. Here, we review recent studies on Api m 10 characteristics as well as its role in component-resolved diagnostics and potential implications for venom-specific immunotherapy (VIT). RECENT FINDINGS: Api m 10 is a major allergen of low abundance in HBV. It is an obviously unstable protein of unknown function that exhibits homologs in other insect species. Despite its low abundance in HBV, 35 to 72% of HBV-allergic patients show relevant sensitization to this allergen. Api m 10 is a marker allergen for HBV sensitization, which in many cases can help to identify primary sensitization to HBV and, hence, to discriminate between genuine sensitization and cross-reactivity. Moreover, Api m 10 might support personalized risk stratification in VIT, as dominant sensitization to Api m 10 has been identified as risk factor for treatment failure. This might be of particular importance since Api m 10 is strongly underrepresented in some therapeutic preparations commonly used for VIT. Although the role of Api m 10 in HBV allergy and tolerance induction during VIT is not fully understood, it certainly is a useful tool to unravel primary sensitization and individual sensitization profiles in component-resolved diagnostics (CRD). Moreover, a potential of Api m 10 to contribute to personalized treatment strategies in HBV allergy is emerging.

Evolution of Api m10 Specific IgE and IgG4 After One Year of Bee Venom Immunotherapy.

Summary: Background. Bee-venom (BV) anaphylaxis can be life-threatening, requiring treatment with BV immunotherapy (bVIT). Different molecular profiles may be associated with different outcomes after bVIT. Methods. In 19 patients with BV anaphylaxis, sensitized both to Api m1 and Api m10, we evaluated sIgE and sIgG4 Api m1 and Api m10 levels before and after 1 year bVIT.Results.7 patients (37%) had higher baseline Api m10 than Api m1 sIgE levels (Api m10 predominant). bVIT reduced sIgE to both components but sIgG4 levels were increased only for Api m1. 5 patients (2 in the Api m10 predominant group) were re-stung without anaphylaxis. Conclusions. Although there was no increase in Api m10 sIgG4 levels after 1 year bVIT, we did not observe relevant differences in other outcomes between patients with predominant Api m1 or Api m10 sensitization.

rApi m 3 and rApi m 10 improve detection of honey bee sensitization in Hymenoptera venom-allergic patients with double sensitization to honey bee and yellow jacket venom.

Recombinant allergens improve the diagnostic precision in Hymenoptera venom allergy (HVA), in particular in patients with double sensitization to both honey bee (HBV) and yellow jacket venom (YJV). While currently available vespid allergens allow the detection of >95% of YJV-allergic patients, the sensitization frequency to the only available HBV marker allergen rApi m 1 in HBV-allergic patients is lower. Here, we demonstrate that sIgE to additional HBV marker allergens rApi m 3 and rApi m 10 allows the detection of genuine HBV sensitization in 46-65% of Api m 1 negative sera. This is of particular relevance in patients with double sensitization to HBV and YJV that did not identify the culprit insect. Addition of sIgE to rApi m 3 and rApi m 10 provides evidence of HBV sensitization in a large proportion of rApi m 1-negative patients and thus provides a diagnostic marker and rationale for VIT treatment with HBV, which otherwise would have been missing.

Real-World Safety and Efficacy Clinical Data of an Improved Allergen-Specific Immunotherapy Product for the Treatment of Bee Venom Allergy.

The aim of this study is to explore the safety and efficacy of bee venom immunotherapy without HSA, in real-life patients. Methods: This is an observational retrospective study developed in seven hospitals in Spain, where patients treated with this immunotherapy were included. They gathered the protocol used to initiate the immunotherapy, adverse reactions, field re-stings, and the patient clinical data (clinical history, biomarkers, and skin prick test). Results: A total of 108 patients were included. In total, 4 protocols were used (5 weeks reaching 200 µg, and 4, 3, and 2 weeks reaching 100 µg). An incidence of systemic adverse reactions for each 100 injections of 1.5, 1.7, 0, and 0.58, respectively, was found. The demographic data showed not to directly affect the appearance of adverse reactions, except for those having a grade 2 systemic reaction with immunotherapy previously had a grade 4 systemic reaction; the IgE to Apis mellifera was 3 times higher in patients with systemic reactions of grade 1 than in the general group, and other specific IgEs were lower in those with systemic reactions. Most of the patients recognized Api m 1 followed by Api m 10. In the sample, 32% experienced spontaneous re-stings, without presenting systemic reactions, after a year of treatment.

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.

Component-resolved evaluation of the content of major allergens in therapeutic extracts for specific immunotherapy of honeybee venom allergy.

Allergen-specific immunotherapy is the only curative treatment of honeybee venom (HBV) allergy, which is able to protect against further anaphylactic sting reactions. Recent analyses on a molecular level have demonstrated that HBV represents a complex allergen source that contains more relevant major allergens than formerly anticipated. Moreover, allergic patients show very diverse sensitization profiles with the different allergens. HBV-specific immunotherapy is conducted with HBV extracts which are derived from pure venom. The allergen content of these therapeutic extracts might differ due to natural variations of the source material or different down-stream processing strategies of the manufacturers. Since variations of the allergen content of therapeutic HBV extracts might be associated with therapeutic failure, we adressed the component-resolved allergen composition of different therapeutic grade HBV extracts which are approved for immunotherapy in numerous countries. The extracts were analyzed for their content of the major allergens Api m 1, Api m 2, Api m 3, Api m 5 and Api m 10. Using allergen-specific antibodies we were able to demonstrate the underrepresentation of relevant major allergens such as Api m 3, Api m 5 and Api m 10 in particular therapeutic extracts. Taken together, standardization of therapeutic extracts by determination of the total allergenic potency might imply the intrinsic pitfall of losing information about particular major allergens. Moreover, the variable allergen composition of different therapeutic HBV extracts might have an impact on therapy outcome and the clinical management of HBV-allergic patients with specific IgE to particular allergens.