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.

Allergen immunotherapy for insect venom allergy: a systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing the EAACI Guidelines on Allergen Immunotherapy (AIT) for the management of insect venom allergy. To inform this process, we sought to assess the effectiveness, cost-effectiveness and safety of AIT in the management of insect venom allergy.

METHODS

We undertook a systematic review, which involved searching 15 international biomedical databases for published and unpublished evidence. Studies were independently screened and critically appraised using established instruments. Data were descriptively summarized and, where possible, meta-analysed.

RESULTS

Our searches identified a total of 16 950 potentially eligible studies; of which, 17 satisfied our inclusion criteria. The available evidence was limited both in volume and in quality, but suggested that venom immunotherapy (VIT) could substantially reduce the risk of subsequent severe systemic sting reactions (OR = 0.08, 95% CI 0.03-0.26); meta-analysis showed that it also improved disease-specific quality of life (risk difference = 1.41, 95% CI 1.04-1.79). Adverse effects were experienced in both the build-up and maintenance phases, but most were mild with no fatalities being reported. The very limited evidence found on modelling cost-effectiveness suggested that VIT was likely to be cost-effective in those at high risk of repeated systemic sting reactions and/or impaired quality of life.

CONCLUSIONS

The limited available evidence suggested that VIT is effective in reducing severe subsequent systemic sting reactions and in improving disease-specific quality of life. VIT proved to be safe and no fatalities were recorded in the studies included in this review. The cost-effectiveness of VIT needs to be established.

Trigeminal nasal-specific neurons respond to nerve growth factor with substance-P biosynthesis

BACKGROUND

Nerve growth factor (NGF) has been found to induce substance-P biosynthesis in large-diameter A-fibres vagal airway neurons. However, the effect of NGF on trigeminal neurons innervating the nasal mucosa of the mouse has not been investigated so far.

OBJECTIVE

NGF has been implicated in allergic diseases by modulating sensory nerves. Therefore, the present study investigated the effect of NGF on neuropeptides expression such as substance-P and glutamate in nasal trigeminal neurons.

METHODS

Using neuronal tracing in combination with double labelling immunohistochemistry the expression of substance-P, glutamate and neurofilament protein 68-kDa expression was examined in nasal-specific trigeminal neurons of BALB/c-mice.

RESULTS

The numbers of Fast blue-labelled trigeminal neurons expressing substance-P were significantly increased after NGF exposure (NGF-treated ganglia: 16.4 +/- 0.6% vs. control: 7.0 +/- 0.4%, P<or=0.001). NGF treatment-induced substance-P biosynthesis in neurofilament-positive (NGF-treated ganglia: 8.6 +/- 0.2% vs. control: 1.1 +/- 0.2%, P<or=0.001) as well as neurofilament-negative (NGF-treated ganglia: 7.8 +/- 0.6% vs. control: 5.9 +/- 0.4%, P=0.05) and non-glutamatergic neurons (NGF-treated ganglia: 11.8 +/- 1.9% vs. control 1.1 +/- 1.0%, P<or=0.001) 24 h after NGF exposure.

CONCLUSION

Under normal conditions, substance-P was expressed in nasal-specific neurofilament-negative, glutamatergic and C-fibre neurons. Nasal-specific trigeminal neurons respond to NGF treatment with substance-P biosynthesis in non-glutamatergic, neurofilament-positive as well as -negative neurons. These findings suggest that nasal-specific trigeminal neurons are composed of heterogenous subpopulations in relation to their peptide profiles and therefore may have different functions in neurogenic airway inflammation.

Allergic airway inflammation induces tachykinin peptides expression in vagal sensory neurons innervating mouse airways

BACKGROUND

Allergic airway inflammation has been shown to induce pro-inflammatory neuropeptides such as tachykinin peptides substance P (SP) and neurokinin A (NKA) together with related peptide like calcitonin gene-related peptide (CGRP) in nodose sensory neurons innervating guinea-pig airways.

OBJECTIVE

The present study was designed to examine the effects of allergen sensitization and challenge on the SP/NKA expression in the jugular-nodose ganglion neurons innervating the murine airways.

METHODS

Using retrograde neuronal tracing technique in combination with double-labelling immunohistochemistry, the expression of SP/NKA was investigated in a murine model of allergic airway inflammation.

RESULTS

Allergic airway inflammation was found to induce the expression of SP/NKA (13.2+/-1.43% vs. 5.8+/-0.37%, P<0.01) in large-diameter (>20 microm) vagal sensory neurons retrograde labelled with Fast blue dye from the main stem bronchi.

CONCLUSION

Based on the induction of tachykinins in airway-specific large-sized jugular-nodose ganglia neurons by allergic airway inflammation, the present study suggests that allergen sensitization and challenge may lead to de novo induction of tachykinins in neurons. This may partly contribute to the pathogenesis of airways diseases such as allergic airway inflammation.

Hymenoptera sting anaphylactic reactions in the Mediterranean population of Albania

BACKGROUND

Relatively few studies have examined the relation of different hymenoptera sting reactions.

OBJECTIVE

To investigate the relation of anaphylactic reactions against stings of different hymenoptera subspecies in the Mediterranean population of Albania.

MATERIALS AND METHODS

A retrospective study was conducted using the clinic files of 111 patients who were diagnosed for hymenoptera sting reactions from 1987 to 1996. Antigens used consisted of purified hymenoptera venom (bee, wasp, and paperwasp). The patients were diagnosed by intracutaneous tests in concentrations of 0.001 microgram/ml, 0.01 microgram/ml, 0.1 microgram/ml, and 1 microgram/ml.

RESULTS

The median age of the patients was 27 years. 57% of stings occurred between 20 to 40 years of age. The majority of anaphylactic reactions were recorded during the months of June to October, 81% of the patients were admitted to the hospital due to Mueller grade II to III reactions. In 26% of all cases, crossreactions (bee-wasp 16%, bee-wasp-paperwasp 7%, wasp-paperwasp 2%, bee-paperwasp 1%) were found. Of all anaphylactic reactions, 64% were attributed to bees, 24% to wasps, 8% to both bees and wasps, and 2% to paperwasps.

CONCLUSIONS

In contrast to industrialized countries such as the United States or Western Europe where urban populations predominate, reactions to bee venom were more prevalent in the present study population.