Effectiveness of specific immunotherapy in the treatment of hymenoptera venom hypersensitivity: a meta-analysis

Global View on Ant Venom Allergy: from Allergenic Components to Clinical Management

Hymenoptera venom allergy is characterised by systemic anaphylactic reactions that occur in response to stings from members of the Hymenoptera order. Stinging by social Hymenoptera such as ants, honeybees, and vespids is one of the 3 major causes of anaphylaxis; along with food and drug exposure, it accounts for up to 43% of anaphylaxis cases and 20% of anaphylaxis-related fatalities. Despite their recognition as being of considerable public health significance, stinging ant venoms are relatively unexplored in comparison to other animal venoms and may be overlooked as a cause of venom allergy. Indeed, the venoms of stinging ants may be the most common cause of anaphylaxis in ant endemic areas. A better understanding of the natural history of venom allergy caused by stinging ants, their venom components, and the management of ant venom allergy is therefore required. This article provides a global view on allergic reactions to the venoms of stinging ants and the contemporary approach to diagnose and manage ant venom allergy.

Allergy and sensitization to Hymenoptera venoms in unreferred adults with a high risk of sting exposure

Background

Hymenoptera venom sensitization in highly exposed individuals frequently requires risk assessment for future severe sting reactions. In this study, we determined the prevalence of Hymenoptera venom sensitization in individuals who hunt and fish and analyzed possible correlations between the severity of sting reactions and the IgE sensitization profile.

Methods

In this cross-sectional study, paper-based, self-filled questionnaires about previous insect stings and sting reactions were obtained from individuals who hunt and fish in Bavaria, Germany. Blood samples were taken and analyzed for the levels of tryptase, total IgE and IgE to honey bee (i1) and wasp (13) venom, the recombinant allergens rApi m 1, rApi m 2, rApi m 3, rApi m 5, rApi m 10, rVes v 1, rVes v 5, and the CCD marker molecule MUXF3. Odd ratios (ORs) for sensitization and anaphylaxis and Pearson's correlations for the different allergens were calculated.

Results

Of 257 participants, 50.2% showed a sensitization to honey bee venom (i1), and 58.4% showed sensitization to wasp venom (i3). A total of 98.4% of participants claimed to have been stung at least once. Anaphylaxis was reported in 18.7%, and a local sting reaction was reported in 18.3%. The highest sensitization rates were found for whole venom extracts, sensitization to any of the available recombinant allergens exceeded sIgE levels to honeybee venom (i1) in 28.5% and to wasp venom (i3) in 52.9% of participants. Participants with a history of more than 5 stings showed a higher risk for anaphylaxis.

Conclusions

Sensitization to Hymenoptera venom and their recombinant allergens are present in the majority of individuals who hunt and fish. Sensitization to distinct recombinant allergens does not necessarily affect the severity of sting reactions including anaphylaxis. A meticulous medical history of the number of previous stings as well as systemic reactions remains essential.

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.

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.

Induction of Bronchial Tolerance After 1 Cycle of Monophosphoryl-A-Adjuvanted Specific Immunotherapy in Children With Grass Pollen Allergies

PURPOSE

Subcutaneous allergen-specific immunotherapy (SCIT) is a well-established and clinically effective method to treat allergic diseases, such as rhinitis and asthma. It remains unclear how soon after initiation of an ultra-short course of grass pollen immunotherapy adjuvanted with monophosphoryl lipid A (MPL)-specific bronchial tolerance can be induced.

METHODS

In a prospective study of 69 children double-sensitized to birch and grass pollens (51 males, average age 11.1 years), development of bronchial tolerance after 1 cycle of SCIT for grass was evaluated. In all the patients, the bronchial allergen provocation test (BAP) was performed before and after treatment. According to the results of the first BAP, the patients were divided into 2 groups: those showing a negative BAP with a decrease in FEV1 of <20% (seasonal allergic rhinitis [SAR] group, n=47); and those showing a positive BAP with a decrease in FEV1 of ≥20% (SAR with allergic asthma [SAR and Asthma] group, n=22). All the patients received MPL-adjuvanted, ultra-short course immunotherapy for birch, but only those with a positive BAP to grass received MPL-SCIT for grass.

RESULTS

After the pollen season, the BAP in the SAR group remained unchanged, while it was improved in the SAR and Asthma group (decrease in FEV1 of 28.8% vs 12.5%, P<0.01). The IgG4 levels increased after SCIT (median before SCIT 0.34 to 11.4 after SCIT), whereas the total and specific IgE levels remained unchanged.

CONCLUSIONS

After 1 cycle of MPL-SCIT, specific bronchial tolerance may be significantly induced, whereas in patients without SCIT, bronchial hyperactivity may remain unchanged.

Specific immunotherapy for allergic rhinitis in children

PURPOSE OF REVIEW

Allergic rhinitis is a highly prevalent inflammatory disease affecting 20-40% of the children worldwide. Allergen-specific immunotherapy (SIT) is an effective treatment for allergic rhinitis. This article reviews the recent advances in SIT for children.

RECENT FINDINGS

In current clinical practice, immunotherapy is delivered as either subcutaneous immunotherapy or sublingual immunotherapy (SLIT). Most meta-analyses and reviews concluded a trend that subcutaneous immunotherapy was better than SLIT in reducing symptoms of allergic rhinitis and rescue medication use, however, SLIT has a better safety profile than subcutaneous immunotherapy. Additionally, the absence of pain on administration of therapy is a character of SLIT, which is well suited for children. T regulatory cells, especially Tr1 cells that secrete interleukin-10 and induce production of immunoglobulin G4, play a role during SIT.

SUMMARY

Although there is substantial evidence for effectiveness of both subcutaneous immunotherapy and SLIT, safer and more effective SIT approaches are needed. New approaches to improve SIT include omalizumab pretreatment, use of recombinant allergens, and alternate routes of administration.

Risk associated with bee venom therapy: a systematic review and meta-analysis

OBJECTIVE

The safety of bee venom as a therapeutic compound has been extensively studied, resulting in the identification of potential adverse events, which range from trivial skin reactions that usually resolve over several days to life-threating severe immunological responses such as anaphylaxis. In this systematic review, we provide a summary of the types and prevalence of adverse events associated with bee venom therapy.

METHODS

We searched the literature using 12 databases from their inception to June 2014, without language restrictions. We included all types of clinical studies in which bee venom was used as a key intervention and adverse events that may have been causally related to bee venom therapy were reported.

RESULTS

A total of 145 studies, including 20 randomized controlled trials, 79 audits and cohort studies, 33 single-case studies, and 13 case series, were evaluated in this review. The median frequency of patients who experienced adverse events related to venom immunotherapy was 28.87% (interquartile range, 14.57-39.74) in the audit studies. Compared with normal saline injection, bee venom acupuncture showed a 261% increased relative risk for the occurrence of adverse events (relative risk, 3.61; 95% confidence interval, 2.10 to 6.20) in the randomized controlled trials, which might be overestimated or underestimated owing to the poor reporting quality of the included studies.

CONCLUSIONS

Adverse events related to bee venom therapy are frequent; therefore, practitioners of bee venom therapy should be cautious when applying it in daily clinical practice, and the practitioner's education and qualifications regarding the use of bee venom therapy should be ensured.

Subcutaneous immunotherapy

BACKGROUND

Allergic rhinitis, asthma, and Hymenoptera sensitivity affect approximately 20%, 9%, and 0.66% to 3.3% of adults in the United States, respectively. Various environmental control measures and pharmacologic options are available for symptomatic treatment of allergic rhinitis and allergic asthma. However, allergen-specific immunotherapy is the only form of treatment that alters the natural history of allergic disease.

METHODS

A literature review was performed. Information from systematic reviews, meta-analyses, and practice parameters were closely examined and summarized, and they are included in this primer.

RESULTS

There is evidence that supports the use of subcutaneous immunotherapy (SCIT) for the treatment of perennial and seasonal allergic rhinitis, asthma, and Hymenoptera sensitivity. Efficacy of SCIT has been established in the adult and pediatric populations. Adverse reactions occur in up to 71% of patients. However, the rate of serious or fatal side effects is very rare.

CONCLUSION

SCIT is safe and effective in the treatment of allergic rhinitis, allergic asthma, and Hymenoptera sensitivity. Adverse reactions occur but, in general, SCIT is well tolerated, and the vast majority of reactions are mild and very rarely fatal.

New strategies for allergen T cell epitope identification: going beyond IgE

BACKGROUND

Type I allergy and allergic asthma are common diseases in the developed world associated with IgE antibodies and Th2 cell reactivity. To date, the only causative treatment for allergic disease is specific immunotherapy (SIT).

METHOD

Here, we review recent works from our laboratory focused on identifying human T cell epitopes associated with allergic disease and their potential use as biomarkers or therapeutic targets for SIT. In previous studies, we have mapped T cell epitopes associated with the major 10 timothy grass (Tg) allergens, defined on the basis of human IgE reactivity by ELISPOT.

RESULTS

Interestingly, in about 33% of allergic donors, no T cell epitopes from overlapping peptides spanning the entire sequences of these allergens were identified despite vigorous T cell responses to the Tg extract. Using a bioinformatic-proteomic approach, we identified a set of 93 novel Tg proteins, many of which were found to elicit IL-5 production in T cells from allergic donors despite lacking IgE reactivity. Next, we assessed T cell responses to the novel Tg proteins in donors who had been treated with subcutaneous SIT. A subset of these proteins showed a strong reduction of IL-5 responses in donors who had received subcutaneous SIT compared to allergic donors, which correlated with patients' self-reported improvement of allergic symptoms.

CONCLUSION

A bioinformatic-proteomic approach has successfully identified additional Tg-derived T cell targets independent of IgE reactivity. This method can be applied to other allergies potentially leading to the discovery of promising therapeutic targets for allergen-specific immunotherapy.

Peanut immunotherapy

Peanut allergy is common and can be a cause of severe, life-threatening reactions. It is rarely outgrown like other food allergies, such as egg and milk. Peanut allergy has a significant effect on the quality of life of sufferers and their families, due to dietary and social restrictions, but mainly stemming from fear of accidental peanut ingestion. The current management consists of strict avoidance, education and provision of emergency medication, but a disease- modifying therapy is needed for peanut allergy. Recent developments involve the use of immunotherapy, which has shown promise as an active form of treatment. Various routes of administration are being investigated, including subcutaneous, oral, sublingual and epicutaneous routes. Other forms of treatment, such as the use of vaccines and anti-IgE molecules, are also under investigation. So far, results from immunotherapy studies have shown good efficacy in achieving desensitisation to peanut with a good safety profile. However, the issue of long-term tolerance has not been fully addressed yet and larger, phase III studies are required to further investigate safety and efficacy. An assessment of cost/benefit ratio is also required prior to implementing this form of treatment. The use of immunotherapy for peanut allergy is not currently recommended for routine clinical use and should not be attempted outside specialist allergy units.

Anaphylaxis: guidelines from the European Academy of Allergy and Clinical Immunology

Anaphylaxis is a clinical emergency, and all healthcare professionals should be familiar with its recognition and acute and ongoing management. These guidelines have been prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Taskforce on Anaphylaxis. They aim to provide evidence-based recommendations for the recognition, risk factor assessment, and the management of patients who are at risk of, are experiencing, or have experienced anaphylaxis. While the primary audience is allergists, these guidelines are also relevant to all other healthcare professionals. The development of these guidelines has been underpinned by two systematic reviews of the literature, both on the epidemiology and on clinical management of anaphylaxis. Anaphylaxis is a potentially life-threatening condition whose clinical diagnosis is based on recognition of a constellation of presenting features. First-line treatment for anaphylaxis is intramuscular adrenaline. Useful second-line interventions may include removing the trigger where possible, calling for help, correct positioning of the patient, high-flow oxygen, intravenous fluids, inhaled short-acting bronchodilators, and nebulized adrenaline. Discharge arrangements should involve an assessment of the risk of further reactions, a management plan with an anaphylaxis emergency action plan, and, where appropriate, prescribing an adrenaline auto-injector. If an adrenaline auto-injector is prescribed, education on when and how to use the device should be provided. Specialist follow-up is essential to investigate possible triggers, to perform a comprehensive risk assessment, and to prevent future episodes by developing personalized risk reduction strategies including, where possible, commencing allergen immunotherapy. Training for the patient and all caregivers is essential. There are still many gaps in the evidence base for anaphylaxis.

Is faster safer? Cluster versus short conventional subcutaneous allergen immunotherapy

AIM

Few studies have compared cluster immunotherapy and conventional administration regimens. The aim of this study was to establish the safety profile of these different regimens in patients with allergic respiratory diseases who received index-of-reactivity (IR)-standardized allergen extracts by the subcutaneous route.

MATERIALS & METHODS

The safety of subcutaneous immunotherapy (SCIT), administered by means of a 4-week cluster titration schedule (cluster-SCIT) or by an 8-week short conventional titration schedule (SC-SCIT), both with a target dose of 8 IR, was assessed in a retrospective, observational, multicenter study.

RESULTS

A total of 658 patients (339 cluster-SCIT and 319 SC-SCIT) were recruited from 92 sites in Spain. Injection site reactions occurred in 25.1 and 27.3% of patients treated with cluster-SCIT and SC-SCIT, respectively. Systemic reactions (European Academy of Allergy and Clinical Immunology criteria) were reported for 0.2% of doses and 1.5% of patients with cluster-SCIT, and 0.7% of doses and 4.4% of patients with SC-SCIT. Most reactions were mild and there were no grade 3 or 4 systemic reactions. No life-threatening systemic reactions, anaphylactic shock, or adverse events leading to therapy discontinuation were reported.

CONCLUSION

The safety profile of the cluster regimen supports the use of accelerated SCIT schedules with IR-standardized allergen extracts compared with short conventional schedules, particularly if similar extracts and application methods are used.

Management of anaphylaxis: a systematic review

To establish the effectiveness of interventions for the acute and long-term management of anaphylaxis, seven databases were searched for systematic reviews, randomized controlled trials, quasi-randomized controlled trials, controlled clinical trials, controlled before-after studies and interrupted time series and - only in relation to adrenaline - case series investigating the effectiveness of interventions in managing anaphylaxis. Fifty-five studies satisfied the inclusion criteria. We found no robust studies investigating the effectiveness of adrenaline (epinephrine), H1-antihistamines, systemic glucocorticosteroids or methylxanthines to manage anaphylaxis. There was evidence regarding the optimum route, site and dose of administration of adrenaline from trials studying people with a history of anaphylaxis. This suggested that administration of intramuscular adrenaline into the middle of vastus lateralis muscle is the optimum treatment. Furthermore, fatality register studies have suggested that a failure or delay in administration of adrenaline may increase the risk of death. The main long-term management interventions studied were anaphylaxis management plans and allergen-specific immunotherapy. Management plans may reduce the risk of further reactions, but these studies were at high risk of bias. Venom immunotherapy may reduce the incidence of systemic reactions in those with a history of venom-triggered anaphylaxis.

Recombinant allergen immunotherapy: clinical evidence of efficacy--a review

Recombinant allergens for immunotherapy aim to overcome the problems of natural extracts as they can be produced in unlimited amounts with exact physiochemical and immunological properties. These can be modified to have more favourable characteristics including reduced IgE reactivity or enhanced immunogenicity. Different types of recombinant allergens have been evaluated in clinical phase II and III trials whilst others are currently under development. In this review, we identified double-blind, placebo-controlled randomised clinical trials assessing the efficacy and safety of various recombinant allergen preparations. The majority of studies have up to now focused on cat, grass, birch, ragweed and bee venom allergens. Some studies have shown some of these preparations to be effective and well tolerated. However, there are still outstanding issues regarding optimum doses, minimising side effects and long-term effects.

Longitudinal study of 954 patients with stinging insect anaphylaxis

BACKGROUND

Stinging insect anaphylaxis (SIA) is a common cause of anaphylaxis and is potentially life-threatening.

OBJECTIVES

To examine US patients with an emergency department (ED) visit or hospitalization for SIA to evaluate postdischarge follow-up care.

METHODS

We identified all patients with an ED visit or hospitalization for SIA during 2002-2008 in the MarketScan Database using International Classification of Diseases, Ninth Revision, Clinical Modification codes (index date was the initial ED visit or hospitalization). Patients were required to have continuous full insurance coverage for 1 year or more before and after index. We examined patient factors during the preindex period, characteristics of the index event, and outcomes during the postindex period. Multivariable logistic regression was used to identify independent predictors of receiving preventive anaphylaxis care.

RESULTS

We identified 954 patients with an ED visit or hospitalization for SIA (mean [SD] age, 46 [19] years; 41% female). A total of 85% of patients were discharged directly from the ED. For those hospitalized, the mean hospital stay was 1 day, and 50% spent time in the intensive care unit. Cardiorespiratory failure occurred in 27% of those hospitalized. During the postindex period, 69% filled 1 or more epinephrine autoinjector prescription, but only 14% had 1 or more allergist/immunologist visit. Independent factors associated with receiving preventive anaphylaxis care during the postindex period were higher household income, no ED visit (for any reason) in the preindex period, and no cardiorespiratory arrest or failure during the index event.

CONCLUSION

Although two-thirds of patients filled a prescription for an epinephrine autoinjector after an ED visit or hospitalization for SIA, only 14% of patients received follow-up care by an allergist/immunologist. This missed opportunity to provide venom immunotherapy, an essentially curative therapy, unnecessarily places patients at risk for recurrent anaphylaxis.

Clinical effectiveness of hymenoptera venom immunotherapy: a prospective observational multicenter study of the European academy of allergology and clinical immunology interest group on insect venom hypersensitivity

BACKGROUND

Treatment failure during venom immunotherapy (VIT) may be associated with a variety of risk factors.

OBJECTIVE

Our aim was to evaluate the association of baseline serum tryptase concentration (BTC) and of other parameters with the frequency of VIT failure during the maintenance phase.

METHODS

In this observational prospective multicenter study, we followed 357 patients with established honey bee or vespid venom allergy after the maintenance dose of VIT had been reached. In all patients, VIT effectiveness was either verified by sting challenge (n = 154) or patient self-reporting of the outcome of a field sting (n = 203). Data were collected on BTC, age, gender, preventive use of anti-allergic drugs (oral antihistamines and/or corticosteroids) right after a field sting, venom dose, antihypertensive medication, type of venom, side effects during VIT, severity of index sting reaction preceding VIT, and duration of VIT. Relative rates were calculated with generalized additive models.

RESULTS

22 patients (6.2%) developed generalized symptoms during sting challenge or after a field sting. A strong association between the frequency of VIT failure and BTC could be excluded. Due to wide confidence bands, however, weaker effects (odds ratios <3) of BTC were still possible, and were also suggested by a selective analysis of patients who had a sting challenge. The most important factor associated with VIT failure was a honey bee venom allergy. Preventive use of anti-allergic drugs may be associated with a higher protection rate.

INTERPRETATION

It is unlikely that an elevated BTC has a strong negative effect on the rate of treatment failures. The magnitude of the latter, however, may depend on the method of effectiveness assessment. Failure rate is higher in patients suffering from bee venom allergy.

Honeybee venom immunotherapy: certainties and pitfalls

The honeybee is an interesting insect because of the fundamental agricultural role it plays, together with the composition of its venom, which presents new diagnostic and immunotherapeutic challenges. This article examines various aspects of honeybee venom allergy from epidemiology to diagnosis and treatment, with special emphasis on venom immunotherapy (VIT). Honeybee venom allergy represents a risk factor for severe systemic reaction in challenged allergic patients, for the diminished effectiveness of VIT, for more frequent side effects during VIT and relapse after cessation of treatment. Some strategies are available for reducing the risk of honeybee VIT-induced side effects; however, there is considerable room for further improvement in these all-important areas. At the same time, sensitized and allergic beekeepers represent unique populations for epidemiological, venom allergy immunopathogenesis and VIT mechanism studies.

Comparison of the long-term efficacy of 3- and 5-year house dust mite allergen immunotherapy

BACKGROUND

The recommended duration of specific immunotherapy (SIT) treatment relies on empiric data and is not well documented.

OBJECTIVE

To detect possible differences in the long-term effectiveness between 3 and 5 years of house dust mite (HDM) SIT in asthmatic children.

METHODS

We performed a 3-year natural history study of 90 asthmatic children who were sensitive only to HDM. Three groups were recruited: 30 who had completed 3 years of HDM SIT (SIT3), 30 who had completed 5 years of HDM SIT (SIT5), and 30 who had an indication for HDM SIT but whose parents refused HDM SIT. Patients attended an enrollment visit in 2007, after SIT discontinuation, and 3 annual follow-up visits at the clinic. The long-term effectiveness of HDM SIT was primarily assessed via analysis of the reduction in required inhaled corticosteroid dose, forced expiratory volume in 1 second, and asthma remission.

RESULTS

A total of 84 children completed the study. Both SIT durations produced excellent results; asthma remission in both SIT3 (50%) and SIT5 (54%) groups was significantly higher when compared with control (3.3%). The minimal controlling inhaled corticosteroid dose reduction in SIT5 group (median, 75%) was significantly higher compared with the SIT3 group (median, 50%) after immunotherapy discontinuation; after 3 years without SIT, no differences were found between the SIT5 and SIT3 groups (median, 100% and 94%, respectively). We observed a slightly higher increase in forced expiratory volume in 1 second in the SIT5 group compared with the SIT3 group.

CONCLUSION

Three years of SIT is an adequate duration for the treatment of childhood asthma associated with HDM allergy because 2 further years of SIT added no clinical benefit.

Subcutaneous allergen immunotherapy for allergic disease: examining efficacy, safety and cost-effectiveness of current and novel formulations

Subcutaneous immunotherapy (SCIT) is a unique therapy for allergic disease because it provides symptomatic relief while modifying the allergic disease by targeting the underlying immunological mechanism. Its efficacy and safety have been established in the treatment of asthma, allergic rhinitis/rhinoconjunctivitis and stinging insect hypersensitivity in numerous controlled clinical trials. This review evaluates a spectrum of clinical factors, ranging from efficacy to cost-effectiveness, which should be considered in evaluating SCIT. The evidence for SCIT safety and efficacy for these conditions is reviewed in an evaluation of the systematic reviews and meta-analyses. The evidence for the persistent and preventive effects of SCIT is also examined. An overview of the SCIT outcomes measures utilized in clinical trials is presented. The cost-effectiveness of SCIT compared with conventional medication treatment, novel indications and formulations for SCIT are also explored in this review.

Risk assessment of Hymenoptera re-sting frequency: implications for decision-making in venom immunotherapy

BACKGROUND

Venom immunotherapy is highly efficacious in preventing anaphylactic sting reactions. However, there is an ongoing discussion regarding patient selection and whether and how to apply a cost-benefit analysis of venom immunotherapy. In order to help decision-making, we investigated the re-sting frequency of hymenoptera-venom-allergic patients to single out those at high risk.

METHODS

In this retrospective study, re-sting data of 96 bee-venom-allergic patients and 95 vespid-venom-allergic patients living mainly in a rural area of Switzerland were analyzed. Hymenoptera venom allergy status was rated according to the classification system of H.L. Mueller [J Asthma Res 1966;3:331-333]. Different risk-groups were defined according to sting exposure and their median sting-free interval was calculated.

RESULTS

The risk factors for a wasp or bee re-sting were outdoor occupation, beekeeping and habitation close to a bee-house. Half of all vespid-venom-allergic outdoor workers were re-stung within 3.75 years compared to 7.5 years for indoor workers. Similarly, 50% of the bee-venom-allergic beekeepers or subjects with a bee-house in the vicinity suffered a bee re-sting within 5.25 years compared to 10.75 years for individuals who were not beekeepers.

CONCLUSIONS

The high degree of exposure of vespid-venom-allergic outdoor workers and bee-venom-allergic beekeepers and subjects living close to bee-houses underlines the high benefit of venom immunotherapy for these patients even if they suffered a non-life-threatening grade II reaction. Yet, bee-venom-allergic individuals with no proximity to bee-houses and with an indoor occupation face a very low exposure risk, which justifies epinephrine rescue treatment for these patients especially if they have suffered from grade II sting reactions.

Early suppression of basophil activation during allergen-specific immunotherapy by histamine receptor 2

BACKGROUND

Early desensitization of FcεRI-bearing mast cells and basophils has been demonstrated in allergen-specific immunotherapy and drug desensitization. However, its mechanisms have not been elucidated in detail. Histamine is one of the main mediators released on FcεRI triggering of basophils and mast cells, and it exerts its functions through histamine receptors (HRs).

OBJECTIVES

We sought to investigate HR expression on basophils of patients undergoing venom immunotherapy (VIT) and its effect on allergen, IgE, and FcεRI cross-linking-mediated basophil function and mediator release.

METHODS

Basophils were purified from the peripheral blood of patients undergoing VIT and control subjects and were studied functionally by using real-time PCR, flow cytometry and ELISA assays.

RESULTS

Rapid upregulation of H2R within the first 6 hours of the build-up phase of VIT was observed. H2R strongly suppressed FcεRI-induced activation and mediator release of basophils, including histamine and sulfidoleukotrienes, as well as cytokine production in vitro.

CONCLUSION

Immunosilencing of FcεRI-activated basophils by means of selective suppression mediated by H2R might be highly relevant for the very early induction of allergen tolerance and the so-called desensitization effect of VIT.

Improving anaphylaxis management in a pediatric emergency department

BACKGROUND

The management of anaphylaxis in pediatric emergency units (PEU) is sometimes deficient in terms of diagnosis, treatment, and subsequent follow-up. The aims of this study were to assess the efficiency of an updated protocol to improve medical performance, and to describe the incidence of anaphylaxis and the safety of epinephrine use in a PEU in a tertiary hospital.

METHODS

We performed a before-after comparative study with independent samples through review of the clinical histories of children aged <14 years old diagnosed with anaphylaxis in the PEU according to the criteria of the European Academy of Allergy and Clinical Immunology (EAACI). Two allergists and a pediatrician reviewed the discharge summaries codified according to the International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) as urticaria, acute urticaria, angioedema, angioneurotic edema, unspecified allergy, and anaphylactic shock. Patients were divided into two groups according to the date of implantation of the protocol (2008): group A (2006-2007; the period before the introduction of the protocol) and group B (2008-2009; after the introduction of the protocol). We evaluated the incidence of anaphylaxis, epinephrine administration, prescription of self-injecting epinephrine (SIE), other drugs administered, the percentage of admissions and length of stay in the pediatric emergency observation area (PEOA), referrals to the allergy department, and the safety of epinephrine use.

RESULTS

During the 4 years of the study, 133,591 children were attended in the PEU, 1673 discharge summaries were reviewed, and 64 cases of anaphylaxis were identified. The incidence of anaphylaxis was 4.8 per 10,000 cases/year. After the introduction of the protocol, significant increases were observed in epinephrine administration (27% in group A and 57.6% in group B) (p = 0.012), in prescription of SIE (6.7% in group A and 54.5% in group B) (p = 0.005) and in the number of admissions to the PEOA (p = 0.003) and their duration (p = 0.005). Reductions were observed in the use of corticosteroid monotherapy (29% in group A, 3% in group B) (p = 0.005), and in patients discharged without follow-up instructions (69% in group A, 22% in group B) (p = 0.001). Thirty-three epinephrine doses were administered. Precordial palpitations were observed in one patient.

CONCLUSION

The application of the anaphylaxis protocol substantially improved the physicians' skills to manage this emergency in the PEU. Epinephrine administration showed no significant adverse effects.

Immunotherapy: The meta-analyses. What have we Learned?

Meta-analysis is a powerful tool for evaluating the efficacy of a therapeutic intervention, and has clearly demonstrated that specific allergen immunotherapy (SIT) is effective for treating allergic rhinitis and asthma. Future research needs to focus on specifying the most effective forms of SIT for specific populations and allergens, using validated clinical outcomes, studying long-term outcomes (particularly the potential disease-modifying effect of immunotherapy), and assessing outcomes regarding health economics. The safety profile of SIT should be evaluated using international guidelines and terminology, and needs to include high-quality surveillance data.

Induction of specific immunotherapy with hymenoptera venoms using ultrarush regimen in children: safety and tolerance

Background & Objective. Ultrarush induction for specific venom immunotherapy has been shown to be reliable and efficacious in adults. In this study its safety and tolerance in children was evaluated. Methods. Retrospective analysis of 102 ultrarush desensitizations carried out between 1997 and 2005 in 94 children, aged 4 to 15 years. Diagnosis and selection for immunotherapy were according to recommendations of the European Academy of Allergy and Clinical Immunology. Systemic adverse reactions (SARs) were described using the classification of H. L. Mueller. Results. All patients reached the cumulative dose of 111.1 μg hymenoptera venom within 210 minutes. Six patients (6%) had allergic reactions grade I; 2 patients (2%) grade II and 5 patients (5%) grade III. Three patients (3%) showed unclassified reactions. SARs did not occur in the 15 patients aged 4 to 8 years and they were significantly more frequent in girls (29%) compared with boys (12%) (P = 0.034, multivariant analysis) and in bee venom extract treated patients (20%) compared to those treated with wasp venom extract (8%) (OR 0.33, 95% Cl 0.07-1.25). Conclusion. Initiation of specific immunotherapy by ultrarush regimen is safe and well tolerated in children and should be considered for treating children with allergy to hymenoptera venom.

Anaphylaxis caused by Hymenoptera stings: from epidemiology to treatment

Hymenoptera venom allergy occasionally causes fatal reactions. The prevalence of systemic reactions (SRs) is 0.3-8.9%, with anaphylaxis in 0.3-42.8% of cases. Factors contributing to reaction severity include older age, insect type, a previous less severe SR, preexisting diseases, concomitant treatments, mast cell diseases and elevated baseline tryptase serum concentration. Venom immunotherapy (VIT) is highly effective, as shown by sting challenge and spontaneous field stings. Indications for VIT are based on history of an SR, positive diagnostic tests, natural history and established risk factors for a severe outcome. Current strategies for reducing adverse reactions include anti-IgE monoclonal antibody pretreatment, and purified aqueous and purified aluminium hydroxide adsorbed preparations. New strategies for VIT, mostly using recombinant allergen, are in development. Further improvements will increase the safety and efficacy of VIT.

SIT beyond respiratory diseases

OBJECTIVE

The goal was to assess the effectiveness of specific immunotherapy (SIT) in reduction of symptoms and medication score in patients with immunoglobulin E (IgE) mediated extrinsic form of atopic dermatitis (AD); and to assess the effectiveness of oral immunotherapy (OIT) as "active" treatment to achieving tolerance for food(s) in patients with IgE mediated food allergy.

DATA SOURCES

Computerized bibliographic searches of MEDLINE (1998-2010) were supplemented by hand searches of reference lists. Studies were included if they were double-blind randomized controlled trials comparing subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT) or OIT with placebo. However uncontrolled studies and case reports were also included.

STUDY SELECTIONS

Thirty-two studies were analyzed. Because of the high heterogeneity of the AD studied only results of 2 placebo controlled studies 1-SCIT and 1-SLIT respectively were comparable. Among OIT studies: 4 carried out with control groups were analyzed.

RESULTS

From 36% to 92% of patients treated with OIT reached tolerance to cow's milk or egg; a rate of 8% to 53% reached partial tolerance. The patients had either clinical history of severe systemic reactions to foods: anaphylaxis, or mild to moderate reactions. Regarding SIT for AD: 72% of patients treated with house dust mite SCIT and 54% treated with SLIT had a significant improvement of SCORAD-Index.

CONCLUSIONS

This review found that OIT with cow's milk or egg is effective in achieving full tolerance or partial tolerance in the majority of patients with IgE mediated food allergy. SIT may represent an additional therapeutic tool for the treatment of extrinsic AD in properly selected patients.

Hymenoptera venom immunotherapy

Subcutaneous venom immunotherapy is the only effective treatment for patients who experience severe hymenoptera sting-induced allergic reactions, and the treatment also improves health-related quality of life. This article examines advances in various areas of this treatment, which include the immunological mechanisms of early and long-term efficacy, indications and contraindications, selection of venom, treatment protocols, duration, risk factors for systemic reactions in untreated and treated patients as well as for relapse following cessation of treatment. Current and future strategies for improving safety and efficacy are also examined. However, although progress in the past few years has been fruitful, much remains to be accomplished.

Three years of specific immunotherapy may be sufficient in house dust mite respiratory allergy

BACKGROUND

Specific immunotherapy (SIT) duration for respiratory allergy is currently based on individual decisions.

OBJECTIVE

To evaluate the differences in clinical efficacy of SIT as a result of the duration between the current recommended limits (3-5 years).

METHODS

A 5-year prospective, controlled clinical trial of SIT blind until the first year and randomization to a 3-year (IT3) or 5-year (IT5) course was conducted. Of the 239 patients with respiratory allergy caused by D pteronyssinus initially included, 142 completed 3 years of SIT with good compliance. Twenty-seven controls were included at the third year. Efficacy of SIT after 3 (T3) and 5 (T5) years was assessed by using clinical scores, visual analog scales (VASs), rhinitis (RQLQ) and asthma (AQLQ) quality of life questionnaires, skin tests, and serum immunoglobulins.

RESULTS

At T3, significant reductions were observed in rhinitis (44% in IT3 and 50% in IT5; P < .001), asthma (80.9 % in IT3 and 70.9% in IT5; P < .001) scores, VAS (P < .001 in both), RQLQ (P < .001 in both) and AQLQ (P < .001 in both). At T5, the clinical benefit was maintained in both groups, and IT5 patients presented additional decreases (19%; P = .019) in rhinitis scores. At Tf, specific IgG(4) measurements were lower in IT3 (P = .03) without detecting differences in IT5. An increase in asthma score of 133% was the only difference observed in controls.

CONCLUSION

Clinical improvement is obtained with 3 years of D pteronyssinus SIT. Two additional years of SIT add clinical benefit in rhinitis only.

Purified vs. nonpurified venom immunotherapy

PURPOSE OF REVIEW

Although highly effective, venom immunotherapy (VIT) may be responsible for local and systemic allergic reactions. There is a good theoretical basis for believing that purified aqueous and purified aluminium hydroxide adsorbed (so-called depot) extracts, commercially available in Europe, have the potential to reduce the incidence of VIT's side effects. The aim of this article is to review the literature on safety and effectiveness of purified preparations as well as compare them with nonpurified extracts.

RECENT FINDINGS

Old and new noncomparative studies reveal good tolerance of purified aqueous and purified depot extracts. In comparative trials purified extracts appear to be better tolerated than nonpurified extracts, whereas depot extracts seem to be safer than the corresponding purified aqueous preparation, especially in the prevention of severe large local reactions. The efficacy of purified aqueous and depot extracts is supported by studies using both sting challenge and in-field stings and is comparable to that of nonpurified preparations.

SUMMARY

The theoretical basis of the safer profile of purified extracts is supported by a number of clinical studies, making the use of purified depot preparations preferable for conventional treatment also by specialists with less experience in managing VIT. In specialized centres purified aqueous extracts may be preferred for faster build-up protocols. However, further prospective controlled studies are needed in order to evaluate the ability of purified extracts to reduce the frequency of severe systemic reactions over the corresponding nonpurified preparation.

Allergen immunotherapy: immunomodulatory treatment for allergic diseases

Allergen immunotherapy is currently the only immune-modifying treatment for allergic disease. At the present time it is indicated for the treatment of allergic rhinitis, asthma and venom hypersensitivity. Efficacy appears to be dose dependent, and the immunological mechanisms responsible for the clinical efficacy of immunotherapy are still being elucidated. Immunological changes associated with immunotherapy include induction of T regulatory cells, increase in allergen-specific immunoglobulin G4, increase in interleukin-10 production and downregulation of the T helper 2 response. The disadvantages of allergen immunotherapy include risk of adverse events and patient time and inconvenience. Risks of immunotherapy range from large local reactions to mild systemic reactions, such as rhinitis. Fatalities from immunotherapy injections have been reported at a rate of approximately one fatality per 2.5 million injections. Conventional subcutaneous immunotherapy build-up schedules involve administration of a single-dose increase each visit and it may take several months before a patient achieves the therapeutic maintenance dose. Accelerated schedules, such as rush and cluster, will allow the patient to achieve the maintenance dose sooner but there may be a greater risk of a systemic reaction. The current focus of immunotherapy research is to develop safer and more effective vaccines. Another approach to enhancing immunotherapy safety is through an alternative delivery method. Sublingual immunotherapy is clearly safer than subcutaneous immunotherapy, but further investigation is needed to determine optimal dose and appropriate patient selection.

Bee venom immunotherapy - how early is it effective?

BACKGROUND

Although the effectiveness of venom immunotherapy (VIT) in bee venom (BV) allergy has been well established over the past 30 years, no previous study has demonstrated its efficacy immediately after reaching the maintenance dose (MD). We examined the effectiveness of bee VIT within a week after the MD was achieved.

METHODS

Bee venom allergic patients underwent conventional or rush VIT. Within 1 week after reaching the 100 microg MD, patients were challenged with a live bee sting.

RESULTS

Seventy-nine of 107 patients (73.8%) who reached the MD agreed to be challenged. Seventy patients (88.6%) tolerated the sting uneventfully. Four patients (5.1%) developed a very mild local transient rash and continued to receive the 100 microg MD. In five patients (6.3%), the sting resulted in a mild-moderate systemic reaction. In four of these, the MD was increased to 200-250 microg. All four patients uneventfully tolerated a repeated sting that was performed within 1 week after achieving the increased MD in three patients and after 14 months in the fourth patient.

CONCLUSIONS

Bee VIT is effective in most patients immediately after the conventional MD has been reached. In the minority of patients who are not protected with this dose, an increased MD will provide appropriate protection immediately after it is achieved. Thus, the dosage of the MD seems to be the major factor affecting protection from re-stings rather than the accumulated venom dose or the duration on the MD.

Basophil sensitivity through CD63 or CD203c is a functional measure for specific immunotherapy

Background

Subcutaneous Immunotherapy (SCIT) modifies the allergic response and relieves allergic symptoms. SCIT is the only and a very effective treatment for insect venom allergy. We hypothesized that basophil sensitivity, measured through the basophil activation test, would decrease during SCIT up dosing. Expression of CD203c was compared to CD63 as marker for basophil activation, using a Bland Altman plot and ROC curves.

Methods

Patients (n = 18) starting subcutaneous SCIT for wasp allergy with an up dosing scheme of 7 to 11 weeks were enrolled. Heparinised blood samples were drawn at weeks 1-4, 7 and at the first maintenance visit. Basophils were stimulated at 7 log dilutions of V. vespula allergen for 15 min, and were stained with CD203c and CD63. Basophils were identified as CD203c⁺ leukocytes, and the proportion of CD63⁺ and CD203c⁺ cells were plotted against allergen concentration. A sigmoid curve was fitted to the points, and the allergen concentration at which half of the maximal activation was achieved, LC50, was calculated. In another series of experiments, LC50 calculated in whole blood (AP) was subtracted from LC50 calculated with basophils suspended in plasma from a nonatopic donor (HS) to determine the protective effect of soluble factors in blood of patients treated with SCIT.

Results

Heparin blood basophil activation was similar through CD63 and CD203c. Basophils were significantly more sensitized three weeks after initiation of SCIT compared to baseline (p < 0,01). The difference in LC50 increased by 1,04 LC50 units (p = 0,04) in patients that had just achieved maintenance dose compared with patients before initiating SCIT. When maintenance allergen concentrations had been reached, an increase in the protective plasma component was documented. Blood basophil concentration was marginally reduced by SCIT.

Conclusion

Basophil activation is a versatile and sensitive tool that measures changes in the humoral immune response to allergen during SCIT.

Specific immunotherapy using Hymenoptera venom: systematic review

CONTEXT AND OBJECTIVE

The only effective treatment for patients who have severe reactions after Hymenoptera stings is venom immunotherapy. The aim of this study was to review the literature to assess the effects of venom immunotherapy among patients presenting severe reactions after Hymenoptera stings.

DESIGN AND SETTING

Randomized controlled trials in the worldwide literature were reviewed. The manuscript was produced in the Discipline of Allergy and Clinical Immunology, Universidade de São Paulo (USP).

METHODS

Randomized controlled trials involving venom immunotherapy versus placebo or only patient follow-up were evaluated. The risk of systemic reactions after specific immunotherapy was evaluated by calculating odds ratios (OR) and their 95% confidence intervals.

RESULTS

2,273 abstracts were identified by the keywords search. Only four studies were included in this review. The chi-square test for heterogeneity showed that two studies were homogeneous and could be included in a meta-analysis. By combining the two studies, the odds ratio became significant: 0.29 (0.10-0.87). However, analysis on the severity of the reactions after immunotherapy showed that the benefits may not be so significant because the reactions were mostly similar to or milder than the original reaction.

CONCLUSIONS

Specific immunotherapy should be recommended for adults and children with moderate to severe reactions, but there is no need to prescribe it for children with skin reactions alone, especially if the exposure is very sporadic. On the other hand, the risk-benefit relation should always be assessed in each case.

Sublingual immunotherapy for children: Are we there yet? Defining its role in clinical practice

Immunotherapy in various forms has been used to treat allergic disorders since the early 19th century. Subcutaneous immunotherapy is now well established for the treatment of insect anaphylaxis and allergic rhinitis. The route of administration and possibility of severe adverse reactions to subcutaneous immunotherapy make sublingual immunotherapy an appealing alternative, especially for the paediatric patient. This form of immunotherapy has been increasingly used in Europe, and over the past decade several meta analyses have attempted to provide evidence for its efficacy in the treatment of seasonal and perennial allergic rhinitis and in asthma, both in the adult and paediatric population. Several trials have also shown a potential immunomodulatory effect of sublingual immunotherapy, with evidence of a reduction in the progression from allergic rhinitis to asthma and reduced new aeroallergen sensitisation. This review will give an overview of the current evidence for sublingual immunotherapy in the paediatric population.

New visions in specific immunotherapy in children: an iPAC summary and future trends

Specific immunotherapy is indicated for confirmed immunoglobulin E-mediated airway diseases using standardized allergen products with documented clinical efficacy and safety. For decades the subcutaneous route of administration (SCIT) has been the gold standard. Recently, the sublingual immunotherapy (SLIT) has also been investigated in children. SCIT, especially with grass and birch pollens but also house dust mites, is an effective treatment in children with allergic rhinitis and asthma when a significant part of their symptoms are caused by these allergens. A long-term effect up to 12 yr after discontinuation of SCIT with timothy allergen has been shown. Efficacy and safety of SLIT in pollen allergic rhinoconjunctivitis have been demonstrated in adults. The evidence in children is a little less convincing, and more data is needed. The clinical relevance, long-term results and the size of the effect, as well as the dose, the treatment regimen and duration has not been sufficiently elaborated. It is demonstrated that SCIT has the potential for preventing the development of asthma in children with allergic rhinoconjunctivitis. Also one randomized study indicates a preventive effect of SLIT in children on the development of asthma. At present, there are no studies who clearly demonstrates either a long-term effect or a preventive effect on the development of asthma of SLIT in children. The areas with lack of evidence should be addressed in well performed prospective, randomized long-term studies both with SCIT and SLIT. This review was initiated by iPAC (international Pediatric Allergy and Asthma Consortium) and aims to review current knowledge related to specific immunotherapy in childhood, and to identify needs for future research in this field.

Analysis of safety, risk factors and pretreatment methods during rush hymenoptera venom immunotherapy

BACKGROUND

The safety profile of venom immunotherapy is a relevant issue. We evaluated the frequency of severe adverse events (SAE), associated risk factors, retrospective comparison of pretreatment protocols including solely H1 receptor blockers and a combination of H1 and H2 receptor blockers during rush Hymenoptera venom immunotherapy.

METHODS

The study group comprised 118 patients. The treatment was initiated according to a 5-day rush protocol with the use of standardized venom allergens of either wasp or honeybee.

RESULTS

During the rush induction, side effects occurred in 18 patients (15.2%), whereas SAE were present in 7 patients (5.9%). Twelve out of 18 (66.6%) developed anaphylactic reactions on the fourth day of the rush protocol, with the majority of cases at a dose of 40 or 60 microg of the venom extract (p = 0.001). The frequency of SAE was also significantly higher on the fourth day than thereafter (p = 0.0001) as well as in patients allergic to bee venom (p = 0.049). All systemic side effects were more frequent in women (p = 0.0065). However, this relation was not true when SAE were consider (p = 0.11). A higher percentage of SAE was observed in the subjects pretreated with both H1 and H2 receptor antagonists than in those pretreated with H1 blocker only (8.8 vs. 4.1%); however, the difference was not significant.

CONCLUSIONS

Considerable severity of allergic adverse events requires particular attention to patients allergic to bee venom and during rush phase, especially when rapidly increasing doses are administered. Pretreatment with H2 blockers is debatable and warrants further investigation.

Advances in hymenoptera venom immunotherapy

PURPOSE OF REVIEW

Venom immunotherapy is highly effective treatment, capable of improving health-related quality of life. This overview examines advances in various aspects of this treatment.

RECENT FINDINGS

New findings on the immunological mechanisms of the early and long-term efficacy of venom immunotherapy have been made. The decision to start and then to stop venom immunotherapy is best made on an individual case basis and should take into account medical and other factors, like the influence on patient quality of life. Venoms for use in immunotherapy should be selected according to the geographical distribution of each species and partial cross-reactivity between certain types of venom. Rapid protocols seem to be as safe as slower ones, though the major incidence of bee venom immunotherapy side-effects remains. Patients suffering from mast cell diseases seem to be at greater risk for an adverse reaction during treatment, without influencing its efficacy that much until the immunotherapy is actually ongoing. A number of new strategies for venom immunotherapy, mostly based on genetic engineering, have been described, and so far only a few have been used in humans.

SUMMARY

Although there has been progress in the past few years, much remains to be accomplished.

Anti-IgE antibodies for the treatment of IgE-mediated allergic diseases

The pharmacological purposes of the anti-IgE therapy are to neutralize IgE and to inhibit its production to attenuate type I hypersensitivity reactions. The therapy is based on humanized IgG1 antibodies that bind to free IgE and to membrane-bound IgE on B cells, but not to IgE bound by the high-affinity IgE.Fc receptors on basophils and mast cells or by the low-affinity IgE.Fc receptors on B cells. After nearly 20 years since inception, therapeutic anti-IgE antibodies (anti-IgE) have been studied in about 30 Phase II and III clinical trials in many allergy indications, and a lead antibody, omalizumab, has been approved for treating patients (12 years and older) with moderate-to-severe allergic asthma. Anti-IgE has confirmed the roles of IgE in the pathogenesis of asthma and helped define the concept "allergic asthma" in clinical practice. It has been shown to be safe and efficacious in treating pediatric allergic asthma and treating allergic rhinitis and is being investigated for treating peanut allergy, atopic dermatitis, latex allergy, and others. It has potential for use to combine with specific and rush immunotherapy for increased safety and efficacy. Anti-IgE thus appears to provide a prophylactic and therapeutic option for moderate to severe cases of many allergic diseases and conditions in which IgE plays a significant role. This chapter reviews the evolution of the anti-IgE concept and the clinical studies of anti-IgE on various disease indications, and presents a comprehensive analysis on the multiple intricate immunoregulatory pharmacological effects of anti-IgE. Finally, it reviews other approaches that target IgE or IgE-expressing B cells.

Premedication with Montelukast Reduces Local Reactions of Allergen Immunotherapy

BACKGROUND

Local reactions (LRs) are a very frequent side effect of specific immunotherapy with allergens and can impair patients' adherence. Antihistamine pretreatment--originally introduced as a safety measure to reduce anaphylactic side effects--has been the only treatment option for LRs so far, although these swellings usually do not appear immediately but after hours. We were interested whether pretreatment with the leukotriene antagonist montelukast would be better suited for preventing those reactions than pretreatment with the antihistamine desloratadine.

METHODS

Fifteen patients with a history of severe anaphylactic reactions to hymenoptera stings were enrolled into a prospective, double-blind, randomized, placebo-controlled pilot study. We selected a rush immunotherapy protocol consisting of 19 injections of hymenoptera venom administered over 5 consecutive days, where the majority is developing LRs, and counted the number of injections until an LR of >3 cm occurred. The patients were randomized to 3 treatment groups: premedication with placebo, 10 mg montelukast and 5 mg of the antihistamine desloratadine.

RESULTS

Compared with placebo, the occurrence of LRs (>3 cm) was significantly delayed by montelukast (p < 0.01, analysis of variance) but not by desloratadine (p = 0.19). The difference between montelukast and desloratadine was close to significant (p = 0.054). Itching, recorded on a scale from 0 to 5, did not differ between the 3 groups.

CONCLUSION

Montelukast can be useful in the prevention of LRs after specific immunotherapy.

Allergen immunotherapy: where is it now?

The scientific basis and the proof of clinical effectiveness of allergen immunotherapy administered by subcutaneous injection (SCIT) are well established. It is effective treatment for sensitivity to Hymenoptera venom and for allergic rhinitis and allergic asthma. SCIT administered in the proper setting reduces the development of new sensitivities and progression from rhinitis to asthma. Further, the beneficial effects persist long after completion of a course of treatment. Although many people enjoy the benefits of SCIT, extension of its use to the many others who might be candidates for this treatment is limited by its drawbacks of safety concerns and the inconvenience of repeated clinic visits over several years to receive the injections. There are many attempts underway to improve on the safety and convenience while still retaining the benefits of SCIT. These include approaches using current allergen extracts, especially by administering them sublingually. Alternatively, through recombinant technology, extracts are being modified to reduce their allergenicity without reducing their immunogenicity. They are being linked to immunostimulatory DNA sequences that will modify their in vivo processing resulting in an enhanced nonallergic response or they are being incorporated into fusion proteins with inhibitory properties for mast cells and basophils.