Venom immunotherapy in the Hymenoptera-allergic pregnant patient

Environmental Exposures and Risks During Pregnancy

The Women in Wilderness Medicine Research Committee of the Wilderness Medical Society conducted a narrative review to address considerations for pregnant individuals in wilderness environments. There is limited evidence behind many opinion-based recommendations on the safety of various environmental exposures in pregnancy. The authors reviewed the literature for the best available evidence, including observational studies, case series, limited controlled trials, and extrapolation from physiological data, as well as evaluating expert consensus statements. The benefits of exposure to natural environments include better pregnancy outcomes and improved maternal mental and physical health. Risks are similar to nonpregnant individuals with the added risks associated with maternal-fetal physiology in wilderness environments and difficulties of evacuation. This narrative review discusses pregnancy-specific concerns in extreme environments, including high altitude, hypothermia, hyperthermia, lightning strikes, envenomations, and common outdoor exposures.

Updates and Recent Advances on Venom Immunotherapy

Purpose of Review

Venom immunotherapy has been utilized to treat Hymenoptera venom allergy since the 1920s. Over the last century, significant advances in the fields of immunology and genetics have led to improvements in the practice of venom immunotherapy. This review encompasses recent advances in the use of venom immunotherapy to provide precise, patient-centered care.

Recent Findings

Research about the mechanism of action of venom immunotherapy continues to highlight the modification of both the innate and adaptive immune systems. Molecular techniques have allowed for the identification of specific venom allergens to improve the diagnostic accuracy and safety of venom immunotherapy. Research continues to support the safety of accelerated schedules which can impact the cost, adherence, and quality of life for patients receiving this treatment modality. Finally, significant advances have led to the elucidation of risk factors that place patients at risk for reactions during and after venom immunotherapy. Creation of risk profiles for venom-allergic patients can thus inform the process of immunotherapy in order to provide personalized and precise care.

Summary

Significant progress in the use of venom immunotherapy makes the practice a dynamic and active field for continued research. Future research needs to build on these recent advances to continue to optimize and enhance this life-saving treatment.

Exposure to Allergen-Specific Immunotherapy in Pregnancy and Risk of Congenital Malformations and Other Adverse Pregnancy Outcomes

BACKGROUND

Owing to insufficient data, current guidelines recommend against initiating allergen-specific immunotherapy (AIT) during pregnancy but suggest that well-tolerated ongoing immunotherapy may be continued.

OBJECTIVE

To evaluate the safety of AIT in pregnancy, especially the risk for congenital malformations.

METHODS

This nationwide Swedish cohort study identified pregnancies exposed to AIT, both subcutaneous and sublingual, through the Swedish Medical Birth register and the Prescribed Drug Register between 2005 and 2014. Information on congenital malformations in offspring was retrieved from the National Patient Register. Using the personal identity number, we linked data between registers. Using logistic regression, we calculated odds ratios (ORs) with 95% CIs for congenital malformations and other adverse pregnancy outcomes after adjusting for potential confounders.

RESULTS

From 2005 to 2014, we identified 924,790 singleton pregnancies. Among these, 743 pregnancies had been exposed to AIT 3 months before conception up until gestational week 22. Allergen-specific immunotherapy in pregnancy was not linked to congenital malformations (OR = 0.90; 95% CI, 0.63-1.27) or other adverse pregnancy outcomes (preterm birth: OR = 0.98; 95% CI, 0.71-1.35; stillbirth: OR = 0.79; 95% CI, 0.26-2.47; or cesarean delivery: OR = 0.91; 95% CI, 0.76-1.09). Stratification by route of immunotherapy, subcutaneous or sublingual, resulted in similar ORs. Restricting the pregnancy cohort to women with asthma or pulmonary disease, nulliparous women, births in 2012 to 2014, or Swedish-born women yielded similar results.

CONCLUSIONS

This nationwide study found no evidence of congenital malformations or other adverse pregnancy outcomes in women treated with AIT in pregnancy.

[Allergen immunotherapy: FAQs and facts]

Die Allergenimmuntherapie (AIT) ist – neben der oft nicht suffizient durchzuführenden Allergenmeidung – die einzige kausale Therapie Ig(Immunglobulin)E-vermittelter Allergien gegen Aeroallergene und Hymenopterengifte. Sie kann je nach Allergen als subkutane Injektion (subkutane Immuntherapie [SCIT]) oder über eine sublinguale Applikation (sublinguale Immuntherapie [SLIT]) erfolgen, kürzlich wurde zudem auch ein Verfahren zur oralen Immuntherapie zur Behandlung der Nahrungsmittelallergie zugelassen. Neben der korrekten Indikationsstellung (positive Anamnese und Diagnostik einer IgE-vermittelten Allergie, Allergenkarenz nicht ausreichend möglich) sind mögliche Kontraindikationen und Risikofaktoren zu beachten. Zudem kann es unter einer AIT zu – potenziell auch lebensgefährlichen – Nebenwirkungen kommen. Im Folgenden sollen häufig gestellte Fragen und Fakten zur Entscheidungsfindung für die Durchführung und zum Risikomanagement der AIT beleuchtet und unter Berücksichtigung der aktuellen Datenlage diskutiert werden.

Pregnancy and Hymenoptera venom allergy

PURPOSE OF REVIEW

To evaluate the indication to perform venom immunotherapy (VIT) during pregnancy considering the risks of adverse events during the build-up phase or the maintenance phase and analyzing specific articles and guidelines on VIT.

RECENT FINDINGS

Only few studies treat this argument and literature only counts one recent study on the topic, whereas recent guidelines state the behavior to keep in pregnancy.

SUMMARY

Hymenoptera venom allergy (HVA) affects about 7.5% of the European population. VIT is the only effective disease-modifying treatment for patients presenting anaphylactic reactions. VIT counts several mechanisms of action, with the increase of IgG1 and IgG4 and a cytokine impairment inducing a Th2-Th1 shift. Pregnancy is a health condition where a Th2 profile is required to prevent fetal rejection, so VIT could be a problem for the fetus when started during pregnancy.

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.

Venom immunotherapy and pregnancy

Introductions

The efficiency of venom immunotherapy (VIT) has been well documented by many studies. However, the most important for VIT is safety, particularly for a pregnant woman and a fetus.

Aim

To establish the influence of continuation of VIT on pregnant women and offspring.

Material and methods

The 6 women became pregnant during a specific immunotherapy. We retrospectively analyzed the influence of the immunotherapy on any complications for the pregnant women and their infants.

Results

Of the 6 patients who participated in this study, four had hyperemesis gravidarum, nausea, and heartburn, and two of them had gestational diabetes mellitus symptoms, typical of pregnancy. The observation indicated that VIT was safe for the pregnant women and their offspring.

Conclusions

The VIT is an appropriate therapeutic method for most patients with severe anaphylactic reactions after a hymenoptera sting. The observation indicated that VIT is safe for pregnant women and for their infants.

Asthma Outcomes and Management During Pregnancy

Asthma during pregnancy poses a common, increasingly prevalent threat to the health of women and their children. The present article reviews recent insights gained from the epidemiology of asthma during pregnancy, demonstrating the many short- and long-term risks to mother and fetus incurred by poorly controlled maternal asthma. We further discuss emerging evidence that active management of asthma during pregnancy can positively influence and perhaps completely mitigate these poor outcomes. Recent high-quality trials examining best methods for asthma treatment are reviewed and synthesized to offer an evidence-based pathway for comprehensive treatment of asthma in the outpatient setting. Safe and effective medications, as well as nonpharmacologic interventions, for asthma during pregnancy are discussed, and treatment options for related conditions of pregnancy, including depression, rhinitis, and gastroesophageal reflux, are presented. Throughout, we emphasize that an effective treatment strategy relies on a detailed patient evaluation, patient education, objective measurement of asthma control, and frequent and supportive follow-up. The cardiovascular and respiratory physiology of pregnancy is reviewed, as well as its implications for the management of patients with asthma, including patients requiring intubation and mechanical ventilation. For the situation when outpatient asthma management has failed, an approach to the critically ill pregnant patient with status asthmaticus is detailed. Multidisciplinary teams that include pulmonary specialists, obstetricians, primary care providers, nurses, pharmacists, and asthma educators improve the care of pregnant women with asthma.

IgE cross-reactivity of phospholipase A2 and hyaluronidase of Apis dorsata (Giant Asian Honeybee) and Apis mellifera (Western Honeybee) venom: Possible use of A. mellifera venom for diagnosis of patients allergic to A. dorsata venom

Diagnostic and therapeutic reagents are unavailable for anaphylaxis arising from stings by Apis dorsata. Venom profiles and cross-reactivity of A. dorsata and Apis mellifera were compared, to ascertain whether venom of A. mellifera can be used for diagnosis in A. dorsata allergy. Both venom profiles were similar by High Performance Liquid Chromatography and SDS-PAGE. Sera of 29 of 30 (96.7%) patients with anaphylaxis to A. dorsata stings had IgE to the phospholipase-2 (PLA₂) doublet (15 and 16 kDa) of A. dorsata venom by immunoblot, compared to 26 of 30 (86.7%) with the PLA₂ of A. mellifera and a purified preparation of PLA₂. Twelve patients (40%) with severe anaphylaxis had IgE reactivity to a 39 kDa protein band of venom of both species, a third band, identified in immunoblot as hyaluronidase. The cross-reactivity of PLA₂ and hyaluronidase of A. dorsata and A. mellifera were further confirmed by immunoblot inhibition results. Twenty five of 30 (83.3%) of our patients had positive venom specific IgE (>0.35 KU_A/L) reactivity to Phadia ImmunoCAPs of A. mellifera venom. The observed IgE cross reactivity suggests the possibility of using A. mellifera venom as a diagnostic test for A. dorsata venom allergy.

Allergen immunotherapy in pregnancy

Background

Allergic diseases such as asthma and allergic rhinitis constitute a significant burden of disease among women of childbearing age and those who are pregnant. Adequately managing these conditions is paramount in reducing negative fetal outcomes as well as maternal complications during pregnancy. However, the potential for harm to both the mother and fetus demands carefully balancing efficacy and safety of treatment. Allergen immunotherapy (AIT) has emerged as a relatively safe and efficacious mode of therapy in both children and adults. AIT has also been considered for use during pregnancy.

Methods

A review of the literature was conducted for data regarding the safety of initiation and continuation of AIT during pregnancy as well as the effect of AIT on the development of atopy in offspring. MEDLINE and the Cochrane Library were searched for clinical trials, randomized control trials, observational studies and journal articles in English using the terms "Pregnancy" and "Immunotherapy" from 1900 to present. This yielded 4 studies (totaling 422 pregnancies receiving AIT) investigating the continuation of AIT in pregnancy, 2 (totaling 31 pregnancies receiving AIT) evaluating AIT initiation during pregnancy and 5 observing the effect of AIT on atopy in offspring.

Results

No significant difference was found in the incidence of prematurity, hypertension (HTN)/proteinuria, congenital malformations or perinatal deaths between the women continued on AIT (both subcutaneous (SC) IT and sublingual (SL) IT to inhalant allergens as well as venom IT) during pregnancy and controls. Similarly, there was no significant difference in maternal or fetal complications between pregnant women initiated on AIT and controls. Among the few pregnant women (10/453 pregnancies) who experienced generalized reactions while receiving AIT, none were found to have fetal complications. Neither SCIT nor SLIT during pregnancy altered the risk of developing atopic disease in offspring.

Conclusions

Based on these data, the continuation of AIT during pregnancy appears safe. Furthermore, the few data available suggest that the initiation of AIT during pregnancy might also be safe, however, more data is required for a definitive conclusion. Lastly, available studies do not show a convincing reduction in the development of atopy in offspring from the administration of AIT during pregnancy.

Clinical contraindications to allergen immunotherapy: an EAACI position paper

Clinical indications for allergen immunotherapy (AIT) in respiratory and Hymenoptera venom allergy are well established; however, clinical contraindications to AIT are not always well documented. There are some discrepancies when classifying clinical contraindications for different forms of AIT as 'absolute' or 'relative'. EAACI Task Force on 'Contraindications to AIT' was created to evaluate and review current literature on clinical contraindications, and to update recommendations for both sublingual and subcutaneous AIT for respiratory and venom immunotherapy. An extensive review of the literature was performed on the use of AIT in asthma, autoimmune disorders, malignant neoplasias, cardiovascular diseases, acquired immunodeficiencies and other chronic diseases (including mental disorders), in patients treated with β-blockers, ACE inhibitors or monoamine oxidase inhibitors, in children under 5 years of age, during pregnancy and in patients with poor compliance. Each topic was addressed by the following three questions: (1) Are there any negative effects of AIT on this concomitant condition/disease? (2) Are more frequent or more severe AIT-related side-effects expected? and (3) Is AIT expected to be less efficacious? The evidence, for the evaluation of these clinical conditions as contraindications, was limited, and most of the conclusions were based on case reports. Based on an extended literature research, recommendations for each medical condition assessed are provided. The final decision on the administration of AIT should be based on individual evaluation of any medical condition and a risk/benefit assessment for each patient.

Venom immunotherapy: clinical efficacy, safety and contraindications

Venom-specific immunotherapy (VIT) is considered for the treatment of patients with IgE-mediated systemic allergic reactions (SARs) after developing a Hymenoptera venom allergy. Tolerance is achieved in a majority of patients after only a few days or even hours of rush immunotherapy. After VIT discontinuation, the allergy returns in up to 15% of patients. During VIT, the majority of patients have local reactions at the site of venom injections. SARs to VIT are much more frequent in honeybee-treated patients than in wasp-treated patients. Increased baseline serum tryptase and increased allergen-specific sensitivity of basophils are other factors that might be associated with systemic reactions (SRs) during VIT. Severe SRs occur mainly during the build-up phase but can also occur in the maintenance phase of the VIT, even in patients with a well-tolerated dose-increase phase. Pre-treatment with humanized anti-IgE antibodies (omalizumab) is effective in patients with repeated SARs; however, this use of omalizumab is off-label. In highly exposed patients with a history of very severe reactions, there are virtually no absolute contraindications for VIT.

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.

Management of insect sting hypersensitivity: an update

Reactions to Hymenoptera insect stings are common. While most are self-limited, some induce systemic allergic reactions or anaphylaxis. Prompt recognition, diagnosis, and treatment of these reactions are important for improving quality-of-life and reducing the risk of future sting reactions. This review summarizes the current recommendations to diagnose and treat Hymenoptera sting induced allergic reactions and highlights considerations for various populations throughout the world.

Insect stings: clinical features and management

BACKGROUND

In human beings, local and systemic reactions can be caused both by blood-sucking insects and by venomous insect stings. In Central Europe, the insects that most commonly cause such reactions are honeybees, certain social wasps, mosquitoes, and flies.

METHODS

This article is based on a selective literature review, including guidelines from Germany and abroad.

RESULTS

Insect venom induces a toxic reaction at the site of the sting. Large local reactions are due to allergy and occur in up to 25% of the population; as many as 3.5% develop IgE-mediated, potentially life-threatening anaphylaxis, of which about 20 people die in Germany each year. Mastocytosis is found in 3% to 5% of patients with sting anaphylaxis, rendering these patients prone to very severe reactions. Blood-sucking by hematophagous insects can elicit a local allergic reaction, presenting as a wheal or papule, in at least 75% of the population. Large local reactions may ensue, but other diseases are rare. The acute symptoms of an insect sting are treated symptomatically. Patients who have had a systemic reaction or a large local reaction due to insect allergy must take permanent measures to avoid further allergen contact, and to make sure they can treat themselves adequately if stung again. Most patients with systemic anaphylactic reactions to bee or wasp stings need specific immunotherapy.

CONCLUSION

Insect stings can cause severe disease. Anaphylaxis due to bee or wasp stings is not a rare event; specific immunotherapy protects susceptible persons from further, potentially life-threatening reactions.

Immunotherapy throughout the decades: from Noon to now

OBJECTIVE

To review major milestones in the development of subcutaneous allergen immunotherapy in 20-year segments.

DATA SOURCES

Review of the literature available in textbooks and journals.

STUDY SELECTION

Articles and books addressing major achievements in the development of subcutaneous allergy immunotherapy were selected for inclusion in this review.

RESULTS

Immunotherapy administration has improved the lives of possibly millions of patients with hay fever. Asthmatic symptoms have been relieved if not ablated in millions as well. Insect venom hypersensitivity became treatable and highly effective. In the beginning years of immunotherapy, it was clear that immunotherapy worked; in the later years, the mechanisms for this efficacy were discovered. In this case, the therapy preceded its validation. Methods, materials, and safety have vastly improved. Postulated mechanisms explain much but not everything.

CONCLUSIONS

There is still research to be accomplished, improvements to be made, and, of course, patients to be made well.

Insect sting allergy

Insect sting allergy has served as an excellent model for the allergic process over the past century. In particular, during the last 30 years, a new form of diagnostic testing and treatment with vo m has been one of the great suc-cess stories in the entire field of allergy. VIT reduces the risk of recurrent life-threatening reactions from about 60% to less than 2%. Progress and further questions continue with a search for a definitive diagnostic test that more accurately predicts which patients are at risk for future reactions, and defines which patients can stop VIT and which ones need to continue treatment.

Prevention and treatment of hymenoptera venom allergy: guidelines for clinical practice

Based on the knowledge of the living conditions and habitat of social Aculeatae a series of recommendations have been formulated which can potentially greatly minimize the risk of field re-sting. After a systemic sting reaction, patients should be referred to an allergy specialist for evaluation of their allergy, and if necessary venom immunotherapy (VIT). An emergency medical kit should be supplied, its use clearly demonstrated and repeatedly practised until perfected. This should be done under the supervision of a doctor or a trained nurse. Epinephrine by intramuscular injection is regarded as the treatment of choice for acute anaphylaxis. H1-antihistamines alone or in combination with corticosteroids may be effective in mild to moderate reactions confined to the skin and may support the value of treatment with epinephrine in full-blown anaphylaxis. Up to 75% of the patients with a history of systemic anaphylactic sting reaction develop systemic symptoms once again when re-stung. Venom immunotherapy is a highly effective treatment for individuals with a history of systemic reaction and who have specific IgE to venom allergens. The efficacy of VIT in yellow jacket venom allergic patients has been demonstrated also by assessing health-related quality of life. If both skin tests and serum venom specific IgE turn negative, VIT may be stopped after 3 years. After VIT lasting 3-5 years, most patients with mild to moderate anaphylactic symptoms remain protected following discontinuation of VIT even with positive skin tests. Longer term or lifelong treatment should be considered in high-risk patients. Because of the small but relevant risk of re-sting reactions, in these patients, emergency kits, including epinephrine auto-injectors, should be discussed with every patient when stopping VIT.

First successful case of in vitro fertilization-embryo transfer with venom immunotherapy for hymenoptera sting allergy

Background

To describe immune and endocrine responses in severe hymenoptera hypersensitivity requiring venom immunotherapy (VIT) during in vitro fertilization (IVF).

Case presentation

A 39-year old patient was referred for history of multiple miscarriage and a history of insect sting allergy. Four years earlier, she began subcutaneous injection of 100 mcg mixed vespid hymenoptera venom/venom protein every 5–6 weeks. The patient had one livebirth and three first trimester miscarriages. Allergy treatment was maintained for all pregnancies ending in miscarriage, although allergy therapy was discontinued for the pregnancy that resulted in delivery. At our institution ovulation induction incorporated venom immunotherapy (VIT) during IVF, with a reduced VIT dose when pregnancy was first identified. Serum IgE was monitored with estradiol during ovulation induction and early pregnancy. Response to controlled ovarian hyperstimulation was favorable while VIT was continued, with retrieval of 12 oocytes. Serum RAST (yellow jacket) IgE levels fluctuated in a nonlinear fashion (range 36–54%) during gonadotropin therapy and declined after hCG administration. A healthy female infant was delivered at 35 weeks gestation. The patient experienced no untoward effects from any medications during therapy.

Conclusion

Our case confirms the safety of VIT in pregnancy, and demonstrates RAST IgE can remain <60% during IVF. With proper monitoring, VIT during IVF can be safe and appropriate for selected patients and does not appear to adversely affect blastocyst implantation, early embryo development or perinatal outcome. Further studies will be needed to develop VIT guidelines specifically applicable to IVF.

Pregnancy and immunology: selected aspects

LEARNING OBJECTIVES

This article reviews current concepts of the immunology of pregnancy and of the diagnosis and management of certain allergic conditions in the pregnant woman: asthma, rhinitis, immunotherapy, and hereditary angioedema (HAE).

DATA SOURCES

Current texts, reviews, and individual studies were picked from the National Library of Medicine database.

RESULTS AND CONCLUSIONS

Knowledge concerning the immunologic paradox of pregnancy continues to evolve. Although the answer is not definitive, attention is being paid to the role of a Th-2 shift in the pregnant uterus. Extensive studies, both epidemiologic and therapeutic, are clarifying the influence of pregnancy on asthma and rhinitis (and vice versa) and the best methods for treatment of these conditions in the pregnant woman. A brief guideline to the handling of hereditary angioedema in pregnancy is presented.

Maintenance venom immunotherapy

PURPOSE OF REVIEW

Venom immunotherapy has proven to be a very effective method for the prevention of future re-sting reactions. However, initiation of the venom injection program is just the beginning. This review looks at recent papers which shed light on other issues that arise during maintenance venom immunotherapy.

RECENT FINDINGS

Prophylactic antihistamines taken before venom injections reduce the frequency of reactions and one report suggests that they may improve efficacy. The schedule of venom injections usually does not have to be adjusted for patients who develop local reactions; a very large reaction may be the exception. Patients who react to stings should have their maintenance doses increased. Most patients are able to extend the interval between injections to 8 weeks in the third year of treatment. Two groups have proposed a maintenance interval of 12 weeks for routine use.

SUMMARY

Our understanding of insect sting sensitivity continues to improve, leading to better outcomes for allergic patients.

Specific IgE antibodies to vespids in the course of immunotherapy with Vespula germanica administered to patients sensitized to Polistes dominulus

Sera from a group of 12 patients with anaphylactic reactions to vespids were studied. Field observations and RAST values suggested that the offending insect was Polistes dominulus (PD). Specific IgE antibodies to PD appeared in all cases and to Vespula germanica (VG) in nine. Absorption studies in these basal sera showed that IgE antibodies to VG were due to cross-reactivity with PD. The RAST value to both venoms was higher after immunotherapy (IT) in six cases. IgE antibodies increased to determinants common to both vespids, and in 41% of the cases to specific epitopes of VG venom allergens not initially detected in the basal sera. In one case antibodies increased only to VG without a corresponding rise to PD. These results indicate that if the correct venom to which the individuals are sensitized is not administered IgE antibodies may appear which were not initially detected in the patients' sera. The levels of these antibodies declined during the course of IT.

Stinging insect allergy

Insect sting anaphylaxis is a relatively common problem estimated to affect at least 0.4% of the population and is responsible for at least 40 deaths per year in the United States. The allergic reactions are mediated by IgE antibodies directed at constituents in honeybee, yellow jacket, hornet, and wasp venoms. In addition, increasing numbers of reactions occur from fire ant stings, non-winged Hymenoptera present in the Southeastern United States. The anaphylactic symptoms are typical of those occurring from any cause. Most reactions in children are mild, frequently involving dermal manifestations (hives, edema) only. The more severe reactions, such as shock and loss of consciousness, can occur at any age but are relatively more common in adults. Following sting anaphylaxis, approximately 50% of unselected patients will continue to have allergic reactions to subsequent stings. The natural history of the disease process is influenced by the severity of the anaphylactic symptoms. Children with dermal reactions only have a benign course and are unlikely to have recurrent reactions. Patients with more severe reactions are at risk for repeat anaphylaxis. Patients with a history of insect sting anaphylaxis and positive venom skin tests should have epinephrine available and are candidates for subsequent venom immunotherapy, which provides almost 100% protection against subsequent re-sting reactions. Recommendations for the duration of immunotherapy are evolving. Venom therapy can be stopped if skin test reactions become negative. For most patients, 3 years of therapy appears adequate, despite persistence of positive venom skin tests.