Allergic reactions to vespids: comparison of sensitivities of two species in a Mediterranean area

We have studied a group of twenty-seven patients who suffer allergic reactions to vespids stings. Specific IgE antibodies to venom extracts from Polistes gallicus and Vespula germanica were measured by RAST, and the crossreactivity between the two venoms was compared using the RAST inhibition technique. We concluded that, in southern Spain, sensitization to P. gallicus was more prevalent than that to V. germanica , with 44% of the subjects in this study reacting to P. gallicus compared with 33% to V. germanica. However, there was a considerable degree of crossreactivity between the two species. It is evident that Polistes is an important species in this area; however, both in Spain and other Mediterranean countries, V. germanica venom is used almost exclusively for diagnosis and immunotherapy.     

Epidemiological study of the prevalence of allergic reactions to Hymenoptera in a rural population in the Mediterranean area

BACKGROUND: Systemic allergic reactions to Hymenoptera venom occur in a percentage that varies from 0.4 to 3.3%. Epidemiological studies indicate that from 15 to 25% of the general population can be sensitized to different Hymenoptera venom as well as the fact that the degree of exposure may be related to the prevalence found in those studies. OBJECTIVE: The objective of this study was to evaluate the prevalence of insect sting allergy and the venom sensitization in a rural population to three Hymenoptera previously found in the area: Polistes dominulus (Pd), Vespula germanica (Vg) and honey bee (Hb). METHODS: A rural community located in the south-east of Spain, close to the Mediterranean Sea, was selected since the stinging Hymenoptera having been previously identified. A random sample of 310 subjects from the village census was studied. A questionnaire and a serum sample were obtained from every patient. The evaluation was conducted by a family doctor, who focused on the reactions to Hymenoptera sting, age, sex, occupation, atopia, previous Hymenoptera sting, stinging insect, interval to last sting and average stings per year. RAST to Hymenoptera venoms were also determined. RESULTS: The prevalence of systemic reactions was 2.3% (57.6% of them had a positive RAST). Large local reactions were found in 26.4% (only 28.5% of them had a positive RAST). Asymptomatic sensitization (positive RAST) was observed in 16.4% of subjects without reaction. Only a weak correlation between subjects with less than 3 years' interval to last sting exposure and positive RAST results was noted, whether they presented with a clinical reaction or not (P < 0.05). CONCLUSIONS: The prevalence of systemic sting reactions in our rural community is higher than other general populations in the same Mediterranean area, and similar to other rural populations studied. The degree of exposure influences not only the prevalence found but also the detection of specific serum IgE.     

Comparison of the allergenicity and antigenicity of Polistes venom and other vespid venoms

The crossantigenicity of Polistes venom with other vespid venoms was examined with rabbit and human antisera. Venom preparations from various Polistes species were obtained by electrical stimulation of individual insects and venom sac dissection. Rabbit antibodies were raised to the venom (P. apachus) and venom sac extract (P. exclamans). Human antisera were obtained from patients allergic to Polistes and other vespid venoms. The venom appeared to be more potent than the venom sac preparations in reactions with rabbit IgG and human IgE antibodies. Among the Polistes species, P. exclamans, P. instablis, and P. apachus venoms showed several lines of precipitation with rabbit antisera, and P. annularis and P. fuscatus venoms only one line, suggesting quantitative or qualitative antigenic differences. In RAST analysis, most sera reacted equally to all Polistes species but occasional exceptions were noted, again suggesting differences in venom allergens. P. exclamans-coupled discs gave the most consistent results. In gel diffusion experiments, there was no crossreactivity between Polistes and yellow jacket venoms and only limited crossreactivity between Polistes and hornet venoms. Patients sensitive to Polistes venom showed varying degrees of reactivity to yellow jacket and hornet venoms in RAST analysis. Patients sensitive to other vespid venoms also showed varying degrees os sensitivity to Polistes venom. Polistes venom appears to contain a genus-unique antigen (allergen). In addition, there appear to be some crossreacting antigens in Polistes and other vespid venoms but to a much lesser degree than found previously in the analysis of the relationship of yellow jacket and hornet venoms.     

Hymenoptera venom allergy: analysis of double positivity to honey bee and Vespula venom by estimation of IgE antibodies to species-specific major allergens Api m1 and Ves v5

Background:  In patients with hymenoptera venom allergy diagnostic tests are often positive with honey bee and Vespula venom causing problems in selection of venoms for immunotherapy.
Methods:  100 patients each with allergic reactions to Vespula or honey bee stings and positive i.e. skin tests to the respective venom, were analysed for serum IgE to bee venom, Vespula venom and crossreacting carbohydrate determinants (CCDs) by UNICAP (CAP) and ADVIA Centaur (ADVIA). IgE-antibodies to species specific recombinant major allergens (SSMA) Api m1 for bee venom and Ves v5 for Vespula venom, were determined by ADVIA. 30 history and skin test negative patients served as controls.
Results:  By CAP sensitivity was 1.0 for bee and 0.91 for Vespula venom, by ADVIA 0.99 for bee and 0.91 for Vespula venom. None of the controls were positive with either test. Double positivity was observed in 59% of allergic patients by CAP, in 32% by ADVIA. slgE to Api m1 was detected in 97% of bee and 17% of Vespula venom allergic patients, slgE to Ves v5 in 87% of Vespula and 17% of bee venom allergic patients. slgE to CCDs were present in 37% of all allergic patients and in 56% of those with double positivity and were more frequent in bee than in Vespula venom allergic patients.
Conclusions:  Double positivity of IgE to bee and Vespula venom is often caused by crossreactions, especially to CCDs. IgE to both Api m1 and Ves v5 indicates true double sensitization and immunotherapy with both venoms.     

Double sensitization to honeybee and wasp venom: immunotherapy with one or with both venoms? Value of FEIA inhibition for the identification of the cross-reacting ige antibodies in double-sensitized patients to honeybee and wasp venom

BACKGROUND: Double sensitization to honeybee (Apis mellifera) and wasp venom (Vespula spp.) as determined by skin test and measurement of specific IgE is common in hymenoptera sting allergy. Double-sensitized patients have either distinct antibodies for each venom or cross-reacting antibodies that recognize similar or identical epitopes in both venoms. Unfortunately, patients often fail to identify the stinging insect which makes it difficult to distinguish cross-reactors from non cross-reactors. However, for economic reasons as well as for the benefit of the patients, it would be useful to identify complete cross-reactors. METHODS: In this study we investigated 24 double-sensitized patients who were candidates for venom immunotherapy. Homologous and heterologous FEIA inhibition was carried out with honeybee (Apis mellifera) and wasp venom (Vespula spp.) preparations from two different providers. The inhibitor concentrations were ranging from 0 to 100 microg protein/ml. RESULTS: Sera of 4 patients were completely cross-reacting for one venom (3 honeybee, 1 wasp), 8 patients were partially cross-reacting and 10 patients were not cross-reacting. Two patients were excluded from the study due to insufficient homologous inhibition. Data from specific IgE measurements, skin test, and clinical history were not useful for the identification of cross-reacting patients. CONCLUSION: FEIA inhibition is easy to perform and useful for the identification of patients with complete cross-reactivity. In these patients immunotherapy might be restricted to one venom which is beneficial for the patient and cost-effective.     

European Polistes venom allergy

The American Polistes species venom mixture--that of P. annularis, P. fuscatus, P. metricus and P. exclamans--was the only commercially available mixture for diagnosis and therapy until 1996. However, these species of Polistes are not present in Europe, where P. dominulus and P. gallicus and to a lesser extent P. nimphus are widespread. The aim of this study was to assess the allergenic differences among the commercial American mix, P. dominulus and P. gallicus venom in European patients and therefore to verify if this mixture is suitable for diagnosis in these patients. We carried out skin tests, radioallergosorbent tests (RAST) and RAST inhibition in Italian patients with adverse reactions to Polistes stings. RAST inhibition results demonstrated that cross-reactivity between the American and European species is only partial and that P. dominulus and P. gallicus venoms have exclusive allergens. Skin tests and direct RAST confirmed these results and also showed that European Polistes venom is more suitable than the American mix in Italian patients. Moreover, we found a high rate of cross-reactivity between P. dominulus and P. gallicus. To conclude, P. dominulus and/or P. gallicus venoms are necessary for diagnosis and therefore in the therapy of European patients.     

Polistes wasp hypersensitivity: diagnosis by venom-induced release of histamine in vitro.

Polistes wasps cause a majority of Hymenoptera-induced anaphylactic reactions in Texas. Using the in vitro release of histamine from basophils of patients allergic to Polistes stings, we have studied the cross-reactivity of venoms from three species of Polistes wasps as well as the cross-reactivity among Polistes, honeybee, and Vespula maculifrons (yellow jacket) venoms. Venom collected by an extrusion technique from Pollistes exclamans, Pollistes apachus, and Pollistes carolina caused release of histamine in seven Polistes-sensitive individuals. The dose-response curves from all three Polistes species were quite similar, suggesting extensive cross-reactivity among these species. None of these patients showed significant release of histamine from leukocytes exposed to yellow jacket or honeybee venom. We conclude that a source of Polistes venom is available for further study and possibly for therapy. It appears that any of three local common species of Polistes wasps could be used. Our studies confirmed earlier reports that Hymenoptera sensitivity if often genus-specific.     

Diagnosis of Polistes wasp hypersensitivity

Patients referred from the Houston, Texas, metropolitan area were evaluated for allergic reactions to insect stings. Forty-eight persons reported at least one systemic reaction caused by a Polistes paper-nest wasp sting. Honey bees, imported fire ants, and other types of Hymenoptera were identified in that order by 19 other subjects with systemic allergic reactions. Life-threatening airway obstruction and/or hypotension were noted by most of our patients. Wasp venom skin testing was positive in 65% of subjects reporting sensitivity to this insect. Skin testing was correlated quantitatively with basophil histamine release, and qualitatively with RAST assays using Polistes wasp venom. Venoms from common species of Polistes were highly cross-reactive as shown by RAST and basophil histamine release. Patients having a positive history and laboratory response (by skin testing, histamine release, or RAST) to Polistes wasp venom also were positive to bee venom about 20% of the time and to another vespid (hornet or yellow jacket) over 50% of the time.     

Allergens in Hymenoptera venom XIV: IgE binding activities of venom proteins from three species of vespids

RAST disks were prepared with purified proteins from the venoms of Vespula squamosa, Dolichovespula maculata, and Polistes exclamans and tested against a panel of sera obtained from patients allergic to each of the venoms. By the use of several criteria, IgE binding was strongest to antigen 5 of V. squamosa and phospholipase of P. exclamans. Hyaluronidase from Polistes had little IgE binding activity. All five proteins tested from D. maculata bound IgE antibodies strongly. Linear correlation analysis suggested that all of the proteins were distinct allergens in each of the venoms. A variety of patterns of response were observed for individual sera with each of the venoms.     

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's era. The levels of these antibodies declined during the course of IT.     

Safety of Hymenoptera venom rush immunotherapy

We studied 97 consecutive patients who had received Hymenoptera venom rush immunotherapy in our department. There were 53 males and 44 females, whose mean age was 46 years (8–74 years). Most study patients had experienced severe anaphylaxis induced by a Hymenoptera sting: the reaction was Müller stage IV in 48 patients. Skin tests were positive for Vespula venom in 85 cases, Polistes venom in 23, and bee venom in 23. Radioallergosorbent test values exceeded 0.70 kIU/1 in 60 cases. Immunotherapy was performed with Vespula venom alone in 73 cases, bee venom alone in five cases, and both Vespula and bee venom in 19 cases. A cutaneous reaction was seen at the injection site in most patients. Four patients also had skin manifestations in areas remote from the injection site. Blood pressure elevation was seen in 11 patients, moderate hypotension in two, rhinitis in one, asthenia or headache in seven, visual disorders and vertigo in two, and transient dyspnea in two. Our protocol has proved very safe, epinephrine never being required in the 97 reported cases.     

Diagnosis of Hymenoptera venom allergy

The purpose of diagnostic procedure is to classify a sting reaction by history, identify the underlying pathogenetic mechanism, and identify the offending insect. Diagnosis of Hymenoptera venom allergy thus forms the basis for the treatment. In the central and northern Europe vespid (mainly Vespula spp.) and honeybee stings are the most prevalent, whereas in the Mediterranean area stings from Polistes and Vespula are more frequent than honeybee stings; bumblebee stings are rare throughout Europe and more of an occupational hazard. Several major allergens, usually glycoproteins with a molecular weight of 10-50 kDa, have been identified in venoms of bees, vespids. and ants. The sequences and structures of the majority of venom allergens have been determined and several have been expressed in recombinant form. A particular problem in the field of cross-reactivity are specific immunoglobulin E (IgE) antibodies directed against carbohydrate epitopes, which may induce multiple positive test results (skin test, in vitro tests) of still unknown clinical significance. Venom hypersensitivity may be mediated by immunologic mechanisms (IgE-mediated or non-IgE-mediated venom allergy) but also by nonimmunologic mechanisms. Reactions to Hymenoptera stings are classified into normal local reactions, large local reactions, systemic toxic reactions, systemic anaphylactic reactions, and unusual reactions. For most venom-allergic patients an anaphylactic reaction after a sting is very traumatic event, resulting in an altered health-related quality of life. Risk factors influencing the outcome of an anaphylactic reaction include the time interval between stings, the number of stings, the severity of the preceding reaction, age, cardiovascular diseases and drug intake, insect type, elevated serum tryptase, and mastocytosis. Diagnostic tests should be carried out in all patients with a history of a systemic sting reaction to detect sensitization. They are not recommended in subjects with a history of large local reaction or no history of a systemic reaction. Testing comprises skin tests with Hymenoptera venoms and analysis of the serum for Hymenoptera venom-specific IgE. Stepwise skin testing with incremental venom concentrations is recommended. If diagnostic tests are negative they should be repeated several weeks later. Serum tryptase should be analyzed in patients with a history of a severe sting reaction.     

Stinging insect allergy: Detection and clinical significance of venom IgE antibodies

Venom-specific IgE antibodies in 109 sera from patients who had had immediate systemic allergic reactions following insect stings were measured by the radioallergosorbent (RAST) procedure. The majority of sera contained IgE antibodies to either bee, yellow jacket, or hornet venoms. Some sera had positive RAST reactions with 2 or 3 venoms, but others contained single venom-specific IgE antibodies. Of 24 patients who had large local reactions, the sera of 12 contained venom IgE antibodies. The RAST procedure provides an accurate means of documenting IgE-mediated allergic sensitivity to stinging insects.     

A critical evaluation of RAST to venoms of Hymenoptera

RAST to venoms were done on 108 sera. Positive RAST to one or more venoms of Hymenoptera found in 51% (41/80) patients with a generalized reaction to the sting of Hymenoptera and in 7% (2/28) of normal controls were critically evaluated. RAST determinations for each sera were done in duplicate and results averaged. The laboratories were not told which sera belonged to patients with allergy to Hymenoptera and which belonged to controls. In ten patients, one half of the original sera were saved and RAST to venoms were repeated approximately 1 years later. Of our positive RASTs, 49% (20/41) had positives to more than one type of venom. The most frequent positive RAST was to yellow jacket followed by hornet, wasp, and honey bee. A high degree of cross-reactivity occurred between venoms of hornet, wasp, and yellow jacket. The frequency of positive RAST was similar in pre-treatment and post-treatment sera from patients on immunotherapy with whole body extract. Specific IgE (RAST) results to venoms did not correlate with the degree of clinical severity of the sting. However, IgG anti-venom antibodies were not considered. Elevated RAST titres were associated with increased total IgE levels in sera of non-atopic patients. A positive RAST to venoms is frequently found in sera of patients stung within 5 years. RAST scores of 2 to 4 were remarkably reproducible, while scores of 1 were not consistently reproducible. RAST results should be interpreted in conjunction with the clinical history.     

Hymenoptera venom allergy: time course of specific IgE concentrations during the first weeks after a sting.

Detection of IgE antibodies specific to honeybee or Vespula venoms is an important criterium firstly for the diagnosis of sensitization and secondly for the indication for a specific immunotherapy. Some authors recommend to postpone blood analysis after an insect sting for a certain time because circulating IgE antibodies might be consumed by the allergic reaction, which would result in a false-negative test outcome. We investigated IgE concentrations during the first weeks after an insect sting in 31 patients with an unequivocal history of an anaphylactic reaction after a honeybee (n = 13) or Vespula (n = 18) sting. Blood samples for analysis of specific IgE concentrations (CAP system, Pharmacia Diagnostics, Sweden) were collected within 2 weeks and 5+/-2 weeks after the insect sting. 12/13 patients with honeybee venom and 14/18 patients with Vespula venom sensitization had CAP classes 1 or higher within the first 2 weeks. Those 5 patients with CAP class 0 within the first 2 weeks had detectable IgE concentrations a few weeks later. We conclude that testing for specific IgE to hymenoptera venoms is in most cases useful even during the first 2 weeks after the hymenoptera sting. This allows early decisions on further diagnostic procedures and the therapeutic way to choose. Patients with no detectable IgE should, however, be retested after a few weeks.     

Antibody binding to venom carbohydrates is a frequent cause for double positivity to honeybee and yellow jacket venom in patients with stinging-insect allergy

BACKGROUND: Up to 50% of patients with stinging-insect allergy have double-positive RAST results to honeybee and yellow jacket (YJ) venom. True double sensitization and crossreactivity through venom hyaluronidases are considered main reasons for this multiple reactivity. OBJECTIVE: We investigated the role of antibodies against cross-reactive carbohydrate determinants in venom double positivity. METHODS: CAP inhibition experiments were performed with crude oilseed rape (OSR) and timothy grass pollen extracts and a neoglycoprotein construct displaying a MUXF glycan, as present in pineapple-stem bromelain (MUXF-BSA). CAP to OSR was used as a rough measure for carbohydrate-specific IgE in individual sera. RESULTS: CAP results to OSR pollen were positive in 2 of 14 single-positive honeybee venom sera, 2 of 16 single-positive YJ venom sera, and 33 (80.5%) of 41 double-positive sera (P < .00001, chi(2) test). CAP inhibition was performed in 16 selected patients with a CAP class of 3 or higher to both venoms. In 9 of 11 patients with a highly positive CAP result to OSR (CAP score to OSR > CAP score to second venom), pollen extracts, MUXF-BSA, or both were able to completely inhibit IgE binding to one of the venoms, whereas this was not the case in 5 patients with a negative or weakly positive CAP result to OSR (CAP score to OSR < CAP score to second venom). CONCLUSIONS: The data suggest that carbohydrate-specific IgE is a major cause for the double positivity to honeybee and YJ venom seen in patients with Hymenoptera allergy. Because these antibodies may have low clinical relevance, they may severely impede the correct diagnosis of Hymenoptera venom allergy.     

Comparison of vespid venoms collected by electrostimulation and by venom sac extraction

Venoms of three vespid species, yellow jacket, bald-faced hornet, and yellow hornet, obtained by either electrostimulation or venom sac extraction were compared with regard to their enzymatic activity, antigenicity, and allergenicity. Phospholipase A, phospholipase B, and hyaluronidase enzymatic activities were present in all six preparations. The activity of venom sac extracts lay in the range found in different batches of venoms obtained by electrostimulation for each species. Analysis of sera from vespid-sensitive patients in the radioallergosorbent test (RAST) with discs coupled with either venom sac extracts or venoms obtained by electrostimulation showed a good correlation of the results within all three species (r = 0.95). In RAST inhibition the potency of venom sac extracts and venom obtained by electrostimulation was similar for each species. Analysis of rabbit antisera to the six preparations revealed similar patterns in immunoelectrophoresis and identity reactions between the major antigens within each species. Tissue protein contamination was detected in all venom sac extracts but not in venoms obtained by electrostimulation.     

The use and interpretation of RAST to stinging insect venoms.

Quality controlled, standardized RAST systems for five stinging insect venoms are described. These systems were evaluated using 375 sera from insect reactive patients from six diverse geographic regions. Ninety-four percent of patients with recent histories of systemic allergic reactions to stings were positive to at least one venom while 4 percent of normal local reactors were positive. The cross reactions between honey bee and vespid venoms were studied by RAST inhibition. A quantitative method for interpretation of venom RAST is presented to account for cross-reactivities and the approach to diagnosis is discussed.     

Determination of IgE antibodies to Polistes dominulus, Vespula germanica and Vespa crabro in sera of patients allergic to vespids

The study was undertaken to investigate the presence of IgE antibodies to Polistes dominulus (PD), Vespula germanica (VG) and Vespa crabro (VC) in a large group of sera belonging to patients sensitized to Vespids in Spain. RAST values showed that although the majority of patients had IgE antibodies to PD, VG and VC, there was a marked predominance of PD. These results were related to the distribution of the insect in the areas where the sera were obtained. Due to geographical and insect distribution differences, the whole area was divided into three zones: Central, East and South. Comparison of the positive RAST values obtained indicated that, although the positivity to PD predominated over VG and this over VC, there were significant differences in percentage positivities to each vespid in the different regions studied. The results of the RAST absorption studies indicated that in most instances patients were originally sensitized to one vespid and were RAST positive to the other venoms due to cross-reactivity. Only in a minority of cases were coexisting antibodies to two insects present. These results show that PD and VG are the important vespids followed to a lesser extent by VC. This study provides relevant information concerning insect distribution sensitivity in a European country.