Relationship of atopy and anaphylactic sensitization: a bee sting allergy model

This study attempts to determine if atopy predisposes to, or affects the severity of, bee sting allergy. 119 consecutive patients with definite systemic reactions to Hymenoptera stings and 119 matched controls without a history of Hymenoptera allergy were interviewed and evaluated. These patients with a definite systemic reaction to Hymenoptera had a mean age of 27 years with an age range of 2-73 years; 38% (forty-five out of 119) were 12 years of age or younger. The frequency of atopy (asthma/allergic rhinitis) was 25% (thirty out of 119), and resembles that found in a general population. In the eighty-nine patients (75%) without a personal history of atopy, only 8% had positive scratch tests to pollens, danders or molds, 44% had a positive family history of atopy and a majority had normal serum total IgE levels. Results of the RAST for specific IgE to venoms of honey bee, yellow jacket, hornet, wasp and to phospholipase A were obtained. Patients with asthma had a significantly more severe reaction to their Hymenoptera sting than non-atopic patients, 65%vs 38%, with P <0.05. The severity of sting reaction in those patients with allergic rhinitis without asthma resembled that of the non-atopic patients. Although atopy does not appear to predispose patients to Hymenoptera allergy, asthmatics’Who also have Hymenoptera allergy do have a significantly more severe reaction to a bee sting.     

Cross‐reactive carbohydrate determinants strongly affect the results of the basophil activation test in hymenoptera‐venom allergy

Background In hymenoptera‐venom allergy, sera of up to 60% of patients show in vitro reactivity to honeybee venom (HBV) and yellow jacket venom (YJV). This phenomenon is mainly caused by specific IgE (sIgE) against cross‐reactive carbohydrate determinants (CCD). Whether or not these antibodies can induce clinical symptoms is a longstanding debate. Objective The aim of this study was to investigate the biological activity of CCD‐sIgE and the suitability of the basophil activation test (BAT) in hymenoptera venom‐allergic patients having CCD‐sIgE. Methods The biological activity of CCD‐sIgE was analysed by application of native and CCD‐depleted YJV and HBV in BAT with the blood of 62 hymenoptera venom‐allergic patients and 16 non‐allergic controls. According to results of intracutaneous skin tests (IC) with YJV and HBV and the existence of CCD‐sIgE, patients were classified into six subgroups. Results In patients with mono‐positive IC and CCD‐sIgE, and thus double‐positive sIgE, BAT with native venoms was also double positive in up to 67% of the patients. In contrast, BAT with CCD‐depleted venoms was positive only with the IC‐positive venom. However, activation of basophils with the IC‐negative venom was significantly lower compared with the IC‐positive one. In IC mono‐positive patients without CCD‐sIgE, BAT was mono‐positive with the IC‐positive venom in the native and in the CCD‐depleted form. CCD‐positive patients with double‐positive IC were a heterogeneous group, with the majority of CCD‐positive patients also being double positive with the native forms of both venoms but mono‐positive with the CCD‐depleted ones. Conclusions In vitro BAT clearly demonstrates biological activity of CCD‐sIgE. However, because most of the patients showed a mono‐positive IC and activation of basophils with the IC‐negative venom was significantly lower compared with the IC‐positive one, the present data suggest that CCD‐sIgE is clinically irrelevant in these patients. Cite this as: M. Mertens, S. Amler, B. M. Moerschbacher and R. Brehler, Clinical & Experimental Allergy, 2010 (40) 1333–1345.     

Prevalence and clinical relevance of specific immunoglobulin E to pollen caused by sting- induced specific immunoglobulin E to cross-reacting carbohydrate determinants in Hymenoptera venoms

BACKGROUND: Hymenoptera stings can induce specific IgE (sIgE) to carbohydrate determinants (CD) on venom glycoproteins that cross-react with CD in pollen. sIgE to such cross-reacting CD (CCD) are believed to have little or no biological activity and thus may cause misdiagnosis of pollen sensitization after a sting. OBJECTIVE: To determine the prevalence of multiple false positive CAP results to pollen because of sting induced anti-CCD sIgE in Hymenoptera venom (HV) allergic patients and to investigate the association of such anti-CCD sIgE with features of 'atopy'. METHODS: Skin prick tests (SPT) and CAP tests with grass, tree and weed pollen and with house dust mite (HDM) were carried out prospectively in 259 HV allergic patients and CAP tests with honeybee (HBV) and yellow jacket (YJV) venom were performed. Patients with negative pollen SPT associated with positive CAP tests to all three pollen groups were operationally defined as 'CCD positive'. We investigated in selected 'CCD positive' patients the presence of anti-CCD sIgE by CAP tests with bromelain and studied the identity of CD in HVs and pollen by mutual sIgE inhibition tests with CD from proteinase treated HBV (HBV-CD) and Lolium perenne (Lol-CD) extracts. RESULTS: sIgE to all three pollen groups without positive SPT or history was found in 16% of 259 patients. The presence of anti-CCD sIgE was substantiated by positive CAP tests with bromelain in 14/14 and by inhibition of all pollen CAP tests with HBV-CD in 8/9 and with Lol-CD in 2/2 patients. Double venom (DV) positive CAP tests were present in 93% of 'CCD positive' patients and were in some associated with DV skin test positivity and allergy. The prevalence of 'CCD positivity' was significantly higher among HBV (23%) than among YJV (11%) allergic patients, but was also unexpectedly high among those with DV allergy (47%). 'CCD positive' patients were younger, had a higher total IgE and more sIgE to HDM than 'CCD negative' patients. CONCLUSION: We have shown that the risk in HV allergic patients for misdiagnosis of multivalent pollen sensitization is 16%, and we have confirmed that sting induced anti-pollen sIgE are directed to similar CD in venoms and pollen. We found evidence that the recognition of CCD might be related to the 'atopic' trait. Importantly, a positive bromelain CAP test does not exclude clinical reactivity to both venoms in 'CCD positive' HV allergic patients.     

Natural rubber latex and hymenoptera venoms share ImmunoglobinE-epitopes accounting for cross-reactive carbohydrate determinants

BACKGROUND: Epidemiological data on the prevalence and risk factors of latex sensitization have suggested a significant association between latex sensitization and the presence of one or more positive skin prick test responses to aeroallergens, food allergens and to one or more insect venoms. Xylose and core 3-fucose are typical complex glycans in plants and are foreign to mammals. Plant N-glycans and insect N-glycans may cross-react in humans. OBJECTIVE: The aim of our study was to investigate whether there are cross-reactive IgE-binding structures in natural rubber latex (NRL) and hymenoptera venoms and to examine their nature. METHODS: Hundred and twenty-five consecutive patients with insect venom allergy were screened for coincidental latex-specific IgE. IgE-binding components in the venoms from Apis mellifera and/or vespula species and in NRL extracts were characterized by IgE-immunoblotting to the natural allergen sources and determination of specific IgE to recombinant allergens. Cross-reactive components were investigated by inhibition experiments. The involvement of carbohydrates in the constitution of cross-reactive IgE-epitopes was further examined by specific IgE-binding to cross-reactive carbohydrate determinants (CCD) in bromelain and horseradish peroxidase as well as by periodate treatment. RESULTS: NRL glove extracts inhibited patients' serum IgE-binding to venom allergens. Vice versa, the IgE-binding to latex glove extracts could be inhibited by pre-incubation with the insect venoms. Specific IgE-binding to recombinant latex allergens was absent, whereas the cross-reactive IgE-epitopes were sensitive to periodate treatment and specific IgE to CCD (MMXF and MUXF type) could be detected. CONCLUSION: Insect venoms and NRL share IgE-binding CCD that may be responsible for positive serological test results to NRL in patients with insect venom allergy. This copositivity occurs frequently (13.6%) among venom-allergic individuals and did not elicit clinical symptoms upon contact to latex in the patients examined. In contrast, true cosensitization to insect venoms and NRL allergens can occur and may not be missed.     

Cupressaceae pollinosis in the Madrid area

Background There is no previous report of Cupressaceae pollinosis in the Madrid area. Objective To ascertain the presence of Cupressaceae pollinosis in the Madrid area. Methods Thirty-six patients were studied who had winter pollinosis symptoms and a positive skin test to C. arizonica. They were skin tested with C. sempervirens (Abeiló, Madrid), C. arizonica (in-house extract) and other common inhalant allergens (Abeiló). Total IgE was measured and specific IgE to C. arizonica, C. sempervirens and J. sabinoides was determined. Results Six of the patients were only sensitized to Cupressaceae pollens, whereas 30 patients had also sensitivity to other pollens (oleaceae 28, plantain 27, grasses 25, chenopodium 25, compositae 23, Parietaria 9) and 18 patients were also sensitized to other inhalant allergens (animals 17, mites 4, moulds 2). Conclusion These results confirm the existence of allergy to Cupressaceae pollens in Madrid (Spain).     

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.     

Identification of a polygalacturonase (Cup s 2) as the major CCD‐bearing allergen in Cupressus sempervirens pollen

As IgE glyco‐epitopes, also referred to as cross‐reactive carbohydrate determinants (CCDs), can share significant structural homologies between different plants, they are prone to extensive cross‐reactivity among allergen pollen extracts. Here, cypress pollen allergens, especially a polygalacturonase (PG), were further characterized using double one‐dimensional electrophoresis (D1‐DE). The presence of specific IgE directed against CCDs was investigated by bromelain IgE inhibition and concanavalin A binding assays using sera of cypress pollen‐sensitized patients. Our results showed that IgE reactivity to CCDs in Cupressus sempervirens pollen extracts is mainly related to bromelain‐type epitopes of a newly identified cypress PG. This glycoprotein has been further characterized through an immunoproteomic approach and officially indexed as Cup s 2 by the WHO/IUIS allergen nomenclature. Cup s 2 could thus be associated with the increased prevalence of IgE reactivity to cypress pollen extracts because of CCD interference.     

Are anaphylactic reactions to snake bites immunoglobulin E‐mediated?

BACKGROUND: Bites by poisonous European snakes of the genus Vipera lead to local tissue damage and systemic symptoms such as generalized oedema, hypotension, gastrointestinal symptoms, haemolysis and renal dysfunction. Not rarely anaphylactic symptoms like urticaria, localized angioedema and asthma are observed. OBJECTIVE: To look for snake venom-specific immunoglobulin (Ig) E antibodies in patients with a history of bites by European vipers and for cross-reactions with Hymenoptera venoms, that have a similar composition. METHOD: Ten patients with a history of bites by Vipera aspis or Vipera berus were investigated. Three patients had been bitten only once, and two of these had developed only local reactions. Four reported previous allergic reactions to Hymenoptera stings. All patients, 10 Hymenoptera venom-allergic and five nonallergic individuals who served as controls underwent i.c. skin test endpoint titration with snake (V. aspis, V. berus) and Hymenoptera venoms (honey bee, Vespula spp.) and were investigated for specific serum IgE antibodies to the same venoms. RESULTS: Seven of the eight patients with systemic snake bite reactions had both positive skin tests and serum IgE antibodies to snake venoms, while these tests were negative in the two patients with only local reactions to snake bites and all controls. Seven of the eight patients with systemic snake bite reaction also had positive skin tests and specific IgE with one or both Hymenoptera venoms. By RAST-inhibition with sera of four patients with high IgE to both Vipera and Hymenoptera venoms, partial cross-reactivity could be demonstrated in one. CONCLUSIONS: Anaphylactic reactions following snake bites may be IgE-mediated, especially in patients with repeated bites.     

Increase of allergen‐specific immunoglobulin E antibodies from 1973 to 1994 in a Finnish population and a possible relationship to Helicobacter pylori infections1

Background The prevalence of atopic diseases – hayfever, asthma and eczema – has increased over the past decades. The increase may be associated with decreased rates of infections such as measles, hepatitis A, tuberculosis, toxoplasmosis, and, as recently suggested, Helicobacter pylori gastritis. Objective Since the increase of atopy has been mainly based on clinical studies, we wanted to study the prevalence of allergen‐specific Immunoglobulin (Ig)E antibodies in two cross‐sectional, adult population‐based serum samples two decades apart. Since the sera had been tested for H. pylori antibodies, we also had a chance to look for a possible relationship between these two findings. Methods We determined the prevalence rate of allergen‐specific serum IgE antibodies against birch and timothy pollen, and cat and dog epithelium allergens by the radioallergosorbent test in a 15–54‐years‐old Finnish population using 326 sera collected in 1973 and 319 sera collected in 1994 from randomly selected subjects. Results From 1973 to 1994 allergen‐specific IgE prevalence rates and IgE antibody levels rose. In 1994, the prevalence rate of positive findings in 15–24‐year‐old population had increased from 11 to 38% (3.5‐fold increase, P = 0.0001, OR 5.12, CI 95% 2.32–11.3). In older 10‐year age groups similar trends did not reach significance, but the overall change was significant with all three cut‐off levels of allergen‐specific IgE analysed. The percentage of IgE‐positive persons rose mainly in the subgroup with no H. pylori antibodies. In 1994 21% of the H. pylori‐negative subjects had IgE antibodies compared with 5% of the H. pylori‐positive subjects (in 1973 11% in both subgroups). Conclusions IgE‐based evidence for an increase in IgE‐mediated allergy was uncovered. The increase occurred mainly in the subgroup with no antibodies to H. pylori, which support the hypothesis that H. pylori could be one of the microbes counteracting atopy.     

Analytic accuracy of specific immunoglobulin E antibody results determined by a blind proficiency survey

Analytic variability affects the accuracy of measurements of specific IgE antibodies, but the frequency of false results attributable to analytic variability is not well documented. We have monitored the accuracy of the results generated in our laboratory by testing aliquots of positive serum pools and a negative serum pool submitted blindly for the measurement of IgE antibodies to 16 different allergens, including foods; weed, grass, and tree pollens; mites, molds, and epithelia; and Hymenoptera venoms. Positive serum pools were prepared to contain modest amounts of IgE antibodies. Tests were performed by immunometric assays with microcrystalline cellulose allergen immunosorbents. Frank false-positive and false-negative results were very uncommon when binding levels were classified by a ratio-based reporting scheme. False-borderline results were more common. A borderline result is truly equivocal and may or may not indicate the presence of low levels of IgE antibodies. Analytic variability adds uncertainty to the measurement of small quantities of IgE antibodies regardless of the classification scheme used to report test results.     

Influence of total IgE levels on the severity of sting reactions in Hymenoptera venom allergy

BACKGROUND: Detection of specific IgE for Hymenoptera venoms and skin tests are well established diagnostic tools for the diagnosis of insect venom hypersensitivity. The aim of our study was to analyze the effect of total IgE levels on the outcome of generalized anaphylactic reactions after a Hymenoptera sting. METHODS: Two hundred and twenty patients allergic to bee, wasp, or European hornet venom were included in the study. Their specific and total IgE levels, serum tryptase levels, skin tests, and sting history were analyzed. RESULTS: In patients with mild reactions (grade I, generalized skin symptoms) we observed higher total IgE levels (248.0 kU/l) compared to patients with moderate reactions (grade II, moderate pulmonary, cardiovascular, or gastrointestinal symptoms; 75.2 kU/l) and severe reactions (grade III, bronchoconstriction, emesis, anaphylactic shock, or loss of consciousness; 56.5 kU/l; P < 0.001). Accordingly, 25% of the patients with low levels of total IgE (<50 kU/l), but no individual with total IgE levels >250 kU/l, developed loss of consciousness (P = 0.001). Additionally, specific IgE levels were related to total IgE levels: Specific IgE levels increased from 1.6 to 7.1 kU/l in patients with low (<50 kU/l) and high (>250 kU/l) total IgE levels, respectively (P < 0.001). Specific IgE levels correlated inversely to the clinical reaction grades, however, this trend was not statistically significant (P = 0.083). CONCLUSION: Patients with Hymenoptera venom allergy and high levels (>250 kU/l) of total IgE, predominantly develop grade I and grade II reactions and appear to be protected from grade III reactions. However, this hypothesis should be confirmed by extended studies with sting challenges.     

IgE to food allergens are highly prevalent in patients allergic to pollens, with and without symptoms of food allergy

Serum samples from 274 patients allergic to one or more of three pollens (birch, grass, mugwort), from 36 patients allergic to cat and/or Dermatophagoides pteronyssinus but not to pollen and from 55 non-allergic controls, as well as 20 cord blood samples, were examined for specific IgE to six ‘pollen-associated’ food allergens In uiing a new sensitive assay (CAP). A questionnaire asking for reactions to food was also sent to all patients. In the pollen group, 111 patients (47%) were positive (≥0.71 kU/l) fora food allergen (392 positive tests). Of these, 92 were sensitive to apple, 68 to potato, 64 to carrot, 63 to celery, 61 to peach and 44 to melon. In the non-allergic group, no IgE to any of the food allergens tested was found, whereas in the group allergic to non-pollen allergens, only one individual had such an IgE. The CAP assay was found to he more sensitive than RAST for the allergens studied. A history of clinical reactions (oral symptoms in 67, rhinoconjunctivitis in 65, asthma in 42 and urticaria in 39) to the corresponding food allergen was reported mainly by patients with positive CAP. In conclusion, we found a high prevalence of IgE to some food allergens in patients allergic to pollen and Ihe absence of such antibodies in the control groups. The new in vitro assay, being moresensitue than previous ones, indicated a high prevalence of food specific IgE in pollen allergic patients, which in many cases did not correspond to clinical symptoms of food allergy.     

Reproducibility of prick skin tests to five common allergens

Thirty-five asthmatic patients had prick skin tests to the common allergens Candida aibicans, Aspergillus fumigatus, grass pollen, horse dander and Dermatophagoides pteronyssinus performed on a regular basis from Autumn 1973 to Autumn 1975. Specific IgE to the same allergens (except C. albicans) was determined at the time of skin testing for the first five seasons. It was found that the position on the volar aspect of the forearm on which the test was performed did not affect the reaction. There was a significant variation in the percentage of patients with positive skin tests to A. fumigatus, grass pollen and horse dander with the latter showing a significant decrease with time. There was evidence of variation in weal size for all but C. albicans, and for grass pollen, horse dander and D. pteronyssinus there were reductions in weal size with time. Significant differences were found for results of Log specific IgE for grass pollen and D. pteronyssinus over the study, but there was no trend. A good correlation between weal size and Log specific IgE for grass pollens and D. pteronyssinus was observed. For the four allergens, the coefficient of concordance between IgE levels within patients for the five seasons was highly significant.     

The allergen profile of beech and oak pollen

Background Beech and oak pollen are potential allergen sources with a world‐wide distribution. Objective We aimed to characterize the allergen profile of beech and oak pollen and to study cross‐reactivities with birch and grass pollen allergens. Methods Sera from tree pollen‐allergic patients with evidence for beech and oak pollen sensitization from Basel, Switzerland, (n=23) and sera from birch pollen‐allergic patients from Vienna, Austria, (n=26) were compared in immunoblot experiments for IgE reactivity to birch (Betula pendula syn. verrucosa), beech (Fagus sylvatica) and oak (Quercus alba) pollen allergens. Subsequently, beech and oak pollen allergens were characterized by IgE inhibition experiments with purified recombinant and natural allergens and with allergen‐specific antibody probes. Birch‐, beech‐ and oak pollen‐specific IgE levels were determined by ELISA. Results Beech and oak pollen contain allergens that cross‐react with the birch pollen allergens Bet v 1, Bet v 2 and Bet v 4 and with the berberine bridge enzyme‐like allergen Phl p 4 from timothy grass pollen. Sera from Swiss and Austrian patients exhibited similar IgE reactivity profiles to birch, beech and oak pollen extracts. IgE levels to beech and oak pollen allergens were lower than those to birch pollen allergens. Conclusion IgE reactivity to beech pollen is mainly due to cross‐reactivity with birch pollen allergens, and a Phl p 4‐like molecule represented another predominant IgE‐reactive structure in oak pollen. The characterization of beech and oak pollen allergens and their cross‐reactivity is important for the diagnosis and treatment of beech and oak pollen allergy.     

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.     

Inhalant allergy to fresh asparagus

Background Two patients experienced itehing conjunctivitis, running nose, tightness of the throat and coughing during preparation of fresh asparagus. Eating asparagus after cooking did not provoke any allergie symptoms. Both patients were atopic. sensitized additionally to pollens of grasses and trees as well as to onion. Objective To assess the hypersensilivity reactions to Iresh and heated asparagus and to investigate any crossreactivities among the allergens. Methods Skin-prick tests were perfonned with commercial allergens and native asparagus and the patienls were tesled with Pharmacia CAP system for specific IgE antibodies against asparagus, onion, garlic, birch pollen, mugwort pollen and two recombinant birch pollen allergens, Bet v I and profilin. Inhibition of IgE antibody binding to solid phase homologous and unrelated allergens by increasing doses of liquid allergens (inhibitors) was studied. Results Skin-prick tests with native green and white asparagus were strongly positive, but negative with cooked asparagus. Both patients had measurable levels of IgE antibodies against asparagus (3.0 and 6.2kU/L respectively) and several other allergens. One patienl was highly sensitive to birch and Bet v I. Both were positive to profilin, mugwort and onion. In all cases the antibody uptake could be extensively and specifically inhibited by homologous allergen. The asparagus-specific IgE antibodies of the two patients could only be inhibited by asparagus. No inhibition was obtained after heating of the asparagus extract to 100°C. Conclusions The patients were speeifically sensitized by asparagus. No immunological crossreactions could be observed. The measurements of IgE antibodies to other allergens were also specific, representing parallel multiple sensitivity. Profilin inhibited profilin-specific IgE binding but did not react with the asparagus-specific IgE antibodies of these patients. The asparagus allergen recognized by the specific IgE antibodies of these patients was thermolabile.     

Hypersensitivity to carrot associated with specific IgE to grass and tree pollens

This study deals with a 34-year-old female cook with no previous history of atopy, who was studied because of allergic rhinoconjunctivitis and contact urticaria in both hands associated with severe itching when she handled raw carrot. The patient had had anaphylactic episodes after accidental ingestion of raw carrots, but she tolerated cooked carrots. Skin prick tests with carrot, celery, and olive, and birch, grass, and mugwort pollens were positive. Total IgE was 411 UI/ml. Specific IgE to olive, grass, and weed pollens were 10.92, 6.17, and 2.4 AU/ml, respectively. The histamine release test was positive for carrot, celery, celeriac, and olive pollen up to a dilution of 1/106. Immunoblot of raw carrot showed a single IgE-binding 18-kDa band. IgE reactivity for raw carrot immunoblot was completely inhibited by carrot and by celery, but not by olive or grass pollens. Specific IgE to olive pollen was not inhibited by carrot. The existence of monosensitization to an 18-kDa protein in carrot and specific IgE to olive pollen has not been reported in the celery-carrot-mugwort-spice syndrome.     

Allergenicity and cross-reactivity of pine pollen

Background Pine pollen has long been considered a non-allergenic pollen. The large size of the grain and its low levels of proteins are the main reasons invoked to explain this low allergenicity. The aim of this study was to describe the main allergenic bands of Pinus radiata ( PR ) and its cross-reactivity with other pine species, other conifers and grass pollen.
Methods Sixty-five pine-pollen-allergic patients (51% also sensitized to grass pollen) were studied. Skin prick tests (SPT) to a battery of allergens including PR, Pinus pinea, Pinus sylvestris, Pinus nigra and Cupressus sempervirens pollens and specific IgE determination to PR and Pinus strobus were performed. IgE-immunoblotting to a PR extract and other pine pollens was also carried out. UniCAP inhibition and immunoblotting inhibition studies were performed to assess the cross-reactivity between different pollens.
Results The SPTs were positive with all the pine pollen extracts tested in 69% of the patients. Specific IgE was positive to PR or P. strobus in 77% of the patients, and to Lolium perenne in 51%. Nine different allergenic bands were detected. The two main allergens were a 42 kDa band recognized by 85% of the patients and a band of approximately 6–8 kDa recognized by 40%. A high degree of cross-reactivity was observed between different pine pollen species, but not between pines and C. sempervirens pollen. A partial cross-reactivity could be seen between pine and grass pollens only in patients also sensitized to L. perenne .
Conclusions Pine pollen should be considered as a potential allergenic pollen especially where this pollen is abundant. The detection of a high number of patients that were monosensitized to pine pollen suggests the possibility of treating these patients with specific immunotherapy.     

Stinging insect allergy: sensitization to vespids in Madrid and surroundings

The study comprised 28 patients from the centre of Spain (Madrid and surroundings) who had suffered systemic reactions when stung by vespids. Specific IgE antibodies to Vespula spp. and Polistes spp. venoms were measured by RAST. All patients had positive RAST to Vespula venom and half of them also had positive RAST to Polistes venom. A patient can be sensitive to both venoms due to either a clinical sensitization to both venoms, or common antigenic determinants. To differentiate these states we used a RAST inhibition assay. We could inhibit Polistes RAST with either Polistes or Vespula venom to a similar degree. Inhibition of Vespula RAST was possible with Vespula venom, but only to a limited degree with Polistes venom. Direct RAST and RAST inhibition studies indicate that in our geographic region sensitization to Vespula venom is more common than to Polistes venom and Polistes might have cross-reactivity in our patients.     

Primary versus secondary immunoglobulin E sensitization to soy and wheat in the Multi-Centre Allergy Study cohort

Background IgE sensitization to soy and wheat is classified as ‘primary’ when generated by food ingestion and ‘secondary’ when it as a consequence of primary sensitization to cross‐reacting pollen antigens via inhalation. The age‐specific relevance of these categories of sensitization throughout childhood is unknown. Objective To monitor the natural course of IgE sensitization against common food allergens in childhood in relation to sensitization against cross‐reactive airborne allergens. Methods The German Multi‐Centre Allergy Study with follow‐up from birth to age 13 recruited initially 1314 children. IgE antibody levels against cow's milk, hen's egg, soy, wheat, mites, cat and dog dander, birch and grass pollens were tested. Longitudinal data were analysed from the 273 children with sera obtained at age 2, 5, 7 and 10 years of age. Results The point prevalence of sensitization (>1.0 kU/L) to milk and egg allergens progressively decreased from about 4% at 2 years to <1% at 10 years. By contrast, the prevalence of IgE to wheat and soy progressively increased with age, from 2% to 7% (soy) and from 2% to 9% (wheat). At 10 years of age, IgE to grass pollen was detected in 97% and 98% of the children reacting against soy and wheat, respectively; IgE to birch pollen was observed in 86% and 82% of the children reacting against soy and wheat, respectively. Early IgE sensitization to soy or wheat preceded that to grass or birch pollen in only 4% and 8% of participants sensitized to soy and wheat, respectively. Conclusion IgE sensitization to soy and wheat is relatively uncommon and mostly primary in early infancy, more frequent and mostly secondary to pollen sensitization at school age. Clinical Implications Awareness should be raised to avoid unnecessary diet restrictions due to the high frequency of clinically irrelevant, secondary sensitization to soy and wheat in schoolchildren with pollinosis.