Relationship between Bet v 1 and Bet v 2 specific IgE and food allergy in children with grass pollen respiratory allergy

Grass allergy is the most common pollinosis in Northern Italy. Some patients with grass allergy show polysensitization against other pollens and plant-derived foods. In these patients oral allergic syndrome (OAS) is frequently associated. To evaluate the correlation between food allergy or food sensitization and specific IgE against panallergens such as Bet v 1 and Bet v 2, we studied 56 children (mean age: 8 years 5 months) suffering from respiratory allergy due to grass pollens were enrolled. Specific IgE against the most important food, inhalant allergen and Bet v 1, Bet v 2 were performed by ImmunoCAP technology (UniCAP 1000, Pharmacia Diagnostics, Uppsala, Sweden). We found 14 children (25%) sensitized to Bet v 1 and 13 (23%) to Bet v 2; in 24 cases (42.3%) a sensitization to at least one of the 2 panallergens was observed. Five of the 14 cases (36%) sensitized to Bet v 1 showed food allergy and 8 (57%) food sensitization; 6 (46%) of the 13 children sensitized to Bet v 2 showed food allergy and 7 (54%) food sensitization; only one case of Bet v 1 specific IgE without food allergy or sensitization was seen. Sixteen subjects (29%) showed food allergy (group A); 20 children (35.5%) multiple sensitizations to inhalant and at least one plant-derived food (group B); 20 subjects (35.5%) only inhalant allergens (group C). Sensitization to Bet v 1 (P<0.03) and Bet v 2 (P<0.009) is from a statistical point of view significantly higher in groups A and B than in group C. In the 16 patients with food allergy hazelnut was the major triggering food (50%), followed by peanut (38%), kiwi (31%), apple and walnut (19%). Specific IgE for Bet v 1 is more associated with nuts and legumes, while Bet v 2 is more related to fresh fruit and vegetables. In conclusion grass pollinosis is frequently associated with polysensitization to other pollen and food allergens. Bet v 1 and Bet v 2 specific IgE are significantly higher in these patients than in patients with grass monosensitization, and this sensitization may be considered a possible risk factors to evolve later into food allergy. Among the offending foods, legumes and the nut group are mostly related to Bet v 1, while vegetables and fresh fruits to Bet v 2.     

Sensitization to different pollens and allergic disease in 4-year-old Swedish children

BACKGROUND: Although the relationship between sensitization to different inhalant allergens in adolescents and adults has been intensively studied, information concerning sensitization in children is scarce in particular to pollens. OBJECTIVES: In 4-year-old children to elucidate the pollen immunoglobulin (IgE) antibody profile (birch only, timothy only and combinations of three pollens (birch, timothy or mugwort) and to relate the results to other inhalant and food allergens, as well as the presence of allergic diseases. METHODS: A total of 2551 4-year-old children belonging to a prospective birth cohort, which has been followed longitudinally (BAMSE), were investigated with respect to IgE antibodies to pollen and other inhalant and food allergens, and expression of allergic disease, based on questionnaire data. RESULTS: Eleven percent (n=285) of the children were sensitized to pollen. Birch was the dominating cause of pollen sensitization (birch sensitization only, n=133); followed by timothy grass pollen (n=56) and a combination of two (n=64) or three (n=30) pollens. A remarkably high proportion of the children sensitized only to birch was also sensitized to other inhalant allergens. This was not seen for children sensitized only to timothy. The highest frequencies of IgE reactivity to food were found in the group of children sensitized to the combination of birch, timothy and mugwort pollen. Children sensitized to timothy only, exhibited symptoms of allergic disease significantly less frequently compared with children sensitized to birch only. Sensitization to birch pollen was found to be closely associated with rhinitis and eczema compared with asthma. The highest frequency of asthma and/or rhinitis and/or eczema was reported in children sensitized to at least two pollens. CONCLUSION: Our results demonstrate that birch is the dominating source of pollen sensitization at the age of four in Sweden. This might associate with the pattern of sensitization to other inhalant and food allergens as well as influence on the expression of allergic disease in this particular age group.     

Molecular characterization of a cross-reactive Juniperus oxycedrus pollen allergen, Jun o 2: A novel calcium-binding allergen

Background: Species belonging to the Cupressaceae family are a relevant source of allergens that are present in a wide number of countries. Objective: We sought to identify, purify, and characterize recombinant allergens from Juniperus oxycedrus, a species belonging to the Cupressaceae family. Methods: Double-stranded cDNA was synthesized from mRNA and cloned into the lambda-ZAP expression vector. IgE screening of the library was performed with a pool of sera from subjects allergic to Cupressaceae. A recombinant 6×His-tagged Juniperus oxycedrus allergen, Jun o 2, was expressed in Escherichia coli and purified by Ni²⁺ affinity chromatography. It was studied further by immunoblotting inhibition with pollen extracts from other Cupressaceae, Oleaceae, Urticaceae, and Graminaceae. The role of protein-bound calcium on the allergen's IgE-binding capacity was tested in a plaque assay in the presence or absence of EGTA. Results: A cDNA coding for a newly identified Juniperus oxycedrus pollen allergen, rJun o 2, was isolated. The deduced amino acid sequence contained four typical Ca²⁺ binding sites and showed a significant sequence similarity to calmodulins. Depletion of Ca²⁺ in the plaque assay led to a loss of IgE-binding capacity of rJun o 2. Immunoblotting inhibition revealed that J. oxycedrus, J. ashei, Cupressus arizonica, C. sempervirens , Parietaria judaica, Olea europaea, and Lolium perenne pollen extracts were able to inhibit IgE binding to blotted rJun o 2 at different concentrations. Conclusion: rJun o 2 contains IgE-binding epitopes shared by taxonomically unrelated species, and therefore it can be regarded as a new panallergen. These findings could contribute to an explanation for the phenomenon of multiple positive test results in polysensitized patients and the potential symptom-eliciting role of allergenic sources previously not encountered. (J Allergy Clin Immunol 1998;101:772-7)     

Juniperus oxycedrus: A new allergenic pollen from the Cupressaceae family

Background: Cupressaceae allergy is a worldwide pollinosis caused by several species. Some species in limited geographic areas pollinate in fall and winter. Juniperus oxycedrus matches these features. Objective: We sought to define the immunochemical, allergologic, and environmental aspects of J. oxycedrus pollen. Methods: Pollen extract from J. oxycedrus was prepared and characterized by biochemical analysis and human specific IgE binding by means of ELISA and immunoblotting. A 3-year phenological study was conducted to define the pollinating period of J. oxycedrus. Forty consecutive patients allergic to cypress were recruited in two areas and divided into two groups according to their exposure to J. oxycedrus pollen. Clinical evaluation, skin prick tests, and specific IgE determination with J. oxycedrus, J. ashei, and Cupressus arizonica extracts were carried out on both groups. Results:J. oxycedrus pollen extract was obtained, and it showed specific IgE binding and wide cross-reactivity with other Cupressaceae species. The extract caused a positive skin test response in all the patients tested, with about 80% of them having detectable specific IgE. Symptoms related to J. oxycedrus pollen exposure were recorded in 72% of the directly exposed patients and occasionally in 9% of the nonexposed patients. In the Mediterranean coastal area considered, J. oxycedrus was the first Cupressaceae species that started to pollinate at the beginning of November and ended in the first part of December. Conclusions:J. oxycedrus represents a newly characterized pollen species of the Cupressaceae family that cross-reacts with other members of the same family. Subjects with cypress allergy have in vivo and in vitro positive test responses for J. oxycedrus and can show symptoms when exposed to its pollen. Finally, the most important feature of J. oxycedrus is its early pollinating period in southern Europe (Italy), causing a further extension of the cypress pollen season in areas where other Cupressaceae species are present. (J Allergy Clin Immunol 1998;101:755-61.)     

Platanus acerifolia pollinosis and food allergy

BACKGROUND: In Mediterranean areas, oral allergy syndrome (OAS) occurs independently of an associated birch pollinosis; moreover, on occasions it presents with no other associated pollinosis. The aim of this study was to assess the possible association of OAS with Platanus acerifolia pollinosis. METHODS: We evaluated consecutive patients seen for pollinosis in an allergy department. Seven hundred and twenty patients were selected on the basis of seasonal or perennial rhinitis, or asthma, or both. Respiratory and food allergies were studied in all patients. Clinical history was recorded and examinations and skin prick tests were performed with a battery of available common inhalant allergens and plant-derived food allergens. Specific IgE levels to P. acerifolia pollen extract and food allergens tested were measured. Molecular masses of the IgE-binding proteins and cross-reactivity among the P. acerifolia pollen and different food extracts were also determined. RESULTS: Of the 720 patients evaluated, 61 (8.48%) were sensitized to P. acerifolia pollen. Food allergy was observed in 32 (52.45%) of the 61 patients sensitized to P. acerifolia pollen. Food allergens most frequently implicated were hazelnuts, peach, apple, peanuts, maize, chickpea and lettuce. Enzyme allergosorbent (EAST)-inhibition showed high inhibition values when P. acerifolia pollen extract was used as free phase. On the contrary low inhibition was observed when plant-derived food allergens were used as free phase and P. acerifolia pollen extract as solid phase. CONCLUSIONS: Cross-reactivity was observed among P. acerifolia pollen and plant-derived foods. OAS in these patients may have been caused by primary respiratory sensitization.     

Allergy in the Mediterranean area I. Pollen counts and pollinosis of Montpellier

The climatic conditions of the Mediterranean area results in vegetation and pollen very different from that of the other parts of Europe. The pollen content of the atmosphere of Montpellier, southern France, was examined using a filter sampler which was shown to be more efficient than most of the current devices for air sampling. Pollen counts were subsequently compared with pollinosis of patients born and living in and around Montpellier. The mean annual pollen counts showed that grass pollens and Cupressaceae pollens (cypress and juniper) are the highest. Some Mediterranean pollens (Oleaceae, London plane, Parietaria) are also important. Plantain and oak pollens are also present in relatively large amounts. Grass pollen allergy was found to be present in 86.5% of pollen-allergic patients. It was followed by plantain, Parietaria, Oleaceae, London plane and Cupressaceae pollens which were allergenic in 13-36% of pollen-allergic patients. Oak and pine pollens were present in large quantities in the counts but few persons were sensitive to oak and none to pine. By contrast, some patients had positive skin tests to alfalfa, red clover, acacia and lime tree pollens though these pollens were almost absent from the counts. In a few cases local sources of these pollens could account for the positive skin tests but cross-sensitivities could also occur. In summary, pollinosis of the Northern Mediterranean area is intermediate between the southern part of the area and the other parts of Europe.     

Seasonal differences in airway hyperresponsiveness in asthmatic patients: relationship with allergen exposure and sensitization to house dust mites

Background The degree of airway hyperresponsiveness in allergic asthmatic patients may be influenced by changes in environmental exposure to inhalant allergens. Objective This study investigates the relationship between seasonal changes in exposure to house dust mite (HDM) allergens and non-specific airway hyperresponsiveness in asthmatic patients with multiple sensitizations to inhaled allergens. Methods In 43 asthmatic patients sensitized to several inhalant allergens, lung function (FEV₁), airway hyperresponsiveness (PC₂₀ histamine), serum total IgE, house dust mite (HDM) specific IgE and number of peripheral blood eosinophils were measured during autumn 1990 (September-November) and spring 1991 (March—May). During each season. floor dust samples were collected twice from living- and bedrooms and the concentration of the HDM allergens Der p 1 and Der p 2 determined. Results More severe airway hyperresponsiveness (lower PC₂₀ histamine) during autumn was only found in patients sensitized to HDM(n= 32; autumn: 2.05mg/mL, spring: 4.51mg/mL (geometric means), P <0.0 1), whereas in patients not sensitized to HDM (n= 11) similar values were observed in both seasons (3.44 and 4.52 mg/mL. respectively, P= 0.56). More severe airway hyperresponsiveness of HDM sensitized patients in autumn was significantly associated with higher Der p 1 concentrations in floor dust. Aside from airway hyperresponsiveness, seasonal changes in serum total IgE and number of peripheral blood eosinophils were seen in patients sensitized to HDM, Conclusions In allergic asthmatic patients, airway hyperresponsiveness may increase during autumn, depending on sensitization to HDM and an increase of exposure to HDM allergen.     

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.     

Characterization of allergens from Trisetum paniceum pollen: an important aeroallergen in Mediterranean continental climatic areas

Background Trisetum paniceum is a grass plant which is characteristic of a Mediterranean continental climate and has been descrihed as one of the major causes of type I allergy in the Madrid region. Objectives To identify and characterize the allergens of Trisetum paniceum pollen. Methods Allergenic extracts were prepared by 24 h incubation of pollens in a buffered solution. Proteins were analysed by a new two-dimensional system in which agarose piates were used for isoelectric focusing. Two-dimensionally resolved proteins were electrically transferred to Immobilon membranes and the allergens immunochemically detected. Proteins from six grass pollens were bound to a membrane and incubated with a pool of serum from grass-pollen-sensitized patients. The bound IgE antibodies were then eluted and used to identify the proteins of Trisetum paniceum pollen that allergenically crossreact with allergens from other pollen grasses. Results Relative to total protein content, Trisetum paniceum pollen had a high proportion of reactive proteins. On the basis of their molecular characteristics, allergens could be classified as group 1,2,4 and 5 components yet included an atypical proportion of basic components. All identified allergens were crossreactive with allergens from the remaining grass pollens studied. Conclusions Trisetum paniceum pollen contains a high proportion of allergens and these include a group of basic proteins which are not detected in other phylogenetically related pollens and could be of atlergological interest.     

Association between sensitized to food allergens and childhood allergic respiratory diseases in Taiwan

BackgroundSensitization to allergen has long been known to be relate to childhood allergic diseases. Polysensitised children have more severe atopic diseases, whereas allergic rhinitis or asthma children with cosensitized to food and inhalant allergens were under-researched.ObjectiveTo realize the association between sensitization to food allergens and pediatric allergic rhinitis and asthma in Taiwan.MethodsWe included 138 participants with sensitized to allergen as assessed by serum-specific IgE. 87 of 138 participants had allergic rhinitis and 51 participants had asthma. All participants underwent a physical examination and measurement of serum total and specific IgE values. Besides, nasal peak expiratory flow rate (nPEFR) that was performed by the participants with allergic rhinitis and were requested to complete the Pediatric Rhinoconjunctivitis Quality of Life Questionnaires (PRQLQ). Lung function test and asthma control test (ACT)/child asthma control test (C-ACT) were performed by the participants with asthma.Results39 of 87 allergic rhinitis participants with sensitized to food and inhalant allergens (AR food group), 48 of 87 allergic rhinitis participants with sensitized to inhalant allergen alone (AR inhalant group). The AR food group had significantly lower nPEFR values and higher total IgE values (p < 0.05) compared with the AR inhalant group. The AR food group had higher PRQLQ scores than the AR inhalant group. 24 of 51 asthma participants with sensitized to food and inhalant allergens (Asthma food group), 27 of 51 asthma participants with sensitized to inhalant allergen alone (Asthma inhalant group). The Asthma food group had significantly higher total IgE values (p < 0.05) compared with the Asthma inhalant group. The Asthma food group had lower lung function test values and asthma control test (ACT) scores than the other group.ConclusionsChildren with cosensitized to food and inhalant allergens have more severe clinical symptoms and abnormal laboratory findings. Sensitization to food allergen was more related to pediatric allergic rhinitis than asthma. We may need larger, longer and extended studies to confirm these findings.     

Quantitative assessments of IgG and IgE antibodies to inhalant allergens in patients with atopic dermatitis

Using antigen-binding radioimmunoassays, we have measured class specific antibodies against two major inhalant allergens, antigen P₁ from D. Pteronyssinus and Rye I from grass pollen, in sera from 69 patients with atopic dermatitis. The results show that many of the patients have IgE ab to these allergens in keeping with their skin tests. In all cases, the IgE ab was paralleled by IgG ab to the same allergen. In many sera, IgE ab to these inhalant allergens made a significant contribution to the total serum IgE. With two other allergens to which these patients had not been exposed, specific IgE ab was detected in only one serum, whereas the 42 sera tested did not contain IgE ab to diphtheria toxin. Eleven of the adult patients with atopic dermatitis had no history of asthma and had strongly positive skin tests. This group of patients had levels of total IgE and specific ab to antigen P₁ that were very similar to those found in a comparable group of patients who had both atopic dermatitis and asthma. Our recent finding that allergens applied to the skin can induce delayed eczematous lesions provides a mechanism by which allergens could contribute to skin lesions. Our present results support the view that specific sensitivity to common allergens should be taken into account in considering the causes of these patients' skin lesions.     

Cross-reactivity among conifer pollens.

BACKGROUND: There are increasing reports of Cupressaceae pollinosis from various geographic areas. Cross-reactivity among a limited number of species within the Cupressaceae family has been suggested. Juniperus ashei (mountain cedar) is the leading cause of respiratory allergy in South Texas. OBJECTIVE: This study examines in vivo and in vitro cross-reactivity among 12 Cupressaceae species, one Taxodiaceae species, one Pinaceae species, and an angiosperm. METHODS: Cross-reactivity among pollen extracts of mountain cedar (MC) and the other 14 trees was investigated by: (1) prick skin testing of each tree pollen extract in ten patients with MC pollinosis. (2) Ouchterlony gel immunodiffusion employing rabbit antisera to MC. (3) IgE immunoblotting using high-titer MC pooled human sera, and immunoblot inhibition after pre-incubation with MC protein. (4) Monoclonal antibody immunoblotting using a murine monoclonal antibody with strong affinity for the gp40 major allergen of MC. RESULTS: Positive skin wheal-and-flare responses occurred to all 12 Cupressaceae and Japanese cedar (the Taxodiaceae), but not to the Pinaceae or the angiosperm. In Ouchterlony gels, lines of identity or partial identity formed between MC and all pollens except the Pinaceae and the angiosperm. Immunoblots demonstrated IgE binding to the 40 to 42 kD protein in each Cupressaceae, and to a parallel band in Japanese cedar at 43 to 46 kD. Immunoblot inhibition by MC pollen was complete for all trees. The monoclonal bound both the 40 to 42 kD protein in 11 of 12 Cupressaceae species and the 46 kD band in Japanese cedar, but bound no protein bands in the Pinaceae or the angiosperm. CONCLUSION: Pollen proteins of the 12 Cupressaceae (including MC) and the Taxodiaceae (Japanese cedar) are extensively cross-reactive. In particular, the MC major allergen, gp40, is cross-reactive with 40 to 42 kD proteins of the other Cupressaceae and with the Japanese cedar major allergen of 46 kD. Component-based immunotherapy may someday allow a standard treatment for both Juniper-allergic and C. japonica-allergic patients.     

Sensitization to tomato peel and pulp extracts in the Mediterranean Coast of Spain: prevalence and co-sensitization with aeroallergens

Background Tomatoes (Lycopersicon esculentum) are consumed world‐wide. The prevalence of sensitization to tomatoes remains unknown. Objective To determine the prevalence of skin test reactivity to tomato and to describe the characteristics of tomato‐sensitized subjects. Methods Individuals attending for the first time during the period of the study to six Allergy centres, located along the Mediterranean coast of Spain, reporting respiratory and/or cutaneous symptoms, were included. All patients were skin prick tested with a battery of inhalant allergens and with peel and pulp of Canary tomato extracts. Results The study included 1734 individuals (757 males, 977 females; 31.9±17.8 years old). The prevalence of sensitization to tomato was 6.52% (113 patients; 65 males, 48 females; 29.5±13 years old). The peel extract was positive in 110 patients and the pulp extract in 47 patients; three patients were positive exclusively to pulp. Only 1.8% of individuals reported symptoms with tomato; 44% of them had skin test negative to both extracts. Among tomato‐sensitized subjects, 16% reported symptoms with tomato, 97% were sensitized to inhalant aeroallergens, including 84% to pollens (mainly Artemisia vulgaris and Platanus hybrida), with differences between Northern and Southern centres. Conclusions The prevalence found of skin test sensitivity to tomato is high. Peel extracts detected most of the sensitized subjects. Most of the sensitized subjects were asymptomatic and some patients reported symptoms without skin test sensitivity. Positive subjects were very frequently sensitized to pollens, suggesting allergen cross‐reactivity. Regional differences may exist, possibly related to the pattern of sensitization to cross‐reacting pollens.     

Hypersensitivity to mugwort (Artemisia vulgaris) in patients with peach allergy is due to a common lipid transfer protein allergen and is often without clinical expression

BACKGROUND: The observation of mugwort-specific IgE antibodies in patients with peach allergy suggests that mugwort sensitization might play a role in sensitization to peach. OBJECTIVE: We sought to study the clinical manifestations of mugwort hypersensitivity in patients with peach allergy, identify the common allergens, and evaluate their IgE crossreactivity. METHODS: Patients with oral allergy syndrome for peach and specific IgE antibodies to mugwort were investigated for respiratory symptoms during the mugwort season. Peach and mugwort allergens were identified by means of SDS-PAGE and IgE immunoblotting. Immunoblotting inhibition experiments were done to study cross-reactivity between peach and mugwort and other pollens. RESULTS: Seventeen patients were studied, 10 with no seasonal respiratory symptoms and 7 with clear late summer respiratory symptoms. In IgE immunoblotting the 10 asymptomatic patients reacted only to a 9-kd allergen of both mugwort and peach, whereas the 7 patients with pollinosis reacted to other allergens. Ten patients with mugwort allergy, no history of allergy to peach, and negative results for peach-specific IgE antibodies were also studied. The mugwort 9-kd protein was identified as a lipid transfer protein (LTP) homologous to peach LTP. Immunoblotting inhibition showed that IgE binding to the peach 9-kd band was totally inhibited by 4 microg of peach LTP but only by 400 microg of mugwort LTP, whereas 4 microg of both mugwort and peach LTP totally inhibited the mugwort immunoblotting. The results were similar with other pollens. CONCLUSIONS: Patients sensitized only to the 9-kd LTP of mugwort do not present hay fever symptoms, and this sensitization is a consequence of the peach sensitization.     

A single mouse monoclonal antibody,E58 modulates multiple IgE epitopes on group 1 cedar pollen allergens

We recently described a dominant role for conformational epitopes on the group 1 allergen of the mountain cedar (Juniperus ashei, Cupressaceae), Jun a 1, in pollen hypersensitivity in South Central U.S.A. Since these epitopes are surface exposed and are likely to be flexible, they may be susceptible to molecular or physical perturbations. This may make Jun a 1 a potential target for new forms of therapy for cedar pollinosis. Here, we describe a mouse monoclonal antibody, termed E58, which binds to the group 1 allergens of the cedar pollens from three highly populated regions of the world (central U.S.A., France and Japan). Upon binding to these allergens, E58 strongly reduces the binding of patient’s IgE antibodies to these dominant allergens. This characteristic of E58, and potentially other similar antibodies, suggests an opportunity to develop preventative or therapeutic agents that may inhibit cedar pollen sensitization or prevent their allergic reactions.     

The most common phenotypes of sensitization to inhalant allergens in childhood

Background Atopic individuals are frequently sensitized to a limited number of certain allergens, although most of them are exposed to multiple inhalant allergens in daily life. Objective We investigated the hypothesis that observed common patterns of sensitization might occur with similar frequency within two independent study populations of school-children. Methods The results were derived from skin-prick tests conducted on two large samples of children (study 1:n= 583; study 2: n= 1099) examined with the same panel of six inhalant allergens. Results In order to ensure that the comparison was uniform, the younger subpopulation of study 1 (n= 147) was compared with the sample of study 2 (n= 374). The highest frequency for monosensitization was found for sensitization to Dermatophagoides pteronyssinus (study 1: 18.4%, study 2: 20.3%), followed by monosensitization to grass pollens (study 1: 12.2%; study 2: 8.8%). Using multiple logistic regression for each specific sensitization, a significantly increased relative risk of sensitization to hazel pollens (study 1 OR 5.9; study 2 OR: 24.3) appeared to be associated with sensitization to birch pollens. The same applied to dog dander (study 1 OR: 7.3; study 2 OR: 2.6), which showed an association with sensitization to cat dander. Conclusion In summary, our data suggest that certain clusters of monosensitization and polysensitization to common inhalant allergens exist among a given population. This may well be a reflection of diversity in disposition to specific sensitization and/or antigen crossreactivity. From a practical point of view the data also might help in counselling parents of allergic children.     

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.     

Sensitization to Lolium multiflorum grass pollen in pollinosis patients: evaluation of allergenic fractions recognized by specific IgE antibodies

BACKGROUND: Lolium multiflorum (Lm) pollen allergens are the major causative agents for rhinoconjunctivitis in Southern Brazil. There have been no studies about the sensitization and allergenic cross-reactivity between Lm and other grass pollens. We evaluated the sensitization of Brazilian pollinosis patients to Lm pollen allergens through skin prick test (SPT) and immunoassays (ELISA and immunoblot). METHODS: Serum samples from 60 patients with pollinosis and positive SPT to grass pollen extracts (Lm+ group), 30 patients with negative SPT to grass pollen, but positive SPT to mite extracts (Lm- group), and 30 nonatopic subjects (NA group) were tested by SPT, ELISA, and immunoblot using Lm extract. Inhibition immunoassays with Lolium perenne (Lp), mixed grass (Gmix) and Lm extracts were also performed. RESULTS: A high concordance was found between the Gmix and Lm extracts in SPT. Positivity rates in SPT were also highly concordant with IgE-ELISA results. The assay was able to detect Lm-specific IgE in >95% of Lm+ patients. A significant self- and cross-inhibition was observed in IgE-ELISA, reflecting a high cross-reactivity between the grass pollen allergens. Immunoblot revealed 13 IgE-binding Lm fractions, from which the bands 28-30 kDa and 31-34 kDa were recognized by >90% of Lm+ patients. CONCLUSION: Lm-specific IgE antibodies are highly cross-reactive with pollen proteins from other grass species. The results indicate that Lm extracts could be used in both SPT and ELISA for a more specific evaluation of IgE responses to Lm grass pollen in Brazilian pollinosis patients.     

Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen

BACKGROUND: Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis. OBJECTIVE: We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP. METHODS: Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing. RESULTS: Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract. CONCLUSIONS: An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy.     

Hypersensitivity to black locust (Robinia pseudoacacia) pollen: "allergy mirages".

BACKGROUND: The allergenicity of the ornamental tree Robinia pseudoacacia, or black locust, is unknown. OBJECTIVE: To evaluate the prevalence of sensitization to R. pseudoacacia pollen, its possible allergenic cross-reactivity with other common pollens, and the potential implication of pollen panallergens (profilin, polcalcin, and 1,3-beta-glucanase) as a cause of sensitization to R. pseudoacacia pollen. METHODS: Skin prick testing with R. pseudoacacia pollen was performed in 149 patients with pollinosis. Nasal challenge with R. pseudoacacia pollen was performed in 10 patients. The prevalence of sensitization to the recombinant forms of profilin (rChe a 2), polcalcin (rChe a 3), and the N-terminal of the 1,3-beta-glucanase (rNtD of Ole e 9) was investigated. Immunoblotting, enzyme-linked immunosorbent assay, and competitive inhibition assays were performed with R. pseudoacacia pollen and recombinant pollen allergens. RESULTS: Sixty-four patients (43%) had positive skin prick test reactions to R. pseudoacacia pollen. Nasal challenge results were positive in 5 sensitized patients and negative in 4 controls and 1 sensitized patient. The allergenic profile of R. pseudoacacia pollen comprises at least the panallergen profilin, a calcium-binding protein, and a 1,3-beta-glucanase. The prevalence of sensitization to rChe a 2, rChe a 3, and rNtD of Ole e 9 was 60%, 33%, and 87%, respectively, among patients sensitized to R. pseudoacacia pollen. Binding of IgE to R. pseudoacacia extract was completely inhibited by Robinia, Chenopodium, Olea, Cupressus, and Lolium extracts. CONCLUSIONS: The high prevalence of R. pseudoacacia pollen sensitization in patients with pollinosis is likely to be due to cross-sensitization to panallergens (profilin, polcalcin, and 1,3-beta-glucanase) from other common pollens. This phenomenon may lead to a diagnosis of "allergy mirages."