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BACKGROUND: Anaphylaxis includes mast cell (MC) activation, but less is known about downstream mechanisms (ie, vascular permeability controlled by endothelial cells [ECs]). The TNF-like weak inducer of apoptosis (TWEAK) and its sole receptor, fibroblast growth factor-inducible molecule 14 (Fn14), belong to the TNF superfamily and are involved in proinflammatory responses.OBJECTIVE: We sought to investigate the role of TWEAK/Fn14 axis in anaphylaxis.METHODS: In vivo vascular permeability and mouse models of passive systemic anaphylaxis (PSA) and active systemic anaphylaxis were applied to wild-type (WT), TWEAK- and Fn14-deficient mice (TWEAK-/- and Fn14-/-, respectively). Primary bone marrow-derived mast cells (BMMCs) and ECs from WT and Fn14-/- or TWEAK-/- mice were studied. The TWEAK/Fn14 axis was also investigated in human samples.RESULTS: Mice with PSA and active systemic anaphylaxis had increased Fn14 and TWEAK expression in lung tissues and increased serum soluble TWEAK concentrations. TWEAK and Fn14 deficiencies prevent PSA-related symptoms, resulting in resistance to decreased body temperature, less severe reactions, and maintained physical activity. Numbers of MCs after PSA are similar between genotypes in different tissue regions, such as ear skin and the trachea, tongue, peritoneum, lungs, and bone marrow. Moreover, in vitro studies revealed no differences in degranulation or mediator release between WT and Fn14-/- BMMCs after IgE-FcεRI stimulation. In vivo and in vitro histamine and platelet-activating factor administration increases Fn14 receptor expression in lungs and ECs. Moreover, Fn14 deficiency in ECs maintained in vitro impermeability when stimulated by mediators or activated BMMCs but not by TWEAK-/- BMMCs, indicating that Fn14 is crucial for endothelial barrier function. TWEAK/Fn14 deletion or TWEAK-blocking antibody prevented histamine/platelet-activating factor-induced vascular subcutaneous permeability. Circulating soluble TWEAK levels were increased in patients with anaphylaxis, and plasma from those patients increased Fn14 expression in ECs.CONCLUSION: The TWEAK/Fn14 axis participates in anaphylactic reactions. Inhibition of TWEAK/Fn14 interaction could be efficacious in anaphylaxis therapy.

Background Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens. Objective We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach. Methods Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed. Results American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age. Conclusions Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.

Background Allergy to kiwi fruit is being increasingly reported, but it has never been evaluated by means of a double-blind, placebo-controlled food challenge (DBPCFC) study. Objective We sought to assess kiwi allergy on the basis of a DBPCFC and identify the patterns of allergen recognition in sensitized patients from a birch-free area. Methods Forty-three patients with allergy symptoms who were sensitized to kiwi were evaluated by means of clinical history, skin tests, IgE determinations, and DBPCFCs. The pattern of allergen recognition was assessed by means of IgE immunoblotting. Sequence analysis of IgE-binding bands was performed by using Edman degradation. Results DBPCFCs were performed in 33 patients; 4 patients had experienced severe anaphylaxis, and 6 patients declined informed consent. DBPCFC results were positive in 23 patients and negative in 10 patients. The most frequent clinical manifestation was oral allergy syndrome. Twenty-one percent of the patients were not allergic to pollen. Forty-six percent of patients experienced systemic symptoms, and this happened with higher frequency in patients not allergic to pollen (100%). Twenty-eight percent of the patients were sensitized to latex. The IgE-binding bands in kiwi extract more frequently recognized by patient sera were those of 30, 24, 66, and 12 kd, and they could not be associated with any pattern of kiwi-induced allergic reactions. Conclusion The results provide evidence that kiwi allergy is not a homogeneous disorder because several clinical subgroups can be established. No definite allergen-recognition pattern was associated with the type of allergic reactions to kiwi. One of 5 patients with kiwi allergy was not allergic to pollen, and these patients had the highest risk of systemic reactions to kiwi.

Background: Preventive measures have been proposed to reduce the risk of sensitization to natural rubber latex (NRL), but this is not always feasible. Objective: The aim of this study was to determine the efficacy and safety of specific immunotherapy with a standardized latex extract in sensitized workers. Methods: Twenty-four patients allergic to NRL with contact urticaria (n = 8) and rhinitis or asthma (n = 16) were included (16 in the active group and 8 in the placebo group). Treatment started in a cluster immunotherapy protocol, with injections every week for 3 months and then every other week for another 3 months. Results: Patients in the active group had significantly lower values than patients in the placebo group in skin terms of reactivity to NRL ( P P = .047), and latex glove use test results ( P = .046) after 6 months of treatment. There were no significant differences between the active and placebo groups in symptom scores, use of medication, self-assessment, or methacholine test results either before or after treatment. Differences in nasal and bronchial symptoms during specific inhalation challenges ( P = not significant and P = .05, respectively) were observed in favor of the active group. In the active group 32 systemic reactions were observed (8% of doses), mostly during the build-up period, being more frequent in patients with respiratory symptoms ( P = .004). All reactions responded promptly to treatment. Conclusion: Clinical efficacy was shown mainly on cutaneous symptoms, although an improvement in rhinitis and asthma symptoms was also observed during specific inhalation challenges. Latex-specific immunotherapy might be a useful approach for the treatment of latex allergy in sensitized workers. (J Allergy Clin Immunol 2003;111:985-94.)

Background: There are few data that link quantified natural rubber latex (NRL) absorbable dusting powder aerosol to biologic responses in NRL-sensitized subjects. Methods: We conducted a study on 30 health care workers with possible occupational asthma. All the subjects but 2 had a positive skin prick test result with NRL extract. Quantified environmental challenge (QEC) with powdered NRL gloves was performed in a 7-m 3 chamber. The patients would don and discard a pair of gloves every 3 minutes up to a maximum of 60 minutes. The concentrations of NRL aeroallergen were measured by a competitive IgE immunoassay. Ocular and respiratory symptoms and pulmonary function were monitored. Results: Twenty-six patients (87%) had rhinoconjunctivitis, 19 (63%) had an asthmatic response (responders), and 1 patient developed eosinophilic bronchitis on QEC. The asthmatic responses were of the early type in 15 patients, dual in 3, and isolated late in 1 patient. The duration of exposures sufficient to elicit asthmatic responses varied from 3 to 114 cumulative minutes. Time-weighted average NRL aeroallergen concentrations during QEC with responders ranged between 199 and 1107 ng/m 3 . NRL concentrations measured at various time points during exposure were reproducible. Measured concentrations of NRL aeroallergen between responders (677 ± 281 ng/m 3 ) and nonresponders (611 ± 351 ng/m 3 ) were not statistically different. The cumulative inhaled NRL aeroallergen dose required for an asthmatic response ranged between 25 to 515 ng. Conclusion: The total dose of latex aeroallergen eliciting an asthmatic response during QEC was mostly affected by the duration of exposure and varied widely from person to person. (J Allergy Clin Immunol 2003;111:788-94

Background: Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization. Objective: The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them. Methods: One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin. Results: The skin test results revealed that peach-allergic patients frequently reacted to most pollens—grasses, weeds, and trees—even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients. Conclusion: The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants—such as profilins—between peach and taxonomically unrelated pollens. (J Allergy Clin Immunol 1999;104:688-94.)

Twenty-eight patients (14 in an active treatment group and 14 in a placebo group) with rhinoconjunctivitis and asthma caused by cat hypersensitivity took part in a placebo-controlled, randomized, double-blind study to evaluate the risk-benefit quotient of the maintenance dose corresponding to 13.2 micrograms Fel d I antigen. The cat extract was biologically standardized and quantified with monoclonal antibodies (100 biological units: 33 microgram of Fel d I antigen, 650 micrograms of albumin, and 99 micrograms of Fel d Bd/K30 antigen). After 1 year of treatment, the systemic reactions to cat extract immunotherapy were mild and infrequent. Improvement was observed in the active treatment group in comparison with the placebo group in the medication-symptoms score (p < 0.001); in skin prick test (p < 0.001), conjunctival provocation test (p < 0.001), and allergen bronchoprovocation test (p < 0.05) results, and in nonspecific bronchial hyperreactivity measured with methacholine, which was not statistically significant. This study demonstrates the favorable risk-benefit quotient of the dose of 13.2 micrograms of Fel d I antigen, which may serve as a future reference in defining the optimum dose and appropriate proportion of antigens that should be administered in cat extract immunotherapy.

from the patient's house were captured, killed by freezing, and then macerated. The total protein concentration of the extract was 2.3 mg/ml (Bio-Rad). The patient had a positive skin prick test result (12 mm diameter wheal with pseudopods). DL extract (10 mg/ml) was coupled to cyanogen bromide-activate d filter paper disks. DL-specific IgE (RAST) was 3.7

S U N D A Y 354 Characterization Of The Allergenic Activity Of Tropomyosin From Aedes Aegypti Mr. Jose F. Cantillo, Prof. Leonardo Puerta, Dr. Enrique FernandezCaldas, Dr. Sylvie Lafosse-Marin; Complutense University of Madrid, Spain; Inmunotek S.L., Alcal a de Henares, Spain, Institute for Immunological Research/University of Cartagena, Cartagena, Colombia, Inmunotek, S.L, Spain, Cabinet de Inmunoallergology, Fort de France, Martinique. RATIONALE: Mosquito bites are an important cause of skin lesions in allergic and non-allergic individuals worldwide. The inhalation of mosquito allergens may also be a cause of allergic respiratory diseases. It has been suggested that there may be cross-reactivity among mosquitoes and other arthropods such as mites, Chironomidae and shrimps. We hypothesized that the panallergen tropomyosin may be involved in this process. METHODS: Tropomyosin was purified from a whole body A. aegypti extract by size exclusion and anionic exchange chromatography. Specific IgE binding to the purified tropomyosin was evaluated by immunoblot and ELISA in allergic patients with positive ELISA to A. aegypti allergenic extract and control individuals. Cross-reactivitywas evaluated by immunoblotting and ELISA inhibitions using tropomyosin derived from the giant tiger prawn Penaeus monodon (nPen m 1) and from the whiteleg shrimp Litopenaeus vannamei (rLit v 1). RESULTS: A purified fraction from the allergenic A. aegypti extract showed four bands of several molecular weights with reactivity to antiPen m 1 rabbit serum, which showed also IgE reactivity to positive sera to mosquito extract. The IgE reactivity to these bands disappears when the sera where adsorbed with shrimps tropomyosin (nPen m 1 and rLit v 1). 25% of the mosquito allergic individuals had detectable specific IgE levels to this fraction. Inhibition of IgE reactivity higher than 90 % was demonstrated in a sera pool adsorded with nPen m 1 and rLit v 1. CONCLUSIONS: We have demonstrated the presence of tropomyosin in A. aegypti extract, which cross-react with shrimp tropomyosins.

Background Lentils are often responsible for allergic reactions to legumes in Mediterranean children. Although the primary sequence of the major allergen Len c 1 is known, the location of the IgE-binding epitopes remains undefined. Objective We sought to identify IgE-binding epitopes of Len c 1 and relate epitope binding to clinical characteristics. Methods One hundred thirty-five peptides corresponding to the primary sequence of Len c 1 were probed with sera from 33 patients with lentil allergy and 15 nonatopic control subjects by means of microarray immunoassay. Lentil-specific IgE levels, skin prick test responses, and clinical reactions to lentil were determined. Epitopes were defined as overlapping signal above interslide and intraslide cutoffs and confirmed by using inhibition assays with a peptide from the respective region. Hierarchic clustering of microarray data was used to correlate binding patterns with clinical findings. Results The patients with lentil allergy specifically recognized IgE-binding epitopes located in the C-terminal region between peptides 107 and 135. Inhibition experiments confirmed the specificity of IgE binding in this region, identifying different epitopes. Linkage of cluster results with clinical data and lentil-specific IgE levels displayed a positive correlation between lentil-specific IgE levels, epitope recognition, and respiratory symptoms. Modeling based on the 3-dimensional structure of a homologous soy vicilin suggests that the Len c 1 epitopes identified are exposed on the surface of the molecule. Conclusion Several IgE-binding sequential epitopes of Len c 1 have been identified. Epitopes are located in the C-terminal region and are predicted to be exposed on the surface of the protein. Epitope diversity is positively correlated with IgE levels, pointing to a more polyclonal IgE response.

acquired sensitization and desensitization also differed between the human and the rabbit, with the rabbit requiring a shorter time to develop desensitization (14 weeks) than the human (21 weeks). This could represent a true difference. It could also have occurred because the human had less frequent mosquito bites than the rabbit and received a relatively low dose of mosquito salivary antigen (100 bites every 2 weeks in a 70 kg human vs 140 bites every week in a 2 kg rabbit). We demonstrate prospectively for the first time that regular, continuous, high-dose, natural allergen exposure eventually leads to desensitization (defined as complete loss of delayed and immediate responsiveness) and that both IgE and IgG are involved in the sensitization process. This model offers an excellent opportunity for further in-depth study of immediate and delayed hypersensitivity responses in humans. The immunologic mechanisms involved may be different in humans than in animals (at least in rabbits) in which IgG acts as a blocking antibody. We thank Dr. Reinhart Brust and Mr. Ben Yang Ding for their contributions to this work.

Rationale Black locust (Robinia pseudoacacia)(Rp) is an ornamental tree that belongs to the Leguminosae family. Although it is mainly pollinated by insects, pollen grains were collected in spore traps from Madrid during its pollination. We investigated the prevalence of sensitization to Rp pollen in patients with seasonal allergic rhinitis or asthma. We also evaluated the sensitization to legumes in a subgroup of patients. Methods Skin prick tests with Rp pollen (ALK-Abello, Madrid) were performed in 114 consecutive patients, with legumes in 35 and Rp pollen nasal challenge in 8. Results A total of 49 patients (43%) were sensitized to Rp pollen. These patients showed a higher prevalence of sensitization to other pollens such as Cupressus arizonica ( p p Conclusions We found a high prevalence of sensitization to Rp pollen among our patients with pollinosis. Rp pollen may give rise to respiratory symptoms in sensitized patients. Patients sensitized to Rp pollen have a higher prevalence of skin sensitization to legumes.

Pectin (E440), a structural polysaccharide found in vegetables, is widely used as an additive in the food and pharmaceutical industries. Allergic reactions to pectin have rarely been reported, only in occupational setting. A 59-year-old male developed widespread urticaria, angioedema, cough and shortness of breath within 15 min after an enema examination with a barium sulphate suspension (Barigraf), requiring epinephrine, fluids and methylprednisolone. Personal history revealed episodes of urticaria, vomits and bronchospasm after eating nuts, some confectioner products and dressing salads. Skin prick test (SPT) were positive to Barigraf and the pectin excipient, eliciting wheals of 15 and 18 mm. SPT were negative to the remaining Barigraf components, common inhalants and latex. SPT and specific IgE determinations to food (CAP, EAST techniques) revealed a strongly positive response to cashew nut and pistachio, being moderate to other nuts, chickpea, bean, peach and orange peel. ELISA-specific IgE was positive to pectin and Barigraf. ELISA-inhibition assays showed a complete inhibition in IgE-binding to Barigraf using pectin in liquid phase, as well as in the opposite way. Moreover, a high inhibition level of IgE-binding to pectin and barigraf was achieved using cashew or pistachio extracts as inhibitors and in a lower level with other nuts. Conclusion We report the first case of IgE-mediated anaphylaxis by pectin contained in a barium suspension. Cross-reactivity was demonstrated with cashew, pistachio and other nuts. Physicians should be aware of allergy to pectin in barium examinations, mainly in patients allergic to vegetables and nuts.

Rationale The causative role of cereal flour, glycolitic enzymes, and egg proteins in bakers with work-related rhinitis and asthma was investigated. Methods Sensitization to baking ingredients was assessed by immunologic tests and confirmed by specific inhalation challenge (SIC). Results Twenty-one bakery workers (20 males; 22 to 60 year-old) with work-related respiratory symptoms were evaluated. They had been working in the baking industry between 2.6 and 46 years. The mean duration of rhinitis and asthma symptoms was 7.66 and 7.05 years, respectively. Sixty-seven percent were atopic and 52% were non-smokers. Methacholine inhalation tests revealed bronchial hyperresponsiveness in all patients but one. Seventeen patients (81%) had positive skin tests (ST) to wheat flour, 76.2% to rye flour, 47.6% to soybean flour, 61.9% to alpha-amylase, 33.3% to hemicellulase, 19% to glucoamylase and 33.3% to storage mites. Twelve patients were exposed to egg aerosols at work. Five of them (41.7%) had positive ST to egg white, 33.3% to ovalbumin, 16.7% to ovomucoid, 41.7% to lysozyme and 25% to egg yolk. SIC tests were performed with wheat flour (n=10), rye flour (n=1), soybean flour (n=6), alpha-amylase (n=12), hemicellulase (n=4), glucoamylase (n=3), ovalbumin (n=2), ovomucoid (n=1) and lysozyme (n=5) in some sensitized workers. Eighty-four percent SIC tests were positive. SIC elicited isolated early asthmatic responses (AR) in 62.1% cases, isolated late AR in 5.4% cases, and dual AR in 32.4% cases. Conclusions Inhalation of cereal flour and baking additives may induce asthmatic reactions in sensitized workers. However, not all bakers sensitized to these agents experienced an asthmatic reaction during SIC.