Lupine-induced anaphylaxis

Protein Concentration Affects the Food Allergen γ-Conglutin Uptake and Bacteria-Induced Cytokine Production in Dendritic Cells

γ-Conglutin (γ-C) from lupin seeds has been identified as a potent allergen with cross reactivity to peanuts. Here, we investigated how γ-C affected the response in bone marrow-derived dendritic cells (DCs) to bacterial stimuli. γ-C enhanced L. acidophilus NCFM (LaNCFM)-induced IL-12, IL-10, and IL-23 dose-dependently. In contrast, together with E. coli Nissle or LPS, γ-C reduced the production of IL-12 but not of IL-23 and IL-10. Enzyme-hydrolyzed γ-C also enhanced LaNCFM-induced IL-12 and IL-23 production. All preparations induced ROS production in the DCs. The mannose receptor ligands mannan and dextran and the clathrin inhibitor monodansylcadaverine partly inhibited the endocytosis of γ-C. Kunitz trypsin inhibitor and the scavenger receptor ligand polyG also enhanced LaNCFM-induced IL-12, indicating the involvement of receptors other than C-type lectin receptors. The endocytosis of labeled γ-C increased dose-dependently by addition of unlabeled γ-C, which coincided with γ-C's tendency to aggregate. Taken together, γ-C aggregation affects endocytosis and affects the cytokine production induced by gram-positive and gram-negative bacteria differently. We suggest that γ-C is taken up by the same mechanism as other food proteins but due to aggregation is present in higher concentration in the DCs. This could influence the resulting T-cell response in a microbial stimuli-dependent way.

Rapid detection of β-conglutin with a novel lateral flow aptasensor assisted by immunomagnetic enrichment and enzyme signal amplification

A simple, rapid and economic lateral flow immunochromatographic assay (LFICA) was designed for ultrasensitive detection of β-conglutin. Instead of antibodies and gold nanoparticles (AuNPs) used in conventional LFICA, a cognate aptamer duo, binding to β-conglutin and Fe₃O₄@Au core-shell nanoparticles, was applied in this study. An enzyme signal amplification strategy was used to enhance sensitivity. In addition, a new magnetic enrichment strategy was employed to further enhance sensitivity of the assay, slowing down movement of the capture probe (i.e., Fe₃O₄@Au nanostructures) using an external magnetic field. The novel LFICA assay can be completed within 20 min and achieved a detection limit of 8 fM, a thousand-times lower than similar assays without magnetic focusing. Overall, our results demonstrated the potential for the proposed LFICA sensor in rapid detection of β-conglutin without any special analytical expertise or instrumentations.

Hidden Causes of Anaphylaxis

PURPOSE OF REVIEW

This study aimed to review important hidden causes of anaphylaxis in ingestants, non-ingestants, and uncommon settings.

RECENT FINDINGS

Multiple new and elusive causes of anaphylaxis have been described over the past 35 years. Further research is required to identify the epidemiology, pathophysiology, and clinical impact of these hidden causes. Although these culprits should be considered in the appropriate clinical scenarios, many remain exceedingly rare.

Less travelled roads in clinical immunology and allergy: drug reactions and the environmental influence

Allergy and clinical immunology are examples of areas of knowledge in which working hypotheses are dominant over mechanistic understanding. As such, sometimes scientific efforts follow major streams and overlook some epidemiologically prevalent conditions that thus become underestimated by the research community. For this reason, we welcome the present issue of Clinical Reviews in Allergy and Immunology that is dedicated to uncommon themes in clinical immunology and allergy. First, comprehensive discussions are provided for allergy phenomena of large potential impact in clinical practice such as reactions to cephalosporins or aspirin-induced asthma and in everyday life such as allergies to food additives or legumes. Further, the issue addresses other uncommon themes such as urticaria and angioedema, cercarial dermatitis, or late-onset inflammation to soft tissue fillers. Last, there will be discussion on transversal issues such as olfactory defects in autoimmunity, interleukin 1 beta pathway, and the search for new serological markers in chronic inflammation. As a result, we are convinced that this issue will be of help to clinicians involved in internal medicine as well as to allergists and clinical immunologists. More importantly, we are convinced that these discussions will be of interest also to basic scientists for the numerous translational implications.

Impact of thermal processing on legume allergens

Food induced allergic manifestations are reported from several parts of the world. Food proteins exert their allergenic potential by absorption through the gastrointestinal tract and can even induce life threatening anaphylaxis reactions. Among all food allergens, legume allergens play an important role in induction of allergy because legumes are a major source of protein for vegetarians. Most of the legumes are cooked either by boiling, roasting or frying before consumption, which can be considered a form of thermal treatment. Thermal processing may also include autoclaving, microwave heating, blanching, pasteurization, canning, or steaming. Thermal processing of legumes may reduce, eliminate or enhance the allergenic potential of a respective legume. In most of the cases, minimization of allergenic potential on thermal treatment has generally been reported. Thus, thermal processing can be considered an important tool by indirectly prevent allergenicity in susceptible individuals, thereby reducing treatment costs and reducing industry/office/school absence in case of working population/school going children. The present review attempts to explore various possibilities of reducing or eliminating allergenicity of leguminous food using different methods of thermal processing. Further, this review summarizes different methods of food processing, major legumes and their predominant allergenic proteins, thermal treatment and its relation with antigenicity, effect of thermal processing on legume allergens; also suggests a path that may be taken for future research to reduce the allergenicity using conventional/nonconventional methods.

Cross-allergic reactions to legumes in lupin and fenugreek-sensitized mice

Several legumes may induce allergy, and there is extensive serological cross-reactivity among legumes. This cross-reactivity has traditionally been regarded to have limited clinical relevance. However, the introduction of novel legumes to Western countries may have changed this pattern, and in some studies cross-allergy to lupin has been reported in more than 60% of peanut-allergic patients. We wanted to explore cross-reactions among legumes using two newly established mouse models of food allergy. Mice were immunized perorally with fenugreek or lupin with cholera toxin as adjuvant. The mice were challenged with high doses of fenugreek, lupin, peanut or soy, and signs of anaphylactic reactions were observed. Cross-allergic mechanisms were investigated using serum mouse mast cell protease-1 (MMCP-1), antibody responses, immunoblotting and ex vivo production of cytokines by spleen cells. Signs of cross-allergy were observed for all the tested legumes in both models. The cross-allergic symptoms were milder and affected fewer mice than the primary allergic responses. The cross-allergy was reflected to a certain extent in the antibody and T-cell responses, but not in serum MMCP-1 levels. Cross-allergy to peanut, soy, fenugreek and lupin was observed in lupin-sensitized and fenugreek-sensitized mice. Differences in serological responses between primary allergy and cross-allergy might be due to mediation through different immune mechanisms or reflect different epitope affinity to IgE. These differences need to be further investigated.

Vicia faba Hypersensitivity and ASA Intolerance in a Farmer: A Case Report

The IgE-mediated allergic reactions to food are caused, generally, by ingestion. However, they can be rarely induced by exposure to airborne food particles through the handling or the cooking. Vicia faba is a vegetable which belongs to Legumes or Fabaceae family, Fabales order. Allergic reactions after ingestion of legumes and cases of asthma after exposure to the cooking vapors have been reported in the literature. A paper assessed the volatile substances (insect repellents) released by V. faba. The authors demonstrated that this plant produces several chemical substances, such as small quantities of methyl salicylate. We describe a case of occupational allergy, induced by handling during picking up of fresh broad beans, in a farmer with history of adverse reaction after eating the cooked and raw vegetable.

Extraction, isolation, and characterization of globulin proteins from Lupinus albus

Lupin has recently been added to the list of allergens requiring mandatory advisory labeling on foodstuffs sold in the European Union, and since December 2008, all products containing even trace amounts of lupin must be labeled correctly. Lupin globulins consist of two major globulins called α-conglutin (11S and "legumin-like") and β-conglutin (7S and "vicilin-like") and another additional two globulins, γ-conglutin and δ-conglutin, which are present in lower amounts. We report on a methodology to facilitate the extraction of each of these proteins using centrifugation and isolation by anion-exchange chromatography followed by size-exclusion chromatography. The isolated subunits were characterized using reducing and non-reducing polyacrylamide gel electrophoresis, western blotting, and peptide mass fingerprinting, all of which revealed that the individual protein subunits are highly pure and can be used as immunogens for the production of antibodies specific for each of the conglutin fractions, as well as standards, and the extraction protocol can be used for the selective extraction of each of the subunits from foodstuffs, thus facilitating a highly accurate determination of the lupin concentration. Furthermore, the subunits can be used to elucidate information regarding the toxicity of each of the subunits, by looking at their interaction with the IgE antibodies found in the serum of individuals allergic to lupin, providing critical information for the definition of the requirements of analytical assays for the detection of lupin in foodstuffs.

Lupine, a source of new as well as hidden food allergens

The present review summarizes current knowledge about lupine allergy, potential sensitization routes, cross-reactions between lupine and other legumes, and the respective IgE-binding proteins. Since the 1990 s, lupine flour is used as a substitute for or additive to other flours, mostly wheat flour, in several countries of the EU. In 1994, the first case of an immediate-type allergy after ingestion of lupine flour-containing pasta was reported. Since then, the number of published incidents following ingestion or inhalation of lupine flour is rising. So far, the Lupinus angustifolius beta-conglutin has been designated as the allergen Lup an 1 by the International Union of Immunological Societies Allergen Nomenclature Subcommittee. Initially, publications focussed on the fact that peanut-allergic patients were at risk to develop anaphylaxis to lupine due to cross-reactivity between peanut and lupine. At present, however, the ratio between cases of pre-existing legume allergy (mostly peanut allergy) to de novo sensitization to lupine seed is nearly 1:1. Although in December 2006, lupine and products thereof were included in the EU foodstuff allergen list according to the Commission Directive 2006/142/EC amending Annex IIIA of Directive 2000/13/EC in order to prevent severe reactions caused by "hidden food allergens", the majority of patients and medical personnel are still not aware of raw lupine seed as potentially dangerous food allergen.

Clinical relevance of sensitization to lupine in peanut-sensitized adults

BACKGROUND

The use of lupine in food has been increasing during the last decade and allergic reactions to lupine have been reported, especially in peanut-allergic patients. The frequency and the degree of cross-reactivity to other legumes are not known. The aim of the study was to investigate the frequency of sensitization to lupine, and in addition to pea and soy, and its clinical relevance, in peanut-sensitized patients. Furthermore, to determine the eliciting dose (ED) for lupine using double-blind placebo-controlled food challenges (DBPCFC).

METHODS

Thirty-nine unselected peanut-sensitized patients were evaluated by skin prick tests (SPT) and ImmunoCAP to lupine, pea, and soy. Clinical reactivity was measured by DBPCFC for lupine, and by history for pea and soy.

RESULTS

Eighty-two percent of the study population was sensitized to lupine, 55% to pea, and 87% to soy. Clinically relevant sensitization to lupine, pea, or soy occurred in 35%, 29%, and 33% respectively of the study population. None of the patients was aware of the use of lupine in food. The lowest ED for lupine, inducing mild subjective symptoms, was 0.5 mg, and the no observed adverse effect level (NOAEL) was 0.1 mg. No predictive factors for lupine allergy were found.

CONCLUSION

In peanut-sensitized patients, clinically relevant sensitization to either lupine or to pea or soy occurs frequently. The ED for lupine is low (0.5 mg), which is only fivefold higher than for peanut. Patients are not aware of lupine allergy and the presence of lupine in food, indicating that education is important to build awareness.

Lupin allergy in peanut-allergic children and teenagers

BACKGROUND

Lupin has now been introduced into food production in the UK. There is a concern that, on account of cross-reactivity, peanut-allergic children are at high risk for lupin allergy.

AIMS

To investigate the prevalence of lupin sensitization and allergy in children with peanut allergy compared with atopic controls.

METHODS

Children (<18 years) were recruited. Peanut-allergic subjects either had a convincing history of peanut allergy with diagnostic peanut skin prick test (SPT) or specific-immunoglobulin E (IgE) results or a positive food challenge. Control subjects were atopic but not peanut-allergic. All subjects had SPT to peanut and lupin. Sensitized subjects were offered a randomized, double-blind, placebo-controlled lupin challenge. Lupin allergy was defined as objective immediate hypersensitivity reaction at food challenge.

RESULTS

Forty-seven peanut-allergic children and 46 atopic controls were recruited. Sixteen peanut-allergic children were sensitized to lupin [34%, 95% confidence interval (CI): 21-49%]. Nine were challenged to lupin. Two reacted (itchy mouth and urticaria; itchy mouth and 20% drop in peak expiratory flow rate) giving a minimum prevalence of lupin allergy in peanut-allergic children of 4.0% (95% CI: 1-15%). Atopic controls were significantly (P = 0.001) less likely to be sensitized to lupin (4%, 95% CI: 1-15%) and had smaller wheals and serum-specific IgE results. None of the atopic controls reacted on lupin challenge, giving a rate of allergy in the atopic controls of 0% (95% CI: 0-8%).

CONCLUSIONS

A small but significant number of children with peanut allergy are allergic to lupin. Sensitization to lupin is much rarer in nonpeanut-allergic atopic subjects.

Lupin sensitization and clinical allergy in food allergic children in Norway

AIM

The aim of the present pilot study was to investigate to what extent children in Norway sensitized to lupin had clinical lupin allergy, and to compare sensitization to lupin with sensitization to other legumes.

METHODS

Thirty-five children with food allergy referred to a national referral hospital were evaluated with skin prick test (SPT) and analysis of serum-specific IgE to lupin, peanut, pea and soy. The children with positive SPTs to lupin were offered oral food challenges with lupin flour.

RESULTS

Fifteen children (43%) had positive SPT and 17 children (49%) had serum-specific IgE to lupin. Ten SPT-positive children underwent oral food challenges and one experienced an allergic reaction to lupin flour. This child was one of six challenged children with IgE antibodies to peanut >15 kU(A)/L. There was a strong relationship between positive SPT to lupin flour and positive SPT to soy and between positive SPT to lupin and specific IgE to soy, pea and peanut.

CONCLUSIONS

Children with sensitization to lupin are not likely to have a clinical lupin allergy. Avoidance of lupin on the basis of lupin sensitization or peanut allergy would lead to unnecessarily strict diets. Food challenge is currently necessary to diagnose lupin allergy.

Lupine-induced anaphylaxis in a child without known food allergy

BACKGROUND

Lupine allergy is caused by ingestion of the flour of a plant called Lupinus albus, a member of the Leguminosae family. Lupine allergy has been described in adult patients previously known to have peanut allergy (cross-reactivity).

OBJECTIVE

To describe the first case of an anaphylactic reaction caused by ingestion of lupine flour in a pediatric patient without a known peanut allergy.

METHODS

Symptom assessment, nutritional history, and skin and blood tests.

RESULTS

An otherwise healthy 8-year-old boy had nose and eye discharge followed by facial edema and difficulty breathing 30 minutes after eating an industrially prepared waffle containing eggs, sugar, and lupine flour. He had no history of food allergy and was eating a normal diet, including peanuts and other legumes. Results of skin prick tests using commercial extracts were positive to peanuts and negative to eggs, soy, and nuts; results of a prick-to-prick test using lupine flour were strongly positive (+ + + +). His total IgE level was 1,237 UI/mL. Specific IgE antibodies were positive to lupine seeds (20.8 kU/L) and peanuts (> 100 kU/L).

CONCLUSIONS

To our knowledge, we describe the first case of an anaphylactic reaction after ingestion of lupine flour in a child without known allergy. In the case of peanut allergy or any anaphylactic reaction without evident cause, especially after industrially prepared food ingestion, lupine should be considered in the list of allergens tested. Lupine is increasingly used in industrially prepared food but is not regularly declared in the composition, leading to difficulties in allergen avoidance.

Lupine allergy: not simply cross-reactivity with peanut or soy

BACKGROUND

Reports of lupine allergy are increasing as its use in food products increases. Lupine allergy might be the consequence of cross-reactivity after sensitization to peanut or other legumes or de novo sensitization. Lupine allergens have not been completely characterized.

OBJECTIVES

We sought to identify allergens associated with lupine allergy, evaluate potential cross-reactivity with peanut, and determine eliciting doses (EDs) for lupine allergy by using double-blind, placebo-controlled food challenges.

METHODS

Six patients with a history of allergic reactions to lupine flour were evaluated by using skin prick tests, CAP tests, and double-blind, placebo-controlled food challenges. Three of these patients were also allergic to peanut. Lupine allergens were characterized by means of IgE immunoblotting and peptide sequencing.

RESULTS

In all 6 patients the ED for lupine flour was 3 mg or less for subjective symptoms and 300 mg or more for objective symptoms. The low ED and moderate-to-severe historical symptoms indicate significant allergenicity of lupine flour. Two patients allergic to lupine but not to peanut displayed IgE binding predominantly to approximately 66-kd proteins and weak binding to 14- and 24-kd proteins, whereas patients with peanut allergy and lupine allergy showed weak binding to lupine proteins of about 14 to 21 or 66 kd. Inhibition of binding was primarily species specific.

CONCLUSION

Lupine allergy can occur either separately or together with peanut allergy, as demonstrated by 3 patients who are cosensitized to peanut and lupine.

CLINICAL IMPLICATIONS

Lupine flour is allergenic and potentially cross-reactive with peanut allergen, thus posing some risk if used as a replacement for soy flour.

Effect of an Instantaneous Controlled Pressure Drop on in vitro Allergenicity to Lupins (Lupinus albus var Multolupa)

BACKGROUND

Lupin seed flour has been reported as a causative agent of allergic reactions, especially in patients with allergy to peanut. Previous studies have demonstrated that autoclave treatment can considerably reduce the allergenicity of lupins.

AIMS

The aim of this work was to evaluate the effect of instantaneous controlled pressure drop (détente instantanée contrôlée, DIC) treatment on lupin in vitro allergenicity.

METHODS

Lupin cotyledons were subjected to instantaneous controlled pressure drop at several pressure and time conditions (3, 4.5 and 6 bar for 1, 2 and 3 min, respectively). Immunoreactivity to raw and DIC-treated extracts was evaluated by Western blot using a serum pool from 19 sensitized patients.

RESULTS

Depending on the operating parameters used during DIC treatment, a reduction in protein solubility of lupin seed was observed. Moreover, drastic modifications in protein profiles were observed after DIC treatment by SDS-PAGE analysis. Western blot experiments showed that the decreases in IgE binding to lupin proteins were associated with the increases in steam pressure and time treatment, and binding was completely abolished by DIC at 6 bar for 3 min.

CONCLUSIONS

The results suggest that DIC treatment could produce a reduction in lupin allergenicity.

Occupational sensitization to lupin in the workplace: occupational asthma, rhinitis, and work-aggravated asthma

BACKGROUND

Lupin is a legume. Its seed can be ground into flour and incorporated into food as a protein source. Cases of rhinitis, urticaria, and anaphylaxis from ingestion of lupin have been reported as well as asthma.

OBJECTIVE

To present a cross-sectional study of workers in a food processing company who were exposed to lupin and developed occupational allergy secondary to inhaling lupin products.

METHODS

Subjects were interviewed using a standardized questionnaire, including demographics and current and past symptoms. They underwent skin prick tests (SPTs) to common aeroallergens and lupin products, spirometry, and off-line exhaled nitric oxide measurement. Symptomatic subjects, sensitized to lupin on SPT, underwent methacholine bronchial provocation challenge. Those with bronchial hyperresponsiveness had specific bronchial provocation challenge to lupin.

RESULTS

A total of 53/54 subjects completed testing (98%). Overall, 21% (11/53) had positive SPT results to lupin. The lupin-sensitive group had a trend toward atopy (P = .06). Seven of 11 (64%) subjects in this group were symptomatic; all had rhinitis, and 2 had wheeze. Two subjects had positive methacholine challenges, and 1 had a positive specific bronchial provocation challenge to lupin with both an early-phase and a late-phase response.

CONCLUSION

Allergy to inhaled lupin occurs in the workplace. A high sensitization rate on SPT was found, which correlated with symptoms. The clinical significance of cross-reactivity between legumes on SPT is unclear.

CLINICAL IMPLICATIONS

Sensitization to the legume, lupin, can occur from exposure at work and carries a high prevalence of clinical symptoms, which in some cases leads to occupational rhinitis and asthma.

Monoclonal Antibodies against the Candidate Lupin Allergens α-Conglutin and β-Conglutin

BACKGROUND

The ingestion of dietary products containing sweet lupin (such as Lupinus albus or Lupinus angustifolius) has been reported to cause IgE-mediated allergic reactions. Recent studies have indicated lupin globulins as important IgE binding proteins. The aim of the present study was to generate and characterize monoclonal antibodies (mAbs) against lupin seed proteins.

METHODS

Mice were immunized with a protein isolate from L. albus and mAbs were obtained by hybridoma techniques. Albumins and globulins were extracted, and the globulin fraction was separated further into conglutins by anion exchange chromatography. Specificities, binding patterns and applications of the mAbs were investigated by immunochemical methods.

RESULTS

Five mAbs were produced: Lu11 (an IgG2b antibody), Lu8, Lu18, Lu34 and Lu35 (all IgM antibodies). The mAbs reacted strongly with protein isolates from both L. albus and L. angustifolius. All mAbs are directed towards the lupin globulin fraction; Lu11 and Lu18 recognize alpha-conglutin, while Lu8, Lu34 and Lu35 recognize beta-conglutin. In addition, Lu11 inhibited the binding of IgE from patients with positive skin prick tests to lupin proteins in a competitive ELISA by approximately 30%. Furthermore, preliminary results show that Lu11 can be used to develop a sensitive method for the detection of alpha-conglutin in foods.

CONCLUSIONS

Lupin globulins are immunogenic and alpha-conglutin is a potential allergen. This is the first study describing mAbs against the candidate lupin allergens, emphasizing the importance of additional studies on conglutins in lupin allergy.

Assessment of Lupin Allergenicity in the Cholera Toxin Model: Induction of IgE Response Depends on the Intrinsic Properties of the Conglutins and Matrix Effects

BACKGROUND

The well-established murine model of IgE-mediated food allergy, based on oral administration of antigen and cholera toxin (CT), has within the previous years been used to evaluate various food proteins. Nonetheless, little knowledge on the factors that determine the allergenicity of food proteins is available so far. The use of proteins from the legume seed Lupinus albus as food ingredients calls for an evaluation of their allergenic potential, and therefore, we applied the cited model to investigate the putative allergenicity of three lupin protein preparations representing different matrices in which the four types of conglutins are present in varying concentrations.

METHODS

Weekly, BALB/c A mice were orally immunized with the three lupin protein products together with CT. Total specific antibodies and IgE were determined by ELISA and Western blotting.

RESULTS

A dose-dependent Ig response against the analyzed proteins was observed for all three lupin products, while IgE responses against conglutins beta, gamma and delta, but not against conglutin alpha, were primarily detected after oral administration of lupin flakes. Whereas no differences among the samples for total specific Ig responses were seen, orally administered lupin flake extracts were much more efficient in inducing a conglutin-specific IgE response compared with fractionated lupin protein products.

CONCLUSIONS

Although the lupin-specific Ig response induced by coadministration of CT and lupin proteins appears to be dose dependent, the IgE response appears to depend merely on some intrinsic properties of the proteins as well as some factors of the protein matrix.

Lupine inhalation induced asthma in a child

The ingestion of lupine seed flour has been reported as a cause of allergic reactions. There is some evidence of its allergenic potential after inhalation. An 8-year-old asthmatic child, who was allergic to peanut, was studied in our clinic with the suspicion of an adverse drug reaction due to salbutamol. He suffered an asthma attack while playing with his brother, who had been eating lupine seed as snack; surprisingly, the asthma attack worsened with salbutamol. The skin tests showed a positive result with Lupinus albus extract, peanut, garbanzo bean, navy bean, pea, green bean, lentil, soy, Olea europea pollen, grass pollen and Plantago lanceolata pollen. The prick-by-prick tests both from dried seeds and those preserved in salt and water were strongly positive. Serum specific IgE antibodies were positive to Lupine albus (1.43 kU/l), peanut (4.32 kU/l), soy (2.15 kU/l), lentil (3.12 kU/l) and garbanzo (0.7 kU/l). After informed consent salbutamol was well tolerated but the patient had asthma in 5 min of manipulation of the lupine seeds. In our case, reactivity with other legumes was also demonstrated, but only peanut allergy was relevant because boiled legumes were tolerated. It is also notorious that anamnesis is so important to assess the true etiological agents of asthma.

Quantitative sandwich ELISA for the determination of lupine (Lupinus spp.) in foods

The use of lupine in foods has increased considerably during the past decade, reflected by a corresponding increase in reported lupine-induced allergic incidents. Lupine allergy may arise either by primary sensitization or by clinical cross-reactivity in peanut-allergic persons. Detection of lupine proteins in food has previously been based on the use of patient serum. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of lupine in processed foods was developed, using a polyclonal rabbit antilupine capture antibody and a biotinylated conjugate of the same antibody for detection. The antibody was highly specific for lupine, apart from minor cross-reactivities to other legumes. The assay had a detection limit of 1 mug/g and was successfully used to quantify lupine protein in various food matrixes. Recoveries ranged from 60 to 116%, while the intra-and interassay coefficients of variation were <6% and <21%, respectively.

Effects of extrusion, boiling, autoclaving, and microwave heating on lupine allergenicity

Lupine flour has been reported as a causative agent of allergic reactions. However, the allergenicity of lupine after thermal processing is not well-known. For this purpose, the allergenic characteristics of lupine seeds after boiling (up to 60 min), autoclaving (121 degrees C, 1.18 atm, up to 20 min and 138 degrees C, 2.56 atm, up to 30 min), microwave heating (30 min), and extrusion cooking were studied. The IgE-binding capacity was analyzed by IgE-immunoblotting and CAP inhibition using a serum pool from 23 patients with lupine-specific IgE. Skin testing was carried out in four patients. An important reduction in allergenicity after autoclaving at 138 degrees C for 20 min was observed. IgE antibodies from two individual sera recognized bands at 23 and 29 kDa in autoclaved samples at 138 degrees C for 20 min. Autoclaving for 30 min abolished the IgE binding to these two components. A previously undetected band at 70 kDa was recognized by an individual serum. Therefore, prolonged autoclaving might have an important effect on the allergenicity of lupine with the majority of patients lacking IgE reactivity to these processed samples.

A Case of Peanut Cross-Allergy to Lupine Flour in a Hot Dog Bread

BACKGROUND

In a case monitored by the Norwegian National Register for Severe Allergic Reactions to Food, a patient with peanut allergy experienced an allergic reaction after eating a particular brand of hot dog bread. The aim of this study was to identify the eliciting allergen.

METHODS

Extracts from the hot dog bread and reference material from peanut, lupine and lupine-fortified food products were analysed by immunochemical methods with patient serum and a new polyclonal anti-lupine antibody.

RESULTS

Evidence could be provided that the hot dog bread contained proteins from lupine but not from peanut.

CONCLUSION

Crossed peanut-lupine allergy can have clinical significance. A peanut-allergic patient reacted against hidden lupine protein in a hot dog bread. Presented with our results, the producer confirmed the use of lupine flour and changed the ingredient list.

[The allergenic significance of legumes]

Leguminous are a cheap source of protein that are cultivated practically throughout the world. They are the main source of food in developing countries. In the Mediterranean area and Middle East, the most commonly consumed legumes are lentils and chickpea. In the United States, United Kingdom and south-east Asia, the major legumes involved in food allergy are considered to be peanut and soy bean, respectively. The clinical manifestations of the allergy to legumes are similar for all legumes and range from oral allergy syndrome, urticaria, angioedema, rhinitis and asthmatic crises to anaphylaxis and even death. Legumes have a high degree of immunological cross-reactivity. Severals authors have described cross-reactivity among different legumes and between legumes and various vegetables. The allergenicity of legumes is mainly is mainly related to allergens from the storage proteins of seeds. Vicilins from this group of proteins could be an important common allergen in clinical allergy to legumes. Profilins are considered to be a cause of cross-reactivity among fruits, vegetables and some pollens and are believed to be a panallergen. Other panallergens of increasing importance are lipid transfer proteins. Few studies have assessed the long-term clinical course of allergy to legumes. Novel therapeutic agents are being investigated for the treatment of peanut allergy and these could be applied to other legumes.

Clinical implications of cross-reactive food allergens

As a consequence of the general increase in allergic sensitization, the prevalence of hypersensitivity reactions to multiple foods that share homologous proteins has become a significant clinical problem. A variety of these allergens conserved among plants (eg, profilin and lipid transfer proteins) and animals (eg, tropomyosin and caseins) have been characterized. Although studies with molecular biologic techniques have elucidated the nature of these ubiquitous allergens, clinical studies have lagged behind. The physician is called on to determine the risk of reaction to related foods among legumes, tree nuts, fish, shellfish, cereal grains, mammalian and avian food products, and a variety of other plant-derived foods that may share proteins with pollens, latex, and each other. Clinical evaluations require a careful history, laboratory evaluation, and in some cases oral food challenges. The pitfalls in the evaluation of food allergy-unreliable histories and limitations in laboratory assessment primarily caused by false-positive skin prick test responses/RAST results are magnified when dealing with cross-reactive proteins. This review focuses on the clinical data regarding cross-reacting food allergens with the goal of providing a background for improved risk assessment and a framework on which to approach these difficult clinical questions.

Occupational IgE-mediated allergy after exposure to lupine seed flour

The ingestion of lupine seed flour (LSF) has been reported as a cause of allergic reactions, particularly in patients sensitized to peanut, but there is little evidence of its allergenic potential after inhalation. We sought to evaluate the clinical and immunologic reactivity to lupine in employees working with this seed flour. An occupational history was obtained in 7 subjects (median age, 35 years) working with LSF at an agricultural research center. Three subjects (1, 6, and 7) reported work-related allergy symptoms immediately after being exposed to lupine. Skin prick test results with LSF extract were positive in these 3 patients with work-related symptoms. Moreover, lupine-specific IgE antibodies were detected in subjects 6 and 7. In subject 6, the controlled exposure to LSF elicited immediate naso-ocular symptoms without changes in FEV(1). In subject 7, a bronchial provocation with LSF extract elicited an immediate fall (25%) in FEV(1). Double-blinded, placebo-controlled LSF oral challenge results were positive in subjects 6 and 7. Immunologic reactivity to other legumes was detected in subjects 6 and 7, but specific inhalation testing and oral challenge results were negative. Thus, the inhalation of lupine flour could be an important cause of allergic sensitization in exposed workers and might give rise to occupational asthma and food allergy.

Peanut and tree nut allergy

Among foods causing allergic reactions in children, peanut (a legume) and tree nuts (ie, walnut, hazel nut, Brazil nut, pecan) have attracted considerable attention for several reasons. Allergies to these foods are common, frequently have an onset in the first few years of life, generally persist, and account for severe and potentially fatal allergic reactions. Furthermore, the ubiquity of these foods in the diet makes avoidance difficult and accidental ingestions, with reactions, common. This review discusses recent and emerging information on the prevalence, clinical characteristics, natural history, genetic basis, and current treatment of these allergies. In addition, recent advances in the molecular and immunologic characteristics of these allergens, and novel therapeutic options under investigation in animal models, are reviewed.