Acetylsalicylic acid desensitization in an allergic pregnant woman post-vascular scaffolds implantation

Summary

The use of acetylsalicylic acid (ASA) desensitization for patients with coronary artery disease (CAD) is growing, but no data are available on desensitization protocol in patients with ASA sensitivity and CAD during pregnancy. This case report shows that ASA desensitization protocol during pregnancy could be safe and effective in a tertiary centre with a multidisciplinary team.

Influencing factors on the safety and effectiveness of venom immunotherapy

BACKGROUND AND OBJECTIVE

The safety profile of venom immunotherapy (VIT) is a relevant issue and considerable differences in safety and efficacy of VIT have been reported. The primary aim of this study was to evaluate the safety of ACE inhibitors and beta-blockers during VIT, which has already been published. For a second analysis, data concerning premedication and venom preparations in relation to systemic adverse events (AE) during the up-dosing phase and the first year of the maintenance phase were evaluated as well as the outcome of field stings and sting challenges.

METHODS

The study was conducted as an open, prospective, observational, multicenter study. In total, 1,425 patients were enrolled and VIT was performed in 1,342 patients.

RESULTS

Premedication with oral antihistamines was taken by 52.1% of patients during the up-dosing and 19.7% of patients during the maintenance phase. Taking antihistamines had no effect on the frequency of systemic AE (p=0.11) but large local reactions (LLR) were less frequently seen (OR: 0.74; 95% CI: 0.58-0.96; p=0.02). Aqueous preparations were preferentially used for up-dosing (73.0%) and depot preparations for the maintenance phase (64.5%). The type of venom preparation neither had an influence on the frequency of systemic AE nor on the effectiveness of VIT (p=0.26 and p=0.80, respectively), while LLR were less frequently seen when depot preparations were used (p<0.001).

CONCLUSION

Pretreatment with oral antihistamines during VIT significantly reduces the frequency of LLR but not systemic AE. All venom preparations used were equally effective and did not differ in the frequency of systemic AE.

IgE-mediated reactivity to non-specific lipid transfer protein (nsLTP): clinical implications and management ‒ consensus document of the Association of Italian Territorial and Hospital Allergists and Immunologists (AAIITO)

Summary

The primary cause of adult-onset food allergy in Mediterranean countries is IgE-mediated reactivity to non-specific Lipid Transfer Protein (nsLTP), with a prevalence of 9.5% in Italy. nsLTP is heat- and pepsin-stable due to its 3D structure, causing severe allergic reactions, even anaphylaxis. It's conserved across plants and a "panallergen" due to homologous forms in various vegetable foods. Found in Rosaceae fruits' skin, it's categorized into nsLTP1 (9 kDa) and nsLTP2 (7 kDa), representing 93% and 7% of the molecules described to date, respectively. Pru p 3 (nsLTP1) from peach is a primary sensitizer, binding more epitopes than other homologs. Cross-reactivity varies in sensitized patients, influenced by IgE levels. Clinical manifestations range from none to various symptoms. Managing patients sensitized to nsLTP without clinical allergy is a challenge. Sensitization hierarchy usually starts with peach, then expands through Prunoideae, Rosaceae, and other foods. Clinical symptoms don't always expand across LTPs. Patients can tolerate some nsLTP-containing foods and consuming them may maintain tolerance. The absence of guidelines led to the Associazione Allergologi Immunologi Italiani Territoriali e Ospedalieri (AAIITO) creating a consensus-based document. Strategies involve avoidance, self-injectable adrenaline, verification through in vivo and in vitro testing, considering cofactors, and peeling fruits. In localized reactions, abstinence is recommended if specific IgE is high. Concurrent pollinosis may complicates diagnosis, but may help management since symptoms are often less severe. Asymptomatic patients are advised to continue normal diets while considering cofactors and total IgE levels. Management strategies should be case-specific, based on expert Consensus Document.

Clinical severity of LTP syndrome is associated with an expanded IgE repertoire, FDEIA, FDHIH, and LTP mono reactivity

Summary

Background. LTP allergy is often a challenge for clinicians. We evaluated a multiplex diagnostic approach with diverse cofactors to stratify LTP syndrome risk. Methods. Of the 1,831 participants screened with 'Allergy Explorer-ALEX-2', 426 had reactions to at least one LTP. Data was gathered and recorded via an electronic database. Results. Reactivity to peach Pru p 3 was found in 77% of individuals with LTP allergy. Higher levels of specific IgE and concurrent sensitization to more than 5 molecules (50% of all LTP-sensitised participants, 62% of symptomatic cases) were significantly associated with an increased risk of severe reactions (p = 0.001). Several cofactors, either alone or in combination, also influenced patients' clinical outcomes. Some cofactors increased the risk of severe reactions, such as mono reactivity to LTP in 44.6% of cases (p = 0.001), FDEIA in 10.8% of patients (p = 0.001), and FDNIH in 11.5% (p = 0.005). On the other hand, reactivity to PR10 (24.2%; p = 0.001), profilin hypersensitivity (10.3%; p = 0.001), and/or atopic dermatitis (16.7%; p = 0.001) had a mitigating effect on symptom severity. Conclusions. Clinical severity of LTP syndrome is associated with an expanded IgE repertoire in terms of the number of LTP components recognized and increased IgE levels in individual molecules. Ara h 9, Cor a 8, and Mal d 3 showed the strongest association with clinical severity. In addition, several cofactors may either exacerbate (FDEIA, FDHIH, and LTP monoreactivity) or ameliorate (atopic dermatitis and co-sensitization to profilin and/or PR10) individual patient outcomes. These factors may be utilized for the daily clinical management of LTP syndrome.

Why lipid transfer protein allergy is not a pollen-food syndrome: novel data and literature review

Summary

Background.Based on the cross-reactivity between pollen lipid transfer proteins (LTPs) and the peach LTP, Pru p 3, it has been suggested that the pollen might initiate the LTP sensitization process. Objective. To establish whether LTP allergy can be considered as a pollen-food syndrome. Methods. The literature was reviewed and new data of component-resolved diagnosis from Italy obtained by both ISAC immunoassay and ImmunoCAP on large populations of LTP hypersensitive patients were provided and analyzed. Results. Among Pru p 3 reactors, patients positive for Art v 3 and Pla a 3 largely exceeded those sensitized to the respective major pollen allergens, Art v 1 and Pla a 1/Pla a 2. Pru p 3 reactivity remained stable around 80-90% at all ages, whereas Art v 3 and Ole e 7 recognition was missing in younger patients. Pru p 3 IgE exceeded IgE specific for pollen LTP at all ages. Inhibition studies carried out on LTP reactors showed that commercial extracts of mugwort and plane pollen were unable to inhibit significantly Pru p 3 IgE reactivity. In follow-up studies, baseline Pru p 3 IgE levels exceeded Art v 3 IgE levels in 84% of those sensitized to both allergens, and all patients positive to only one LTP allergen at baseline were sensitized to Pru p 3. Further, most of the patients who did not show any LTP reactivity at baseline became exclusive Pru p 3 reactors. On ImmunoCAP singleplex Pru p 3 IgE levels exceeded Art v 3 IgE levels in 89% of cases (p less than 0.0001). Most literature data were in keeping with these new observations. Conclusions. The evidence for LTP syndrome being a pollen-food syndrome is presently very thin. Our data do not rule out the possible sensitization to the protein, via the airways or the skin.

Recommendations for the Use of Tryptase in the Diagnosis of Anaphylaxis and Clonal Mastcell Disorders

Summary

Tryptase is a serin-protease produced and released by mast cells after IgE-mediated or non-IgE mediated stimuli. We here review the various aspects related to the molecular characteristics of the enzyme and its biological effects, the genetic basis of its production and the release kinetics. Recommendations for the clinical use of tryptase measurement developed by a task force of Società Italiana di Patologia Clinica e Medicina di Laboratorio and Associazione Allergologi Immunologi Italiani Territoriali e Ospedalieri are given on the best procedure for a correct definition of the reference values in relation to the inter-individual variability and to the correct determination of tryptase in blood and other biological liquids, in the diagnosis of anaphylaxis (from drugs, food, insect sting, or idiophatic), death from anaphylaxis (post mortem assessment) and cutaneous or clonal mastcell disorders.

Favorable Prognosis of Wheat Allergy in Adults

BACKGROUND AND OBJECTIVE

Wheat ingestion can lead to disorders such as IgE-mediated food allergy and wheat-dependent exercise-induced anaphylaxis (WDEIA), both of which are associated with impaired quality of life and significant morbidity. Allergy to wheat is relatively benign in children, although its natural history in adults is still unknown. Objective: We used placebo-controlled challenge to evaluate the natural history of wheat hypersensitivity in atopic patients with adultonset wheat allergy.

METHODS

We enrolled 13 patients from an initial cohort of adult patients with IgE-mediated wheat allergy (mean age, 40 years). After diagnosis, the patients observed a wheat-free diet and were followed as outpatients for 5 years to evaluate wheat exposure. Wheat-IgEtiters were determined at the end of follow-up, and a second wheat-challenge was performed.

RESULTS

Ten out of 13 patients took part in the study. The mean period of wheat avoidance was 4.2 years. Three patients had spontaneously reintroduced wheat before the second evaluation, after a mean (IQR) of 28 (18-36) months, with only mild gastrointestinal discomfort at reintroduction. At the end of follow-up, 9 of the 10 patients were wheat-tolerant. Two patients had a history of WDEIA. We observed a reduction in IgE levels, with median (IQR) IgE falling from 2.77 (0.35-100) kU/L at diagnosis to 0.88 (0.1-20.8) kU/L. The association between IgE and a negative challenge result was not statistically significant.

CONCLUSION

IgE-mediated wheat allergy in adults is benign and represents a temporary break in gastrointestinal tolerance. Future studies may improve our knowledge of wheat allergens, routes of and factors leading to sensitization, and prognostic biomarkers.

Galactose-α-1,3-galactose syndrome: an Italian survey

Summary

Background. The term of α-Gal syndrome, which includes the delayed allergy to red meat and the allergic reactions following the administration of cetuximab, is associated to the presence of specific IgE to α-Gal. In Italy, only anecdotal cases were reported so far. The Association of Italian Allergists (AAITO) carried out a survey with the aim of evaluating presence, characteristics, clinical features, and distribution of the syndrome in Italy. Methods. A web structured questionnaire was made available on the website of AAIITO from July 2016 to January 2017. It included 31 multiple-choice questions concerning different items, including the site of physicians, the number of patients diagnosed as having cetuximab allergy and/or delayed red meat allergy, recall of tick bites, symptoms, time to reactions, elicitor foods, reactions with foods other than meat, and in-vivo and in-vitro tests used for the diagnosis. Results. Seventy-nine physicians completed the questionnaire. Nine cases of allergy to cetuximab and 40 cases of delayed red meat allergy were recorded across Italy. 22.5% of patients with cetuximab allergy and 62.5% of those with delayed red meat allergy recalled a tick bite. 75% of patients with delayed red meat allergy experienced symptoms after eating beef (butcher's cut in 72.5%). Urticaria was the most frequent clinical manifestation (65% of cases). In 60.6% of cases symptoms appeared 2 - 4 hours after meat ingestion, while in 7.9% symptoms appeared after > 4 hours. The most used diagnostic methods were the intradermal test for cetuximab allergy (88.9%) and the detection of IgE to α-Gal (55.5%) for red meat allergy. Most case reports came from Northern Italy. Conclusions. α-Gal syndrome is present in Italy and beef is the most frequent offending food. In most cases symptoms were not severe.

Hymenoptera Venom Allergy: Management of Children and Adults in Clinical Practice

Hymenoptera venom allergy is an epidemiologically underestimated condition and a major cause of morbidity worldwide. Preventing future allergic reactions in patients who experience a systemic reaction is based on the correct management of the emergency followed by an accurate diagnosis, prescription of adrenaline autoinjectors, and, where indicated, specific venom immunotherapy. Some epidemiological studies highlight our poor knowledge of this disease and the frequent inadequacy of its management. Moreover, they emphasize the importance of such a life-saving treatment as specific immunotherapy. The availability of high-quality hymenoptera venom extracts for diagnostic and therapeutic use has dramatically improved the prognosis and quality of life of allergic patients. Subcutaneous venom immunotherapy is currently the most effective form of allergen-based immunotherapy, with a carry-over effect lasting up to several years after its interruption. This report on the management of hymenoptera venom-allergic children and adults was prepared by a panel of Italian experts. The main objective of this consensus document is to review the scientific evidence related to diagnosis, therapy, and management of patients allergic to hymenoptera venom. Thus, we can improve our knowledge of the disease and promote good clinical practices. The present document provides practical suggestions for correct diagnosis, prescription of emergency therapy and immunotherapy, and strategies for patient care.

EAACI guidelines on allergen immunotherapy: Hymenoptera venom allergy

Hymenoptera venom allergy is a potentially life-threatening allergic reaction following a honeybee, vespid, or ant sting. Systemic-allergic sting reactions have been reported in up to 7.5% of adults and up to 3.4% of children. They can be mild and restricted to the skin or moderate to severe with a risk of life-threatening anaphylaxis. Patients should carry an emergency kit containing an adrenaline autoinjector, H₁ -antihistamines, and corticosteroids depending on the severity of their previous sting reaction(s). The only treatment to prevent further systemic sting reactions is venom immunotherapy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Venom Immunotherapy as part of the EAACI Guidelines on Allergen Immunotherapy initiative. The guideline aims to provide evidence-based recommendations for the use of venom immunotherapy, has been informed by a formal systematic review and meta-analysis and produced using the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included representation from a range of stakeholders. Venom immunotherapy is indicated in venom-allergic children and adults to prevent further moderate-to-severe systemic sting reactions. Venom immunotherapy is also recommended in adults with only generalized skin reactions as it results in significant improvements in quality of life compared to carrying an adrenaline autoinjector. This guideline aims to give practical advice on performing venom immunotherapy. Key sections cover general considerations before initiating venom immunotherapy, evidence-based clinical recommendations, risk factors for adverse events and for relapse of systemic sting reaction, and a summary of gaps in the evidence.

Allergy to LTP: to eat or not to eat sensitizing foods? A follow-up study

Summary

Background. Follow-up data about the onset of novel food allergies in patients allergic to lipid transfer protein (LTP) are missing. We investigated the occurrence of novel allergies over time in LTP hypersensitive patients. Methods. Sixty-seven LTP-allergic patients recommended to avoid foods responsible for systemic reactions and encouraged to eat other sensitizing foods avoiding the association with known co-factors, were re-evaluated after ≥ 1 year to assess the occurrence of allergy to novel foods. IgE to rPru p 3, rBet v 1, and r Phl p 12 were measured. Results. At baseline, the most frequent offending foods were Rosaceae / Prunoideae, tree nuts, and peanut. Most patients reacted to > 1 food, and 77% experienced systemic allergic reactions. Those monosensitized to LTP showed a higher prevalence of food-induced systemic reactions than patients co-sensitized to profilin and/or PR-10 (p < 0.01). Baseline Pru p 3 IgE levels did not differ between patients with local symptoms or systemic symptoms. 1-16 years after the baseline evaluation 18/67 (27%) patients had experienced new food allergies; 8 and 10 reported local or systemic symptoms following the ingestion of previously tolerated foods. Again, most new allergies were caused by Rosaceae / Prunoideae, tree nuts, and peanut. The clinical evolution did not depend on baseline total IgE, co-sensitization to PR-10 and/or profilin, or Pru p 3 IgE levels. Conclusions.Rosaceae / Prunoideae, nuts and peanut are the most frequent cause of new food allergies in the long term. Their exclusion from patient's diets at baseline should be considered on an individual basis.

The clinical relevance of lipid transfer protein

Despite a huge number of studies, many aspects of the lipid transfer protein (LTP) syndrome, the most frequent primary food allergy in Mediterranean countries, remain unclear. Its peculiar geographical distribution, along with the extreme variability of its clinical expression, makes this type of food allergy something unique in the panorama of IgE-mediated food-induced allergic reactions. This review article tried to summarize the current knowledge about the most important aspects of LTP sensitization and allergy, along with the importance of positive and negative co-factors in the clinical expression of the syndrome as well as the issues regarding the cross-reactivity between LTPs present in botanically related and unrelated foods. Further, the possible absence of the protein from some plant foods is discussed.

Illness perception, mood and coping strategies in allergic rhinitis: are there differences among ARIA classes of severity?

BACKGROUND

This study was designed to assess if illness perception, mood state and coping strategies differ according to allergic rhinitis (AR) persistence and severity.

METHODS

Illness perception, mood profiles, coping behaviors and rhinitis symptoms were assessed by means of validated tools inpatients classified according to the Allergic Rhinitis and Its Impact on Asthma (ARIA) guidelines.

RESULTS

Two hundred and thirty-one patients underwent data analysis. No difference in age, sex, socio-economic status, smoking habits was detected comparing patients according to AR severity, duration or 4 ARIA classes. Patients with intermittent AR reported higher scores than those with persistent AR in confusion-bewilderment of Profile of Mood States (POMS); patients with moderate/severe rhinitis had significantly higher scores than those with mild rhinitis in TSSS, Identity and Consequences. No differences were detected in all assessed outcomes in the 4 ARIA classes.

CONCLUSIONS

The patient's perspective about AR is independent of persistence and severity of symptoms. This may explain why AR remains under-diagnosed and under-treated, even in its most severe forms. Self-management plans should consider the patient's perspective.

Allergen immunotherapy for insect venom allergy: a systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing the EAACI Guidelines on Allergen Immunotherapy (AIT) for the management of insect venom allergy. To inform this process, we sought to assess the effectiveness, cost-effectiveness and safety of AIT in the management of insect venom allergy.

METHODS

We undertook a systematic review, which involved searching 15 international biomedical databases for published and unpublished evidence. Studies were independently screened and critically appraised using established instruments. Data were descriptively summarized and, where possible, meta-analysed.

RESULTS

Our searches identified a total of 16 950 potentially eligible studies; of which, 17 satisfied our inclusion criteria. The available evidence was limited both in volume and in quality, but suggested that venom immunotherapy (VIT) could substantially reduce the risk of subsequent severe systemic sting reactions (OR = 0.08, 95% CI 0.03-0.26); meta-analysis showed that it also improved disease-specific quality of life (risk difference = 1.41, 95% CI 1.04-1.79). Adverse effects were experienced in both the build-up and maintenance phases, but most were mild with no fatalities being reported. The very limited evidence found on modelling cost-effectiveness suggested that VIT was likely to be cost-effective in those at high risk of repeated systemic sting reactions and/or impaired quality of life.

CONCLUSIONS

The limited available evidence suggested that VIT is effective in reducing severe subsequent systemic sting reactions and in improving disease-specific quality of life. VIT proved to be safe and no fatalities were recorded in the studies included in this review. The cost-effectiveness of VIT needs to be established.

Shrimp Allergy: Analysis of Commercially Available Extracts for In Vivo Diagnosis

BACKGROUND AND OBJECTIVE

Skin prick testing (SPT) with commercial extracts is the first step in the diagnosis of shrimp allergy, although its clinical efficiency is unknown. Objective: To analyze the clinical usefulness of all commercial crustacean extracts available for SPT in Italy.

METHODS

We performed a multicenter study of 157 shrimp-allergic patients who underwent SPT with 5 commercial crustacean extracts and with house dust mite (HDM) extract. Commercial extracts were analyzed using SDS-PAGE and compared with a freshly prepared in-house shrimp extract. IgE to Pen a 1/Pen m 1, Pen m 2, and Pen m 4 was determined, and immunoblot analysis was performed on a large number of sera.

RESULTS

The skin reactions caused by commercial crustacean extracts were extremely heterogeneous, resulting in 32 clinical profiles, with marked differences in protein content and missing proteins at molecular weights corresponding to those of major shrimp allergens. Only strong Pen a 1/Pen m 1 reactors reacted to both HDM and all 5 commercial extracts in SPT. Most patients, including those who were tropomyosin-negative, reacted to HDM. Patients reacted to a large and variable array of proteins, and IgE reactivity was common at high molecular weights (>50 kDa).

CONCLUSIONS

The in vivo diagnosis of shrimp allergy must continue to be based on SPT with fresh material. Shrimp-allergic patients frequently react to a number of ill-defined high-molecular-weight allergens, thus leaving currently available materials for component-resolved diagnosis largely insufficient. Mites and crustaceans probably share several allergens other than tropomyosin.

Self-medication of anaphylactic reactions due to Hymenoptera stings-an EAACI Task Force Consensus Statement

An anaphylactic reaction due to a Hymenoptera sting is a clinical emergency, and patients, their caregivers as well as all healthcare professionals should be familiar with its recognition and acute management. This consensus report has been prepared by a European expert panel of the EAACI Interest Group of Insect Venom Hypersensitivity. It is targeted at allergists, clinical immunologists, internal medicine specialists, pediatricians, general practitioners, emergency department doctors, and any other healthcare professional involved. The aim was to report the scientific evidence on self-medication of anaphylactic reactions due to Hymenoptera stings, to inform healthcare staff about appropriate patient self-management of sting reactions, to propose indications for the prescription of an adrenaline auto-injector (AAI), and to discuss other forms of medication. First-line treatment for Hymenoptera sting anaphylaxis is intramuscular adrenaline. Prescription of AAIs is mandatory in the case of venom-allergic patients who suffer from mast cell diseases or with an elevated baseline serum tryptase level and in untreated patients with a history of a systemic reaction involving at least two different organ systems. AAI prescription should also be considered in other specific situations before, during, and after stopping venom immunotherapy.

Alpha-gal anaphylaxis: the first case report in Italy

We report the case of a 55-year-old man who went into anaphylactic shock six hours after eating a meal containing meat. He reported having had several tick bites in months before the reaction. The serum specific IgE showed strong positivity to alpha-gal. This is clearly alpha-gal anaphylaxis with delayed onset after meat ingestion caused by tick bite, confirmed by alpha-gal IgE positivity.

Two cases of elevated tryptase in abdominal aortic aneurysm

INTRODUCTION

From the literature, patients with a history of anaphylaxis to hymenoptera venom and positive specific IgE have shown a correlation between elevated tryptase levels and two clinical situations: systemic mastocytosis and an increased risk of reactions to venom immunotherapy or hymenoptera sting. Other clinical scenarios could explain elevated tryptase levels.

MATERIAL AND METHODS

A 67 year old male (P1) and a 77 year old male (P2) were evaluated for previous severe anaphylaxis to hymenoptera sting. They underwent standard diagnostic work-up for hymenoptera venom allergy. Having found elevated tryptase levels, these were followed by a bone marrow biopsy to rule out systemic mastocytosis.

RESULTS

P1: specific IgE and skin tests were positive for Vespula species; tryptase 52.8 ng/ml; P2: specific IgE and skin tests were positive for Vespa cabro and tryptase 153 ng/ml. Bone marrow biopsy results were negative for mastocytosis. We carried out magnetic resonance imaging, in P1 to better characterize the severe osteoporosis and in P2 because during physical examination a pulsating mass had been identified in the mesogastrium, and an aneurysm of the abdominal aorta which required surgical intervention in both patients was detected. Eight months after surgery, tryptase levels had diminished significantly (P1: 11.6 ng/ml and P2: 14.5 ng/ml).

DISCUSSION

The elevated tryptase levels were correlated to abdominal aneurysm in both patients. In fact, post-surgery tryptase levels dramatically decreased. These two cases demonstrate that high tryptase levels in subjects with a history of hymenoptera venom anaphylaxis can be associated to undiagnosed aneurysmatic disease.

Hypersensitivity to Tomato (Lycopersicon esculentum) in Peach-Allergic Patients: rPrup 3 and rPrup 1 Are Predictive of Symptom Severity

Background: The role of allergens in the severity of tomato allergy symptoms has not yet been studied.

OBJECTIVES

To evaluate the relationship between severe allergic reactions to peach and tomato and between tomato allergy symptoms and the pattern of IgE positivity for rPru p 1, rPru p 3, rPru p 4, rBetv 1, rBetv 2, rBetv4, rPhl p 1, and rPhl p 12 in order to identify the role of recombinant allergens in the severity of reactions to tomato.

METHODS

We studied peach-allergic patients with clinical reactions to tomato by performing an open food challenge, skin prick test, and determination of serum specific IgE to tomato and to recombinant peach, birch, and grass allergens. Statistical analysis was carried out to evaluate the relationship between the severity of tomato symptoms and IgE positivity to the different allergens and to peach-induced symptoms.

RESULTS

We found a significant association between severe reactions to tomato and severe reactions to peach (P = .01 7) and levels of IgE to rPru p3 (P = .029) and between mild tomato allergy symptoms and levels of IgE to rPru p1 (P = .047), anti-rBetv 1 (P = .0414), anti-rBetv 2 (P = .0457), and Phleum pratense (P = .0022).

CONCLUSION

We observed a significant relationship between peach and symptoms of tomato allergy. IgE positivity for rPru p3 seems to be a surrogate biochemical marker for severe tomato allergy, whereas the presence of anti-rPru p 1 IgE may be an indicator of mild tomato allergy.

Detection of 20 kDa and 32 kDa IgE-binding proteins as the major allergens in Italian sesame seed allergic patients

BACKGROUND

Sesame seed allergy, a potentially very severe food allergy, seems on the rise worldwide but is still uncommon in Italy. The aim of the present study was to investigate the allergenic profile of Italian sesame seed-allergic patients.

METHODS

Patients with genuine sesame seed allergy diagnosed over one year in a large number of allergy centers scattered through Italy were considered for the study. Their IgE reactivity to sesame seed allergens was characterized by immunoblot analysis.

RESULTS

Eleven sesame seed allergic patients were detected and studied. 10/10 patients showed IgE reactivity against a sesame allergen at about 20 kDa, and 7/10 showed an extremely strong reactivity at about 32 kDa. The same 7 sera reacted also against a 28 kDa allergen, although such reactivity was significantly weaker in 6/7 cases. Eight patients showed IgE reactivity at about 48 kDa, and 5 sera reacted against higher m.w. proteins at about 67 kDa. Two sera showed IgE reactivity at about 43 kDa as well. Only one serum appeared to react to 2S-albumin.

CONCLUSIONS

Italian sesame seed-allergic patients react mostly against allergens other than those described so far as major ones. A large number of recombinant sesame allergens will be needed for a comprehensive component- resolved diagnosis of allergy to this food.

Heterogenity of IgE response to walnut and hazelnut in Italian allergic patients

BACKGROUND

The prevalence of IgE reactivity against genuine walnut and hazelnut allergens is poorly defined.

OBJECTIVE

The IgE response to walnut and hazelnut was investigated in Italian patients with primary allergy to these nuts.

METHODS

Sera from 36 patients allergic to hazelnut and/or walnut, not reactive to PR-10, profilin, and LTP, underwent immunoblot analysis with extracts of both nuts.

RESULTS

Most patients had a history of systemic symptoms following the ingestion of the offending food(s). Twelve patients were sensitized to both walnut and hazelnut, and 13 were sensitized to other nuts and seeds (cashew, peanut, sesame, pine nut, almond, Brazil nut, and pistachio). On walnut immunoblot, the 7 sera which scored positive showed much variability in their IgE profile. Two reacted uniquely at 10 kDa, and the others at 35 , 40, 45, 50, 67, and > 67 kDa. The profiles obtained under reducing and non-reducing conditions showed several differences. The 7 sera positive on hazelnut immunoblot under reducing conditions recognized sera at 10 kDa and at <10 kDa (n=1), 20 kDa (n=4), at about 22, 24, 30, 40, 43, 58, 60, and 90 kDa, and higher m.w. in other cases. Under non-reducing conditions IgE reactivity at 20, 28, 35, 40, 45, 60, 90, and 100 kDa, was detected. Only two sera scored positive under both conditions and showed an IgE profile that partly changed from one assay to another.

CONCLUSION

The current list of walnut and hazelnut allergens is far from being complete. Both reducing and non-reducing conditions are needed to detect IgE reactivity in individual patients.

Anisakis simplex: current knowledge

Anisakiasis, firstly described in 1960s in the Netherlands, is a fish-borne parasitic disease caused by the consumption of raw or undercooked fish or cephalopods contaminated by third stage (13) larvae of the Anisakidae family, in particular Anisakis simplex (As), A. pegreffii and Pseudoterranova decipiens. Every year, approximately 20,000 cases of anisakiasis were reported worldwide, over 90% are from Japan and most others in Spain, the Netherlands and Germany, depending on the habits of fish consuming. Live As larvae can elicit i) a parasitic infection of the digestive tract or, occasionally, other organs, causing erosive and/or haemorrhagic lesions, ascites, perforations until granulomas and masses, if larva is not removed, and ii) allergic reactions, as anaphylaxis, acute/chronic urticaria and angioedema. Like other parasite infestations, As larva induces an immune adaptive response characterised by T-lymphocyte proliferation with polyclonal and monoclonal (responsible for As allergic symptoms) IgE production, eosinophilia and mastocytosis. Several As allergens, many of which thermostable, were described In particular the major allergen Ani s 1 and Ani s 7 could characterized a past or a recent infection. There is a general agreement that an active infection is required to initiate allergic sensitivity to Anisakis. Until now, the only effective treatment for anisakiasis is the endoscopic removal of live larvae and the best protection against anisakiasis is to educate consumers about the dangers of eating raw fish and to recommend avoiding the consumption of raw or inadequately thermally treated marine fish or cephalopods.

Characterization of the T-cell epitopes of the major peach allergen Pru p 3

BACKGROUND

Pru p 3 is the major peach allergen recognized by more than 90% of peach-allergic individuals of the Mediterranean area. Identification of the dominant Pru p 3 T-cell epitopes can improve our understanding of the immune responses against this protein and could be helpful in the development of hypoallergenic immunotherapy. For this purpose, we examined the phenotypes, specificities and cytokine secretion profiles of proliferating T cells in response to Pru p 3 in peach-allergic individuals.

METHODS

Peripheral blood mononuclear cells from 15 peach-allergic patients were incubated with Pru p 3. The proliferation of antigen-specific T-cell lines (TCLs) was assessed by tritiated methylthymidine incorporation. T-cell epitopes were identified by analyzing the reactivity of TCLs against 8 overlapping peptides spanning the entire length of Pru p 3. We characterized the phenotype of Pru-p-3-specific TCLs by flow cytometry and analyzed their production of interleukin (IL) 4 and gamma-interferon (IFN-gamma) by ELISA.

RESULTS

Ninety-two Pru-p-3-specific TCLs were isolated (stimulation index > or =5). These TCLs proliferated mainly in response to Pru p 3(12-27) and Pru p 3(57-72). Pru-p-3-specific TCLs were mainly CD4+ (81%) and expressed cell surface CD30. In addition, TCLs produced high levels of IL-4 and low levels of IFN-gamma, indicating a Th2 phenotype.

CONCLUSIONS

Two immunodominant T-cell-reactive regions of Pru p 3 were identified: Pru p 3(12-27) and Pru p 3(57-72). These peptides showed a differential ability to elicit a Th2 response. Taken together, our results provide a better understanding of the immunological T-cell reactivity against Pru p 3.

Sublingual immunotherapy in polysensitized patients: effect on quality of life

BACKGROUND

Quality of life (QOL) is an important issue in allergic rhinitis and has been evaluated in a number of studies that have shown how it is impaired in untreated patients and improved by effective treatment. However, there are no data concerning QOL after sublingual immunotherapy (SLIT) in polysensitized patients.

OBJECTIVE

To evaluate the effect, in real-life clinical practice, of SLIT on QOL in a population of polysensitized patients with allergic rhinitis.

METHODS

We prospectively evaluated 167 consecutively enrolled polysensitized patients with allergic rhinitis. QOL was measured in all cases with the Rhinoconjunctivitis Quality of Life Questionnaire at baseline and after 1 year of SLIT (performed in approximately 70% of cases using single allergen extracts provided by the same manufacturer).

RESULTS

The most frequent causes of sensitization were grass pollen, Parietaria, and house dust mites. The mean number of sensitizations per patient was 3.65. SLIT was performed with 1 extract in 123 patients (73.6%), with 2 extracts in 31 patients (18.6%), and with more than 2 extracts in 13 patients (7.8%). The mean values of all the QOL items improved significantly (P < .01 in all cases), with the following reductions noted: activities, 3.96 to 2.89; sleep, 2.07 to 1.56; general problems, 2.16 to 1.5; practical problems, 3.69 to 2.58; nasal symptoms, 3.57 to 2.50; eye symptoms, 2.92 to 1.83; and emotional aspects, 2.2 to 1.44.

CONCLUSIONS

This study provides evidence that QOL can be improved in polysensitized patients treated with SLIT, and that the use of just 1 or 2 allergen extracts seems to be sufficient and effective in terms of improving QOL.

Characteristics of patients with allergic polysensitization: the POLISMAIL study

BACKGROUND

The natural history of respiratory allergy is commonly characterized by a worsening of symptom severity, frequent comorbidity of rhinitis and asthma, and polysensitization to aeroallergens. The polysensitization phenomenon starts since childhood and is rare to find monosensitized adult patients. However, there are few studies investigating the characteristics of polysensitized patients.

METHODS

This study was performed on a large cohort of patients with allergic rhinitis (assessed by ARIA criteria) and/or mild to moderate asthma (assessed by GINA). The kind and the number of sensitizations, their patterns, and the relation with quality of life (QoL) measured by the Juniper's RQLQ guestionnaire, were evaluated.

RESULTS

Globally 418 patients (50.2% males, 49.8% females, mean age 26.4 years, range 3.5-65 years, 64 smokers, 371 non-smokers) were enrolled: 220 had allergic rhinitis alone, and 198 allergic rhinitis and asthma. The mean number ofsensitizations was 2.6. Three hundred-five patients (73%) had persistent rhinitis (PER), 220 of them with moderate-severe form. There was no significant derence in rate of rhinitis and asthma in monosensitized or polysensitized patients. Most patients were sensitized to pollens, whereas only 24.2% of them were sensitized to perennial allergens. Polysensitization was significantly associated with some issues of QoL, confirming previous findings, but not with number ofsensitizations.

CONCLUSIONS

This study provides data confirming for poly-sensitized patients the relevance of ARIA classification of AR. PER is the most common form of AR in this cohort, symptoms are frequently moderate-severe, and asthma is present in about the half of patients with AR.

Maize food allergy: a double-blind placebo-controlled study

BACKGROUND

Maize allergy is not very common especially in Europe. The number of studies that address IgE mediated maize allergy is all too few.

OBJECTIVE

Evaluate subjects with a history of maize allergy by double-blind, placebo-controlled food challenge; identify the spectrum of symptoms manifested during challenge; determine the lowest provocation dose (PD) during challenge; determine the performance characteristics of maize skin prick test and specific IgE.

METHODS

Twenty-seven patients with a history of maize allergy were enrolled to be evaluated by skin test, specific IgE and double-blind placebo-controlled maize challenge.

RESULTS

Forty-eight percent of the patients were challenge positive. PD range was 0.1-25 g. Fifty-four percent of the maize allergic subjects had a PD that was < or = 2.5 g; two subjects reacted to 100 mg of maize. Comparison of maize specific IgE levels and skin test results to the challenge results revealed the following (specific IgE level/skin testing): sensitivity 1.00/0.846, specificity 0.077/0.384, positive predictive value 0.520/0.579, and negative predictive value 1.00/0.714.

CONCLUSION

Maize is a cause of IgE-mediated allergic reactions to foods in adults and children. Nearly half of the subjects recruited were confirmed by challenge to be allergic to maize. Twenty-three percent of the positive challenge patients manifested symptoms that involved two organ systems, thus fulfilling the criteria for maize induced anaphylaxis. Maize is allergenic and can pose a risk for symptomatic food allergy at a dose of 100 mg.

Influence of cultivar and processing on cherry (Prunus avium) allergenicity

Oral allergy syndrome is an immediate food allergic event that affects lips, mouth, and pharynx, is often triggered by fruits and vegetables, and may be associated with pollinosis. Here, we report on the allergenic pattern of different varieties of cherry (Prunus avium) and results obtained by applying several technological processes to the selected varieties. Whole cherries were submitted to chemical peeling, thermal treatment, and syruping processes, and the relative protein extracts were analyzed by in vitro (sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analysis) and in vivo tests (skin prick test). Electrophoretic analyses demonstrated that there was no marked difference among cherry cultivars. Chemical peeling successfully removed Pru av 3, a lipid transfer protein (LTP) responsible for oral allergy syndrome in patients without pollinosis, leading to the industrial production of cherry hypoallergenic derivatives. Furthermore, the syruping process removed almost all allergenic proteins to whom patients with pollinosis are responsive. In vivo tests confirmed electrophoretic results.

New plant-origin food allergens

Plant-origin foods, especially nuts and seeds, are the most important sources of food allergic reactions. An important characteristic is the quantitative and qualitative variability of their content in allergenic molecules, depending on plant growth, ripening, environmental stresses or industrial processing. In this review we will focus on newly identified allergens. Recent research have characterized and extensively studied their biochemistry, structure and immunological properties.

Lipid transfer proteins and 2S albumins as allergens

Plant lipid transfer proteins, a widespread family of proteins, have been recently identified as important food allergens. Their common structural features, such as eight conserved cysteines forming disulfide bridges, basic isoelectric point and high similarity in amino acid sequence, are the basis of allergic clinical cross-reactivity. This has been demonstrated for the LTP allergens of the Prunoideae subfamily, whose similarity is about 95% as demonstrated for the purified allergens of peach, apricot, plum and apple. A relevant aspect is the existence of sequence homology of LTPs of botanically unrelated foods, as demonstrated for LTPs of maize and peach. A class of food allergens of well recognized clinical importance is that of seed storage 2S albumins. They have been identified in the most diffused edible seeds and nuts, such as mustard, sesame, Brazil nut, walnut and peanut. In particular, a strong correlation between IgE-binding to these proteins and food-induced anaphylaxis has been demonstrated for Brazil nut and sesame seeds.

Characterization of the major allergen of plum as a lipid transfer protein

BACKGROUND

Allergy to Prunoideae fruit (plum, peach, cherry and apricot) is one of the most frequent food allergies in southern Europe. All these fruits cross-react in vivo and in vitro, as they share their major allergen, a 9 kD lipid transfer protein (LTP).

OBJECTIVE

The aim of the study was the identification and molecular characterization of the major allergen of plum.

METHODS

The IgE pattern of reactivity to plums was investigated by SDS-PAGE and immunoblotting with the sera of 23 patients. The identified major allergen was purified by HPLC, using a cationic-exchange column followed by gel-filtration. Further characterization was achieved by periodic-Schiff stain, isoelectrofocusing and N-terminal amino acid sequencing.

RESULTS AND CONCLUSIONS

The major allergen of plum is a 9 kD lipid transfer protein, not glycosylated and with a basic character (pI>9), highly homologous to the major allergen of peach.

Determination of the primary structure of two lipid transfer proteins from apricot (Prunus armeniaca)

It has been recently demonstrated that the major allergen of apricot is a protein of molecular mass (Mr) 9000 belonging to the family of Lipid Transfer Protein. The aim of this study was the determination of the primary structure of apricot LTP by micro-sequencing and mass spectrometric analyses. Apricot LTP is a 91 amino acids protein like peach and almond LTPs with a sequence identity of 91% and 94%, respectively. Like for the peach LTP, out of the 25 amino acids forming the inner surface of the tunnel-like hydrophobic cavity in maize ns-LTP, 16 are identical and 7 similar in the apricot LTP, supporting the hypothesis of a similar function.

The major allergen of sesame seeds (Sesamum indicum) is a 2S albumin

BACKGROUND

Allergic reactions induced by ingestion of foods containing sesame seeds are a well recognized cause of severe food-induced anaphylaxis.

OBJECTIVE

This study aimed to identify and characterize the clinically most important major allergen of sesame seeds.

METHODS

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and IgE immunoblotting were performed on sera of 10 patients selected for severe and documented allergic reaction after eating food containing sesame. The major allergen was purified by gel filtration and characterized by isoelectric point (pI), glycosylation and amino acid sequencing.

RESULTS

All the patients had positive IgE antibodies and skin prick tests (SPTs) to sesame. The major, clinically most important allergen was a protein with molecular mass of about 9000. It was not glycosylated, the amino acid sequence showed it was a 2S albumin with a pI of 7.3; the small and the large subunits, forming the whole protein, showed pI values of 6.5 and 6.0.

Incidence of anaphylaxis in the emergency department of a general hospital in Milan

OBJECTIVE

To evaluate incidence and causes of anaphylactic reactions in the emergency room (E.R.) of a general hospital in Milan during a 2-year period.

METHODS

We retrospectively studied the computerized records of patients discharged from an E.R. with a diagnosis of anaphylactic reaction. Anaphylaxis was established on the presence of at least two cutaneous, respiratory, gastrointestinal or cardiovascular system symptoms.

RESULTS

During 1997 and 1998, out of 38 685 patients referred to the E.R., 13 had severe anaphylaxis with loss of consciousness (LOC) and 127 had anaphylactic symptoms, without LOC. Of the 13 patients with LOC, a possible cause was identified in 12 (five foods, six drugs, one hair dye). In the other 127 patients anaphylaxis was related to foods in 49 cases (38.5%), drugs in 44 (34.6%), unknown causes in 29 (22.8%), hymenoptera stings in two (1.5%), and other causes in three (2.3%).

CONCLUSION

The incidence of anaphylactic reactions was 0.4% and mainly affected females and atopic subjects. Foods, particularly fruits and vegetables, appeared to be the most important cause; other important causes were non steroidal antiinflammatory drugs and beta-lactam antibiotics.

The maize major allergen, which is responsible for food-induced allergic reactions, is a lipid transfer protein

BACKGROUND

Cereals are the most important nutritional component in the human diet. Food-induced allergic reactions to these substances therefore have serious implications, and exhaustive diagnosis is required. Such diagnosis is still difficult because of the incomplete knowledge about major cereal allergens. In particular, few food-induced allergic reactions to maize have been reported, and no information on the allergenic proteins is available.

OBJECTIVE

Having observed several anaphylactic reactions to maize, we planned a study to identify maize major allergens and cross-reactivity with other cereals, as well as to peach because the majority of patients also reacted to Prunoideae fruits.

METHODS

Twenty-two patients with systemic symptoms after maize ingestion and positive skin prick test responses and serum-specific IgE antibodies to maize were selected. The IgE-reactivity pattern was identified by SDS-PAGE and immunoblotting. The major allergen identified was then purified by HPLC and characterized by mass spectrometry, determination of the isoelectric point value, and N-terminal amino acid sequencing.

RESULTS

Sera from 19 (86%) of the 22 patients recognized a 9-kd protein, thus confirming this as the maize major allergen. This protein had an isoelectric point of greater than 9, a molecular mass of 9047.0 d, and no glycosylation. Determination of its N-terminal sequence showed that it was a lipid transfer protein (LTP). By using immunoblotting-inhibition experiments, we demonstrated that the LTP cross-reacts completely with rice and peach LTPs but not with wheat or barley LTPs. N-terminal sequence of the 16-kd allergen (recognized by 36% of patients) showed it to be the maize inhibitor of trypsin. This protein cross-reacts completely with grass, wheat, barley, and rice trypsin inhibitors.

CONCLUSION

The major allergen of maize is an LTP with a molecular weight of 9 kd that is highly homologous with the peach LTP, the major allergen of the Prunoideae subfamily.

Hazelnut allergy: a double-blind, placebo-controlled food challenge multicenter study

BACKGROUND

Tree nuts are a common cause of food allergy in Europe. However, few studies deal with real food allergy to hazelnuts in subjects believed to be allergic to this food.

OBJECTIVE

We sought to select subjects with a history of allergic reactions on ingestion of hazelnut and determine how many of these have true allergy by means of the double-blind, placebo-controlled food challenge (DBPCFC).

METHODS

Eighty-six subjects with a history of symptoms after hazelnut ingestion were recruited from 3 allergy centers (Milan, Zurich, and Copenhagen). All subjects underwent skin prick tests (SPTs) with aeroallergens and hazelnut, as well as having their specific hazelnut IgE levels determined. Diagnosis of clinical relevant food allergy was made on the basis of the DBPCFC.

RESULTS

Sixty-seven (77.9%) of 86 subjects had a positive DBPCFC result; 8 were placebo responders, and 11 were nonresponders. Of the 11 nonresponders, 4 had positive open-challenge test results. Of the DBPCFC-positive subjects, 87% also had positive skin test responses to birch pollen extract. Specific IgE determination for hazelnut (positive CAP response >/=0.7 kU/L [ie, class 2]) showed a sensitivity of 0.75, a positive predictive value (PPV) of 0.92, a specificity of 0.16, and a negative predictive value (NPV) of 0.05. Skin tests with commercial hazelnut extract produced a sensitivity of 0.89, a PPV of 0.92, a specificity of 0.05, and an NPV of 0.05. Skin tests with natural food produced a sensitivity of 0.88, a PPV of 0.94, a specificity of 0.27, and an NPV of 0.15.

CONCLUSION

This study shows that hazelnut is an allergenic source that can cause real food allergy, as confirmed by DBPCFC. Skin and IgE tests demonstrated reasonable sensitivity and PPV but a very low specificity and NPV, thus implying that these should not be used to validate the diagnosis of food allergy to hazelnut.

Technological processes to decrease the allergenicity of peach juice and nectar

Among vegetable foods peach (Prunus persica) has been recognized as a significant cause of allergy. The protein, which is considered to be the major peach allergen, has been named Pru p 1. Because peaches are consumed both as fresh fruits and after processing to obtain peach juice, nectar, jam, syrupy peach, etc., research was carried out to identify a technological process for production of hypo- or nonallergenic peach-based products. SDS-PAGE and immunoblotting analysis of extracts prepared from four commercial peach nectars showed that the Pru p 1 was not removed, and neither was its allergenic activity decreased by technological treatments carried out for nectar production. Some treatments oriented toward a removal of or, at least, a decrease in the allergenic power were assumed and verified at laboratory scale. A variable considered was heat treatment at 121 degrees C for 10 and 30 min: this treatment was not able to decrease the allergenicity of the Pru p 1 protein. Furthermore, the protein band was still present even after 60-min reaction with two different acidic proteases. The two technological treatments that were found to decrease the major allergen of peach were chemical lye peeling of fruits and ultrafiltration of juice through membranes with suitable cutoff. On the basis of the results obtained from this research, a processing flow sheet was defined to obtain hypoallergenic or probably nonallergenic limpid juices and nectars. These products may represent, besides finished foods, intermediates to obtain various products after addition of further ingredients such as pectins, sugars, and fiber.

Evidence for a lipid transfer protein as the major allergen of apricot

BACKGROUND

Apricots are widely grown in Europe, and allergic reactions are becoming more common, especially oral allergy syndrome. Apricot belongs to the botanical subfamily of Prunoideae, which includes peach, the major allergen of which was identified as a 9-kd protein, a lipid transfer protein (LTP).

OBJECTIVE

The aim of the study was to evaluate the IgE reactivity pattern to an apricot extract in subjects with allergic reactions to apricot, as demonstrated by a positive oral challenge response.

METHODS

Thirty patients were investigated. All the patients displayed oral allergy syndrome (2 with systemic reactions) to apricot, with positive open food challenge responses, skin prick test responses, and serum-specific IgE antibodies to apricot. The IgE reactivity pattern to apricot extract was identified by using SDS-PAGE and immunoblotting. The major allergen, a 9-kd protein, was then purified by HPLC and characterized by periodic acid-Schiff stain, isoelectric point determination, and N-terminal amino acid sequencing.

RESULTS

The sera from all patients allergic to apricot recognized the 9-kd protein, whereas none of the other allergens, with molecular weights from 15 to 80 kd, acted as a major allergen. The 9-kd allergen has an isoelectric point of 8.7 and is not glycosylated. Determination of the N-terminal 34 amino acid sequence showed that it belongs to the LTP family, with a 94% homology with the LTP from peach. IgE blotting of the apricot extract was completely inhibited by the 9-kd purified LTP from peach.

CONCLUSIONS

The major allergen of apricot is an LTP, which is highly cross-reactive with the LTP from peach.

Clinical role of a lipid transfer protein that acts as a new apple-specific allergen

BACKGROUND

Allergy to apple is commonly associated with birch pollinosis because the two share homologous allergens. However, some patients have apple allergy but no birch pollinosis, suggesting that there are allergens that do not cross-react with birch.

OBJECTIVE

The aim of the study was to evaluate the IgE reactivity pattern to an apple extract in subjects with allergic reactions to apple, with and without birch hay fever.

METHODS

Forty-three patients with oral allergy syndrome for apple and positive open food challenge, skin prick test, and serum specific IgE antibodies to apple were admitted to the study. Thirty-two had birch pollinosis (documented by specific IgE for birch) and 11 were not allergic to birch. The IgE reactivity pattern to apple extract was identified by SDS-PAGE and immunoblotting. The consistent allergen, a 9-kd protein, was then purified by HPLC and characterized by periodic acid-Schiff staining, isoelectric point, and N-terminal amino acid sequencing.

RESULTS

The sera from 28% of patients allergic to apple with birch pollinosis, but from all patients allergic only to apple, recognized the 9-kd protein. This protein has an isoelectric point of 7.5 and is not glycosylated. Determination of its partial amino acid sequence showed that it belongs to the family of lipid transfer proteins, which act as major allergens in Prunoideae fruits.

CONCLUSIONS

These results indicate that a lipid transfer protein is an important allergen in patients allergic to apple but not to birch pollen. The prevalent IgE reactivity to this allergen in subjects with no birch pollinosis and the physicochemical characteristics of this protein suggest that sensitization may occur through the oral route.

Complete amino acid sequence determination of the major allergen of peach (Prunus persica) Pru p 1

The major protein allergen of peach (Prunus persica), Pru p 1, has recently been identified as a lipid transfer protein (LTP). The complete primary structure of Pru p 1, obtained by direct amino acid sequence and liquid chromatography-mass spectrometry (LC-MS) analyses with the purified protein, is described here. The protein consists of 91 amino acids with a calculated molecular mass of 9178 Da. The amino acid sequence contains eight strictly conserved cysteines, as do all known LTPs, but secondary structure predictions failed to classify the peach 9 kDa protein as an 'all-alpha type', due to the high frequency of amino acids (nine prolines) disrupting alpha helices. Although the sequence similarity with maize LTP is only 63%, out of the 25 amino acids forming the inner surface of the tunnel-like hydrophobic cavity in maize ns-LTP 16 are identical and 7 similar in the peach homolog, supporting the hypothesis of a similar function.

The major allergen of peach (Prunus persica) is a lipid transfer protein

BACKGROUND

Allergy to fresh fruits and vegetables is mostly observed in subjects with pollinosis, especially from birch, because of cross-reacting allergens in vegetable foods and pollens. However, allergic reactions to fruits, specifically Rosaceae fruits, have been reported in subjects without pollinosis.

OBJECTIVE

This study evaluated the pattern of IgE reactivity, identifying the allergen responsible in 2 groups of patients with oral allergy syndrome to peach with or without birch pollinosis.

METHODS

The allergenic components of peach were detected by SDS-PAGE and immunoblotting. The major peach allergen was purified by HPLC with a cation-exchange column followed by gel filtration chromatography. Its IgE-binding capacity and its homology with the protein of the crude extract were demonstrated by immunoblotting inhibition techniques. To better characterize this allergen, periodic acid-Schiff stain and isoelectrofocusing were used. The amino acid sequencing was done with a gas-phase sequencer.

RESULTS

SDS-PAGE and immunoblotting of the 15 patients allergic to peach, 8 without and 7 with birch pollinosis, showed that they all recognized a protein with a molecular weight of 9 kd. This was the only allergen recognized by patients not sensitized to pollen, whereas the birch pollen-sensitive patients had IgE binding to other allergenic proteins at higher molecular weights. The purified 9-kd protein retained its IgE-binding capacity, was negative to periodic acid-Schiff stain, and had an isoelectric point value of greater than 9. A search in the Swiss Prot Bank showed this was a lipid transfer protein, belonging to a group of molecules involved in the defensive system of plants.

CONCLUSIONS

The major allergen of peach is a 9-kd protein belonging to the group of lipid transfer proteins. This is the only allergen recognized by patients allergic to peach but not sensitized to birch pollen.

Sensitization to the major allergen of Brazil nut is correlated with the clinical expression of allergy

BACKGROUND

Only a few studies have investigated the clinical role of food allergens, especially the relationship between sensitization to a given allergen and occurrence of adverse reactions when eating the relevant food item.

OBJECTIVE

This study evaluated the clinical role of the allergens of Brazil nut by comparing the patterns of IgE binding in sera from 11 patients with anaphylaxis after eating Brazil nuts with those from 10 subjects with no symptoms to this food item. Both groups had specific IgE to Brazil nut.

METHODS

Allergens in the in-house extract of Brazil nut were identified by SDS-PAGE/immunoblotting, the major allergen was purified by HPLC, and its N-terminal sequence was determined by a protein sequencer.

RESULTS

SDS-PAGE/immunoblotting detected a number of allergenic components with molecular weights ranging from 4 to 58 kd. All sera from symptomatic patients recognized a 9-kd allergen corresponding (as established by amino acid sequencing) to a 2S albumin already described as a major allergen of Brazil nut, whereas the other allergens each bound IgE from less than 50% of sera. No sera from asymptomatic subjects showed IgE binding to the 9-kd allergen, but they did recognize components from 25 to 58 kd, which are minor allergens.

CONCLUSIONS

These findings indicate that the allergen underlying clinical reactions to Brazil nut is a 2S albumin of 9 kd and that in vitro reactivity to this allergen identifies subjects who react in vivo to ingestion of this food.