Olive allergen-specific IgE responses in patients with Olea europaea pollinosis

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Cross-Reactive Aeroallergens: Which Need to Cross Our Mind in Food Allergy Diagnosis?

Secondary food allergies due to cross-reactivity between inhalant and food allergens are a significant and increasing global health issue. Cross-reactive food allergies predominantly involve plant-derived foods resulting from a prior sensitization to cross-reactive components present in pollen (grass, tree, weeds) and natural rubber latex. Also, primary sensitization to allergens present in fungi, insects, and both nonmammalian and mammalian meat might induce cross-reactive food allergic syndromes. Correct diagnosis of these associated food allergies is not always straightforward and can pose a difficult challenge. As a matter of fact, cross-reactive allergens might hamper food allergy diagnosis, as they can cause clinically irrelevant positive tests to cross-reacting foods that are safely consumed. This review summarizes the most relevant cross-reactivity syndromes between inhalant and food allergens. Particular focus is paid to the potential and limitations of confirmatory testing such as skin testing, specific IgE assays, molecular diagnosis, and basophil activation test.

Russian olive (Elaeagnus angustifolia) as a herbal healer

Introduction:Elaeagnus spp. is one in the family of riparian trees growing near the rivers or water corridors. In this family, Elaeagnus angustifolia (Russian olive) is famous because of its medical applications.

Methods: A comprehensive review was performed to extract the related data from published literature.

Results: Traditionally, it has been used as an analgesic, antipyretic and diuretic herbal medicine. A large number of compounds have been derived from Russian olive and made this plant a source of flavonoids, alkaloids, minerals and vitamins. Although the purpose of most studies is to use this plant for preparation of herbal medicines and as an ingredient for drug formulation, there is no available drug dosage form commercially.

Conclusion: This review aimed to provide the most important documentary information on the active components of Elaeagnus spp. and their relation to the pharmacological properties and compare them with reported medicinal effects.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Exploratory study of tolerability and immunological effect of a short up-dosing immunotherapy phase with a standardised allergen extract derived from pollen of Olea europaea

BACKGROUND

A new subcutaneous specific immunotherapy (SCIT) product adsorbed on aluminium hydroxide has been developed with a short and simplified up-dosing phase, containing a biologically standardized allergen pollen extract from Olea europaea.

OBJECTIVE

To assess the tolerability profile of the updosing phase and its immunological effect, in terms of specific IgG4 and IgE levels and immediate skin reactivity.

MATERIAL AND METHODS

The study was an exploratory, multi-centre, open-label, single-arm, phase II/III clinical trial. Adults with a clinical history of allergic rhinoconjunctivitis with/without asthma due to sensitization to olive pollen were selected. Five up-dosing doses (300, 600, 3000, 6000 and 15000SQ+) were administered at weekly intervals, followed by a maintenance dose (15000SQ+) after 2 weeks. Adverse events were collected during the 30 min observation period after injections, after a telephone contact 2 days after each visit, and after reviewing the subjects' diary. IgG4 and IgE levels and immediate skin reactivity were evaluated at the beginning and at the end of the trial.

RESULTS

Ninety-three subjects were included in the trial (mean age, 35.7 ± 10.3 years; women, 66.7 %). A total of 95 adverse drug reactions, all mild in intensity and non-serious, were reported during the trial: 85 local in 34.4 % subjects, 9 systemic in 4.3 % subjects and one non-specific (grade 0). Within 6 weeks, significant changes in IgG4 and IgE levels and in immediate skin reactivity to Olea europaea were accomplished.

CONCLUSION

This new SCIT derived from pollen of Olea europaea presented a good tolerability profile and induced significant immunological responses already after a 6 week treatment. However, the non-controlled design may limit the interpretation of these results.

TRIAL REGISTRATION

EudraCT no: 2011-004852-20; ClinicalTrials.gov Identifier: NCT01674595.

Polymorphisms of tumor necrosis factor-α, transforming growth factor-β, and interleukin-10 in asthma associated with olive pollen sensitization

Sensitization to specific olive pollen-allergens (Ole e 2 and 10) has been correlated with a clinical pattern of asthma. This study analyzes the association between several polymorphims of TNFA (G-308A, C-857T, and C-1031T), IL10 (C-571A and A-1117G), and TGFB (C-509-T) and these sensitizations. These polymorphisms were genotyped by allelic discrimination, in olive pollen-allergic patients (phenotyped for specific Ole e 2 and 10 sensitizations) and healthy controls. Levels of serum-soluble cytokines were correlated with specific genotypes and clinical phenotypes. The results showed that heterozygous TGFB C-509T genotype, besides having the lowest sera TGF- levels, was significantly increased in olive pollen-allergic patients compared with controls. According specific sensitizations, CC genotype of IL10 C-571A could be a protective factor for Ole e 2 sensitization and mainly for asthmatic Ole e 2 sensitized patients compared with asthmatic non-Ole e 2 sensitized patients (OR: 0.26, P = 0.008). In contrast, heterozygous CA genotype was increased in Ole e 2 asthmatic subjects compared to asthmatic non-Ole e 2 sensitized patients. Lastly, heterozygous TNFA G-308A genotype was associated with Ole e 10 sensitization (OR: 2.5, P = 0.04). In conclusion, these results suggest a role of TGF-β1 in olive-pollen sensitization and TNF-α and IL-10 genotypes in the asthma induced by specific olive-pollen allergens.

The spectrum of olive pollen allergens. From structures to diagnosis and treatment

Olive tree is one of the main allergy sources in Mediterranean countries. The identification of the allergenic repertoire from olive pollen has been essential for the development of rational strategies of standardization, diagnosis, and immunotherapy, all of them focused to increase the life quality of the patients. From its complex allergogram, twelve allergens - Ole e 1 to Ole e 12 - have been identified and characterized to date. Most of them have been cloned and produced as recombinant forms, whose availability have allowed analyzing their three-dimensional structures, mapping their T-cell and B-cell epitopes, and determining the precise allergenic profile of patients for a subsequent patient-tailored immunotherapy. Protein mutant, hypoallergenic derivatives, or recombinant fragments have been also useful experimental tools to analyze the immune recognition of allergens. To test these molecules before using them for clinic purposes, a mouse model of allergic sensitizations has been used. This model has been helpful for assaying different prophylactic approaches based on tolerance induction by intranasal administration of allergens or hypoallergens, used as free or integrated in different delivery systems, and their findings suggest a promising utilization as nasal vaccines. Exosomes - nanovesicles isolated from bronchoalveolar lavage fluid of tolerogenic mice - have shown immunomodulatory properties, being able to protect mice against sensitization to Ole e 1.

Calcium-binding proteins and their role in allergic diseases

Calcium-binding proteins (CBPs) are ubiquitous pollen allergens and important food allergens in fish and amphibians. Calcium-binding allergens containing two EF-hands (polcalcins) have been detected and characterized in pollen from trees, grasses, and weeds. Timothy grass Phl p 7 is the most cross-reactive allergen among polcalcins. Although there is cross-reactivity described within the subfamilies of calcium-binding allergens, there are no strong indications for IgE cross-reactivity between CBPs from plants, fish, and humans. Therefore, Phl p 7 could be used as marker to identify multiple pollen-sensitized patients, whereas cod Gad c 1 or carp Cyp c 1 could be selected for the diagnosis of fish allergy. Hom s 4, a calcium-binding autoantigen, might be an interesting candidate to monitor chronic skin inflammation in atopic and nonatopic individuals. Diagnostic tests containing these molecules could allow the identification of most patients sensitized to calcium-binding allergens/antigens. In general, IgE recognition of calcium-binding allergens is influenced by binding or release of calcium ions. This knowledge could be used to engineer hypoallergenic CBPs for specific immunotherapy.

Emerging pollen allergens

Numerous pollen allergens have been reported over the last few years. Most of them belong to well-known families of proteins but some others constitute the first member of new allergenic families. Some of the factors that can contribute to the detection and identification of new pollen allergens are: a) advances in the technology tools for molecular analysis; and b) the deep knowledge of many allergenic sources. The combination of these factors has provided vast information on the olive pollen allergogram and the identification of minor allergens that become major ones for a significant population. The close taxonomical relationship between olive tree and ash -both Oleaceae- has permitted to identify Fra e 1 (the Ole e 1-like allergen) in ash pollen and to detect the presence of protein homologues of Ole e 3 and Ole e 6. In the other hand, extensive areas of south Europe are suffering an increasing desertification. As a consequence of this, new botanical species are spontaneously growing in these areas or being used in greening ground programs: Chenopodium album and Salsola kali are some examples recently recognized as allergenic woods. The identification of the complete panel of allergens from the hypersensitizing sources might help to develop more accurate diagnosis, and efficient and safer therapy tools for Type-I allergic diseases.

Allergenic contribution of the IgE-reactive domains of the 1,3-beta-glucanase Ole e 9: diagnostic value in olive pollen allergy

BACKGROUND

Designing of methods for an accurate diagnosis is a main goal of allergy research. Olive pollen allergy is currently diagnosed using commercially available pollen extracts that do not allow identification of the molecules that elicit the disease.

OBJECTIVE

To analyze the suitability of using the N- and C-terminal domains (NtD and CtD, respectively) of the 1,3-beta-glucanase Ole e 9, a major allergen from olive pollen, for in vitro diagnosis.

METHODS

Serum samples from 55 olive-allergic patients were assayed using enzyme-linked immunosorbent assay to study hypersensitive patients with IgE reactivity to Ole e 9. The specific IgEs to NtD and CtD, obtained by recombinant technology, were determined by means of immunoblotting, enzyme-linked immunosorbent assay, and inhibition assays.

RESULTS

Thirty-one of 33 serum samples from Ole e 9-allergic patients were IgE reactive to recombinant NtD (rNtD) (n = 26 [79%]), recombinant CtD (rCtD) (n = 22 [67%]), or both (n = 17 [52%]). Nine patients (27%) were exclusively reactive to rNtD and 5 (15%) to rCtD. Inhibition assays of IgE binding to Ole e 9 with a mixture of both domains abolished 90% of the binding, whereas 44% and 45% were abolished when rNtD and rCtD were used, respectively.

CONCLUSIONS

Because sensitization to NtD or CtD of Ole e 9 could be correlated to vegetable food-latex-pollen cross-reactivity processes or to the exacerbation and persistence of asthma, respectively, these molecules could be used in vitro as markers of disease to classify patients and to design a patient-tailored immunotherapy approach.

A comparative analysis of the cross-reactivity in the polcalcin family including Syr v 3, a new member from lilac pollen

BACKGROUND

Polcalcins are pollen-specific allergens with two EF-hand calcium-binding sites that exhibit strong cross-reactivity. Our objective was to isolate and express the cDNA coding of the EF-hand calcium-binding allergen from lilac pollen and to study cross-reactivity with other polcalcins from related and nonrelated pollen sources with different specific antibodies and sera from two different populations.

METHODS

Specific cDNA was amplified by PCR, cloned and expressed in Escherichia coli. Purification was achieved by gel permeation and ion exchange chromatographies. ELISA titration and inhibition assays were performed using the recombinant forms of Syr v 3, Ole e 3, Che a 3 and Phl p 7 with sera from two Spanish regions with different sensitization profiles, as well as Phl p 7- and Ole e 3-specific polyclonal rabbit antisera, and an Ole e 3-specific monoclonal antibody.

RESULTS

Syr v 3 displays two EF-hand consensus sites and 8863 Da of theoretical molecular mass. The allergen consists of 80 residues with identities ranging from 66 to 87% with polcalcins included in this study. Syr v 3, Ole e 3, Che a 3 and Phl p 7 showed a similar IgG- and IgE-binding capacity although differences at quantitative level were observed depending on the population of patients' sera.

CONCLUSION

Syr v 3 is a polcalcin with structural and antigenic similarities to the members of this family. Diagnosis of polcalcin-sensitized patients could be performed whatever polcalcin used, whereas for immunotherapy, primary sensitization to a particular allergenic source should be considered.

Cloning, expression, and clinical significance of the major allergen from ash pollen, Fra e 1

BACKGROUND

Ash tree, an Oleaceae member, is considered an important source of pollen allergy in Central Europe. Fra e 1 is a protein of the Ole e 1-like family, which regulates pollen tube growth. It has been suggested to be a relevant allergen from ash pollen.

OBJECTIVE

Cloning Fra e 1-cDNA and overproducing a properly folded recombinant allergen to analyze its clinical significance.

METHODS

Fra e 1-encoding cDNA was amplified by PCR, cloned in Escherichia coli , and sequenced. The recombinant allergen was produced in Pichia pastoris and used in immunoblotting, ELISA, histamine release, and skin prick tests. Sera and blood cells from patients sensitized to ash pollen as well as anti-Ole e 1 monoclonal and polyclonal antisera were used.

RESULTS

Recombinant Fra e 1 (rFra e 1) is a glycoprotein of 145 amino acids exhibiting 82%, 88%, and 91% identity with Syr v 1, Ole e 1, and Lig v 1, allergens of the Oleaceae family. It was secreted to the extracellular medium of the yeast cultures and purified by means of 3 chromatographic steps. IgG from Ole e 1-specific antibodies recognized rFra e 1. IgE antibodies from ash-sensitized patients bound to rFra e 1 with a prevalence of 75%. The recombinant allergen induced histamine release. Twenty-nine of 30 ash-sensitized patients were positive to rFra e 1 by skin prick tests.

CONCLUSION

Fra e 1 is a relevant allergen in ash pollen sensitization. It has been efficiently produced in P pastoris and could be used in diagnosis.

Ole e 2 and Ole e 10: new clinical aspects and genetic restrictions in olive pollen allergy

BACKGROUND

The clinical characteristics in olive pollen allergy are dependent on the antigenic load, the allergens profile, and the genetic restrictions. Our objective was to determine specific response pattern in Ole e 2 and Ole e 10 sensitization at those levels.

METHODS

We studied 146 patients with seasonal rhinitis and/or asthma and positive prick test to Olea europaea pollen. IgE against Ole e 2 and Ole e 10 were detected by skin prick test and ELISA. HLA-DRB1 and HLA-DQB1 loci were typed by polymerase chain reaction sequence-specific primers method.

RESULTS

A total of 102 (69.9%) and 79 (54.0%) patients showed significant IgE antibody response against Ole e 2 and Ole e 10, respectively. There was a significant association between Ole e 2 (OR 2.2, P = 0.04) and Ole e 10 reactivities (OR 2.8, P = 0.007) with asthma. In addition, total and specific IgE antibody levels significantly correlated with asthma (P < 0.05). Patients who reacted to both allergens reached the highest asthma risk factor (OR 4.3, P = 0.002). Phenotypic frequency of DR7 (OR 5.4, Pc = 0.003) and DQ2 (OR 3.6, Pc = 0.02) were increased in positive Ole e 2 patients compared with control subjects. DR2(15) phenotypic frequency was significantly increased (OR 5.6, Pc = 0.02) in positive Ole e 10 patients compared with control subjects.

CONCLUSIONS

Our data suggest an association of Ole e 2 and Ole e 10 with bronchial asthma. Also, we found a genetic control of Ole e 2 and Ole e 10 IgE-specific responses that could be relevant to clinical disease in olive pollen allergy.

Allergenicity and cross-reactivity of Russian olive pollen (Eleagnus angustifolia)

BACKGROUND

The purposes of this study were: to determine the prevalence of sensitization and immunochemical characterization of Eleagnus angustifolia pollen (Russian olive) that belongs to the family Eleagnaceae.

METHODS

A total of 134 patients with rhinoconjunctivitis and/or asthma were studied. Its allergenicity, cross-reactivity with olive pollen and the presence of Ole e 1 and Ole e 4-like molecules were evaluated.

RESULTS

Eleagnus angustifolia pollen was detected from May to June. Seventy-three of 134 (30.5%) had positive skin test to E. angustifolia, all of them were positive to olive. There was a good correlation between specific immunoglobulin (Ig)E levels to E. angustifolia and Olea europaea (r = 0.77, P = 0.002). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) immunoblots revealed major IgE-binding bands in the E. angustifolia extract of 43 and 63.7 kDa. The E. angustifolia extract was not able to inhibit olive, whereas O. europaea inhibited E. angustifolia up to 41%. The presence of Ole e 1- and Ole e 4-like allergens in E. angustifolia extract was confirmed by enzyme-linked immunosorbent (ELISA) inhibition assays. Nasal challenge with E. angustifolia was positive in three of six patients with positive skin test to both pollens and negative in five patients with positive skin test only to O. europaea.

CONCLUSIONS

This study confirms that E. angustifolia is capable of sensitizing individuals in Madrid. A minimal-to-moderate cross-reactivity with olive pollen was established, suggesting some cross-reactivity but not excluding co-sensitization.

Therapeutic points of intervention and clinical implications: role of desloratadine

Desloratadine, a potent, once-daily, orally active, nonsedating, histamine H1-receptor antagonist, inhibits the release of histamine and other inflammatory mediators. Once-daily desloratadine therapy rapidly reduces the symptoms of perennial allergic rhinitis and seasonal allergic rhinitis (SAR), reduces the use of inhaled albuterol by patients with SAR and concomitant asthma, and improves symptoms and quality of life in patients with chronic idiopathic urticaria. An open-label, observational study in SAR patients revealed that desloratadine therapy significantly reduced nasal, ocular, dermal, asthma, and total symptoms, and enabled half of the patients with concomitant asthma to reduce their use of asthma medications. Globally, more than 91% of patients and physicians judged desloratadine to have excellent or good efficacy, and more than 98% judged it to have excellent or good tolerability. Furthermore, desloratadine therapy improved quality of life, decreasing by more than 10-fold the percentage of patients whose daily activities and/or sleep were moderately or severely affected by SAR. Allergic rhinitis, a major chronic airway disease that is a risk factor for asthma, warrants extended diagnostic procedures and well-tolerated therapy that encompasses the entire airway, addresses multiple steps in the allergic inflammatory cascade, and is effective on nasal, ocular, dermal, asthma, and total symptoms.