Evaluation of ash pollen sensitization pattern using proteomic approach with individual sera from allergic patients

Outdoor airborne allergens: Characterization, behavior and monitoring in Europe

Aeroallergens or inhalant allergens, are proteins dispersed through the air and have the potential to induce allergic conditions such as rhinitis, conjunctivitis, and asthma. Outdoor aeroallergens are found predominantly in pollen grains and fungal spores, which are allergen carriers. Aeroallergens from pollen and fungi have seasonal emission patterns that correlate with plant pollination and fungal sporulation and are strongly associated with atmospheric weather conditions. They are released when allergen carriers come in contact with the respiratory system, e.g. the nasal mucosa. In addition, due to the rupture of allergen carriers, airborne allergen molecules may be released directly into the air in the form of micronic and submicronic particles (cytoplasmic debris, cell wall fragments, droplets etc.) or adhered onto other airborne particulate matter. Therefore, aeroallergen detection strategies must consider, in addition to the allergen carriers, the allergen molecules themselves. This review article aims to present the current knowledge on inhalant allergens in the outdoor environment, their structure, localization, and factors affecting their production, transformation, release or degradation. In addition, methods for collecting and quantifying aeroallergens are listed and thoroughly discussed. Finally, the knowledge gaps, challenges and implications associated with aeroallergen analysis are described.

Mass Spectrometry-Based Identification of Bioactive Bee Pollen Proteins: Evaluation of Allergy Risk after Bee Pollen Supplementation

Bee pollen, because of its high content of nutrients, is a very valuable medicinal and nutritional product. However, since its composition is not completely studied, the consumption of this product may cause adverse effects, including allergic reactions. Therefore, this study aimed to discover and characterize the bioactive proteins of bee pollen collected in Poland, focusing mainly on the allergens. For this purpose, the purified and concentrated pollen aqueous solutions were analyzed using the nanoLC-MALDI-TOF/TOF MS analytical platform. As a result of the experiments, 197 unique proteins derived from green plants (Viridiplantae) and 10 unique proteins derived from bees (Apis spp.) were identified. Among them, potential plant allergens were discovered. Moreover, proteins belonging to the group of hypothetical proteins, whose expression had not been confirmed experimentally before, were detected. Because of the content of bioactive compounds-both beneficial and harmful-there is a critical need to develop guidelines for standardizing bee pollen, especially intended for consumption or therapeutic purposes. This is of particular importance because awareness of the allergen content of bee pollen and other bee products can prevent health- or life-threatening incidents following the ingestion of these increasingly popular "superfoods".

Omics technologies in allergy and asthma research: An EAACI position paper

Allergic diseases and asthma are heterogenous chronic inflammatory conditions with several distinct complex endotypes. Both environmental and genetic factors can influence the development and progression of allergy. Complex pathogenetic pathways observed in allergic disorders present a challenge in patient management and successful targeted treatment strategies. The increasing availability of high-throughput omics technologies, such as genomics, epigenomics, transcriptomics, proteomics, and metabolomics allows studying biochemical systems and pathophysiological processes underlying allergic responses. Additionally, omics techniques present clinical applicability by functional identification and validation of biomarkers. Therefore, finding molecules or patterns characteristic for distinct immune-inflammatory endotypes, can subsequently influence its development, progression, and treatment. There is a great potential to further increase the effectiveness of single omics approaches by integrating them with other omics, and nonomics data. Systems biology aims to simultaneously and longitudinally understand multiple layers of a complex and multifactorial disease, such as allergy, or asthma by integrating several, separated data sets and generating a complete molecular profile of the condition. With the use of sophisticated biostatistics and machine learning techniques, these approaches provide in-depth insight into individual biological systems and will allow efficient and customized healthcare approaches, called precision medicine. In this EAACI Position Paper, the Task Force "Omics technologies in allergic research" broadly reviewed current advances and applicability of omics techniques in allergic diseases and asthma research, with a focus on methodology and data analysis, aiming to provide researchers (basic and clinical) with a desk reference in the field. The potential of omics strategies in understanding disease pathophysiology and key tools to reach unmet needs in allergy precision medicine, such as successful patients' stratification, accurate disease prognosis, and prediction of treatment efficacy and successful prevention measures are highlighted.

An allergenic plant calmodulin from Artemisia pollen primes human DCs leads to Th2 polarization

Artemisia pollen is the major cause of seasonal allergic respiratory diseases in the northern hemisphere. About 28.57% of Artemisia allergic patients’ IgE can recognize ArtCaM, a novel allergenic calmodulin from Artemisia identified in this study. These patients exhibited stronger allergic reactions and a longer duration of allergic symptoms. However, the signaling mechanism that triggers these allergic reactions is not fully understood. In this study, we found that extracellular ArtCaM directly induces the maturation of human dendritic cells (DCs), which is attributed to a series of Ca²⁺ relevant cascades, including Ca²⁺/NFAT/CaMKs. ArtCaM alone induces inflammatory response toward Th1, Th17, and Treg. Interestingly, a combination of ArtCaM and anti-ArtCaM IgE led to Th2 polarization. The putative mechanism is that anti-ArtCaM IgE partially blocks the ArtCaM-induced ERK signal, but does not affect Ca²⁺-dependent cascades. The crosstalk between ERK and Ca²⁺ signal primes DCs maturation and Th2 polarization. In summary, ArtCaM related to clinical symptoms when combined with anti-ArtCaM IgE, could be a novel allergen to activate DCs and promote Th2 polarization. Such findings provide mechanistic insights into Th2 polarization in allergic sensitization and pave the way for novel preventive and therapeutic strategies for efficient management of such pollen allergic disease.

Efficacy and Safety of Rupatadine Fumarate Combined with Acupoint Application in Allergic Rhinitis Complicated with Diabetes

The prevalence of allergic rhinitis has exhibited an upward trend, and diabetes is a common endocrine metabolic disorder. Treatment of allergic rhinitis complicated with diabetes has been marginally explored. This study aimed to observe the effect of rupatadine fumarate combined with acupoint application in the treatment of allergic rhinitis complicated with diabetes and its effect on serum IgE levels. Totally 80 patients with allergic rhinitis complicated with diabetes admitted to our hospital from December 2019 to December 2020 were recruited and assigned to receive either rupatadine fumarate (control group) or rupatadine fumarate plus acupoint application (research group). The clinical observation indexes of the two groups of patients before and after treatment were analyzed, and the clinical efficacy of the two groups was evaluated. Rupatadine fumarate plus acupoint application was associated with a significantly higher efficacy (23 cases of markedly effective, 14 cases of effective, and 3 cases of ineffective) versus rupatadine fumarate alone (14 cases of markedly effective, 16 cases of effective, and 10 cases of ineffective) (χ 2 = 4.501, p = 0.034). The immunoglobulin E (IgE) and nasal mucosal eosinophils (EOS) levels of the two groups of patients after treatment decreased significantly, and the research group had lower results (p < 0.05). Patients in the research group showed significantly lower syndrome scores than those in the control group (p < 0.05). Rupatadine fumarate plus acupoint application resulted in significantly lower physical sign scores and interleukin-4 (IL-4) levels and higher levels of interferon-gamma (INF-γ) versus rupatadine fumarate alone (p < 0.05). The two groups showed a similar incidence of adverse events (p > 0.05). Rupatadine fumarate plus acupoint application may offer a viable alternative for the treatment of allergic rhinitis as it alleviates the clinical symptoms, improves the treatment efficiency, and enhances the anti-allergic effect of the drug, with a high safety profile.

Identification of an allergenic calmodulin from Amaranthus palmeri pollen

INTRODUCTION

Pollens are an important source of allergens that trigger rhinitis or asthma. The allergenic extracts of pollens used to diagnose and treat allergies contain different allergenic antigens. Isolated allergenic proteins are employed in in vitro assays, skin tests and allergenic-specific immunotherapy. Calcium-binding allergens are clinically relevant antigens, and their allergenicity can be affected by Ca²⁺ binding. In this work, a calmodulin was identified as an allergen from Amaranthus palmeri pollen, an important source of pollinosis in Europe, Asia and North America.

MATERIALS AND METHODS

Allergenic calmodulin from A. palmeri pollen was isolated by size-exclusion chromatography and reverse-phase chromatography and identified by mass spectrometry. Sensitization to isolated calmodulin was evaluated by skin prick tests in patients with allergy to A. palmeri pollen.

RESULTS

Size-exclusion chromatography yielded two fractions that were recognized by the IgE of patients allergic to A. palmeri pollen. Mass spectrometry analysis of the fractions from reverse-phase chromatography showed peptide sequences that identified a calmodulin. Skin prick tests showed that the isolated calmodulin was recognized by 56% of patients allergic to A. palmeri pollen.

CONCLUSION

A. palmeri pollen calmodulin could be a clinically relevant allergen in patients sensitized to this source.

Tree Allergen Pollen-Related Content as Pollution Source in the City of Ourense (NW Spain)

Allergies became a major public health problem, identified as an important global pandemic with a considerable impact on the worldwide economy. In addition, a higher prevalence of pollen Type I sensitization cases in urban environments in comparison with the rural territories was detected. Our survey sought to assess the main biological pollution episodes caused by the aeroallergens of the major allergenic tree species in urban environments. A Hirst-type volumetric device was used for pollen sampling and a Burkard Cyclone sampler for the detection of tree atmospheric allergens over two years. The main allergens of Alnus, Fraxinus, Betula, Platanus and Olea, were detected in the atmosphere. Three peaks of important pollen concentrations were recorded throughout the year. The developed regression equations between pollen counts and allergen proteins registered great R2 values. The number of days with probability of allergenic symptoms was higher when the pollen and allergen data were assessed altogether. Fraxinus allergens in the atmosphere were detected using Ole e 1 antibodies and the Aln g 1 allergens with Bet v 1 antibodies, demonstrating the cross-reaction processes between the principal allergenic proteins of the Oleaceae and Betulaceae families. Long Distance Transport processes (LDT) showed that pollen from Betula populations located in mountainous areas increased the secondary peaks of pollen and allergen concentrations, and air masses from extensive olive orchards of North-Eastern Portugal triggered the highest concentrations in the atmosphere of Olea pollen and Ole e 1 allergens.

Delineation of the Olive Pollen Proteome and Its Allergenome Unmasks Cyclophilin as a Relevant Cross-Reactive Allergen

Olive pollen is a major allergenic source worldwide due to its extensive cultivation. We have combined available genomics data with a comprehensive proteomics approach to get the annotated olive tree (Olea europaea L.) pollen proteome and define its complex allergenome. A total of 1907 proteins were identified by LC-MS/MS using predicted protein sequences from its genome. Most proteins (60%) were predicted to possess catalytic activity and be involved in metabolic processes. In total, 203 proteins belonging to 47 allergen families were found in olive pollen. A peptidyl-prolyl cis-trans isomerase, cyclophilin, produced in Escherichia coli, was found as a new olive pollen allergen (Ole e 15). Most Ole e 15-sensitized patients were children (63%) and showed strong IgE recognition to the allergen. Ole e 15 shared high sequence identity with other plant, animal, and fungal cyclophilins and presented high IgE cross-reactivity with pollen, plant food, and animal extracts.

Component resolved analysis of ash pollen allergy in Bavaria

Background

Sensitization to ash pollen is underestimated in various regions. The prevalence in Germany is about 10%. However, allergy to ash pollen is widely overlooked by allergists, since the pollination period of ash and birch in central Europe closely overlap and rhinoconjunctival symptoms during April/May are often assigned to birch pollen. Component resolved analysis of the different ash allergens is not routinely available. Therefore, we would like to question the usefulness of component resolved diagnostic via olive components, as ash and olive are both part of the Oleaceae family.

Methods

113 patients with nasal provocation and skin prick test to ash were retrospectively compared regarding their specific immunoglobulin E antibody profiles with response to native ash extract, rOle e 1, nOle e 7 and rOle e 9.

Results

In nasal provocation testing 58% of 113 patients sensitized to ash were allergic, 42% were only sensitized without showing symptoms. Skin prick testing and serology against native ash extract detected most patients sensitized to ash pollen, whereas rOle e 1 was less sensitive. However, the value of measurements of skin prick test, serology to native ash extract and rOle e 1 did not allow a differentiation between an allergy and clinically silent sensitization. Specific antibodies to nOle e 7 and rOle e 9 were only seen in individual patients and were all positive for native ash extract and rOle e 1.

Conclusion

Skin prick testing and serology to native extract of ash pollen are the most reliable tools to diagnose a sensitization to ash pollen for patients living in Germany. Component resolved diagnostic to the major allergen rOle e 1 as representative of the Oleaceae family is possible but was less sensitive. Diagnostic of nOle e 7 and rOle e 9 did not show any additional benefit. Regarding differentiation between allergy and clinically silent sensitization to ash pollen, provocation is the leading diagnostic tool. Concluding, in routine clinical practice the standard methods-skin prick test, serology to native ash extract and provocation testing-remain crucial in the diagnosis and differentiation of ash sensitization and allergy.

Double One-Dimensional Electrophoresis (D1-DE) Adapted for Immunoproteomics

The classical proteomics approach for the identification of allergen candidates consists on the separation of proteins by high-resolution two-dimensional electrophoresis (2-DE) with subsequent IgE immunoblotting and further analysis of IgE-reactive protein spots with mass spectrometry. In this approach at least two gels most be run. One gel is used for staining and the other is for immunoblotting by antibodies labeled with specific immunostains. Additional functional characterizations require either protein purification or 2-DE replicates and appear to be time- and reagent-consuming. Here we described a modified double one-dimensional electrophoresis (D1-DE) allowing the conversion of a protein spot previously visualized by 2-DE into an extended protein band. In D1-DE, the purity of the protein of interest is similar to 2-DE spots, but its abundance is many times higher than what can be found in a 2-DE single spot allowing many other functional analyses from a single D1-DE separation.

Identification of a polygalacturonase (Cup s 2) as the major CCD-bearing allergen in Cupressus sempervirens pollen

As IgE glyco-epitopes, also referred to as cross-reactive carbohydrate determinants (CCDs), can share significant structural homologies between different plants, they are prone to extensive cross-reactivity among allergen pollen extracts. Here, cypress pollen allergens, especially a polygalacturonase (PG), were further characterized using double one-dimensional electrophoresis (D1-DE). The presence of specific IgE directed against CCDs was investigated by bromelain IgE inhibition and concanavalin A binding assays using sera of cypress pollen-sensitized patients. Our results showed that IgE reactivity to CCDs in Cupressus sempervirens pollen extracts is mainly related to bromelain-type epitopes of a newly identified cypress PG. This glycoprotein has been further characterized through an immunoproteomic approach and officially indexed as Cup s 2 by the WHO/IUIS allergen nomenclature. Cup s 2 could thus be associated with the increased prevalence of IgE reactivity to cypress pollen extracts because of CCD interference.

Immunoproteomics of tree of heaven (Ailanthus atltissima) pollen allergens

Ailanthus altissima pollen (AAP) is considered as an emerging cause of respiratory allergy in United States, Italy and Iran. However, the allergenic composition of AAP is still unknown and has yet to be characterized. The present study aimed to identify AAP allergens using a proteomics-based approach. For this purpose, optimized AAP protein extracts were analyzed using 1D- and 2D- gel electrophoresis and confronted to twenty sera from individuals with respiratory allergy during the AAP season. Candidate allergens were detected using the serum from an allergic patient with clinical history of AAP pollinosis. IgE-binding spots were identified using MALDI-TOF/TOF mass spectrometry and database searching. According to our results, AAP extracts were rich in proteins (up to 16.25mg/ml) with a molecular-weight distribution ranging from 10 to 175kDa. Two-D electrophoresis of AAP extracts revealed 125 protein spots from which 13 were IgE reactive. These IgE-binding proteins were identified as enolase, calreticulin, probable pectate lyase 6, conserved hypothetical protein and ras-related protein RHN1-like. By our knowledge, this study is the first report identifying AAP allergens. These findings will open up further avenues for the diagnosis and immunotherapy of the AAP allergy as well as for the cloning and molecular characterization of relevant allergens.

BIOLOGICAL SIGNIFICANCE

Ailanthus altissima colonizes new areas every year in Iran and is spreading aggressively worldwide. According to USDA, the tree of heaven is now present as an invasive plant in 30 states in US (www.invasivespeciesinfo.gov/plants/treeheaven.shtml) and come to dominate large areas in many regions. Up to now, several cases of allergy to A. altissima pollen have been reported in United States, Italy and Iran [1-4]. However, there is still no information on the sensitizing allergens and the molecular origin of these clinical symptoms, which constitutes a serious threat to patients suffering from respiratory allergies in these regions. To our knowledge, the current study describes, therefore, the first panel of proteins responsible for IgE-mediated A. altissima pollinosis by using a gel-based proteomic approach. This work represents the pioneer proteomic investigation on Simaroubaceae spp. and provides useful insights for further studies on the allergens of this widely distributed plant family.

Urtica dioica pollen allergy: Clinical, biological, and allergomics analysis

BACKGROUND

The most emblematic members of Urticaceae at allergic risk level are wall pellitories (Parietaria), whereas nettle (Urtica) pollen is considered as poorly allergenic. No allergen from nettle pollen has yet been characterized, whereas 4 are listed for Parietaria pollen by the International Union of Immunological Societies. Clinical and biological profiles of 2 adult men who developed symptoms against nettle pollen and/or leaves were studied.

OBJECTIVE

To characterize the allergic reaction and identify the potential nettle pollen sensitizing allergens.

METHODS

IgE-mediated reaction to nettle pollen extract was evaluated by skin prick test, immunoassay, nasal provocation, and basophil activation test. To characterize specific nettle pollen allergens, an allergomic (IgE immunoproteomic) analysis was performed combining 1- and 2-dimensional electrophoresis, IgE immunoblots of nettle pollen extract, identification of allergens by mass spectrometry, and database queries.

RESULTS

The results of biological and immunochemical analyses revealed that the allergic rhinitis was due to Urtica dioica pollen in both patients. The allergomic analysis of nettle pollen extract allowed the characterization of 4 basic protein allergens: a thaumatin-like protein (osmotin) with a relative molecular mass of 27 to 29 kDa, a pectinesterase (relative molecular mass, 40 kDa), and 2 other basic proteins with relative molecular masses of 14 to 16 kDa and 43 kDa. There is no or only very weak allergen associations between pellitory and nettle pollen.

CONCLUSION

Exposure to nettle pollen can be responsible of allergic symptoms, and several allergens were characterized. Unravelling the allergens of this underestimated allergy might help to improve diagnosis and care for patients, to predict cross-reactivities and design adapted specific immunotherapy.

Fraxinus pollen and allergen concentrations in Ourense (South-western Europe)

In temperate zones of North-Central Europe the sensitization to ash pollen is a recognized problem, also extended to the Northern areas of the Mediterranean basin. Some observations in Switzerland suggest that ash pollen season could be as important as birch pollen period. The allergenic significance of this pollen has been poorly studied in Southern Europe as the amounts of ash pollen are low. Due to the high degree of family relationship with the olive pollen major allergen (backed by a sequence identity of 88%), the Fraxinus pollen could be a significant cause of early respiratory allergy in sensitized people to olive pollen as consequence of cross-reactivity processes. Ash tree flowers in the Northwestern Spain during the winter months. The atmospheric presence of Ole e 1-like proteins (which could be related with the Fra a 1 presence) can be accurately detected using Ole e 1 antibodies. The correlation analysis showed high Spearman correlation coefficients between pollen content and rainfall (R(2)=-0.333, p<0.01) or allergen concentration and maximum temperature (R(2)=-0.271, p<0.01). In addiction CCA analysis showed not significant differences (p<0.05) between the component 1 and 2 variables. PCFA analysis plots showed that the allergen concentrations are related to the presence of the Fraxinus pollen in the air, facilitating the wind speed its submicronic allergen proteins dispersion. In order to forecast the Fraxinus allergy risk periods, two regression equations were developed with Adjusted R(2) values around 0.48-0.49. The t-test for dependent samples shows no significant differences between the observed data and the estimated by the equations. The combination of the airborne pollen content and the allergen quantification must be assessed in the epidemiologic study of allergic respiratory diseases.

Tree pollen allergens-an update from a molecular perspective

It is estimated that pollen allergies affect approximately 40% of allergic individuals. In general, tree pollen allergies are mainly elicited by allergenic trees belonging to the orders Fagales, Lamiales, Proteales, and Pinales. Over 25 years ago, the gene encoding the major birch pollen allergen Bet v 1 was the first such gene to be cloned and its product characterized. Since that time, 53 tree pollen allergens have been identified and acknowledged by the WHO/IUIS allergen nomenclature subcommittee. Molecule‐based profiling of allergic sensitization has helped to elucidate the immunological connections of allergen cross‐reactivity, whereas advances in biochemistry have revealed structural and functional aspects of allergenic proteins. In this review, we provide a comprehensive overview of the present knowledge of the molecular aspects of tree pollen allergens. We analyze the geographic distribution of allergenic trees, discuss factors pivotal for allergic sensitization, and describe the role of tree pollen panallergens. Novel allergenic tree species as well as tree pollen allergens are continually being identified, making research in this field highly competitive and instrumental for clinical applications.

Ash pollen allergy: reliable detection of sensitization on the basis of IgE to Ole e 1

Background: Alongside hazel, alder and birch pollen allergies, ash pollen allergy is a relevant cause of hay fever during spring in the European region. For some considerable time, ash pollen allergy was not routinely investigated and its clinical relevance may well have been underestimated, particularly since ash and birch tree pollination times are largely the same. Ash pollen extracts are not yet well standardized and diagnosis is therefore sometimes unreliable. Olive pollen, on the other hand, is strongly cross-reactive with ash pollen and is apparently better standardized. Therefore, the main allergen of olive pollen, Ole e 1, has been postulated as a reliable alternative for the detection of ash pollen sensitization. Methods: To determine to what extent specific IgE against Ole e 1 in patients with ash pollen allergy is relevant, we included 183 subjects with ash pollen allergy displaying typical symptoms in March/April and positive skin prick test specific IgE against Ole e 1 (t224) and ash pollen (t25) and various birch allergens (Bet v 1, Bet v 2/v 4) in a retrospective study. Results: A significant correlation was seen between specific IgE against Ole e 1 and ash pollen, but also to a slightly lesser extent between IgE against Ole e 1 and skin prick test with ash pollen, the latter being even higher than IgE and skin prick test both with ash pollen. No relevant correlation was found with birch pollen allergens, demonstrating the very limited cross-reactivity between ash and birch pollen. Conclusion: It appears appropriate to determine specific IgE against Ole e 1 instead of IgE against ash pollen to detect persons with ash pollen allergy. Our findings may also support the idea of using possibly better standardized or more widely available olive pollen extracts instead of ash pollen extract for allergen-specific immunotherapy.

Proteomics of cypress pollen allergens using double and triple one-dimensional electrophoresis

Italian cypress (Cupressus sempervirens, Cups) pollen causes allergic diseases in inhabitants of many of the cities surrounding the Mediterranean basin. However, allergens of Cups pollen are still poorly known. We introduce here a novel proteomic approach based on double one-dimensional gel electrophoresis (D1-DE) as an alternative to the 2-DE immunoblot, for the specific IgE screening of allergenic proteins from pollen extracts. The sequential one-dimensional combination of IEF and SDS-PAGE associated with IgE immunoblotting allows a versatile multiplexed immunochemical analysis of selected groups of allergens by converting a single protein spot into an extended protein band. Moreover, the method appears to be valuable for MS/MS identification, without protein purification, of a new Cups pollen allergen at 43 kDa. D1-DE immunoblotting revealed that the prevalence of IgE sensitization to this allergen belonging to the polygalacturonase (PG) family was 70% in tested French allergic patients. In subsequent triple one-dimensional gel electrophoresis, the Cups pollen PG was shown to promote lectin-based protein-protein interactions. Therefore, D1-DE could be used in routine work as a convenient alternative to 2-DE immunoblotting for the simultaneous screening of allergenic components under identical experimental conditions, thereby saving considerable amounts of sera and allergen extracts.