Molecular profiles of IgE to Phleum pratense in children with grass pollen allergy: implications for specific immunotherapy

IgE to cyclophilins in pollen-allergic children: Epidemiologic, clinical, and diagnostic relevance of a neglected panallergen

BACKGROUND

Cyclophilins are ubiquitous panallergens whose epidemiologic, diagnostic, and clinical relevance is largely unknown and whose sensitization is rarely examined in routine allergy practice.

OBJECTIVE

We investigated the epidemiologic, diagnostic, and clinical relevance of cyclophilins in seasonal allergic rhinitis and its comorbidities.

METHODS

We examined a random sample of 253 (25%) of 1263 Italian children with seasonal allergic rhinitis from the Panallergens in Pediatrics (PAN-PED) cohort with characterized disease phenotypes. Nested studies of sensitization prevalence, correlation, and allergen extract inhibition were performed in patients sensitized to birch pollen extract but lacking IgE to Bet v 1/2/4 (74/1263) or with highest serum level of IgE to Bet v 1 (26/1263); and in patients with sensitization to various extracts (ragweed, mugwort, pellitory, Plantago, and plane tree), but not to their respective major allergenic molecule, profilins, and polcalcins. IgE to cyclophilin was detected with recombinant Bet v 7, and extract inhibition tests were performed with the same rBet v 7.

RESULTS

IgE to rBet v 7 was detected in 43 (17%) of 253 patients. It was associated with asthma (P < .028) and oral allergy syndrome (P < .017) in univariate but not multivariate analysis adjusted for IgE to profilins (Phl p 12), PR-10s (Bet v 1), and lipid transfer proteins (Pru p 3). IgE to rBet v 7 was also highly prevalent (47/74, 63%) among patients with unexplained sensitization to birch pollen extract. In patients with unexplained sensitization to ragweed, mugwort, pellitory, Plantago and plane tree pollen, the levels of IgE to those extracts correlated with the levels of IgE to rBet v 7, and they were also significantly inhibited by rBet v 7 (inhibition range 45%-74%).

CONCLUSIONS

IgE sensitization to cyclophilin is frequent in pollen-allergic patients living in temperate areas and can produce "false" positive outcomes in skin prick and IgE tests to pollen extracts. Molecular diagnostic guidelines should include this panallergen family.

A pediatric randomized, controlled trial of German cockroach subcutaneous immunotherapy

BACKGROUND

Cockroach allergy contributes to morbidity among urban children with asthma. Few trials address the effect of subcutaneous immunotherapy (SCIT) with cockroach allergen among these at-risk children.

OBJECTIVES

We sought to determine whether nasal allergen challenge (NAC) responses to cockroach allergen would improve following 1 year of SCIT.

METHODS

Urban children with asthma, who were cockroach-sensitized and reactive on NAC, participated in a year-long randomized double-blind placebo-controlled SCIT trial using German cockroach extract. The primary endpoint was the change in mean Total Nasal Symptom Score (TNSS) during NAC after 12 months of SCIT. Changes in nasal transcriptomic responses during NAC, skin prick test wheal size, serum allergen-specific antibody production, and T-cell responses to cockroach allergen were assessed.

RESULTS

Changes in mean NAC TNSS did not differ between SCIT-assigned (n = 28) versus placebo-assigned (n = 29) participants (P = .63). Nasal transcriptomic responses correlated with TNSS, but a treatment effect was not observed. Cockroach serum-specific IgE decreased to a similar extent in both groups, while decreased cockroach skin prick test wheal size was greater among SCIT participants (P = .04). A 200-fold increase in cockroach serum-specific IgG4 was observed among subjects receiving SCIT (P < .001) but was unchanged in the placebo group. T-cell IL-4 responses following cockroach allergen stimulation decreased to a greater extent among SCIT versus placebo (P = .002), while no effect was observed for IL-10 or IFN-γ.

CONCLUSIONS

A year of SCIT failed to alter NAC TNSS and nasal transcriptome responses to cockroach allergen challenge despite systemic effects on allergen-specific skin tests, induction of serum-specific IgG4 serum production and down-modulation of allergen-stimulated T-cell responses.

Heterogeneity of sensitization profiles and clinical phenotypes among patients with seasonal allergic rhinitis in Southern European countries-The @IT.2020 multicenter study

BACKGROUND

Pollen allergy poses a significant health and economic burden in Europe. Disease patterns are relatively homogeneous within Central and Northern European countries. However, no study broadly assessed the features of seasonal allergic rhinitis (SAR) across different Southern European countries with a standardized approach.

OBJECTIVE

To describe sensitization profiles and clinical phenotypes of pollen allergic patients in nine Southern European cities with a uniform methodological approach.

METHODS

Within the @IT.2020 multicenter observational study, pediatric and adult patients suffering from SAR were recruited in nine urban study centers located in seven countries. Clinical questionnaires, skin prick tests (SPT) and specific IgE (sIgE) tests with a customized multiplex assay (Euroimmun Labordiagnostika, Lübeck, Germany) were performed.

RESULTS

Three hundred forty-eight children (mean age 13.1 years, SD: 2.4 years) and 467 adults (mean age 35.7 years SD: 10.0 years) with a predominantly moderate to severe, persistent phenotype of SAR were recruited. Grass pollen major allergenic molecules (Phl p 1 and/or Phl p 5) ranged among the top three sensitizers in all study centers. Sensitization profiles were very heterogeneous, considering that patients in Rome were highly poly-sensitized (sIgE to 3.8 major allergenic molecules per patient), while mono-sensitization was prominent and heterogeneous in other cities, such as Marseille (sIgE to Cup a 1: n = 55/80, 68.8%) and Messina (sIgE to Par j 2: n = 47/82, 57.3%). Co-sensitization to perennial allergens, as well as allergic comorbidities also broadly varied between study centers.

CONCLUSIONS

In Southern European countries, pollen allergy is heterogeneous in terms of sensitization profiles and clinical manifestations. Despite the complexity, a unique molecular, multiplex, and customized in-vitro IgE test detected relevant sensitization in all study centers. Nevertheless, this geographical diversity in pollen allergic patients imposes localized clinical guidelines and study protocols for clinical trials of SAR in this climatically complex region.

Hot topics in allergen immunotherapy, 2023: Current status and future perspective

The importance of allergen immunotherapy (AIT) is multifaceted, encompassing both clinical and quality-of-life improvements and cost-effectiveness in the long term. Key mechanisms of allergen tolerance induced by AIT include changes in memory type allergen-specific T- and B-cell responses towards a regulatory phenotype with decreased Type 2 responses, suppression of allergen-specific IgE and increased IgG1 and IgG4, decreased mast cell and eosinophil numbers in allergic tissues and increased activation thresholds. The potential of novel patient enrolment strategies for AIT is taking into account recent advances in biomarkers discoveries, molecular allergy diagnostics and mobile health applications contributing to a personalized approach enhancement that can increase AIT efficacy and compliance. Artificial intelligence can help manage and interpret complex and heterogeneous data, including big data from omics and non-omics research, potentially predict disease subtypes, identify biomarkers and monitor patient responses to AIT. Novel AIT preparations, such as synthetic compounds, innovative carrier systems and adjuvants, are also of great promise. Advances in clinical trial models, including adaptive, complex and hybrid designs as well as real-world evidence, allow more flexibility and cost reduction. The analyses of AIT cost-effectiveness show a clear long-term advantage compared to pharmacotherapy. Important research questions, such as defining clinical endpoints, biomarkers of patient selection and efficacy, mechanisms and the modulation of the placebo effect and alternatives to conventional field trials, including allergen exposure chamber studies are still to be elucidated. This review demonstrates that AIT is still in its growth phase and shows immense development prospects.

IgE to cross-reactive carbohydrate determinants (CCD) in childhood: Prevalence, risk factors, putative origins

BACKGROUND

IgE antibodies to cross-reactive carbohydrate determinants (CCD) are usually clinically irrelevant but they can be a cause of false positive outcomes of allergen-specific IgE tests in vitro. Their prevalence and levels have been so far cross-sectionally examined among adult allergic patients and much less is known about their origins and relevance in childhood.

METHODS

We examined CCD with a cross-sectional approach in 1263 Italian pollen allergic children (Panallergen in Paediatrics, PAN-PED), as well as with a longitudinal approach in 612 German children (Multicenter Allergy Study, MAS), whose cutaneous and IgE sensitization profile to a broad panel of allergen extracts and molecules was already known. The presence and levels of IgE to CCD were examined in the sera of both cohorts using bromelain (MUXF3) as reagent and a novel chemiluminescence detection system, operating in a solid phase of fluorescently labelled and streptavidin-coated paramagnetic microparticles (NOVEOS, HYCOR, USA).

RESULTS

IgE to CCD was found in 22% of the Italian pollen allergic children, mainly in association with an IgE response to grass pollen. Children with IgE to CCD had higher total IgE levels and were sensitized to more allergenic molecules of Phleum pratense than those with no IgE to CCD. Among participants of the German MAS birth cohort study, IgE to CCD emerged early in life (even at pre-school age), with IgE sensitization to group 1 and 4 allergen molecules of grasses, and almost invariably persisted over the full observation period.

CONCLUSIONS

Our results contribute to dissect the immunological origins, onset, evolution and risk factors of CCD-sIgE response in childhood, and raise the hypothesis that group 1 and/or 4 allergen molecules of grass pollen are major inducers of these antibodies through an antigen-specific, T-B cell cognate interaction.

Dissecting Airborne Allergens

Asthma is a heterogeneous and very complex group of diseases, and includes different clinical phenotypes depending on symptoms, progression, exacerbation patterns, or responses to treatment, among other characteristics. The allergic phenotype is the most frequent, especially in pediatric asthma. It is characterized by sensitization (the production of specific IgEs) to allergens and frequent comorbidity with rhinitis as well as atopic dermatitis. Given the complexity of allergic asthma, knowledge of it must be approached from different points of view: clinical, histological, physiological, epidemiological, biochemical, and immunological, among others. Since partial approaches do not allow for the understanding of this complexity, it is necessary to have multidimensional knowledge that helps in performing the optimal management of each case, avoiding a "blind men and elephant parable" approach. Allergens are antigens that trigger the production of specific IgE antibodies in susceptible individuals, who present symptoms that will depend on the type and intensity of the allergenic load as well as the tissue where the interaction occurs. Airborne allergens cause their effects in the respiratory tract and eyes, and can be indoor or outdoor, perennial, or seasonal. Although allergens such as mites, pollens, or animal dander are generally considered single particles, it is important to note that they contain different molecules which could trigger distinct specific IgE molecules in different patients. General practitioners, pediatricians, and other physicians typically diagnose and treat asthma based on clinical and pulmonary function data in their daily practice. This nonsystematic and nonexhaustive revision aims to update other topics, especially those focused on airborne allergens, helping the diagnostic and therapeutic processes of allergic asthma and rhinitis.

Early inhalant allergen sensitization at component level: an analysis in atopic Dutch children

Background

Allergic rhinitis is a common respiratory disease in children and sensitization to inhalant allergens plays a significant role in its development. However, limited knowledge exists regarding sensitization profiles of inhalant allergen components in atopic children, particularly in the very young individuals. Understanding these profiles could provide insights into the early development of allergic rhinitis. The objective of this cross-sectional retrospective study was to evaluate the IgE-sensitization profiles to multiple inhalant allergen components and their clinical relevance in Dutch atopic children, with specific focus on children under the age of 4 years.

Methods

A total of 243 atopic children were included in the study and sensitization profiles were analyzed using multiplex microarray analysis (ISAC). Clinical information was obtained from records of a pediatric allergy outpatient clinic between 2011 and 2020. Specific IgE responses to inhalation allergen components from five allergen sources (grass pollen, tree pollen, house dust mite, cat and dog), were examined. The study encompassed children of different age groups and compared those with and without symptoms.

Results

The results demonstrated that sensitization to inhalant allergen components was present in 92% of the cohort. Sensitization was already evident at a young age (87%), including infancy, with a rapid increase in prevalence after 1 year of age. House dust mite emerged as the most predominant sensitizing allergen in early childhood, followed by tree pollen in later years. Sensitization patterns were similar between symptomatic and asymptomatic children, although symptomatic children exhibited higher frequencies and values. The sensitization profiles in very young children were comparable to those of children across all age groups.

Conclusion

These findings highlight the presence of sensitization to inhalant allergen components and the early onset of allergic rhinitis before the age of 4, including infancy, in Dutch atopic children. Notable allergen molecules in Dutch atopic children under the age of 4 years include Bet v 1, Fel d 1, Der f 1, Der p 1, Der p 10 and Phl p 4, with house dust mite sensitization being the most common among Dutch infants. Moreover, the prevalence of sensitization to inhalant allergens in this Dutch cohort surpassed that of general European populations, emphasizing the importance of early assessment and management of allergic rhinitis in young atopic children.

Factors predicting the outcome of allergen-specific nasal provocation test in children with grass pollen allergic rhinitis

Background

Nasal provocation testing (NPT) is a reference methodology to identify the culprit allergen in patients with allergic rhinitis. Selecting the right allergen for NPT is particularly difficult in poly-sensitized patients with seasonal allergic rhinitis (SAR). Predictors of NPT outcomes may facilitate the proper use of this test or even substitute it.

Objective

To identify predictors of grass pollen NPT outcome from an array of clinical data, e-diary outcomes, and allergy test results in poly-sensitized pediatric patients with SAR.

Methods

Poly-sensitized, SAR patients with grass pollen allergy, participating in the @IT.2020 pilot project in Rome and Pordenone (Italy), participated in a baseline (T0) visit with questionnaires, skin prick testing (SPT), and blood sampling to measure total (ImmunoCAP, TFS, Sweden) and specific IgE antibodies to grass pollen extracts and their major allergenic molecules (ESEP, Euroimmun Labordiagnostika, Germany). During the pollen season, patients filled the AllergyMonitor® e-diary app measuring their symptoms, medication intake, and allergy-related well-being via the Visual Analogue Scale (VAS). After the pollen season (T1), patients answered clinical questionnaires and underwent a nasal provocation test (NPT) with grass pollen extract.

Results

We recruited 72 patients (age 14.3 ± 2.8 years, 46 males) sensitized to grass and/or other pollens, including olive (63; 87.5%) and pellitory (49; 68.1%). Patients positive to grass pollen NPT (61; 84.7%), compared to the negative ones, had worse VAS values in the e-diary, larger SPT wheal reactions, and higher IgE levels, as well as specific activity to timothy and Bermuda grass extracts, rPhl p 5 and nCyn d 1. A positive NPT to grass pollen was predicted by an index combining the specific activity of IgE towards Phl p 5 and Cyn d 1 (AUC: 0.82; p < 0.01; best cut-off ≥7.25%, sensitivity 70.5%, specificity: 90.9%). VAS results also predicted NPT positivity, although with less precision (AUC: 0.77, p < 0.01; best cut-off ≥7, sensitivity: 60.7%, specificity: 81.8%).

Conclusions

An index combining the specific activity of IgE to rPhl p 5 and nCyn d 1 predicted with moderate sensitivity and high specificity the outcome of a grass pollen NPT in complex, poly-sensitized pediatric patients with seasonal allergic rhinitis. Further studies are needed to improve the index sensitivity and to assess its usefulness for NPT allergen selection or as an alternative to this demanding test procedure.

Isolating the species element in grass pollen allergy: A review

Grass pollen is a leading cause of allergy in many countries, particularly Europe. Although many elements of grass pollen production and dispersal are quite well researched, gaps still remain around the grass species that are predominant in the air and which of those are most likely to trigger allergy. In this comprehensive review we isolate the species aspect in grass pollen allergy by exploring the interdisciplinary interdependencies between plant ecology, public health, aerobiology, reproductive phenology and molecular ecology. We further identify current research gaps and provide open ended questions and recommendations for future research in an effort to focus the research community to develop novel strategies to combat grass pollen allergy. We emphasise the role of separating temperate and subtropical grasses, identified through divergence in evolutionary history, climate adaptations and flowering times. However, allergen cross-reactivity and the degree of IgE connectivity in sufferers between the two groups remains an area of active research. The importance of future research to identify allergen homology through biomolecular similarity and the connection to species taxonomy and practical implications of this to allergenicity is further emphasised. We also discuss the relevance of eDNA and molecular ecological techniques (DNA metabarcoding, qPCR and ELISA) as important tools in quantifying the connection between the biosphere with the atmosphere. By gaining more understanding of the connection between species-specific atmospheric eDNA and flowering phenology we will further elucidate the importance of species in releasing grass pollen and allergens to the atmosphere and their individual role in grass pollen allergy.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Molecular allergy diagnosis is sensitive and avoids misdiagnosis in patients sensitized to seasonal allergens

Background

The specificity of extract‐based pollen allergy diagnosis is decreased due to cross‐reactivity via cross‐reactive carbohydrate determinants (CCDs) or panallergens such as profilins or polcalcins. This study aimed to explore the prevalence of sensitization to seasonal extracts, CCDs, profilin and polcalcin and investigate the sensitivity and specificity of seasonal molecular allergy diagnosis (MAD) using commercially available test methods.

Methods

2948 patients were screened for specific immunoglobulin E to ash, birch, mugwort, ragweed and timothy grass pollen extracts and grouped according to the number of positive tests (1–5). 100 patients from each group and a control group were randomly selected to calculate the prevalence of CCD and panallergen sensitization. With 742 patients, sensitivity and specificity of MAD (Alt a 1, Fra/Ole e 1, Bet v 1, Phl p 1, Art v 1, and Amb a 1) was determined.

Results

1627 patients (55.2%) were positive to at least one, and 1002 patients (34.0%) were positive to multiple of the five pollen allergens investigated; 18.5% of the pollen‐sensitized patients had sensitization to CCDs or panallergens. Specifically, sensitization to CCDs, profilins, and polcalcins was observed in 8.7%, 10.9%, and 2.9% of these patients, respectively. The sensitivity of MAD was high, with sensitivities between 96.2% and 100% using ImmunoCAP and 91.5% and 100% using ALEX². Specificity was 100% for both assays.

Conclusions

Due to cross‐reactivity, about one‐fifth of pollen‐sensitized patients is at risk of misdiagnosis. However, MAD is sensitive, specific and helps to avoid misdiagnosis and select primary allergen sources for immunotherapy.

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.

Biodegradation of Congo Red Using Co-Culture Anode Inoculum in a Microbial Fuel Cell

Congo red is an azo dye widely used as a colouring agent in textile industries. It is a serious threat due to its carcinogenic effects. Its degradation has been challenging due to its complex yet stable structure. The present study was aimed to investigate the effective degradation of Congo red by bioremediating bacteria isolated from different environments. To investigate predominant microorganisms that degrade Congo red and its functions in microbial fuel cells (MFCs), strains isolated from cow dung (Enterococcus faecalis SUCR1) and soil (Pseudomonas aeruginosa PA1_NCHU) were used as a co-culture inocula. The remarkable results establish that E. faecalis as an excellent microbial source for the biological degradation of dye-contaminated wastewater treatment alongside bioactive treating wastewater with varied concentrations of congo red dye. The highest efficiency percentage of dye degradation was 98% after 3 days of incubation at pH 7 and 37 °C, whereas findings have shown that the decolorization at pH 5 and 6 was lower at 66% and 83.3%, respectively, under the same incubation conditions. Furthermore, the co-culture of E. faecalis SUCR1 and P. aeruginosa at a 1:1 ratio demonstrated improved power generation in MFCs. The maximum power density of 7.4 W/m3 was recorded at a 150 mg L−1 concentration of Congo red, indicating that the symbiotic relation between these bacterium resulted in improved MFCs performance simultaneous to dye degradation.

Serum IgE profiles in Chinese pollinosis patients with grass pollen sensitisation

Purpose

Methods

Results

Conclusions

Sensitization Profiles of Timothy Grass Pollen in Northern China

Purpose

Grass pollen is an important cause of IgE-mediated allergy in countries worldwide, especially within Europe. However, there has been no research on grass pollen allergy in northern China. We aimed to determine the status of grass pollen allergy and the sensitization patterns to Phleum pratense (P. pratense) in northern China.

Patients and Methods

Pollen data were collected for three geographic areas (Beijing, Shenmu, Shizuishan) in northern China. The study enrolled 101 patients (62 men; age range, 1–64 years; median age, 10 years) who had allergic rhinoconjunctivitis and/or asthma during the grass pollen season and positive skin prick test results positive to P. pratense. Serum-specific IgE (sIgE) against Phl p 1, Phl p 2, Phl p 5, Phl p 6, Phl p 7, Phl p 12 was measured by ImmunoCAP.

Results

The pollen season of P. pratense was from June to September in Beijing, May to September in Shenmu and July to August in Shizuishan. P. pratense pollen accounted for 2–3% of the annual pollen index of total pollen counts. Among 101 patients with positive skin prick test results to P. pratense, 72% had detectable sIgE to P. pratense. Phl p 12 was the most frequently recognized component (45%), followed by Phl p 1 (22%), Phl p 5 (14%), Phl p 6 (8%) and Phl p 7 (3%). No patients had sIgE to Phl p 2. Ten sensitization patterns to the six components were observed. High rate of sIgE to Phl p 12 was positively correlated with co-sensitization to weed or tree pollen.

Conclusion

Considering the pollen concentration, P. pratense was a minor pollen allergen in northern China and its pollen season overlapped with that of weed pollen. IgE sensitization to P. pratense was likely to be induced by cross-reactivity between grass pollen allergy and weed/tree pollen allergy.

Molecular allergology and its impact in specific allergy diagnosis and therapy

Progressive knowledge of allergenic structures resulted in a broad availability of allergenic molecules for diagnosis. Component-resolved diagnosis allowed a better understanding of patient sensitization patterns, facilitating allergen immunotherapy decisions. In parallel to the discovery of allergenic molecules, there was a progressive development of a regulation framework that affected both in vitro diagnostics and Allergen Immunotherapy products. With a progressive understanding of underlying mechanisms associated to Allergen immunotherapy and an increasing experience of application of molecular diagnosis in daily life, we focus in analyzing the evidences of the value provided by molecular allergology in daily clinical practice, with a focus on Allergen Immunotherapy decisions.

Comparative proteomics of common allergenic tree pollens of birch, alder, and hazel

BACKGROUND

In addition to known allergens, other proteins in pollen can aid the development of an immune response in allergic individuals. The contribution of the "unknown" protein allergens is apparent in phylogenetically related species where, despite of high homology of the lead allergens, the degree of allergenic potential can vary greatly. The aim of this study was to identify other potentially allergenic proteins in pollen of three common and highly related allergenic tree species: birch (Betula pendula), hazel (Corylus avellana) and alder (Alnus glutinosa).

METHODS

For that purpose, we carried out a comprehensive, comparative proteomic screening of the pollen from the three species. In order to maximize protein recovery and coverage, different protein extraction and isolation strategies during sample preparation were employed.

RESULTS

As a result, we report 2500-3000 identified proteins per each of the pollen species. Identified proteins were further used for a number of annotation steps, providing insight into differential distribution of peptidases, peptidase inhibitors and other potential allergenic proteins across the three species. Moreover, we carried out functional enrichment analyses that, interestingly, corroborated high species similarity in spite of their relatively distinct protein profiles.

CONCLUSION

We provide to our knowledge first insight into proteomes of two very important allergenic pollen types, hazel and alder, where not even transcriptomics data are available, and compared them to birch. Datasets from this study can be readily used as protein databases and as such serve as basis for further functional studies.

Allergen Immunotherapy in Pediatric Respiratory Allergy

Purpose of Review

Atopic diseases such as asthma and allergic rhinitis are highly prevalent in children. Common triggers include tree and grass pollens, house dust mites, molds, and animal dander. These diseases are most often treated symptomatically; however, many patients show partial or poor response and require long-term medication use. Allergen immunotherapy (AIT) stands as the only treatment modality that can alter the underlying disease process and potentially offer a cure. In this review article, we discuss the merits of AIT with particular emphasis on its efficacy and safety in pediatric patients. We also discuss the challenges for AIT implementation and present an overview of current research that aims at improving its applicability for the treatment of allergic diseases.

Recent Findings

Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are both safe and efficacious treatment options in children with allergic rhinitis and allergic asthma. Additionally, AIT has efficacy in preventing the development of asthma in children. Although there are clear advantages with AIT, there are challenges to overcome to optimize treatment. Solutions include improved diagnostics with pre-treatment biomarkers and molecular multiplex assays, biomarkers for prediction of response (e.g., basophil activation markers), improved allergen immunogenicity with the use of recombinant AIT, adjuvants, and allergoids, and lastly improved safety with the concurrent use of omalizumab.

Summary

AIT has shown safety and efficacy in major clinical trials for the treatment of allergic rhinitis and allergic asthma in children. AIT provides a curative treatment option for atopic disorders and should be considered in children with allergic rhinitis and allergic asthma. There are many continued advances being made in the field of allergy to further improve the safety and efficacy profile and shorten the duration of AIT treatment.

Immunological Responses and Biomarkers for Allergen-Specific Immunotherapy Against Inhaled Allergens

Long-term efficacy that occurs with allergen immunotherapy of proven value is associated with decreases in IgE-dependent activation of mast cells and tissue eosinophilia. This suppression of type 2 immunity is accompanied by early induction of regulatory T cells, immune deviation in favor of T_H1 responses, and induction of local and systemic IgG, IgG₄, and IgA antibodies. These "protective" antibodies can inhibit allergen-IgE complex formation and consequent mast cell triggering and IgE-facilitated T_H2-cell activation. Recent studies have highlighted the importance of innate responses mediated by type 2 dendritic cells and innate lymphoid cells in allergic inflammation. These cell types are under the regulation of cytokines such as thymic stromal lymphopoietin and IL-33 derived from the respiratory epithelium. Novel subsets of regulatory cells induced by immunotherapy include IL-35-producing regulatory T cells, regulatory B cells, a subset of T follicular regulatory cells, and IL-10-producing group 2 innate lymphoid cells. These mechanisms point to biomarkers that require testing for their ability to predict clinical response to immunotherapy and to inform novel approaches for better efficacy, safety, and long-term tolerance.

IgE-reactivity profiles to allergen molecules in Russian children with and without symptoms of allergy revealed by micro-array analysis

BACKGROUND

The analysis of longitudinal birth cohorts with micro-arrayed allergen molecules has provided interesting information about the evolution of IgE sensitization in children. However, so far no cross-sectional study has been performed comparing IgE sensitization profiles in children with and without symptoms of allergy. Furthermore, no data are available regarding molecular IgE sensitization profiles in children from Russia.

METHODS

We recruited two groups of age- and gender-matched children, one (Group 1: n = 103; 12.24 ± 2.23 years; male/female: 58/45) with symptoms and a second (Group 2: n = 97; 12.78 ± 2.23 years; male/female: 53/44), without symptoms of allergy according to international ISAAC questionnaire. Children were further studied regarding symptoms of allergy (rhinitis, asthma, atopic dermatitis) according to international guidelines, and skin prick testing with a panel of aeroallergen extracts was performed before sera were analyzed in an investigator-blinded manner for IgE specific to more than 160 micro-arrayed allergen molecules using ImmunoCAP ISAC technology.

RESULTS

IgE sensitization = or >0.3 ISU to at least one of the micro-arrayed allergen molecules was found in 100% of the symptomatic children and in 36% of the asymptomatic children. Symptomatic and asymptomatic children showed a comparable IgE sensitization profile; however, frequencies of IgE sensitization and IgE levels to the individual allergen molecules were higher in the symptomatic children. Aeroallergen sensitization was dominated by sensitization to major birch pollen allergen, Bet v 1, and major cat allergen, Fel d 1. Food allergen sensitization was due to cross-sensitization to PR10 pollen and food allergens whereas genuine peanut sensitization was absent.

CONCLUSION

This is the first study analyzing molecular IgE sensitization profiles to more than 160 allergen molecules in children with and without symptoms of allergy. It detects similar molecular IgE sensitization profiles in symptomatic and asymptomatic children and identifies Bet v 1 and Fel d 1 as the predominant respiratory allergen molecules and PR10 proteins as the major food allergens and absence of genuine peanut allergy in Moscow region (Russia).

Allergenicity at component level of sub-pollen particles from different sources obtained by osmolar shock: A molecular approach to thunderstorm-related asthma outbreaks

BACKGROUND

The so-called "thunderstorm asthma" (TA) is an uncommon but dramatic outbreak of asthma attacks occurring during a thunderstorm in the pollen and moulds season. Mechanisms which make the pollen able to enter the deeper airways and provoke severe asthma symptoms are still unclear.

OBJECTIVE

To test the hypothesis that sub-pollen particles (SPPs) originated from the rupture by an osmotic shock of pollen associated with TA contain allergens.

METHODS

After hydration, SPPs released from pollen grains of grass, pellitory, olive, cypress, ragweed and birch were isolated and determined by microscopy. Allergens were determined by in vitro ELISA inhibition tests indirectly using the sera from 10 polyreactive patients. An inhibition <50% was considered as negative, 50%-75% moderate and > 75% complete.

RESULTS

The inhibition experiments showed that the SPPs from birch and cypress were unable to inhibit serum IgE reactivity to Bet v 1 and Cup a 1, respectively. Ragweed SPPs inhibited ragweed pollen extract and Amb a 1 by 75.8 ± 0.11% and 81.2 ± 0.15%, respectively. Olive and pellitory SPPs retained almost the whole IgE-binding capability in all cases tested. Grass SPPs inhibited 32 ± 0.06% of Lolium perenne Lol p 1 and 65% of Phleum pratense extracts, but results were highly variable for individual allergens (97.5%-0.03% for Phl p 2, 45.3 ± 0.12% for Phl p 5, 24.7 ± 0.22% for Phl p 6, and 38.3 ± 0.2% for Phl p 1).

CONCLUSIONS

Inhibition experiments confirm the hypothesis that SSPs obtained after the osmotic shock of pollen involved in TA, namely grass, pellitory and olive tree pollen, contain allergens and therefore they can induce severe asthma attacks during thunderstorms.

Proyecto VALIDA: Validation of ALlergy In vitro Diagnostics Assays (Herramientas y recomendaciones para la valoración de las pruebas in vitro en el diagnóstico de la alergia)

En la evaluación del paciente con sospecha de alergia las pruebas de detección y cuantificación de la inmunoglobulina E (IgE) específica in vitro se usan de manera habitual en los laboratorios clínicos para ayudar en el diagnóstico de la alergia. Actualmente existen diferentes alternativas comerciales para realizar estos ensayos, pero los resultados obtenidos por cada uno de ellos pueden variar, lo que condiciona el diagnóstico y el tratamiento que se le proporcionará al paciente. Con el fin de dar respuesta a los retos planteados por las diferencias entre las distintas técnicas para la determinación in vitro de la IgE específica, un grupo de expertos ha recogido en un documento una serie de recomendaciones sobre las implicaciones que puede tener el uso de una determinada técnica in vitro y el impacto en el manejo del paciente alérgico que suponen las diferencias entre las distintas técnicas. La lectura y el análisis de este documento de consenso ayudarán a entender las implicaciones que tiene el cambio de método de diagnóstico in vitro en el manejo del paciente con alergia, en su calidad de vida y en los costes socioeconómicos asociados a la enfermedad.

VALIDA project: Validation of allergy in vitro diagnostics assays (Tools and recommendations for the assessment of in vitro tests in the diagnosis of allergy)

In vitro allergen-specific immunoglobulin E (IgE) detection and quantification tests are routinely performed in clinical laboratories to diagnose patients with a suspected allergy. Numerous commercial assays are available to test for allergies, but the results can vary widely, thereby influencing both diagnosis and treatment. Given the challenges posed by differences in the various assays for in vitro determination of specific IgE, a group of experts has compiled in a document a series of recommendations on the implications that the use of a certain in vitro technique may have and the impact on the management of the allergic patient that the differences between the various techniques represent. The reading and analysis of this consensus document will help to understand the implications of the change of in vitro diagnostic method in the management of the patient with allergy, in the quality of life and in the socioeconomic costs associated with the disease.

Egg Allergy: Diagnosis and Immunotherapy

Hypersensitivity or an allergy to chicken egg proteins is a predominant symptomatic condition affecting 1 in 20 children in Australia; however, an effective form of therapy has not yet been found. This occurs as the immune system of the allergic individual overreacts when in contact with egg allergens (egg proteins), triggering a complex immune response. The subsequent instantaneous inflammatory immune response is characterized by the excessive production of immunoglobulin E (IgE) antibody against the allergen, T-cell mediators and inflammation. Current allergen-specific approaches to egg allergy diagnosis and treatment lack consistency and therefore pose safety concerns among anaphylactic patients. Immunotherapy has thus far been found to be the most efficient way to treat and relieve symptoms, this includes oral immunotherapy (OIT) and sublingual immunotherapy (SLIT). A major limitation in immunotherapy, however, is the difficulty in preparing effective and safe extracts from natural allergen sources. Advances in molecular techniques allow for the production of safe and standardized recombinant and hypoallergenic egg variants by targeting the IgE-binding epitopes responsible for clinical allergic symptoms. Site-directed mutagenesis can be performed to create such safe hypoallergens for their potential use in future methods of immunotherapy, providing a feasible standardized therapeutic approach to target egg allergies safely.

Planning and approach to allergen-specific immunotherapy in polyallergic patients

Allergy immunotherapy (AIT) is currently the only disease-modifying treatment for allergic-respiratory diseases. Polysensitization may increase the severity of current disease resulting in subsequent asthma development in patients with allergic rhinitis. Due to the absence of general recommendations for the practical approach to polysensitized patients, clinical management is not standardized. The correlation between sensitizations and clinical symptoms, elimination of possible pollen cross-reactivities and principles of homologous allergen groups will guide the allergists to deduce the most relevant allergens for AIT. In the highlight of the previously proposed approach strategies to polyallergic patients, hereby we propose a revised practical stepwise approach based on the current European Medicine Agency (EMA) guidelines. However, more supporting data from well-designed, controlled, future studies are needed to improve clinical management recommendations for AIT in polyallergic patients.

30 years of sublingual immunotherapy

Allergen Immunotherapy (AIT) was introduced in clinical practice on an empirical basis more than 100 years ago. Since the first attempts, AIT was administered subcutaneously. Indeed, other routes of administration were proposed and studied, in particular to improve the safety, but only the sublingual route (SLIT) achieved a credibility based on evidence and was then accepted as a viable "alternative" option to the subcutaneous route. SLIT was largely used in clinical trials and clinical practice in this last 30 years. Thus, a large amount of data is available, coming from either controlled trials and postmarketing surveillance studies. It is clear that SLIT is overall effective, but it is also clear that the efficacy is not "class-related," as derived from meta-analyses, but restricted to each specific product. The 30-year lasting use of SLIT allowed to clarify many clinical aspects, such as efficacy, safety, use in asthma, regimens of administration, and optimal doses. In parallel, the mechanisms of action of AIT were elucidated, and new indications were proposed (eg food allergy, atopic dermatitis). In addition, the introduction of molecular-based diagnosis, allowed to better refine the prescription of SLIT, based on specific sensitization profiles. The present article will describe the origin and evolution of SLIT for respiratory allergy, taking into account the clinical context that suggested this form of treatment, the recently developed aspects, the future perspectives and unmet needs, This is not, therefore, a systematic review, rather a narrative historical description of the past history, and a look forward to the future opportunities.

Molecular diagnosis for allergen immunotherapy

The extensive use of allergen molecules in birth cohort studies revealed that atopic sensitization is a sequential IgE response to distinct non-cross-reacting molecules from the same allergenic source (ie, molecular spreading), starting with an initiator molecule. This phenomenon reaches different degrees of progression (monomolecular, oligomolecular, and polymolecular) according to the individual atopic propensity and allergen exposure, thus producing an extreme heterogeneity of IgE sensitization profiles in patient populations. In patients with allergic rhinitis, the broader the IgE molecular sensitization profile, the greater is the risk of asthma and other allergic comorbidities, such as oral allergy syndrome. Hence it has been proposed to anticipate immunologic intervention at disease onset (early allergen immunotherapy) or even earlier during the preclinical sensitization stage (allergen immunoprophylaxis). Diagnostic algorithms based on singleplex or multiplex molecular IgE tests allow the discrimination of genuine from cross-reacting sensitization and the selection of the right extracts for allergen immunotherapy composition. Patients with extreme molecular poly-sensitization and greater risk of asthma or other IgE-mediated comorbidities, can be easily identified by means of allergen microarray or macroarray procedures and might benefit from anti-IgE treatment. IgE molecular tests have opened the era of precision allergology, and their routine use should aim at cost-effectiveness, according to the principles of the Choosing Wisely initiative.

A WAO - ARIA - GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

Precision allergy molecular diagnostic applications (PAMD@) is increasingly entering routine care. Currently, more than 130 allergenic molecules from more than 50 allergy sources are commercially available for in vitro specific immunoglobulin E (sIgE) testing. Since the last publication of this consensus document, a great deal of new information has become available regarding this topic, with over 100 publications in the last year alone. It thus seems quite reasonable to publish an update. It is imperative that clinicians and immunologists specifically trained in allergology keep abreast of the new and rapidly evolving evidence available for PAMD@.

PAMD@ may initially appear complex to interpret; however, with increasing experience, the information gained provides relevant information for the allergist. This is especially true for food allergy, Hymenoptera allergy, and for the selection of allergen immunotherapy. Nevertheless, all sIgE tests, including PAMD@, should be evaluated within the framework of a patient's clinical history, because allergen sensitization does not necessarily imply clinical relevant allergies.

Sensitization to grass allergens: Phl p1, Phl p5 and Phl p7 Phl p12 in adult and children patients in Beja (Southern Portugal)

BACKGROUND

In Portugal, the pollen types most implicated in respiratory allergy are grasses, olive and parietaria. The knowledge of sensitizations to molecular allergens in children and adults can contribute to better diagnosis and treatment of this pathology.

METHODS

ImmunoCAP singleplex technology was used for molecular allergens and Phadia 250® automatic equipment. g205 (Phl p1); g215 (Phl p5b); g210 (Phl p7); and g212 (Phl p12) allergen determinations were made in 45 patients with positive grass sensitization tests.

RESULTS

The majority of patients are sensitized to Phl p1 (91%) and Phl p1+/Phl p5-/Phl p7-/Phl p12- was the most dominant profile (40%). In the adult group, the IgE averages for Phl p1 were approximately 10.46, while they were 8.43 for Phl p5, 0.69 for Phl p7, and 0.06 for Phl p12. In the child group, these values were higher: 22.49, 20.23, 3.89, and 0.35, respectively. For allergens Phl p1, Phl p5, and Phl p7, these differences between the child and adult population were not statistically significant (p=0.754, p=0.806 and p=0.102, respectively), but for Phl p12, a statistically significant difference (p=0.018) was observed.

CONCLUSIONS

IgE antibodies Phl p1 is the most important allergic marker and sensitivities caused by Phl p12 give rise to higher IgE values in children.

Early molecular biomarkers predicting the evolution of allergic rhinitis and its comorbidities: A longitudinal multicenter study of a patient cohort

BACKGROUND

Pollen-related seasonal allergic rhinoconjunctivitis (SAR) is a very frequent pediatric disease in Westernized countries. Risk factors and disease phenotypes have been thoroughly examined in several cross-sectional studies. By contrast, only a few studies have examined disease evolution in patient cohorts. We investigated predictive biomarkers of disease evolution in a large cohort of children with SAR.

METHODS

During 2015-2017 (follow-up), we re-examined 401 patients from those enrolled in 2009-2011 (baseline) by the "Panallergens in Pediatrics" study, a large multicenter survey of Italian children with SAR. Information on clinical history (standard questionnaire, AllergyCARD®; TPS, Italy) and skin prick tests for inhalant and foods extracts (ALK-Abelló, Hørsholm, Denmark) was acquired as at baseline visit. Evolution in clinical and sensitization data of patients was analyzed over time, as well as their association with the main baseline characteristics and atopy risk factors.

RESULTS

The average age of participants was 10.4 ± 3.4 years at baseline and 16.2 ± 3.6 years at follow-up. SAR persisted in 93.3% of patients at follow-up and became more frequently associated with asthma (from 36.7% at baseline to 48.6% at follow-up) and oral allergy syndrome (OAS, from 23.4% to 37.7%). Compared to baseline, the prevalence of skin sensitization to some pollens (Phleum pratense, Corylus avellana, Platanus acerifolia, Artemisia vulgaris) and vegetables (hazelnut, wheat, and apple) significantly decreased at follow-up. Earlier onset of SAR and polysensitization at baseline were associated with incident asthma at follow-up. The presence at baseline of serum IgE to the following allergen molecules was identified as biomarkers of clinical evolution: (a) Phl p 1, for persistence of SAR; (b) Phl p 5, for persistence of both rhinitis and asthma; (c) Pru p 3, for new onset of asthma; (d) Bet v 1, for persistence of OAS.

CONCLUSIONS

Seasonal allergic rhinoconjunctivitis is clinically heterogeneous in its evolution from childhood to adolescence. The detection of serum IgE to specific molecules (Phl p 1, Phl p 5, Bet v 1, Pru p 3) may be useful as biomarkers to predict SAR persistence and future onset of comorbidities, such as asthma and/or OAS.

Detection of genuine grass pollen sensitization in children by skin testing with a recombinant grass pollen hybrid

BACKGROUND

Skin testing represents a commonly used first diagnostic method in clinical practice, but allergen extracts may vary in composition and often contain cross-reactive allergens and therefore do not always allow the precise identification of the sensitizing allergen source. Our aim was to investigate the suitability of a single recombinant hybrid molecule, consisting of the four major timothy grass pollen allergens (Phl p 1, Phl p 2, Phl p 5, and Phl p 6) for in vivo diagnosis of genuine grass pollen allergy in children suffering from pollinosis.

METHODS

Sixty-four children aged from 6 to 17 years with a positive skin reaction and/or specific IgE to grass pollen extract and respiratory symptoms of pollinosis as well as 9 control children with allergy to other allergen sources were studied. SPT was performed with the recombinant hybrid, the four recombinant timothy grass pollen allergens, and grass pollen extract. Specific IgE reactivity to 176 micro-arrayed allergen molecules was determined using ImmunoCAP ISAC technology. IgE reactivity to the hybrid was detected by non-denaturing RAST-based dot blot assay.

RESULTS

Genuine grass pollen sensitization was confirmed in 94% of the children with positive SPT to grass pollen extract by SPT and IgE reactivity to the hybrid. The four hybrid-negative children showed IgE reactivity to cross-reactive allergens such as Phl p 4, Phl p 11, and Phl p 12 and had also sensitizations to pollen allergens from unrelated plants.

CONCLUSIONS

The recombinant hybrid molecule represents a useful tool for in vivo diagnosis of genuine grass pollen sensitization.

Molecular Diagnosis of Allergy: The Pediatric Perspective

In times of "Precision Medicine" it is fundamental to identify the individual disease phenotype in order to provide an individualized therapy for every patient. This concept is also becoming increasingly important for the treatment of allergic diseases. Thanks to the biological engineering of recombinant and native allergens for the assessment of allergen-specific IgE antibodies, it is now possible to easily obtain the individual sensitization profile of a patient. This allows the allergist to precisely identify the primary elicitor of an IgE response and, based on this knowledge, to choose the best treatment option. Several studies have observed the longitudinal evolution of sensitization profiles and identified a phenomenon termed "molecular spreading," which describes a broadening of the recognized allergen spectrum from a source over time. Additionally, the identification of marker proteins, which can trigger an IgE response or correlate with an increased risk for certain clinical symptoms, helps to establish an individual risk profile. This information may not only affect the decision-making concerning immunotherapy, but also opens up avenues for future investigations with regard to prevention strategies. We provide here an overview on the role of individual sensitization patterns and their predictive value.

Molecular diagnostics improves diagnosis and treatment of respiratory allergy and food allergy with economic optimization and cost saving

BACKGROUND

Component resolved diagnosis (CRD) allows to precisely identify the sensitization to specific molecules of a given allergenic source, resulting in an important improvement in clinical management, particularly of polysensitized subjects. This will end in the correct prescription of allergen immunotherapy (AIT) for respiratory allergy and in adequate avoidance diets or prescription of self-injectable adrenaline in food allergy.

OBJECTIVE

The aim of this multicenter, real life study is to evaluate the percentage change of the diagnostic-therapeutic choice in polysensitized patients with respiratory allergy and in patients with food allergy, after using CRD compared to a first level diagnosis, along with an economic analysis of the patient's overall management according to the two different approaches.

METHODS

An overall number of 462 polysensitized patients, as suggested by skin prick tests (SPT), and with clinical symptoms related to a respiratory (275 pts) or food (187 pts) allergy, were recruited. All patients underwent CRD for specific IgE against food or inhalant recombinant molecules, which were chosen according to medical history and positivity to SPT. The first diagnostic-therapeutic hypothesis, based only on medical history and SPT, was recorded for each patient while the final diagnostic-therapeutic choice was based on the results from CRD. The rate of change of the diagnostic-therapeutic choice from the first hypothesis to the final choice was statistically evaluated. The economic impact of CRD on the overall management of the allergic patients was analyzed to evaluate whether the increase in the diagnostic costs would be compensated and eventually exceeded by savings coming from the improved diagnostic-therapeutic appropriateness.

RESULTS

An approximate 50% change (k index 0.54) in the prescription of AIT for respiratory allergy as well as a change in the prescription of self-injectable adrenaline (k index 0.56) was measured; an overall saving of financial resources along with a higher diagnostic-therapeutic appropriateness was also detected.

CONCLUSION

There is moderate agreement concerning prescription of AIT and self-injectable adrenaline before and after performing CRD: this highlights the usefulness of CRD, at least in polysensitized patients, in indicating the risk assessment and therefore the correct therapy of respiratory and food allergy, which results in a cost-saving approach.

Efficacy and effectiveness of omalizumab in the treatment of childhood asthma

INTRODUCTION

Omalizumab is a monoclonal antibody that binds and inhibits free serum immunoglobulin E, a mediator involved in the clinical manifestations of allergic asthma. Evidence for its efficacy and safety in the treatment of moderate-to-severe allergic asthma is based primarily on studies in adolescents and adults. However, there is increasing evidence of its utility in children with allergic asthma aged 6-12 years. Areas covered: This article reviews efficacy, safety, and effectiveness of omalizumab in the treatment of moderate-to-severe allergic asthma in children aged 6-12 years in clinical trials and in studies in clinical practice. Pharmacoeconomic aspects of its use among this population and the positioning of omalizumab in pediatric asthma management guidelines are also discussed. Additionally, an algorithm for the management of poorly controlled severe pediatric asthma in children older than 6 years is proposed. Electronic databases, such as PubMed, were searched for terms Asthma and Omalizumab and for asthma management guidelines. Expert commentary: Add-on omalizumab is an effective maintenance therapy in children aged 6-12 years with poorly controlled moderate-to-severe allergic asthma treated with medium-high inhaled corticosteroids doses and inhaled long-acting β2-agonists. Omalizumab appears safe in children in both clinical trials and real-life setting and may be cost-effective.

Molecular sensitization patterns and influence of molecular diagnosis in immunotherapy prescription in children sensitized to both grass and olive pollen

BACKGROUND

The overlapping grass and olive pollen seasons in Spain and the phenomenon of cross-reactivity can make it difficult to determine the true causative agent of seasonal allergic rhinitis when only skin prick tests with whole extracts are used. The aim of the GRAMOLE study was to determine sensitization patterns to the major grass and olive pollen allergens detected using specific recombinant IgE and to explore how this knowledge affected physicians' choice of allergen-specific immunotherapy.

METHODS

Epidemiological, observational, multicenter, cross-sectional study. Results from children under 18 years of age diagnosed with seasonal allergic rhinitis by positive skin prick tests to olive and grass pollen were analyzed. Specific IgE to Phl p 1+5, Ole e 1, and Phl p 7+12 was determined. Investigators specified the optimal composition of allergen immunotherapy before and after knowing the results of the molecular diagnosis.

RESULTS

A total of 281 patients with a mean age of 13.4 years were included. Double sensitization to both major allergens was found in vitro in 76% of children for an IgE cutoff point of 0.35 kU/L. When the molecular diagnosis results were known, specialists changed the composition of the prescribed immunotherapy in 52.87% of cases.

CONCLUSIONS

Double sensitization to grass and olive pollen is common in Spain and also occurs in the pediatric population. Molecular diagnosis using specific IgE may help improve immunotherapy selection in polysensitized patients.

Extended IgE profile based on an allergen macroarray: a novel tool for precision medicine in allergy diagnosis

Background

Precision medicine (PM) is changing the scope of allergy diagnosis and treatment. An in vitro IgE assay, a prototype PM method, was developed in the sixties and has garnered increasing interest because of the introduction of recombinant components in the test. More recently, microarrays of allergen components have significantly improved the ability to describe the IgE profile. Aim of this study was to evaluate the characteristics of the newly developed Allergy Explorer (ALEX), a macroarray containing both extracted "whole" allergens and molecular components. This method allows the acquisition of an IgE profile comprising 282 reagents (157 allergen extracts and 125 components), resulting in the widest screening of potential allergens available.

Methods

Sera from 43 patients with allergies were assayed with ALEX and then with ImmunoCAP ISAC. The results of the two tests were compared, and the consistency of the molecular results with the presence of IgE in the relevant extract was also evaluated.

Results

A good correlation between ISAC and ALEX was observed. The ALEX results for second-level tests (i.e., specific IgE to complete extracted allergens) were consistent with the results obtained for the relevant components.

Discussion

Despite differences in the methodology, the IgE profiles detected for molecular allergens by ALEX and ISAC were very similar. The differences were mainly related to the lower dynamic range of ALEX and to the use of a CCD inhibitor in the first incubation phase, which reduced the binding of IgE to CCD, as represented in the extracted allergens and components.

Conclusion

Based on our findings, ALEX is a novel tool for describing the IgE profile in a PM setting, where the IgE assay must be performed on many allergens and components. In particular, polysensitized patients and patients with pollen-food syndrome will have a real advantage due the combination of the second and third levels of allergy diagnostics in the same chip.

New biomolecular tools for aerobiological monitoring: Identification of major allergenic Poaceae species through fast real-time PCR

Grasses (Poaceae) are very common plants, which are widespread in all environments and urban areas. Despite their economical importance, they can represent a problem to humans due to their abundant production of allergenic pollen. Detailed information about the pollen season for these species is needed in order to plan adequate therapies and to warn allergic people about the risks they take in certain areas at certain moments. Moreover, precise identification of the causative species and their allergens is necessary when the patient is treated with allergen‐specific immunotherapy. The intrafamily morphological similarity of grass pollen grains makes it impossible to distinguish which particular species is present in the atmosphere at a given moment. This study aimed at developing new biomolecular tools to analyze aerobiological samples and identifying major allergenic Poaceae taxa at subfamily or species level, exploiting fast real‐time PCR. Protocols were tested for DNA extraction from pollen sampled with volumetric and gravimetric methods. A fragment of the matK plastidial gene was amplified and sequenced in Poaceae species known to have high allergological impact. Species‐ and subfamily‐specific primer–probe systems were designed and tested in fast real‐time PCRs to evaluate the presence of these taxa in aerobiological pollen samples. Species‐specific systems were obtained for four of five studied species. A primer–probe set was also proposed for the detection of Pooideae (a grass subfamily that includes also major cereal grains) in aerobiological samples, as this subfamily includes species carrying both grass allergens from groups 1 and 5. These, among the 11 groups in which grass pollen allergens are classified, are considered responsible for the most frequent and severe symptoms.

Diagnostic relevance of IgE sensitization profiles to eight recombinant Phleum pratense molecules

BACKGROUND

Grass pollen-related seasonal allergic rhinoconjunctivitis (SARg) is clinically heterogeneous in severity, comorbidities, and response to treatment. The component-resolved diagnostics disclosed also a high heterogeneity at molecular level. Our study aimed at analyzing the characteristics of the IgE sensitization to Phleum pratense molecules and investigating the diagnostic relevance of such molecules in childhood.

METHODS

We examined 1120 children (age 4-18 years) with SARg. Standardized questionnaires on atopy were acquired through informatics platform (AllergyCARD™). Skin prick tests were performed with pollen extracts. Serum IgE to airborne allergens and eight P. pratense molecules (rPhl p 1, rPhl p 2, rPhl p 4, rPhl p 5b, rPhl p 6, rPhl p 7, rPhl p 11, rPhl p 12) were tested by ImmunoCAP FEIA.

RESULTS

The analysis of IgE responses against eight P. pratense molecules showed 87 profiles. According to the number of molecules recognized by IgE, the more complex profiles were characterized by higher serum total IgE, higher grass-specific serum IgE, and higher number and degree of sensitization to pollens. The most frequent IgE sensitization profile was the monomolecular Phl p 1. Sensitization to Phl p 7 was a reliable biomarker of asthma, whereas Phl p 12 of oral allergy syndrome. Sensitization to Phl p 7 was associated with a higher severity of SARg, and complex profiles were associated with longer disease duration.

CONCLUSIONS

In a large pediatric population, the complexity of IgE sensitization profiles against P. pratense molecules is related to high atopic features although useless for predicting the clinical severity. The detection of serum IgE to Phl p 1, Phl p 7, and Phl p 12 can be used as clinical biomarkers of SARg and comorbidities. Further studies in different areas are required to test the impact of different IgE molecular profiles on AIT response.

A Component-resolved Diagnostic Approach for a Study on Grass Pollen Allergens in Chinese Southerners with Allergic Rhinitis and/or Asthma

Sensitization to grass pollen imposes a global risk for allergic airway diseases. Although prevention relies on local investigation of the pollen allergens, data on this topic are limited in southern China. Any available data were obtained by self-report questionnaires, skin prick tests, and total or specific IgE tests using crude extracts. For many reasons, these methods are unreliable. Serum sIgE reactivity to Bermuda grass, Timothy grass, and Humulus scandens allergens in a cohort of patients from Greater Guangzhou (southern China's largest city and its outskirts) with allergic rhinitis and/or asthma were examined using a fully-automated immunoassay analyzer as a component-resolved diagnostics (CRD) tool. For the first time, a considerably high prevalence of Bermuda grass sIgE positivity was demonstrated in Chinese southerners with allergic rhinitis and/or asthma. In these patients, a subtle prevalence of sensitization to Timothy grass and Humulus scandens was also noted, which may arise from cross-reactivity, as the latter two are not common in the region. This was also supported by the detection of allergen components. Fully-automated immunoassay analyzers may offer satisfactory consistency between regions, laboratories, and institutions and over time. The automaticity of the instrument may enable a standardized detection that would not have been readily revealed before the advent of CRD. This is a study that uses a CRD approach to investigate sensitization to grass pollen allergens in southern China. It adds to current evidence in the literature. Future studies are needed to validate these findings. However, although CRD is a useful tool, the findings made with the fully-automated immunoassay analyzer should not substitute for other laboratory investigations, clinical evaluations, and physician expertise.

The clinical relevance of birch pollen profilin cross-reactivity in sensitized patients

BACKGROUND

Overlapping seasons and cross-reactivity, especially to grass pollen profilin, can hamper the diagnosis of birch pollen allergy. To identify the primary sensitizing allergen and the clinical relevance of cross-sensitization, we correlated sensitization profiles with in vitro and in vivo tests, symptom scores, and pollen counts.

METHODS

A total of 433 patients with positive skin prick test (SPT) to birch pollen were analyzed regarding IgE to major birch and grass pollen allergens Bet v 1 and Phl p 1/p 5 and the profilins Bet v 2 and Phl p 12. Subgroups were analyzed by basophil activation test (BAT) and CAP-FEIA-based cross- and self-inhibition tests.

RESULTS

A total of 349 patients were sensitized to Bet v 1, 44 patients to both Bet v 1 and Bet v 2, and 15 patients to Bet v 2 only. From Bet v 2-sensitized patients, 40 were also sensitized to Phl p 12. Ex vivo, Bet v 2 and Phl p 12 induced dose-dependent activation in basophils of these patients. Cross- and self-inhibition tests with both allergens confirmed cross-reactivity. However, semiquantitative analysis of SPTs demonstrated markedly increased reactivity to grass compared to birch pollen extract in Bet v 2 only sensitized patients. Accordingly, in most of those patients, clinical symptoms precisely correlated with grass pollen counts.

CONCLUSION

Identification of the clinically relevant and sensitizing allergen needs correlation of actual pollen counts with clinical symptoms and sensitization status to major allergens. Semiquantitative analysis of SPT or BAT and determining profilin-specific IgE can contribute to making the diagnosis.

Comparison of two diagnostic techniques, skin-prick test and component resolved diagnosis in the follow-up of a cohort of paediatric patients with pollinosis. Multicentre pilot study in a highly exposed allergenic area

BACKGROUND

Over the last years, different works have been published about the importance of incorporating new diagnosis techniques in allergic patients such as component-resolved diagnosis (CRD). The objective of this study is to compare the evolution of allergic sensitisation profiles by means of CRD and cutaneous tests (SPT) on pollen-allergic patients.

METHODS

A total of 123 patients aged between 2 and 14 years were included in an open, prospective, multicentre study. All the children had symptoms suggestive of seasonal respiratory allergic disease, with the diagnosis confirmed by cutaneous tests. Specific-IgE to major pollen-allergens (CRD) and SPT were performed at basal and after three years of follow-up.

RESULTS

Out of 123 patients included, a total of 85 were analysed. The mean age was 8±3 years. Significant changes in the allergic sensitisation profiles were observed for the most prevalent allergens (Olea and grass) but it is in grass, the most relevant allergen in terms of allergen pressure, where changes in both absolute and relative frequencies between SPT and CRD were more evident.

CONCLUSION

CRD seems to be an essential tool to carry out an appropriate follow-up of patients with allergic respiratory disease, as well as to decide on the immunotherapy composition that best matches the allergic sensitisation profile of patients.

Climate change: consequences on the pollination of grasses in Perugia (Central Italy). A 33-year-long study

Many works carried out in the last decades have shown that the pollen season for taxa flowering in winter and spring, in temperate regions, has tended to be earlier, probably due to the continuous rise in temperature. The mean annual temperature in Perugia, Central Italy, was about 0.5 °C higher in the last three decades compared with that registered from 1952 to 1981. The increase of temperature took place mainly in winter and spring, while no significant variation was recorded during the summer and autumn. This scenario shows variations in the timing and behavior of flowering of many spontaneous plants such as grasses, whose phenology is strongly influenced by air temperature. This work reports fluctuations in the airborne grass pollen presence in Perugia over a 33-year period (1982-2014), in order to study the influence of the warming registered in recent years on the behavior of pollen release of this taxon. The grass pollen season in Perugia typically lasts from the beginning of May to late July. The start dates showed a marked trend to an earlier beginning of the season (-0.4 day/year), as well as a strong correlation with the average temperatures of March and April. The peak is reached around 30th May, but the annual pollen index (API) is following a decreasing trend. The correlation between starting dates and spring temperatures could be interesting for the constitution of a forecasting model capable of predicting the presence of airborne grass pollen, helping to plan therapies for allergic people.

Allergy immunotherapy across the life cycle to promote active and healthy ageing: from research to policies: An AIRWAYS Integrated Care Pathways (ICPs) programme item (Action Plan B3 of the European Innovation Partnership on active and healthy ageing) and the Global Alliance against Chronic Respiratory Diseases (GARD), a World Health Organization GARD research demonstration project

Allergic diseases often occur early in life and persist throughout life. This life-course perspective should be considered in allergen immunotherapy. In particular it is essential to understand whether this al treatment may be used in old age adults. The current paper was developed by a working group of AIRWAYS integrated care pathways for airways diseases, the model of chronic respiratory diseases of the European Innovation Partnership on active and healthy ageing (DG CONNECT and DG Santé). It considered (1) the political background, (2) the rationale for allergen immunotherapy across the life cycle, (3) the unmet needs for the treatment, in particular in preschool children and old age adults, (4) the strategic framework and the practical approach to synergize current initiatives in allergen immunotherapy, its mechanisms and the concept of active and healthy ageing.