A comprehensive analysis of middle-European molecular sensitization profiles to pollen allergens

Polysensitisation is associated with more severe symptoms: The reality of patients with allergy

BACKGROUND

Studying the sensitisation profiles of patients with allergies allows for a deeper understanding of the disease which may facilitate the selection of the best-personalised allergen immunotherapy. This observational, cross-sectional, multicentre study aimed to demonstrate the heterogeneity of the German population with allergies by analysing specific immunoglobulin E (sIgE) patterns towards aeroallergens and exploring the relationship between sensitisation and clinical symptoms.

METHODS

In total, 500 patients with allergies from different regions of Germany were recruited based on their case histories, clinical allergic symptoms and skin prick test data for aeroallergens. Serum samples were analysed using ImmunoCAP assays to determine sIgE levels for 33 allergenic sources and 43 molecular allergens.

RESULTS

Most patients (81%) were polysensitised. Betula verrucosa pollen was the most common cause of sensitisation (59%), followed by Phleum pratense (58%) and Dermatophagoides pteronyssinus (44%). The highest prevalence rates of molecular allergens were observed for Bet v 1 (84%) from birch pollen, Phl p 1 from grass pollen (82%), Der p 2 (69%) from mites and Fel d 1 (69%) from cat. Polysensitisation was significantly associated with the presence of asthma and the severity of rhinitis symptoms.

CONCLUSIONS

Our findings show a high rate of polysensitisation and emphasise the importance of molecular diagnosis for more precise and comprehensive insights into sensitisation patterns and their association with clinical symptoms. These data may help improve personalised diagnosis and immunotherapy adapted to the needs of individual patients in the region.

Efficacy and safety of subcutaneous immunotherapy with polymerized allergen mixtures in polyallergic patients - ARES observational study

BACKGROUND

Administration of allergen mixtures of many components comprises the most common approach for American allergists regarding the management of polyallergic patients. European allergists, however, are more reluctant to this type of treatment due to the potential drawbacks of mixing extracts.

RESEARCH DESIGN AND METHODS

To assess the efficacy and safety of subcutaneous immunotherapy (SCIT) with polymerized allergen mixtures without dilutional effect in polyallergic patients.This observational, prospective, multicenter study included patients (between 5 and 60 years) with respiratory allergic diseases that had been prescribed with SCIT with mixtures of two pollen or mite extracts. Changes in Symptoms and Medication Score (SMS) and in rhinitis quality of life questionnaire (RQLQ), subjective clinical improvement, treatment satisfaction and tolerability were assessed after the 1-year treatment.

RESULTS

A total of 115 patients were included in the assessment. Mean global SMS decreased from 3.5 (SD = 1.1) to 1.6 (SD = 1.2) points, with a mean absolute reduction of 1.6 (SD = 1.3) points in the RQLQ score (p < 0.001, Wilcoxon test). General subjective clinical improvements and a good treatment satisfaction and tolerability were observed.

CONCLUSION

SCIT with polymerized allergen mixtures from either pollen or mite extracts proved to be an effective and safe treatment option for polyallergic patients suffering from allergic respiratory diseases.

Molecular allergology: a clinical laboratory tool for precision diagnosis, stratification and follow-up of allergic patients

Identification of the molecular culprits of allergic reactions leveraged molecular allergology applications in clinical laboratory medicine. Molecular allergology shifted the focus from complex, heterogeneous allergenic extracts, e.g. pollen, food, or insect venom, towards genetically and immunologically defined proteins available for in vitro diagnosis. Molecular allergology is a precision medicine approach for the diagnosis, stratification, therapeutic management, follow-up and prognostic evaluation of patients within a large range of allergic diseases. Exclusively available for in vitro diagnosis, molecular allergology is nonredundant with any of the current clinical tools for allergy investigation. As an example of a major application, discrimination of genuine sensitization from allergen cross-reactivity at the molecular level allows the proper targeting of the culprit allergen and thus dramatically improves patient management. This review aims at introducing clinical laboratory specialists to molecular allergology, from the biochemical and genetic bases, through immunological concepts, to daily use in the diagnosis and management of allergic diseases.

Assessing IgE sensitization profiles to birch and timothy grass pollen allergens in birch pollen allergic blood donors using an oligoplex specific IgE assay

IgE sensitization profiles to single birch allergens in birch-sensitized patients differ among European countries. The aim of this study was to determine the distribution of specific IgE antibodies to major and minor birch pollen allergens in a population of allergic Norwegian individuals by using a birch allergic blood donor population as a surrogate sample. Sixty blood donors were recruited and sampled based on birch allergy symptoms such as rhinitis, rhinoconjunctivitis and/or mild asthma in previous seasons. All sera were collected before start of the pollen season and tested using a line blot assay (Euroimmun AG, Lübeck, Germany) for IgE to birch and timothy pollen. Both extracts, single allergens, and cross-reacting carbohydrate determinants (CCD) were analysed. Only donors with specific IgE to birch and/or timothy grass were further evaluated. Specific IgE to birch pollen extract was found in 52 sera, and sensitization to timothy grass in 40 sera. Specific IgE to Bet v 1 was predominant in contrast to Bet v 4 which was absent. However, sensitization to the minor allergens Bet v 2 and 6 was always found together with high levels of IgE to Bet v 1. Subjects sensitized to the profilin Bet v 2 from birch were also sensitized to Phl p 12 from timothy grass. In conclusion, there was predominantly Bet v 1 sensitization in this cohort and low sensitization to minor allergens and cross-reactive allergens (Bet v 2, Bet v 4, Phl p 7 and Phl p 12).

A comprehensive analysis of the components of common weed pollen and related allergens in patients with allergic diseases in southern China

BACKGROUND

Pollen allergens are vital contributors to allergic diseases. The frequency and coreactivity pattern of allergens are closely related to geographical distribution.

OBJECTIVE

In this study, we aimed to characterize the prevalence of the molecular components of the common weed pollen allergens, birch pollen, walnut, and cross-reactive carbohydrate determinant (CCD), as well as investigate the relationship between the allergens and CCD in Chinese pollen-sensitized patients with allergic diseases.

METHODS

Based on previous vegetation surveys, serum samples from 165 pollen-sensitized patients with allergic diseases in Guangdong Province in southern China were used to test 19 crude allergen extracts, their components, and CCD using component-resolved diagnosis (CRD). Moreover, the potential associations among CCD, allergens, and their components were described.

RESULTS

In the 165 samples, the most common sensitized allergens were goosefoot (43.0%), ragweed (40.6%), walnut (37.6%), walnut tree (37.6%), and mugwort (37.0%), followed by platane (35.2%), cocklebur (27.9%), and birch (24.2%). The positivity rate of CCD was 39.4%. Among the samples positive for mugwort, 11 (18.0%), 15 (24.6%), and 15 (24.6%) were positive for Art v 1, Art v 2, and Art v 3, respectively. Among the 67 patients sensitized to ragweed, only five (7.5%) were positive for Amb a 1. In the 40 patients sensitized to birch, Bet v 2 had the highest positivity rate (40.0%). There were 62 patients who were sensitized to walnut. Their components had a lower positivity rate (less than 15%). The hierarchical clustering and optimal scale analysis showed that Art v 4 and Bet v 2 were closely related, and 91.9% of CCD-positive samples were polysensitized. Meanwhile, Spearman's rank correlation method showed that CCD was closely correlated with the sensitization of crude allergen extracts, and there was a low correlation between CCD and allergen components. CCD was highly correlated with goosefoot, ragweed, and walnut trees (r＞0.8). Moreover, there was a strong relationship between the levels of Jug r 3 and Art v 3 (r = 0.78; P < 0.001).

CONCLUSIONS

In southern China, the weed pollens (ragweed, cocklebur, and goosefoot) exhibited higher positivity rates in adults and had a stronger relationship with CCD but not with mugwort. The positivity rate of allergen components was not high. CCD-positive samples were always polysensitized.

Molecular Profile of Specific IgE to Allergenic Components in Allergic Adults Using Allergen Nano-Bead Array

BACKGROUND

An increasing interest in the field of molecular diagnosis of allergy has been developed in recent years and it goes to be as the routine in-vitro protocol in allergy diagnosis. Friendly Allergen Nano-bead Array (FABER) is a new multiplex assay for the evaluation of specific IgE against 244 allergens including whole extracts and allergenic molecules. The research intended to assess the pattern of IgE sensitization to allergenic components of allergens in allergic adults using FABER 244.

METHODS

Sixty patients with allergic diseases entered this cross-sectional study. Specific IgE to 122 whole allergens extracts and 122 allergenic components was assessed using an allergen nano-bead array (FABER) for all patients. This test includes inhalant and food allergens.

RESULTS

Thirty-seven patients were male (61.7%). The mean (SD) age of patients was 30.73(±6.87) years. As the allergen nano-bead array results showed, Lolium perenne (63.3%), Phleum pretense (60%), and Platanus acerifolia (51.7%) were considered as the most common IgE-sensitizations to the aeroallergen extracts. Moreover, Lol p 1, Phl p 1.0102, and Cup a 1 were found as the most frequent allergenic components in our allergic patients. Among protein families, CCD bearing proteins, expansin, cysteine protease, and profilin families illustrated the highest allergic sensitization.

CONCLUSIONS

The results of the present study demonstrated that despite the higher prevalence of sensitization to Salsola kali (47.2%) using extract-based assays in the previous phase of this research, allergenic components of grasses (Lol p 1, Phl p 1.0102), Cup a 1 as well as Sal k1 as the major components of Cupressuss arizonica and Salsola kali showed the higher sensitization, respectively in adults' allergic patients using FABER test.

Exposure to green space and pollen allergy symptom severity: A case-crossover study in Belgium

BACKGROUND

The prevalence of pollen allergy has increased due to urbanization, climate change and air pollution. The effects of green space and air pollution on respiratory health of pollen allergy patients are complex and best studied in spatio-temporal detail.

METHODS

We tracked 144 adults sensitized to Betulaceae pollen during the tree pollen season (January-May) of 2017 and 2018 and assessed their spatio-temporal exposure to green space, allergenic trees, air pollutants and birch pollen. Participants reported daily symptom severity scores. We extracted 404 case days with high symptom severity scores and matched these to 404 control days. The data were analyzed using conditional logistic regression with a 1:1 case-crossover design.

RESULTS

Case days were associated with exposure to birch pollen concentration (100 grains/m³) [adjusted odds ratio 1.045 and 95% confidence interval (1.014-1.078)], O₃ concentration (10 μg/m³) [1.504 (1.281-1.766)] and PM₁₀ concentration (10 μg/m³) [1.255 (1.007-1.565)] on the day of the severe allergy event and with the cumulative exposure of one and two days before. Exposure to grass cover (10% area fraction) [0.655 (0.446-0.960)], forest cover (10% area fraction) [0.543 (0.303-0.973)] and density of Alnus (10%) [0.622 (0.411-0.942)] were protective for severe allergy, but only on the day of the severe allergy event. Increased densities of Betula trees (10%) were a risk factor [unadjusted OR: 2.014 (1.162-3.490)].

CONCLUSION

Exposure to green space may mitigate tree pollen allergy symptom severity but only when the density of allergenic trees is low. Air pollutants contribute to more severe allergy symptoms. Spatio-temporal tracking allows for a more realistic exposure assessment.

Analysis of Results of Specific IgE in 100 Atopic Dermatitis Patients with the Use of Multiplex Examination ALEX2-Allergy Explorer

Background and aim: Progress in laboratory diagnostics of IgE-mediated allergy is the use of component-resolved diagnosis. Our study analyses the results of specific IgE to 295 allergen reagents (117 allergenic extracts and 178 molecular components) in patients suffering from atopic dermatitis (AD) with the use of ALEX2 Allergy Explorer. Method: The complete dermatological and allergological examination, including the examination of the sensitization to molecular components with ALEX2 Allergy Explorer testing, was performed. The statistical analysis of results was performed with these methods: TURF (total unduplicated reach and frequency), best reach and frequency by group size, two-sided tests, Fisher’s exact test, and chi-square test (at an expected minimum frequency of at least 5). Results: Altogether, 100 atopic dermatitis patients were examined: 48 men, 52 women, the average age 40.9 years, min. age 14 years, max. age 67 years. The high and very high level of specific IgE was reached in 75.0% of patients to 18 molecular components: from PR-10 proteins (Aln g 1, Bet v 1, Cor a1.0103, Cor a1.0401, Fag s 1), lipocalin (Can f 1), NPC2 family (Der f 2, Der p 2), uteroglobin (Fel d 1), from Alternaria alternata (Alt a 1), Beta expansin (Lol p 1, Phl p 1), molecular components from Timothy, cultivated rye (Secc pollen) and peritrophin-like protein domain Der p 23. The high and very high level of specific IgE to other lipocalins (Fel d 7, Can f 4), to arginine kinase (Bla g 9, German cockroach), and to allergen extracts Art v (mugwort), and Cyn d (Bermuda grass) reached 52.0% of patients. The severity of AD is in significant relation to the sensitization to molecular components of storage mites (Gly d 2, Lep d 2—NPC2 family), lipocalins (Can f 1, Can f 2, Can f 4, and Can f 6), arginine kinase (Asp f 6, Bla g 9, Der p 20, Pen m 2), uteroglobin (Fel d 1, Ory c 3), Mn superoxide dismutase (Mala s 11), PR-10 proteins (Fag s 1, Mal d 1, Cor a 1.0401, Cor a 1.0103), molecular components of the peritrophin-like domain (Der p 21, Der p 23), and to Secc pollen. In the subgroup of patients suffering from bronchial asthma, the significant role play molecular components from house dust mites and storage mites (Lep d 2, Der p 2, Der f 2—NPC2 family), cysteine protease (Der p 1), peritrophin-like protein domain (Der p 21, Der p 23), enolase from Alternaria alternata (Alt a 6), and Beta expansin Phl p 1. Conclusion: The results of our study demonstrate the detailed profile of sensitization to allergens reagents (allergen extract and molecular components) in patients with atopic dermatitis. We show the significance of disturbed epidermal barrier, resulting in increased penetration of allergens. We confirmed the significant relationship between the severity of AD, the occurrence of bronchial asthma and allergic rhinitis, and high levels of specific IgE to allergen reagents. Our results may be important for regime measures and immunotherapy; Der p 23 shall be considered as an essential component for the diagnosis and specific immunotherapy of house dust mite allergy.

Atopic Dermatitis and Sensitisation to Molecular Components of Alternaria, Cladosporium, Penicillium, Aspergillus, and Malassezia-Results of Allergy Explorer ALEX 2

Progress in laboratory diagnostics of IgE-mediated allergies is being made through the use of component-resolved diagnosis. The aim of our study is to analyze the sensitization profile to allergen reagents in patients suffering from atopic dermatitis with the use of the ALEX 2–Allergy Explorer and especially to show the sensitization to molecular components of molds and yeast. The complete dermatological and allergological examination including the examination of the sensitization to allergen reagents with Allergy Explorer ALEX 2 testing was performed. The relation between the sensitization to molecular components of molds and yeast and the severity of atopic dermatitis, and the occurrence of bronchial asthma and allergic rhinitis was evaluated. Altogether, 100 atopic dermatitis patients were examined—48 men and 52 women, with an average age of 40.9 years. The sensitization to Mala s 6, Mala s 11, Sac c, Asp f 6, Cla h and Cla h 8 correlates to the severity of atopic dermatitis. The sensitization to Sac c, Alt a 6, Cla h, Cla h 8 was observed significantly more frequently in patients suffering from bronchial asthma to Mala s 6 in patients suffering from allergic rhinitis. In patients with severe form of atopic dermatitis (AD), a very high level of specific IgE was recorded to Mala s 11 (in 36%) and to Asp f 6 (in 12%).

Evaluation of safety and tolerability of a rush up-dosing allergen-specific immunotherapy with grass pollen, birch, hazel, and alder allergoid in children with allergic rhinoconjunctivitis, with or without asthma

Background:

Usually, the number of injections required to achieve the maintenance dose in subcutaneous immunotherapy (SCIT) is relatively small for some of the currently used allergens, but this may still be uncomfortable for patients, thus compromising adherence and compliance.

Objective:

The purpose of this study was to evaluate the safety and tolerability of a dose acceleration of a conventional induction schedule using an allergoid extract of grass pollen, birch, hazel, and alder, needed to achieve the ideal maintenance dose.

Methods:

In this open-label study, 34 patients with allergic rhinoconjunctivitis, with or without asthma, were treated with SCIT using an allergoid for grass pollen or birch or mix trees with an increase in accelerated induction dose comprising only 3 injections, one per week, compared to a conventional induction pattern in five injections (once a week). Safety determination was assessed by evaluating local and systemic adverse events. Tolerability was evaluated by patients and physicians who performed the treatment.

Results:

No treatment-related adverse events were observed in any of the patients undergoing rush SCIT. No local reactions, no systemic reactions of any degree (WAO Grade) have been observed. Tolerability has always been rated as very good by both patients and physician.

Conclusions:

The induction phase, needed to achieve the monthly maintenance dose for a pollen extract, can be greatly accelerated, ensuring a tolerability comparable to that of the conventional schedule. (www.actabiomedica.it)

Sensitization to Molecular Components in 104 Atopic Dermatitis Patients in Relation to Subgroups of Patients Suffering from Bronchial Asthma and Allergic Rhinitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease. The progression from AD to bronchial asthma (AB) and allergic rhinitis (AR) is called atopic march. The aim of this study was to evaluate the difference in the sensitization to molecular components in patients suffering from AD in relation to subgroups of patients with AR and AB.

MATERIAL AND METHODS

The complete dermatological and allergological examinations were performed. Specific IgE antibodies against 112 molecular components were measured with the multiplex ImmnoCAP ISAC test.

RESULTS

Altogether 104 atopic dermatitis patients (50 men, 54 women) at the average age 40.1 years were examined. The sensitization to molecular components was confirmed in 93.3% of patients. The sensitization to components of mites, grasses, trees, animals, moulds, and shrimps was significantly more frequent in patients with severe form of AD and the sensitization to components of grasses, trees, and moulds was significantly higher in subgroup of patients with AB. In subgroup of patients suffering from AR the higher occurrence of pollen-derived and pollen-food derived PR-10 proteins, grasses, mites, and animals was observed also.

CONCLUSIONS

We have confirmed the significant differences in the sensitization to molecular components in patients suffering from severe form of AD, and in subgroups of patients suffering from AB and AR. These molecular components may play the important role in the consecutive development of different allergy pathologies called atopic march.

In vivo Induction of Functional Inhibitory IgG Antibodies by a Hypoallergenic Bet v 1 Variant

Allergic sensitization to the major allergen Bet v 1 represents the dominating factor inducing a vast variety of allergic symptoms in birch pollen allergic patients worldwide, including the pollen food allergy syndrome. In order to overcome the huge socio-economic burden associated with allergic diseases, allergen-specific immunotherapy (AIT) as a curative strategy to manage the disease was introduced. Still, many hurdles related to this treatment exist making AIT not the patients’ first choice. To improve the current situation, the development of hypoallergen-based drug products has raised attention in the last decade. Herein, we investigated the efficacy of the novel AIT candidate BM4, a hypoallergenic variant of Bet v 1, to induce treatment-relevant cross-reactive Bet v 1-specific IgG antibodies in two different mammals, Wistar rats and New Zealand White rabbits. We further analyzed the cross-reactivity of BM4-induced Wistar rat antibodies with the birch pollen-associated food allergens Mal d 1 and Cor a 1, and the functional capability of the induced antibodies to act as IgE-blocking IgG antibodies. Enzyme-linked immunosorbent assay (ELISA) was used to determine the titers of rat IgG1, IgG2a, IgG2b, and IgE, as well as rabbit IgG and IgE antibodies. To address the functional relevance of the induced IgG antibodies, the capacity of rat sera to suppress binding of human IgE to Bet v 1 was investigated by using an inhibition ELISA and an IgE-facilitated allergen-binding inhibition assay. We found that the treatment with BM4 induced elevated Bet v 1-specific IgG antibody titers in both mammalian species. In Wistar rats, high BM4-specific IgG1, IgG2a, and IgG2b titers (10⁴ to 10⁶) were induced, which cross-reacted with wild-type Bet v 1, and the homologous allergens Mal d 1 and Cor a 1. Rat allergen-specific IgG antibodies sustained upon treatment discontinuation. Sera of rats immunized with BM4 were able to significantly suppress binding of human IgE to the wild-type allergens and CD23-mediated human IgE-facilitated Bet v 1 binding on B cells. By contrast, treatment-induced IgE antibody levels were low or undetectable. In summary, BM4 induced a robust IgG immune response that efficiently blocked human IgE-binding to wild-type allergens, underscoring its potential therapeutic value in AIT.

Can smartphone data identify the local environmental drivers of respiratory disease?

Asthma and allergic rhinitis (or hay fever) are ubiquitous, chronic health conditions that seasonally affect a sizeable proportion of the population. Both are commonly triggered or exacerbated by environmental conditions including aeroallergens, air quality and weather. Smartphone technology offers new opportunities to identify environmental drivers by allowing large-scale, real-time collection of day-to-day symptoms. As yet, however, few studies have explored the potential of this technology to provide useful epidemiological data on environment-symptom relationships. Here, we use data from the smartphone app 'AirRater' to examine relationships between asthma and allergic rhinitis symptoms and weather, air quality and pollen loads in Hobart, Tasmania, Australia. We draw on symptom data logged by app users over a three-year period and use time-series analysis to assess the relationship between symptoms and environmental co-variates. Symptoms are associated with particulate matter (IRR 1.06, 95% CI: 1.04-1.08), maximum temperature (IRR 1.28, 95% CI: 1.13-1.44) and pollen taxa including Betula (IRR 1.04, 95% CI: 1.02-1.07), Cupressaceae (IRR 1.02, 95% CI: 1.01-1.04), Myrtaceae (IRR 1.06, 95% CI: 1.02-1.10) and Poaceae (IRR 1.05, 95% CI: 1.01-1.09). The importance of these pollen taxa varies seasonally and more taxa are associated with allergic rhinitis (eye/nose) than asthma (lung) symptoms. Our results are congruent with established epidemiological evidence, while providing important local insights including the association between symptoms and Myrtaceae pollen. We conclude that smartphone-sourced data can be a useful tool in environmental epidemiology.

Analysis of Sensitization Profiles in Central European Allergy Patients Focused on Animal Allergen Molecules

INTRODUCTION

Frequently observed multiple sensitizations to several animals highlights the importance of a molecular diagnosis, distinguishing between sensitizations specific to single species and sensitizations due to cross-reactivity.

OBJECTIVE

The aim of our study was to assess the usefulness of a molecular diagnosis in the description of sensitization profiles in allergy patients living in Central Europe, with a particular focus on animal-derived molecules.

METHODS

The molecular diagnosis was performed using the ImmunoCAP ISAC microarray. Results of 1,255 allergy patients were subjected to statistical analysis.

RESULTS

The highest sensitization rates were observed for uteroglobin Fel d 1 (31.8%) and kallikrein Can f 5 (16.4%), followed by animal lipocalins Can f 1 (13.9%), Equ c 1 (6.2%), Fel d 4 (5.3%), Can f 2 (4.2%), and Mus m 1 (4.1%). Sensitization rates to serum albumins Fel d 2, Can f 3, Equ c 3, and Bos d 6 were very low, with the highest being 3.2% to Fel d 2. Detailed subanalysis confirmed the dominant role of Fel d 1 or Can f 5 and/or Can f 1 in cat- or dog-sensitized patients, respectively. Further analysis focused on lipocalins and albumins confirmed a high rate of cosensitizations within both groups.

CONCLUSION

The sensitization to animal allergen molecules is very frequent in Central Europe. The most common is sensitization to species-specific cat uteroglobin Fel d 1 and dog kallikrein Can f 5, followed by sensitizations to animal lipocalins. Our data suggest that commonly observed multiple sensitizations detected by extract approach can be explained not only by true cosensitization, but also by cross-reactivity, mainly in the frame of lipocalins. Cross-reactive serum albumins are minor sensitizers and are probably not important from this point of view.

Fast up-dosing with a birch allergoid is safe and well tolerated in allergic rhinitis patients with or without asthma

AIM

Subcutaneous immunotherapy is effective in treating allergic rhinoconjunctivitis and asthma, but is still inconvenient when heavy schedules are used. A faster dose escalation is desirable.

MATERIALS & METHODS

In this open-label, Phase II trial, 130 adults were randomized 1:1 to receive a birch pollen allergoid subcutaneous immunotherapy. Group I with four weekly injections and Group II with seven weekly injections. Safety, tolerability and immunogenicity were assessed.

RESULTS

Mild-to-moderate treatment-related adverse events were reported for 57.7% of the patients (Group I: 36, Group II: 39). Tolerability was assessed by physicians and rated as 'good' or 'very good' for 55 patients in Group I (87.3%) and for 63 patients in Group II (94.0%). Levels of IgG and IgG₄ increased before and after treatment significantly (p < 0.0001) in both groups.

CONCLUSION

Standard versus fast dose escalation is comparable in terms of safety and tolerability.

Birch pollen allergy in Europe

Birch and other related trees of the families Betulaceae and Fagaceae (alder, hazel, oak, hornbeam, chestnut, and beech) constitute the birch homologous group. This grouping is primarily based on the extensive IgE cross-reactivity of allergen homologs to the major birch allergen Bet v 1. Birch pollen is the most dominant tree pollen in Northern and Central Europe and is a major cause of allergic rhinitis and, possibly, asthma symptoms. Over the last few decades, levels of birch pollen have risen and the period of exposure has increased due to climate changes. Subsequently, the prevalence of birch pollen sensitization has also increased. The cross-reactivity and sequential pollen seasons within the birch homologous group create a prolonged symptomatic allergy period beyond birch pollen alone. Furthermore, many plant food allergens contain homologs to Bet v 1, meaning that the majority of patients with birch pollen allergy suffer from secondary pollen food syndrome (PFS). As a result, the negative impact on health-related quality of life (HRQoL) in patients allergic to birch pollen is significant. The purpose of this manuscript was to narratively review topics of interest such as taxonomy, cross-reactivity, prevalence, clinical relevance, PFS, and HRQoL with regard to birch pollen allergy from a European perspective.

Fusion proteins consisting of Bet v 1 and Phl p 5 form IgE-reactive aggregates with reduced allergenic activity

The cross-linking of effector cell-bound IgE antibodies by allergens induces the release of inflammatory mediators which are responsible for the symptoms of allergy. We demonstrate that a recombinant hybrid molecule consisting of the major birch (Bet v 1) and grass (Phl p 5) pollen allergen exhibited reduced allergenic activity as compared to equimolar mixes of the isolated allergens in basophil activation experiments. The reduced allergenic activity of the hybrid was not due to reduced IgE reactivity as demonstrated by IgE binding experiments using sera from allergic patients. Physicochemical characterization of the hybrid by size exclusion chromatography, dynamic light scattering, negative-stain electron microscopy and circular dichroism showed that the hybrid occurred as folded aggregate whereas the isolated allergens were folded monomeric proteins. IgG antibodies raised in rabbits against epitopes of Bet v 1 and Phl p 5 showed reduced reactivity with the hybrid compared to the monomeric allergens. Our results thus demonstrate that aggregation can induce changes in the conformation of allergens and lead to the reduction of allergenic activity. This is a new mechanism for reducing the allergenic activity of allergens which may be important for modifying allergens to exhibit reduced side effects when used for allergen-specific immunotherapy.

Cross-sectional study on sensitization to mite and cockroach allergen components in allergy patients in the Central European region

Background

The major sources of allergens in the indoor air include house dust mites, dander derived from domestic animals and rodents, cockroach, and several fungi. Mites are the main cause of allergies in some countries with a warmer climate, but the epidemiological significance of mite and cockroach allergens in Central Europe has not been established yet.

Methods

We assessed sensitization profiles of allergy patients in a Central European region in regard to sensitization to mites and cockroach. We used molecular diagnosis by means of the microarray ISAC, and we investigated 1766 patients with clinical suspicion to an allergic disorder. 1255 of them were positive to at least one allergen component, and this group was subjected to statistical analysis.

Results

The sensitization to at least one mite-specific molecule (Der p 1, 2, Der f 1, 2) was observed relatively frequently in 32.7% of patients. Specific IgE to mite group 2 molecules is almost fully cross-reactive. Group 1 allergens are also cross-reactive, but in some patients, a species-specific response was observed. Relatively high rate of sensitization both to group 1 and 2 allergens in our patients indicates the greater role of co-sensitizations. Isolated sensitizations to molecules derived from glyciphagid mites Lep d 2 and/or Blo t 5 without sensitization to other mite-derived molecules were observed only exceptionally (in 0.6% of cases). True sensitization to at least one cockroach-specific molecule (Bla g 1, 2, 5) was very rare (in 0.6% of cases), and nearly all of them were co-sensitizations with other noncockroach-derived molecules. Sensitization to an inhaled tropomyosin was observed rarely in 2.2% of patients (Der p 10 in 1.9% and Bla g 7 in 1.5%). Co-sensitization of inhaled tropomyosins with the respective mite- or cockroach-specific molecules was observed only in the minority of patients suggesting the different route of sensitization being more frequent.

Conclusions

The majority of patients are co-sensitized to several molecules of the respective allergen source. The knowledge of this molecular spectrum of sensitization is important for optimal diagnosis and treatment in respect to allergen content in mite extracts used for diagnostic and therapeutic purposes. In regard to the sensitization patterns of Central European patients, it is necessary to point out the importance of quantifying at least three major mite components Der f 1, Der p 1 and Der f 2 (or Der p 2).

Debates in allergy medicine: Molecular allergy diagnosis with ISAC will replace screenings by skin prick test in the future

In today's clinical practice patients' skin is used as screening organ for diagnosing type 1 allergy. According to European guidelines skin prick testing with a panel of 18 allergen extracts is recommended, in the US between 10 to 50 allergens are used. The specificity and sensitivity of skin testing is individually highly variable depending on age, body mass, and skin barrier status. In atopic inflammation skin testing gives more false positive results. Smaller skin area and strain limits prick testing in small children. Although the risk for systemic reactions in skin prick testing is very small, emergency medications must be available. Considering the fact that IgE is the only reliable biomarker for type I allergy, upfront IgE screening with ISAC, followed by fewer skin tests to approve positive sensitizations, is proposed. It is time to arrive in the age of molecular allergy diagnosis in daily patient care.

Recombinant Allergens in Structural Biology, Diagnosis, and Immunotherapy

The years 1988-1995 witnessed the beginning of allergen cloning and the generation of recombinant allergens, which opened up new avenues for the diagnosis and research of human allergic diseases. Most crystal and solution structures of allergens have been obtained using recombinant allergens. Structural information on allergens allows insights into their evolutionary biology, illustrates clinically observed cross-reactivities, and makes the design of hypoallergenic derivatives for allergy vaccines possible. Recombinant allergens are widely used in molecule-based allergy diagnosis such as protein microarrays or suspension arrays. Recombinant technologies have been used to produce well-characterized, noncontaminated vaccine components with known biological activities including a variety of allergen derivatives with reduced IgE reactivity. Such recombinant hypoallergens as well as wild-type recombinant allergens have been used successfully in several immunotherapy trials for more than a decade to treat birch and grass pollen allergy. As a more recent application, the development of antibody repertoires directed against conformational epitopes during immunotherapy has been monitored by recombinant allergen chimeras. Although much progress has been made, the number and quality of recombinant allergens will undoubtedly increase and keep improving our knowledge in basic scientific investigations, diagnosis, and therapy of human allergic diseases.

Cross-sectional study on allergic sensitization of Austrian adolescents using molecule-based IgE profiling

BACKGROUND

Allergen-specific IgE antibodies are a hallmark of type I allergy. The aim of this cross-sectional study was to analyze the sensitization profiles of an Austrian adolescent population utilizing molecule-based IgE diagnosis.

METHODS

Serum samples of 501 nonselected pupils from Salzburg, Austria, were tested in ImmunoCAP ISAC^® for IgE reactivity to 112 single allergens. Sensitization profiles were assessed and statistically coordinated with reported allergies.

RESULTS

In the population aged 12-21 years, 53.5% showed IgE reactivity to at least one allergen tested. The highest prevalence was found for Phl p 1 from grass pollen (26.5%), group 2 mite allergens (18.2%), Bet v 1 from birch pollen (16.3%) and Fel d 1 from cat (14.4%). The majority of participants showed a complex sensitization profile and reacted on average to 9 allergens. Pollen sensitization was highly prevalent (41.7%) and mainly driven by group I grass and PR-10 allergens of the Betulaceae family, while Pla l 1 represented the most relevant weed. Diagnosed and self-reported allergies were noted in 21.9% and 45.5% of participants, respectively, and correlated well with in vitro results. Among atopic individuals, 71.4% reported to suffer from at least one allergy; concordance was found for grass and cat sensitization, while venom- and weed pollen-positive individuals were frequently asymptomatic.

CONCLUSIONS

More than half of the tested adolescent population had already established an atopic status presenting a complex IgE reactivity profile dominated by pollen sensitization. Detailed molecule-based analysis allows determining relevant biomarkers and monitoring of the atopic status in populations.

Performance evaluation of ImmunoCAP® ISAC 112: a multi-site study

BACKGROUND

After the re-introduction of ImmunoCAP® ISAC sIgE 112 on the market, we undertook a study to evaluate the performance of this multiplex-based immunoassay for IgE measurements to allergen components.

METHODS

The study was carried out at 22 European and one South African site. Microarrays from different batches, eight specific IgE (sIgE) positive, three sIgE negative serum samples and a calibration sample were sent to participating laboratories where assays were performed according to the manufacturer's instructions.

RESULTS

For both the negative and positive samples results were consistent between sites, with a very low frequency of false positive results (0.014%). A similar pattern of results for each of the samples was observed across the 23 sites. Homogeneity analysis of all measurements for each sample were well clustered, indicating good reproducibility; unsupervised hierarchical clustering and classification via random forests, showed clustering of identical samples independent of the assay site. Analysis of raw continuous data confirmed the good accuracy across the study sites; averaged standardized, site-specific ISU-E values fell close to the center of the distribution of measurements from all sites. After outlier filtering, variability across the whole study was estimated at 25.5%, with values of 22%, 27.1% and 22.4% for the 'Low', 'Moderate to High' and 'Very High' concentration categories, respectively.

CONCLUSIONS

The study shows a robust performance of the ImmunoCAP® ISAC 112 immunoassay at different sites. Essentially the same results were obtained irrespective of assay site, laboratory-specific conditions and instruments, operator, or the use of microarrays from different batches.

Multiplex component-based allergen microarray in recent clinical studies

During the last decades component-resolved diagnostics either as singleplex or multiplex measurements has been introduced into the field of clinical allergology, providing important information that cannot be obtained from extract-based tests. Here we review recent studies that demonstrate clinical applications of the multiplex microarray technique in the diagnosis and risk assessment of allergic patients, and its usefulness in studies of allergic diseases. The usefulness of ImmunoCAP ISAC has been validated in a wide spectrum of allergic diseases like asthma, allergic rhinoconjunctivitis, atopic dermatitis, eosinophilic esophagitis, food allergy and anaphylaxis. ISAC provides a broad picture of a patient's sensitization profile from a single test, and provides information on specific and cross-reactive sensitizations that facilitate diagnosis, risk assessment, and disease management. Furthermore, it can reveal unexpected sensitizations which may explain anaphylaxis previously categorized as idiopathic and also display for the moment clinically non-relevant sensitizations. ISAC can facilitate a better selection of relevant allergens for immunotherapy compared with extract testing. Microarray technique can visualize the allergic march and molecular spreading in the preclinical stages of allergic diseases, and may indicate that the likelihood of developing symptomatic allergy is associated with specific profiles of sensitization to allergen components. ISAC is shown to be a useful tool in routine allergy diagnostics due to its ability to improve risk assessment, to better select relevant allergens for immunotherapy as well as detecting unknown sensitization. Multiplex component testing is especially suitable for patients with complex symptomatology.

Pollen Allergens for Molecular Diagnosis

Pollen allergens are one of the main causes of type I allergies affecting up to 30% of the population in industrialized countries. Climatic changes affect the duration and intensity of pollen seasons and may together with pollution contribute to increased incidences of respiratory allergy and asthma. Allergenic grasses, trees, and weeds often present similar habitats and flowering periods compromising clinical anamnesis. Molecule-based approaches enable distinction between genuine sensitization and clinically mostly irrelevant IgE cross-reactivity due to, e. g., panallergens or carbohydrate determinants. In addition, sensitivity as well as specificity can be improved and lead to identification of the primary sensitizing source which is particularly beneficial regarding polysensitized patients. This review gives an overview on relevant pollen allergens and their usefulness in daily practice. Appropriate allergy diagnosis is directly influencing decisions for therapeutic interventions, and thus, reliable biomarkers are pivotal when considering allergen immunotherapy in the context of precision medicine.

An accelerated dose escalation with a grass pollen allergoid is safe and well-tolerated: a randomized open label phase II trial

Background

The number of injections in the dose escalation of subcutaneous immunotherapy (SCIT) is small for some currently used hypoallergenic allergoids, but can still be inconvenient to patients and can impair compliance. The aim of this trial was to compare safety and tolerability of an accelerated to the conventional dose escalation scheme of a grass pollen allergoid.

Methods

In an open label phase II trial, 122 patients were 1:1 randomized for SCIT using a grass pollen allergoid with an accelerated dose escalation comprising only 4 weekly injections (Group I) or a conventional dose escalation including 7 weekly injections (Group II). Safety determination included the occurrence of local and systemic adverse events. Tolerability was assessed by patients and physicians.

Results

Treatment-related adverse events were observed in 22 (36.1 %) patients in Group I and 15 (24.6 %) in Group II. Local reactions were reported by 18 patients in Group I and 11 in Group II. Five Grade 1 systemic reactions (WAO classification) were observed in Group I and 2 in Group II. Grade 2 reactions occurred 3 times in Group I and 2 times in Group II. Tolerability was rated as “good” or “very good” by 53 (86.9 %) patients in Group I and 59 (100 %) in Group II by investigators. Forty-eight patients in Group I (80.0 %) and 54 in Group II (91.5 %) rated tolerability as “good” or “very good”.

Conclusions

The dose escalation of a grass pollen allergoid can be accelerated with safety and tolerability profiles comparable to the conventional dose escalation.

Prevalence and Clinical Relevance of IgE Sensitization to Profilin in Childhood: A Multicenter Study

BACKGROUND

Little is known about the prevalence and clinical relevance of hypersensitivity to the plant panallergen profilin in children.

OBJECTIVES

The present study aimed to investigate prevalence, risk factors and clinical relevance of profilin sensitization in a large cohort of Italian children of different ages living in different geographic areas.

METHODS

Children with pollen allergy enrolled by 16 pediatric outpatient clinics sited in three main geographic areas of Italy were studied. SPT were carried out with commercial pollen extracts and a commercial purified date palm pollen profilin. IgE specific for allergenic pollen molecules, Phl p 12 (grass profilin) and Pru p 3 (peach lipid transfer protein) were tested by ImmunoCAP FEIA.

RESULTS

IgE to Phl p 12 (≥0.35 kU/l) was observed in 296 of the 1,271 participants (23%), including 17 of the 108 (16%) preschool children. Profilin SPT was positive (≥3 mm) in 320/1,271 (25%) participants. The two diagnostic methods were concordant in 1,151 (91%, p < 0.0001) cases. Phl p 12 IgE prevalence declined from northern to southern Italy and was directly associated with IgE to Phl p 1 and/or Phl p 5 and Ole e 1. Among children with IgE to Phl p 12, OAS was provoked by kiwi, melon, watermelon, banana, apricot and cucumber.

CONCLUSIONS

Profilin sensitization is very frequent among pollen-allergic children, occurs at a very young age and contributes to the development of childhood OAS with a typical pattern of offending foods. Pediatricians should always consider IgE sensitization to profilin while examining pollen-allergic children, even if they are at preschool age.

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.

HIV-Specific Antibody Responses in HIV-Infected Patients: From a Monoclonal to a Polyclonal View

HIV infections represent a major global health threat, affecting more than 35 million individuals worldwide. High infection rates and problems associated with lifelong antiretroviral treatment emphasize the need for the development of prophylactic and therapeutic immune intervention strategies. It is conceivable that insights for the design of new immunogens capable of eliciting protective immune responses may come from the analysis of HIV-specific antibody responses in infected patients. Using sophisticated technologies, several monoclonal neutralizing antibodies were isolated from HIV-infected individuals. However, the majority of polyclonal antibody responses found in infected patients are nonneutralizing. Comprehensive analyses of the molecular targets of HIV-specific antibody responses identified that during natural infection antibodies are mainly misdirected towards gp120 epitopes outside of the CD4-binding site and against regions and proteins that are not exposed on the surface of the virus. We therefore argue that vaccines aiming to induce protective responses should include engineered immunogens, which are capable of focusing the immune response towards protective epitopes.

Molecular evolution of hypoallergenic hybrid proteins for vaccination against grass pollen allergy

More than 10% of the population in Europe and North America suffer from IgE-associated allergy to grass pollen. In this article, we describe the development of a vaccine for grass pollen allergen-specific immunotherapy based on two recombinant hypoallergenic mosaic molecules, designated P and Q, which were constructed out of elements derived from the four major timothy grass pollen allergens: Phl p 1, Phl p 2, Phl p 5, and Phl p 6. Seventeen recombinant mosaic molecules were expressed and purified in Escherichia coli using synthetic genes, characterized regarding biochemical properties, structural fold, and IgE reactivity. We found that depending on the arrangement of allergen fragments, mosaic molecules with strongly varying IgE reactivity were obtained. Based on an extensive screening with sera and basophils from allergic patients, two hypoallergenic mosaic molecules, P and Q, incorporating the primary sequence elements of the four grass pollen allergens were identified. As shown by lymphoproliferation experiments, they contained allergen-specific T cell epitopes required for tolerance induction, and upon immunization of animals induced higher allergen-specific IgG Abs than the wild-type allergens and a registered monophosphoryl lipid A-adjuvanted vaccine based on natural grass pollen allergen extract. Moreover, IgG Abs induced by immunization with P and Q inhibited the binding of patients' IgE to natural allergens from five grasses better than IgG induced with the wild-type allergens or an extract-based vaccine. Our results suggest that vaccines based on the hypoallergenic grass pollen mosaics can be used for immunotherapy of grass pollen allergy.

Early childhood IgE reactivity to pathogenesis-related class 10 proteins predicts allergic rhinitis in adolescence

BACKGROUND

Component-resolved diagnosis might improve the prediction of future allergy in young children.

OBJECTIVE

We sought to investigate the association between IgE reactivity to the pathogenesis-related class 10 (PR-10) protein family and allergic rhinitis to birch pollen (ARbp) from early childhood up to age 16 years.

METHOD

Questionnaire data and sera obtained at 4, 8, and 16 years of age from the Barn/Children Allergi/Allergy Milieu Stockholm Epidemiologic (BAMSE) study birth cohort were used. Sera from 764 children were analyzed for IgE reactivity to 9 PR-10 allergen proteins at the 3 time points by using an allergen chip based on ISAC technology. ARbp was defined as upper airway symptoms during birch pollen exposure.

RESULTS

IgE reactivity to Bet v 1 was found in 12%, 17%, and 25% of children at 4, 8, and 16 years of age. IgE reactivity of PR-10 proteins showed a hierarchic intrarelationship: Bet v 1 > Mal d 1 > Cor a 1.04 > Ara h 8 > Pru p 1 > Aln g 1 > Api g 1 > Act d 8 > Gly m 4. There was an increased risk of incidence and persistence of ARbp up to age 16 years with increasing levels of Bet v 1-specific IgE or increasing numbers of IgE-reactive PR-10 proteins at 4 years. Children with severe ARbp at age 16 years had higher levels of Bet v 1-specific IgE at age 4 years compared with children with mild symptoms.

CONCLUSION

ARbp at age 16 years can be predicted by analysis of IgE reactivity to PR-10 proteins in early childhood.