Perspectives in allergen immunotherapy: 2019 and beyond

Safety of 300IR house dust mite sublingual tablet from pooled clinical trial and post-marketing data

Background

The 300IR house dust mite (HDM) sublingual immunotherapy (SLIT) tablet is approved for treatment of HDM-induced allergic rhinitis (AR). To provide a comprehensive review of the 300IR HDM-SLIT tablet safety profile based on randomized controlled trial (RCT) pooled data and post-marketing (PM) pharmacovigilance data.

Methods

Subjects (5-65 years) with confirmed HDM-AR with or without controlled asthma were treated with 300IR or placebo in 8 RCTs. Reported treatment-emergent adverse events (TEAEs) were pooled and analyzed descriptively in subsets of adults/adolescents and children. Adverse reactions (ADRs) collected from spontaneous reporting and PM studies through a pharmacovigilance system since the first marketing authorization were also analyzed.

Results

Across RCTs, 1853 subjects were treated with the 300IR HDM-SLIT tablet and 1846 with placebo. In both subsets of adults/adolescents and children whichever their asthma status, treatment-related TEAEs of higher incidence in active groups vs placebo were mostly consistent with mild or moderate local application-site reactions. They were mainly reported on the first days of treatment and decreased over time. 4 severe laryngopharyngeal reactions (2 requiring adrenaline/epinephrine) and 1 moderate eczema considered serious rapidly resolved with medications; no anaphylaxis was reported. In PM settings, ADRs reported in more than 235,000 patients were in line with RCT findings. Severe systemic reactions occurred rarely; 12 anaphylactic reactions resolved safely (5 with adrenaline). No new safety signal was raised.

Conclusion

Safety data from RCTs and more than 7 years of real-life experience confirmed the favorable safety profile of 300IR HDM-SLIT tablet in patients across different regions, regardless of age and asthma status.

Clinical trial registrations

NCT00674700; Retrospectively registered 06 May 2008.NCT01199133; Retrospectively registered 09 September 2010.NCT01527188; Retrospectively registered 01 February 2012.NCT02443805; Registered 29 April 2015/EudraCT 2014-004223-46; Registered 16 September 2015.jRCT2080221872/JapicCTI-121917; Registered 01 August 2012.jRCT2080222929/JapicCTI-15298; Registered 04 August 2015.

Progressive clinical effects of the combination omalizumab and HDM - allergen immunotherapy in asthma

OBJECTIVE

The combination of allergen immunotherapy (AIT) and omalizumab is used to treat patients at risk of anaphylaxis. There is currently a very little evidence that this combination increases the effectiveness of AIT in patients with inhalant allergies. The study aimed to evaluate the effectiveness of HDM-SCIT therapy (injection immunotherapy for house dust mites) in combination with omalizumab in treating HDM-induced asthma.

METHODS

This study was a placebo-controlled, randomized, multicenter trial including 82 patients with HDM-driven mild to moderate asthma. Omalizumab alone (A), HDM SCIT + omalizumab (B), SCIT alone (C), or placebo (D) for 24 months were applied. All patients received asthma treatment in accordance with GINA recommendations. The treatment efficacy was defined by a reduction in the daily dose of inhaled steroids (ICS) and a reduction in the number of asthma exacerbations (AX).

RESULTS

After 24 months of therapy, a statistically significant reduction in the daily doses of ICS in groups A and B was observed (p = 0.021 and p = 0.008). Daily ICS reduction was considerably more significant in group B (p = 0.01). During 24 months of observation, the AX was significantly reduced in all study groups, with the greatest significant difference observed between groups A and B and groups C and D (placebo) as follows: 0.42 patient/per year vs. 0.39 vs. 0.84 vs. 0.91 (p = 0.023).

CONCLUSION

The combination of HDM SCIT and omalizumab is significantly and progressively reducing ICS use and AX in a 24-month study. The combination is significantly more effective than the single treatments or placebo.

Genetically predicted N-methylhydroxyproline levels mediate the association between naive CD8+ T cells and allergic rhinitis: a mediation Mendelian randomization study

Background

Allergic rhinitis (AR), a prevalent chronic inflammatory condition triggered by immunoglobulin E (IgE), involves pivotal roles of immune and metabolic factors in its onset and progression. However, the intricacies and uncertainties in clinical research render current investigations into their interplay somewhat inadequate.

Objective

To elucidate the causal relationships between immune cells, metabolites, and AR, we conducted a mediation Mendelian randomization (MR) analysis.

Methods

Leveraging comprehensive publicly accessible summary-level data from genome-wide association studies (GWAS), this study employed the two-sample MR research method to investigate causal relationships among 731 immune cell phenotypes, 1400 metabolite levels, and AR. Additionally, employing the mediation MR approach, the study analyzed potential mediated effect of metabolites in the relationships between immune cells and AR. Various sensitivity analysis methods were systematically employed to ensure the robustness of the results.

Results

Following false discovery rate (FDR) correction, we identified three immune cell phenotypes as protective factors for AR: Naive CD8br %CD8br (odds ratio (OR): 0.978, 95% CI = 0.966-0.990, P = 4.5×10-4), CD3 on CD39+ activated Treg (OR: 0.947, 95% CI = 0.923-0.972, P = 3×10-5), HVEM on CD45RA- CD4+ (OR: 0.967, 95% CI = 0.948-0.986, P = 4×10-5). Additionally, three metabolite levels were identified as risk factors for AR: N-methylhydroxyproline levels (OR: 1.219, 95% CI = 1.104-1.346, P = 9×10-5), N-acetylneuraminate levels (OR: 1.133, 95% CI = 1.061-1.211, P = 1.7×10-4), 1-stearoyl-2-arachidonoyl-gpc (18:0/20:4) levels (OR: 1.058, 95% CI = 1.029-1.087, P = 5×10-5). Mediation MR analysis indicated a causal relationship between Naive CD8br %CD8br and N-methylhydroxyproline levels, acting as a protective factor (OR: 0.971, 95% CI = 0.950-0.992, P = 8.31×10-3). The mediated effect was -0.00574, accounting for 26.1% of the total effect, with a direct effect of -0.01626. Naive CD8+ T cells exert a protective effect on AR by reducing N-methylhydroxyproline levels.

Conclusion

Our study, delving into genetic information, has substantiated the intricate connection between immune cell phenotypes and metabolite levels with AR. This reveals a potential pathway to prevent the onset of AR, providing guiding directions for future clinical investigations.

Elevated aluminum excretion in patients by long-term subcutaneous immunotherapy - A cross-sectional case-control study

BACKGROUND

Aluminum (Al) adjuvants have been used in vaccines and subcutaneous immunotherapy (SCIT) for decades. Despite indisputable neurotoxic properties of Al, there is no clear evidence of a causal relationship between their use and any neurotoxic side effects. However, recent rat studies have shown an accumulation of Al from adjuvants in tissues, especially in bones.

OBJECTIVES

Since the human toxicokinetics of Al-adjuvants are poorly understood, this study aimed to evaluate whether up-dosed or long-term SCIT with Al-coupled extracts leads to increased Al load in humans.

METHODS

This observational cross-sectional case-control study explored Al excretion in hymenoptera venom allergy patients recruited in 2020 before initiation (n = 10) and during ongoing (n = 12) SCIT with Al-based preparations. Urine samples were collected before and 24 h after the SCIT injections and analyzed for aluminum content by using atomic absorption spectrometry. The cumulative administered Al dose was extracted from patient records. Patients receiving long-term immunotherapy were treated between 2.8 and 13.6 years (mean 7.1). Other potential sources of Al exposure were surveyed.

RESULTS

Patients who had received Al-coupled immunotherapy for several years showed significantly (p < 0.001) higher Al excretion than the controls at initiation of immunotherapy (mean 18.2 μg/gC vs. 7.9 μg/gC) and predominantly (73%) were above the 95th percentile of the general populations' exposure (>15 μg/gC), however, without reaching levels of toxicological concern (>50 μg/gC). Taking both groups together excreted Al levels correlated with the cumulative administered Al dose from SCIT (linear regression: Alurine = 8.258 + 0.133*Alcum; p = 0.001).

DISCUSSION

These results suggest a relevant iatrogenic contribution of long-term SCIT to human internal Al burden and potential accumulation. Considering the medical benefits of Al-adjuvants and SCIT a differentiated risk-benefit analysis is needed. For certain scenarios of potential toxicological concern in clinical practice biomonitoring might be advisable.

Safety of subcutaneous immunotherapy with Novo-Helisen-Depot in the children: a retrospective analysis from a single center in Northern China

Background

Little is known about the safety of mite extract product Novo-Helisen Depot (NHD) as subcutaneous immunotherapy (SCIT) in the children with mite allergy especially immediate/late local reaction (LRs).

Methods

We conducted a retrospective study analyzing the adverse events of the children undergoing subcutaneous immunotherapy with NHD. Adverse events included local and systemic adverse reactions (SRs) at the very early and late stage. The correlation of the basic characteristics, laboratory analysis results, LRs and SRs were analyzed.

Results

Two hundred and eighty-seven patients received at least 15 months of subcutaneous immunotherapy with NHD were included in the analysis. Skin-prick testing (SPT) results of D. pteronyssinus was associated with an increased risk of immediate LRs in build-up phase (OR = 1.53, 95% CI: 1.02, 2.37) and delayed LRs in maintenance phase (OR = 1.58, 95% CI: 1.05, 2.46), while SPT results of D. farinae was associated with an increased risk of SRs (OR = 3.22, 95% CI: 1.17, 10.00) and severe SRs (OR = 7.68, 95% CI: 1.13, 109.50). Serum IgE level of D. pteronyssinus was associated with an increased risk of SRs (OR = 1.01, 95% CI: 1.00, 1.03). Patients with both asthma and allergic rhinitis was associated with an increased risk of SR, and severe SRs (P < 0.05).

Conclusion

NHD as SCIT is safe. The children with higher SPT level with D. farinae or D. pteronyssinus, higher serum IgE level of D. pteronyssinus, children with both asthma and allergic rhinitis, and the children with treatment interruption had higher risk of adverse events.

Long-term effects of pollen allergoid tyrosine-adsorbed subcutaneous immunotherapy on allergic rhinitis and asthma

BACKGROUND

Allergen immunotherapy (AIT) may have a long-term disease-modifying effect. The aim of this study was to demonstrate the long-term effects of pollen allergoid tyrosine-adsorbed subcutaneous AIT on allergic rhinitis (AR) and asthma (AA) in clinical practice.

METHODS

This retrospective study, funded by an AIT manufacturer, analysed the impact of AIT on AR progression and onset of need for AA medication, using a German database covering ~35% of national prescriptions during 2008-2020. Anonymized prescription data of AR patients aged 5-65 years treated with grass or tree pollen AIT between 2009 and 2013 and followed for at least 2 years after AIT cessation were compared with matched control patients with seasonal AR.

RESULTS

181,496 patients received AIT prescriptions. 5959 fulfilled the inclusion criteria. The median AIT treatment duration was 1092 days and the follow-up duration was 6.4 years. Less patients treated with AIT received prescriptions for symptomatic AR medication in the follow-up versus controls (AIT: OR: 0.37; 95% Confidence Interval (CI) 0.34, 0.40; p < .001, tyrosine-adsorbed AIT: OR: 0.27; 95% CI 0.20, 0.35 p < .001). Less asthmatic patients under AIT received prescriptions for AA medications versus controls (AIT: OR: 0.48; 95% CI 0.41, 0.55; p < .001, tyrosine-adsorbed AIT: OR: 0.48; 95% CI 0.29, 0.79; p = .004). AR and AA medication prescriptions for AIT patients were reduced in the follow-up versus baseline and controls (AIT: AR: 20.0%; 1.5 vs. 0.2 prescriptions; AA: 29.1%; 2.0 vs. 0.6 prescriptions, p < .001; tyrosine-adsorbed AIT: AR: 24.2%, 1.4 vs. 0.2 prescriptions; AA: 35.6%, 2.1 vs. 0.6 prescriptions, p < .001). The probability of AA medication onset in non-asthmatic patients during follow-up was reduced for AIT patients compared to controls (OR: 0.77, 95% CI 0.66, 0.90; p = .001). All endpoints were significant for children/adolescents and adults in stratified analyses.

CONCLUSIONS

We found evidence for long-term effects up to 9.5 years for tyrosine-adsorbed AIT.

[Allergen-specific immunotherapy : A brief overview in association with allergic conjunctivitis]

Allergen-specific immunotherapy (AIT) is the only causal and disease-modifying treatment for immunoglobulin E (IgE)-mediated type I allergies. Regular exposure to the causative allergen results in an immunomodulatory effect by which the predominant T‑helper (Th) 2 lymphocyte response is shifted to a Th1 lymphocyte response and more allergen-specific blocking immunoglobulins are produced. The approval of substances for AIT is regulated by the Therapy Allergens Ordinance (TAV). There are subcutaneous and/or sublingual AITs for the following indications: allergic rhinitis, allergic conjunctivitis, allergic asthma and insect venom allergy. In this article the indications for allergic conjunctivitis are discussed in particular. Clinical symptoms and a relevant type 1 sensitization are the prerequisites for the indications for AIT. The assessment of the indications and carrying out an AIT should only be carried out by physicians who have been trained in allergology.

Effect of sublingual immunotherapy on clinical and laboratory autoimmunity

Background: There still are few data on the long-term safety of sublingual immunotherapy (SLIT). The aim of this study was to assess the appearance of autoimmune diseases in patients before and after SLIT. Materials & methods: New cases of autoimmune diseases were monitored. Patients in the SLIT group (n = 816) were compared with controls (n = 1096). Results: The new incidences of autoimmune diseases in the SLIT group were lower compared with the control group: 18 (2.2%) versus 58 (5.3%); p < 0.05. Systemic lupus erythematosus, psoriasis and Hashimoto appeared much more often in the control group. Conclusion: SLIT had no significant effect on the induction of autoimmune diseases.

Future Directions of Allergen Immunotherapy for Allergic Rhinitis: Experts' Perspective

Allergen immunotherapy (AIT) is broadly used all over the world as the only available disease-modifying treatment option. The aim of this experts' perspective is to address 7 important unmet needs for the further direction of AIT and to provide the readership with the authors' positions on these topics. An international group of experts in the field of AIT have formulated 7 important aspects for the future position of AIT, performed a current literature review, and proposed a consented position on these topics. The aspects discussed and consented by the authors include: (1) alternative routes of allergen application in AIT, (2) potential of recombinant vaccines, (3) the role of allergy diagnosis based on component-resolved diagnosis for AIT composition, (4) the impact of COVID-19 vaccination for further innovations in AIT, (5) potential of combining biologics to AIT, (6) future innovations in high-risk children/adolescents, and (7) the future regulatory position on AIT. Important unmet needs and topics for AIT have been addressed in this expert review. The authors' views and personal position on these 7 aspects have also been elaborated.

Clinical relevance of pre- and coseasonal sublingual immunotherapy with a 300 index of reactivity 5-grass SLIT tablet in allergic rhinoconjunctivitis

BACKGROUND

There is considerable interest in improving the scoring methods for evaluating the efficacy of allergen immunotherapy (AIT) and to show if this is associated with clinically meaningful results from the patient's perspective. We aimed to assess the efficacy and clinical relevance of a 300 index of reactivity (IR) 5-grass pollen sublingual immunotherapy (SLIT) tablet in children, adolescents and adults with moderate to severe grass-induced allergic rhinoconjunctivitis (ARC) with or without controlled asthma using the combined symptom and medication score CSMS0-36 .

METHODS

The data of the European population that participated in 3 Phase III, international, randomized double-blind placebo-controlled clinical trials were analyzed post hoc.

RESULTS

A total of 864 patients randomized to 300 IR 5-grass tablet or placebo were analyzed. Over the primary evaluation period, the difference in CSMS0-36 between the 300 IR and placebo groups was statistically significant (point estimates: -2.51, CI95% [-3.88; -1.14], p < 0.0001 in clinical trial1; -2.31, CI95% [-3.39; -1.23], p < 0.0001 in CT2; and -2.31, CI95% [-3.58; -1.03], p = 0.0004 in CT3). The relative differences between the 300 IR 5-grass tablet and placebo were -29.7%, -33.8%, and -26.3%, respectively. The results based on CSMS0-36 were consistent with those obtained with the primary endpoints of the trials and support the consideration of the 2-point threshold of the CSMS0-36 for clinical relevance of AIT.

CONCLUSION

Post hoc analysis of 3 CTs with the 300 IR 5-grass SLIT tablet confirmed its significant and clinically relevant effect in the European population with grass pollen-induced ARC with or without controlled asthma.

Exploring the potential and safety of quantum dots in allergy diagnostics

Biomedical investigations in nanotherapeutics and nanomedicine have recently intensified in pursuit of new therapies with improved efficacy. Quantum dots (QDs) are promising nanomaterials that possess a wide array of advantageous properties, including electronic properties, optical properties, and engineered biocompatibility under physiological conditions. Due to these characteristics, QDs are mainly used for biomedical labeling and theranostic (therapeutic-diagnostic) agents. QDs can be functionalized with ligands to facilitate their interaction with the immune system, specific IgE, and effector cell receptors. However, undesirable side effects such as hypersensitivity and toxicity may occur, requiring further assessment. This review systematically summarizes the potential uses of QDs in the allergy field. An overview of the definition and development of QDs is provided, along with the applications of QDs in allergy studies, including the detection of allergen-specific IgE (sIgE), food allergens, and sIgE in cellular tests. The potential treatment of allergies with QDs is also described, highlighting the toxicity and biocompatibility of these nanodevices. Finally, we discuss the current findings on the immunotoxicity of QDs. Several favorable points regarding the use of QDs for allergy diagnosis and treatment are noted.

Comparison of allergen immunotherapy practice patterns in inhalant allergies in the United States of America and Europe: Similarities and differences 2023

IgE-mediated atopic diseases such as allergic rhinitis and rhinoconjunctivitis are common chronic diseases in the western world. Allergen immunotherapy (AIT) plays a fundamental role in the treatment of allergic patients by modulating the underlying immune mechanisms. Though this treatment is integrated in practice-patterns globally, many differences are found in the application of AIT on the national or international level due to heterogeneous methods, and clinical recommendations are given in different parts of the world. This review from authors in Europe and the United States highlights differences and similarities in important aspects of AIT application in the 2 global regions. First, the regulatory situation differs regarding marketing authorization and licensing. Secondly, differences are elaborated in manufacturing practices, marketing distribution and formulations of AIT products. Thirdly, clinical administration patterns in the current guidelines show similarities in indications and contraindications of AIT, but also are divergent in some practical aspects. Informing the readership on similarities, as well as differences of standards in AIT in the United States and Europe, the authors highlight the unmet need of thorough harmonization of standards of AIT, as it is the only disease modifying treatment option available for patients with allergic rhinitis and rhinoconjunctivitis.

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.

Pathogenesis of allergic diseases and implications for therapeutic interventions

Allergic diseases such as allergic rhinitis (AR), allergic asthma (AAS), atopic dermatitis (AD), food allergy (FA), and eczema are systemic diseases caused by an impaired immune system. Accompanied by high recurrence rates, the steadily rising incidence rates of these diseases are attracting increasing attention. The pathogenesis of allergic diseases is complex and involves many factors, including maternal-fetal environment, living environment, genetics, epigenetics, and the body's immune status. The pathogenesis of allergic diseases exhibits a marked heterogeneity, with phenotype and endotype defining visible features and associated molecular mechanisms, respectively. With the rapid development of immunology, molecular biology, and biotechnology, many new biological drugs have been designed for the treatment of allergic diseases, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-5, and anti-thymic stromal lymphopoietin (TSLP)/IL-4, to control symptoms. For doctors and scientists, it is becoming more and more important to understand the influencing factors, pathogenesis, and treatment progress of allergic diseases. This review aimed to assess the epidemiology, pathogenesis, and therapeutic interventions of allergic diseases, including AR, AAS, AD, and FA. We hope to help doctors and scientists understand allergic diseases systematically.

Current advances in house dust mite allergen immunotherapy (AIT): Routes of administration, biomarkers and molecular allergen profiling

Allergy to house dust mites (HDM) is a perennial respiratory disease that affect more than half a billion people worldwide. Dermatophagoides pteronyssinus and D. farinae, two HDM species, are major sources of indoor allergens triggering allergic inflammation. Although symptomatic drugs are widely used to block the allergic reaction, allergen immunotherapy is the only curative treatment of IgE-mediated type I respiratory allergies. In this article, we review recent advances in various routes of allergen immunotherapy. We particularly focus on subcutaneous (SCIT) and sublingual (SLIT) immunotherapy, used as a reference therapy since they have transformed allergic treatments by improving symptoms (asthma and rhinitis) as well as the quality of life of patients. We also highlight recent data in more exploratory routes (i.e., oral, intralymphatic, epicutaneous and intradermal) and discuss respective advantages of various route, as well as their foreseen modes of action. Finally, we provide an update on biomarkers as well as on the relevance of the molecular profiling of allergic individuals related to treatment efficacy or asthma prediction.

Deciphering Differential Behavior of Immune Responses as the Foundation for Precision Dosing in Allergen Immunotherapy

Like in many fields of medicine, the concept of precision dosing has re-emerged in routine practice in allergology. Only one retrospective study on French physicians' practice has addressed this topic so far and generated preliminary data supporting dose adaptation, mainly based on experience, patient profile understanding and response to treatment. Both intrinsic and extrinsic factors shape the individual immune system response to allergen immunotherapy (AIT). Herein, we focus on key immune cells (i.e., dendritic cells, innate lymphoid cells, B and T cells, basophils and mast cells) involved in allergic disease and its resolution to further understand the effect of AIT on the phenotype, frequency or polarization of these cells. We strive to discriminate differences in immune responses between responders and non-responders to AIT, and discuss the eligibility of a non/low-responder subset for dose adaptation. A differential behavior in immune cells is clearly observed in responders, highlighting the importance of conducting clinical trials with large cohorts of well-characterized subjects to decipher the immune mechanism of AIT. We conclude that there is a need for designing new clinical and mechanistic studies to support the scientific rationale of dose adaptation in the interest of patients who do not properly respond to AIT.

Cationic liposomes bearing Bet v 1 by coiled coil-formation are hypo-allergenic and induce strong immunogenicity in mice

Although aluminum hydroxide (alum) is widely accepted and used as safe vaccine adjuvant, there is some concern about possible toxicity upon long-lasting repeated exposure during subcutaneous allergen immunotherapy (SCIT). Our objective was to evaluate allergen-bearing liposomes as possible alternative for alum-adsorption in SCIT. A self-assembling, coiled-coil forming peptide pair was used to anchor the major birch pollen allergen Bet v 1 to the surface of cationic liposomes. The resulting nanoparticulate liposomes were characterized with respect to their physicochemical, allergenic and immunological properties. Allergenicity was studied by ImmunoCAP inhibition and rat basophil leukemia (RBL) cell assays. Immunogenicity (immunoglobulin responses) and immune skewing (cytokine responses) were evaluated upon immunization of naïve mice, and compared to alum-adsorbed Bet v 1. Bet v 1-bearing cationic liposomes with a diameter of ∼200 nm showed a positive zeta potential. The coiled-coil conjugation of Bet v 1 to the surface of liposomes resulted in about a 15-fold lower allergenicity than soluble Bet v 1 as judged by RBL assays. Moreover, the nanoparticles induced Bet v 1-specific IgG1/IgG2a responses in mice that were several orders of magnitude higher than those induced by alum-adsorbed Bet v 1. This strong humoral response was accompanied by a relatively strong IL-10 induction upon PBMC stimulation with Bet v 1. In conclusion, their hypo-allergenic properties, combined with their capacity to induce a strong humoral immune response and a relatively strong IL-10 production, makes these allergen-covered cationic liposomes a promising alternative for aluminum salt-adsorption of allergen currently used in SCIT.

Application of Extracellular Vesicles in Allergic Rhinitis: A Systematic Review

The pathophysiology of allergic rhinitis (AR), one of the most common diseases in the world, is still not sufficiently understood. Extracellular vesicles (EVs), which are secreted by host and bacteria cells and take part in near and distant intracellular communication, can provide information about AR. Recently, attention has been drawn to the potential use of EVs as biomarkers, vaccines, or transporters for drug delivery. In this review, we present an up-to-date literature overview on EVs in AR to reveal their potential clinical significance in this condition. A comprehensive and systematic literature search was conducted following PRISMA statement guidelines for original, completed articles, available in English concerning EVs and AR. For this purpose, PubMed/MEDLINE, Scopus, Web of Science, and Cochrane, were searched up until 10 Novenmber 2022. From 275 records, 18 articles were included for analysis. The risk of bias was assessed for all studies as low or moderate risk of overall bias using the Office and Health Assessment and Translation Risk of Bias Rating Tool for Human and Animal Studies. We presented the role of exosomes in the pathophysiology of AR and highlighted the possibility of using exosomes as biomarkers and treatment in this disease.

Diagnosis and treatment of adult asthma patients in Serbia: a 2022 experts group position statement

INTRODUCTION

Asthma is the most common non-communicable chronic lung condition across all ages. Epidemiological data indicate that many asthma patients in Serbia remain undiagnosed and untreated. The implementation of recent global advances in asthma management is limited due to the lack of a systematic approach, drug availability and regulatory affairs. In addition, the global coronavirus disease pandemic has posed a significant challenge, particularly in resource-limited settings.

AREAS COVERED

In this paper, we propose an algorithm for treating adult asthma patients in Serbia. We performed PubMed database search on published asthma clinical trials and guidelines from 1 January 2015 to 10 March 2020. The consensus process incorporated a modified Delphi method that included two rounds of e-mail questionnaires and three rounds of national asthma expert meetings. We focus on 1) objective diagnosis of asthma, 2) the implementation of up-to-date therapeutic options, and 3) the identification and referral of severe asthma patients to newly established severe asthma centers.

EXPERT OPINION

Regional specificities and variations in healthcare systems require the adaptation of evidence-based knowledge. Practical, clinically oriented algorithms designed to overcome local barriers in healthcare delivery may facilitate timely and adequate asthma diagnosis and the local implementation of current advances in asthma management.

Subcutaneous birch pollen allergen immunotherapy with a depigmented polymerized extract shows only sustained and long-term efficacy in a subgroup of monosensitized adults and adolescents with allergic rhinitis

Background

Allergen immunotherapy (AIT) is an approved treatment for seasonal respiratory allergic diseases. A depigmented polymerized birch pollen extract for subcutaneous allergen immunotherapy (SCIT) has been demonstrated to be efficacious and safe in patients allergic to birch pollen and its homologous group.

Objective

To determine whether SCIT with a birch pollen formulation (5000 depigmented polymerized (DPP) units/mL) shows sustained and long‐term efficacy in adults and adolescents with birch‐pollen induced allergic rhinitis with or without intermittent asthma.

Methods

A multicentre (n = 66), double‐blind, placebo‐controlled Phase III clinical trial was performed in the Czech Republic, Finland, Germany, Latvia, Lithuania, Poland and Russia. Participants were randomized 2:1 to active treatment (birch 5000 DPP/ml) or placebo for three years of SCIT and followed up for two treatment‐free years. The primary efficacy endpoint was the EAACI's combined symptom and medication score for rhinoconjunctivitis (CSMS_EAACI).

Results

A total of 973 participants were screened and 649 were randomized (active treatment: n = 434; placebo: n = 215). The intention‐to‐treat analysis of the CSMS_EAACI in the overall study population did not demonstrate statistically significant differences in years 1, 2 and 3. In a post‐hoc analysis, among the subgroup of patients monosensitized to birch pollen allergen only (n = 200), we observed a statistically significant difference (active treatment vs. placebo) in the CSMS_EAACI in year 2, 3 and 5. The AIT's safety profile was good.

Conclusions

SCIT with a depigmented polymerized birch pollen extract was safe. Sustained and long‐term efficacy in years 2, 3 and 5 in monosensitized patients, but not in polysensitized patients was demonstrated.

(EudraCT 2012‐000414‐11)

Correlation of the combined symptom and medication score with quality of life, symptom severity and symptom control in allergic rhinoconjunctivitis

Background

The European Academy of Allergy and Clinical Immunology recommended the Combined Symptom and Medication Score (CSMS) as primary endpoint in clinical trials on allergen‐specific immunotherapy (AIT) in allergic rhinoconjunctivitis. Here, the correlation between the CSMS and the validated standardised Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ(S)), Rhinitis Control Assessment Test (RCAT) and Visual Analogue Scale (VAS) was analysed.

Methods

Two prospective, multicentre, non‐interventional studies on tree pollen, grass pollen and house dust mite allergic patients were performed. The first study comprised 167 patients receiving AIT (AIT population), and the second included 56 patients treated with symptomatic medication only (control population). For up to two seasons (pollen)/exposure periods (house dust mites), participants documented their symptoms and medication intake in a CSMS diary, including VAS. In addition, the standardised RQLQ(S) and the RCAT were completed during study visits.

Results

Comparison between CSMS and RQLQ(S) revealed a positive correlation in the AIT population (r = 0.426) and in the control population (r = 0.569). For CSMS and RCAT, a negative correlation with r = −0.409 (AIT) and r = −0.547 (control) was shown. Positive correlation between CSMS and VAS was also demonstrated with r = 0.585 (AIT) and r = 0.563 (control).

Conclusion

These results support the assumption that the CSMS correlates with quality of life, symptom severity and symptom control on the one hand, while the moderate strength of correlations on the other hand mirrors distinctions of the CSMS compared to the assessments used here.

First-in-human phase 2 trial with mite allergoids coupled to mannan in subcutaneous and sublingual immunotherapy

BACKGROUND

Polymerized allergens conjugated to non-oxidized mannan (PM-allergoids) are novel vaccines targeting dendritic cells (DCs). Previous experimental data indicate that PM-allergoids are readily taken up by DCs and induce Treg cells. This first-in-human study was aimed to evaluate safety and to find the optimal dose of house dust mite PM-allergoid (PM-HDM) administered subcutaneously (SC) or sublingually (SL).

METHODS

In a randomized, double-blind, double-dummy, placebo-controlled trial, 196 subjects received placebo or PM-HDM at 500, 1000, 3000, or 5000 mannan-conjugated therapeutic units (mTU)/mL in 9-arm groups for 4 months. All subjects received 5 SC doses (0.5 ml each) every 30 days plus 0.2 ml SL daily. The primary efficacy outcome was the improvement of titrated nasal provocation tests (NPT) with D. pteronyssinus at baseline and at the end of the study. All adverse events and reactions were recorded and assessed. Secondary outcomes were the combination of symptom and medication scores (CSMS) and serological markers.

RESULTS

No moderate or severe adverse reactions were reported. Subjects improving the NPT after treatment ranged from 45% to 62% in active SC, 44% to 61% in active SL and 16% in placebo groups. Statistical differences between placebo and active groups were all significant above 500 mTU, being the highest with 3000 mTU SL (p = 0.004) and 5000 mTU SC (p = 0.011). CSMS improvement over placebo reached 70% (p < 0.001) in active 3000 mTU SC and 40% (p = 0.015) in 5000 mTU SL groups.

CONCLUSIONS

PM-HDM immunotherapy was safe and successful in achieving primary and secondary clinical outcomes in SC and SL at either 3000 or 5000 mTU/ml.

Single-cell immunoprofiling after immunotherapy for allergic rhinitis reveals functional suppression of pathogenic Th2 cells and clonal conversion

BACKGROUND

Allergic rhinitis is a growing problem worldwide. Currently, the only treatment that can modify the disease is antigen-specific immunotherapy; however, its mechanism(s) of action is not fully understood.

OBJECTIVE

To comprehensively investigate the role and changes of antigen-specific T cells before and after sublingual immunotherapy (SLIT) for Japanese cedar pollinosis (JCP).

METHODS

We cultured PBMCs obtained both before and at 1 year after initiating SLIT and used a combination of single-cell RNA sequence and repertoire sequencing. To investigate biomarkers, we used PBMCs from patients participating a phase II/III trial of SLIT tablets for JCP and PBMCs from good and poor responders in outpatients.

RESULTS

Antigen-stimulated culturing after SLIT led to clonal expansion of Th2 and Treg cells, and most of these CD4⁺ T cells retained their CDR3 regions before and after treatment, indicating antigen-specific clonal responses and differentiation secondary to SLIT. However, SLIT reduced the number of clonal functional Th2 cells but increased the Trans-type Th2 cell population that expresses musculin (MSC), TGF-β, and IL-2. Trajectory analysis suggested that SLIT induced clonal differentiation of the Trans-type Th2 cells differentiated into Treg cells. Using real-time PCR, we found that the MSC levels increased in the active SLIT group and good responders after 1 year of treatment.

CONCLUSION

The combination of single-cell RNA sequencing and repertoire analysis helped reveal a part of the underlying mechanism-that SLIT promotes the expression of MSC on pathogenic Th2 cells and suppresses their function; MSC may be a potential biomarker of SLIT for allergic rhinitis.

Long-term efficacy of the sublingual and subcutaneous routes in allergen immunotherapy

Allergen immunotherapy is highly effective in selected patients with allergic rhinitis, allergic asthma, and Hymenoptera venom allergy. Unlike anti-allergic drugs, both subcutaneous and sublingual immunotherapies have been shown to modify the underlying cause of the disease, with proved long-term clinical benefits after treatment cessation. In this review, we analyzed 10 randomized, double-blind, placebo controlled clinical trials of allergen immunotherapy that included blinded follow-up for at least 1 year after treatment withdrawal. Three studies of pollen subcutaneous immunotherapy provided evidence that a sustained, tolerogenic effect of subcutaneous immunotherapy can be achieved after 3 years of treatment. Six trials of sublingual immunotherapy provided robust evidence for long-term clinical benefit and persistent immunologic changes after grass pollen, house-dust mite, or Japanese cedar immunotherapy, whereas a clinical trial of both sublingual and subcutaneous grass pollen immunotherapies showed that 2 years of immunotherapy were efficacious but insufficient to induce long-term tolerance. These studies strongly supported international guidelines that recommend at least 3 years of allergen immunotherapy of proven value to achieve disease modification and sustained clinical and immunologic tolerance.

Subcutaneous allergen immunotherapy in the treatment of allergic respiratory disease

Subcutaneous immunotherapy is recognized as a cornerstone in the management of allergic respiratory disease in patients who are properly characterized with allergy and with allergic rhinoconjunctivis and/or well-controlled asthma, and who are willing to adhere to the rigorous treatment program. A key tenet is that it affords the opportunity to effect long-term clinical remission through its disease-modifying properties. Furthermore, it has the potential to prevent the progression of allergic rhinitis to asthma, prevent new allergen sensitivities, and improve a patient's quality of life.

A three-stage design for allergen immunotherapy trials

BACKGROUND

Clinical trials of allergen immunotherapy (AIT) may require up to 5 years to complete. These lengthy trials may be complicated by high and potentially differential dropouts, especially among participants who perceive that they are receiving placebo. We propose a three-stage design in which the placebo group in Stage 1 crosses over to receive active treatment in Stage 2. In Stage 3, AIT is discontinued to determine whether benefit is maintained post-treatment. We apply inferential statistics to support the three-stage design for clinical trials to determine clinical efficacy, treatment response over time, and sustained response to AIT.

METHODS

The proposed framework constitutes a series of hypothesis tests for comparing treatment responses at the end of each stage. A simulation study was performed to illustrate the statistical properties under varying statistical missing mechanisms and effect sizes.

RESULTS

The statistical properties in terms of bias and statistical power were consistent with what are expected from conventional analyses. Specifically, the extent of bias depended on the missing mechanism and magnitude. The statistical powers were largely driven by effect and sample sizes as well as prespecified success margins. As an illustration, assuming relative treatment differences of 25% and stagewise dropout rate of 15%, a sample size of 200 per group may achieve 93% power to demonstrate a treatment effect and 60% power to demonstrate a maintained response post-treatment.

CONCLUSIONS

Inferential statistics support our proposed study design for evaluating benefits of AIT over time and inform clinical understanding and decisions.

Coordinated IgG2 and IgE responses as a marker of allergen immunotherapy efficacy

BACKGROUND

IgG2 responses are associated with repeated antigen exposure and display highly mutated variable domains. A recent study highlighted a role of IgG2+ memory B cells and allergen-specific IgG2 levels after a 3rd consecutive pre-seasonal sublingual allergen immunotherapy (AIT) with grass pollen tablet. Herein, we aim to explore changes in allergen-specific IgG2 in individuals undergoing house dust mite immunotherapy (HDM-AIT) and explore whether the interrelationship with other humoral responses (i.e., IgG4 and IgE) may discriminate between high and low responders.

METHODS

Levels of serum Dermatophagoides pteronyssinus and Dermatophagoides farinae-specific IgG2, IgG4, and IgE antibodies were measured by ELISA or ImmunoCap in a sub-group of individuals enrolled in a randomized, double-blind, placebo-controlled, sublingual AIT study evaluating the safety and efficacy of a 300 IR HDM tablet.

RESULTS

After 1-year sublingual AIT, HDM-specific serum IgG2 responses increase mostly in high versus low responders and are distinctive according to the clinical benefit. Higher correlation between HDM-specific IgG2, IgE, and/or IgG4 responses is seen in subjects benefiting the most from HDM-AIT as indicated by changes in Average Total Combined Scores. More strikingly, statistically significant correlation between HDM-specific IgG2 and IgE responses is only observed in individuals stratified as high responders.

CONCLUSIONS

We provide evidence for coordinated serum immune responses upon AIT in HDM-allergic subjects exhibiting high clinical benefit when compared with low responders. Assessing HDM-specific IgE, IgG2, and IgG4 in serum could be used as follow-up combined markers to support decision as to AIT continuation and/or adaptation.

Update on the use of allergen challenge chambers in immunotherapy: clinical implications

PURPOSE OF REVIEW

This review aims to reflect on and discuss recent evidence of applicability of allergen exposure chambers (AEC) for allergen immunotherapy studies, especially focussing on validation of AECs, technical documentation and future perspectives.

RECENT FINDINGS

Publications covered by this review summarize the historical background, current status of research use and validation of AEC systems. It describes identified unmet needs regarding comparability of AEC systems, reproducibility of clinical assessments and correlation of AEC-induced symptoms with scores under natural environmental exposure. Furthermore, new information on technical specifications, for example, dimensions, allergen dispersal and validation procedures is highlighted and future activities of the EAACI AEC task force group regarding harmonization of clinical endpoints are delineated.

SUMMARY

AECs are in use for evaluation of allergic patients for over three decades now. As different systems largely vary regarding technical set up and standard assessments, detailed technical documentation must be available. To gain acceptance of regulatory authorities for pivotal immunotherapy trials conducted with the use of AEC system, harmonization of clinical assessments as well as documentation of correlation of clinical AEC outcomes with environmental exposure clinical scores is required.

Allergen immunotherapy during the COVID-19 pandemic-A survey of the German Society for Allergy and Clinical Immunology

Background

When the coronavirus pandemic 2019 (COVID‐19) emerged, concerns were also raised regarding the safety of allergen immunotherapy (AIT). The German Society for Allergology and Clinical Immunology (DGAKI) conducted a survey to collect real‐world data on the daily routine of administering subcutaneous AIT (SCIT) and sublingual AIT (SLIT) during the COVID‐19 pandemic.

Methods

A web‐based retrospective survey using the online platform survio with 26 standardized questions was used to survey physicians treating allergic patients during the pandemic.

Results

Three hundred and forty‐five physicians who regularly offer and perform AIT in German‐speaking countries responded to the questions. 70.4% of the respondents stated that they regularly initiated and dosed up SCIT for inhalant allergies (41.4% venom‐SCIT, 73.6% SLIT), and 85.2% of the respondents stated that they continued SCIT for inhalant allergies during the maintenance phase in a regular way (59.1% venom‐SCIT, 90.4% SLIT) in healthy patients without current symptoms indicating an infection with COVID‐19. With regard to tolerability, there was no evidence for increased occurrence of adverse events in patients without current symptoms of COVID‐19 infection during the pandemic.

Conclusions

This retrospective study demonstrated adherence to national and international position papers of AIT during the COVID‐19 pandemic in German‐speaking countries. Besides, the survey has confirmed a good tolerability of AIT for both SCIT and SLIT.

Allergen immunotherapy in MASK-air users in real-life: Results of a Bayesian mixed-effects model

Background

Evidence regarding the effectiveness of allergen immunotherapy (AIT) on allergic rhinitis has been provided mostly by randomised controlled trials, with little data from real‐life studies.

Objective

To compare the reported control of allergic rhinitis symptoms in three groups of users of the MASK‐air^® app: those receiving sublingual AIT (SLIT), those receiving subcutaneous AIT (SCIT), and those receiving no AIT.

Methods

We assessed the MASK‐air^® data of European users with self‐reported grass pollen allergy, comparing the data reported by patients receiving SLIT, SCIT and no AIT. Outcome variables included the daily impact of allergy symptoms globally and on work (measured by visual analogue scales—VASs), and a combined symptom‐medication score (CSMS). We applied Bayesian mixed‐effects models, with clustering by patient, country and pollen season.

Results

We analysed a total of 42,756 days from 1,093 grass allergy patients, including 18,479 days of users under AIT. Compared to no AIT, SCIT was associated with similar VAS levels and CSMS. Compared to no AIT, SLIT‐tablet was associated with lower values of VAS global allergy symptoms (average difference = 7.5 units out of 100; 95% credible interval [95%CrI] = −12.1;−2.8), lower VAS Work (average difference = 5.0; 95%CrI = −8.5;−1.5), and a lower CSMS (average difference = 3.7; 95%CrI = −9.3;2.2). When compared to SCIT, SLIT‐tablet was associated with lower VAS global allergy symptoms (average difference = 10.2; 95%CrI = −17.2;−2.8), lower VAS Work (average difference = 7.8; 95%CrI = −15.1;0.2), and a lower CSMS (average difference = 9.3; 95%CrI = −18.5;0.2).

Conclusion

In patients with grass pollen allergy, SLIT‐tablet, when compared to no AIT and to SCIT, is associated with lower reported symptom severity. Future longitudinal studies following internationally‐harmonised standards for performing and reporting real‐world data in AIT are needed to better understand its ‘real‐world’ effectiveness.

One hundred and ten years of Allergen Immunotherapy: A journey from empiric observation to evidence

One hundred and ten years after Noon's first clinical report of the subcutaneous application of allergen extracts, allergen immunotherapy (AIT) has evolved as the most important pillar of the treatment of allergic patients. It is the only disease-modifying treatment option available and the evidence for its clinical efficacy and safety is broad and undisputed. Throughout recent decades, more insights into the underlying mechanisms, in particular the modulation of innate and adaptive immune responses, have been described. AIT is acknowledged by worldwide regulatory authorities, and following the regulatory guidelines for product development, AIT products are subject to a rigorous evaluation before obtaining market authorization. Knowledge and practice are anchored in international guidelines, such as the recently published series of the European Academy of Allergy and Clinical Immunology (EAACI). Innovative approaches continue to be further developed with the focus on clinical improvement by, for example, the usage of adjuvants, peptides, recombinants, modification of allergens, new routes of administration, and the concomitant use of biologicals. In addition, real-life data provide complementary and valuable information on the effectiveness and tolerability of this treatment option in the clinical routine. New mobile health technologies and big-data approaches will improve daily treatment convenience, adherence, and efficacy of AIT. However, the current coronavirus disease 2019 (COVID-19) pandemic has also had some implications for the feasibility and practicability of AIT. Taken together, AIT as the only disease-modifying therapy in allergic diseases has been broadly investigated over the past 110 years laying the path for innovations and further improvement.

Bet v 1-displaying elastin-like polypeptide nanoparticles induce a strong humoral and weak CD4+ T-cell response against Bet v 1 in a murine immunogenicity model

There is growing concern about the toxicity of colloidal aluminum salts used as adjuvants in subcutaneous allergen immunotherapy (SCIT). Therefore, alternative adjuvants and delivery systems are being explored to replace alum in SCIT. We applied micellar elastin-like polypeptides (ELPs), a type of self-assembling protein, to replace alum as vaccine adjuvant in birch pollen SCIT. ELP and an ELP-Bet v 1 fusion protein were expressed in E. coli and purified by immuno-affinity chromatography and inverse-transition cycling (ITC). Nanoparticles self-assembled from ELP and a 9:1 ELP/ELP-Bet v 1 mixture were characterized by using dynamic light scattering and atomic force microscopy. Allergenicity was assessed by measuring mediator release from rat basophilic leukemia cells transformed with the human FcϵR1 and sensitized with sera derived from human birch pollen allergic patients. Humoral and T-cell immunity were investigated by immunizing naïve mice with the ELP/ELP-Bet v 1 nanoparticles or alum-adsorbed Bet v 1, both containing 36 µg Bet v 1. ELP and ELP/ELP-Bet v 1 self-assembled at 37°C into spherically shaped micelles with a diameter of ~45 nm. ELP conjugation made Bet v 1 hypo-allergenic (10-fold). Compared to alum-adsorbed Bet v 1, ELP/ELP-Bet v 1 nanoparticles induced stronger IgG responses with an earlier onset. Additionally, ELP/ELP-Bet v 1 did not induce Th2 skewing cytokines and IgE. The hypoallergenic character and strong humoral immune response in the absence of a Th2-skewing T-cell response make ELP-based nanoparticles a promising candidate to replace alum in SCIT.

Development and validation of combined symptom-medication scores for allergic rhinitis

BACKGROUND

Validated combined symptom-medication scores (CSMSs) are needed to investigate the effects of allergic rhinitis treatments. This study aimed to use real-life data from the MASK-air^® app to generate and validate hypothesis- and data-driven CSMSs.

METHODS

We used MASK-air^® data to assess the concurrent validity, test-retest reliability and responsiveness of one hypothesis-driven CSMS (modified CSMS: mCSMS), one mixed hypothesis- and data-driven score (mixed score), and several data-driven CSMSs. The latter were generated with MASK-air^® data following cluster analysis and regression models or factor analysis. These CSMSs were compared with scales measuring (i) the impact of rhinitis on work productivity (visual analogue scale [VAS] of work of MASK-air^® , and Work Productivity and Activity Impairment: Allergy Specific [WPAI-AS]), (ii) quality-of-life (EQ-5D VAS) and (iii) control of allergic diseases (Control of Allergic Rhinitis and Asthma Test [CARAT]).

RESULTS

We assessed 317,176 days of MASK-air^® use from 17,780 users aged 16-90 years, in 25 countries. The mCSMS and the factor analyses-based CSMSs displayed poorer validity and responsiveness compared to the remaining CSMSs. The latter displayed moderate-to-strong correlations with the tested comparators, high test-retest reliability and moderate-to-large responsiveness. Among data-driven CSMSs, a better performance was observed for cluster analyses-based CSMSs. High accuracy (capacity of discriminating different levels of rhinitis control) was observed for the latter (AUC-ROC = 0.904) and for the mixed CSMS (AUC-ROC = 0.820).

CONCLUSION

The mixed CSMS and the cluster-based CSMSs presented medium-high validity, reliability and accuracy, rendering them as candidates for primary endpoints in future rhinitis trials.

Nonpharmacological measures to prevent allergic symptoms in pollen allergy: A critical review

Allergic rhinoconjunctivitis (hay fever) is the most common chronic disease in all industrialized nations. Therapy consists essentially in the use of anti-allergic and anti-inflammatory drugs, which mostly show a good and quick effect. With allergen-specific immunotherapy, there is also a causal possibility of tolerance induction. There is currently a considerable undersupply, as those affected trivialize the symptoms and often have concerns about long-term drug therapy. There is also great interest in using non-medicinal measures to prevent and/or relieve allergic symptoms on the assumption that these are free from side effects. In this publication, we present non-drug methods for which clinical studies are available in the literature. The methods have varying degrees of effectiveness. An evidence-based comparative assessment between the methods is not possible. There are also hardly any studies in comparison to standard drug therapy. A large number of the interventions consist of allergen reduction, e.g., with air filters, or cleaning of the mucous membranes with nasal irrigation, etc., none of which should be seen as a substitute but as a supplement to drug therapy.

Technical standards in allergen exposure chambers worldwide - an EAACI Task Force Report

Allergen exposure chambers (AECs) can be used for controlled exposure to allergenic and non-allergenic airborne particles in an enclosed environment, in order to (i) characterize the pathological features of respiratory diseases and (ii) contribute to and accelerate the clinical development of pharmacological treatments and allergen immunotherapy for allergic disease of the respiratory tract (such as allergic rhinitis, allergic rhinoconjunctivitis, and allergic asthma). In the guidelines of the European Medicines Agency for the clinical development of products for allergen immunotherapy (AIT), the role of AECs in determining primary endpoints in dose-finding Phase II trials is emphasized. Although methodologically insulated from the variability of natural pollen exposure, chamber models remain confined to supporting secondary, rather than primary, endpoints in Phase III registration trials. The need for further validation in comparison with field exposure is clearly mandated. On this basis, the European Academy of Allergy and Clinical Immunology (EAACI) initiated a Task Force in 2015 charged to gain a better understanding of how AECs can generate knowledge about respiratory allergies and can contribute to the clinical development of treatments. Researchers working with AECs worldwide were asked to provide technical information in eight sections: (i) dimensions and structure of the AEC, (ii) AEC staff, (iii) airflow, air processing, and operating conditions, (iv) particle dispersal, (v) pollen/particle counting, (vi) safety and non-contamination measures, (vii) procedures for symptom assessments, (viii) tested allergens/substances and validation procedures. On this basis, a minimal set of technical requirements for AECs applied to the field of allergology is proposed.

Absolute quantification of Bet v 1 in birch polymerized allergenic extracts via mass spectrometry-targeted analysis

BACKGROUND

Quantifying major allergens is essential for evaluating the quality and efficacy of allergenic extracts. They are usually measured in non-polymerized extracts using immunoassays. However, the direct measurement of allergens in allergoids is currently not supported. This study set out to develop a method for quantifying Bet v 1 in polymerized birch extracts using mass spectrometry-based targeted analysis.

METHODS

Three isotopically labelled peptide sequences of Bet v 1 were synthetized and used as internal standards for the development of a mass spectrometry-based targeted analysis. The calibration curves of the three peptides to assess the linearity and limit of detection, as well as reverse calibration curves with a constant amount of sample, were constructed. The Bet v 1 content was determined and measured in 18 batches of depigmented (native extracts purified by a mild acid treatment) and depigmented-polymerized extracts.

RESULTS

Bet v 1 isoforms were identified in both type of extracts by mass spectrometry. According to mass spectrometry-targeted analysis depigmented and depigmented-polymerized extracts exhibited mean values of 70.5 and 73.5 µg Bet v 1/mg of lyophilized extract, respectively. A statistically significant correlation between the allergen content of both extracts was identified. Statistically significant differences were observed when the Bet v 1 content in non-polymerized extracts was measured via mass spectrometry (70.5 ± 11.6 µg/mg) or immunoassay (83.7 ± 19.8 µg/mg).

CONCLUSIONS

These results represent the first direct quantification of Bet v 1 in allergoids using mass spectrometry-based targeted analysis. The proposed method demonstrates robustness and reliability and constitutes a promising alternative for detailed characterization of polymerized allergenic extracts.

Bridging micro/nano-platform and airway allergy intervention

Allergic airway diseases, with incidence augmenting visibly as industrial development and environmental degradation, are characterized by sneezing, itching, wheezing, chest tightness, airway obstruction, and hyperresponsiveness. Current medical modalities attempt to combat these symptoms mostly by small molecule chemotherapeutants, such as corticosteroids, antihistamines, etc., via intranasal approach which is one of the most noninvasive, rapid-absorbed, and patient-friendly routes. Nevertheless, inherent defects for irritation to respiratory mucosa, drug inactivation and degradation, and rapid drug dispersal to off-target sites are inevitable. Lately, intratracheal micro/nano therapeutic systems are emerging as innovative alternatives for airway allergy interventions. This overview introduces several potential application directions of mic/nano-platform in the treatment of airway allergic diseases, including carriers, therapeutic agents, and immunomodulators. The improvement of the existing drug therapy of respiratory allergy management by micro/nano-platform is described in detail. The challenges of the micro/nano-platform nasal approach in the treatment of airway allergy are summarized and the development of micro/nano-platform is also prospected. Although still a burgeoning area, micro/nano therapeutic systems are gradually turning to be realistic orientations as crucial future alternative therapeutic options in allergic airway inflammation interventions.

Immunotherapy With Recombinant Alt a 1 Suppresses Allergic Asthma and Influences T Follicular Cells and Regulatory B Cells in Mice

Background

Alternaria is a major source of asthma-inducing allergens. Allergen-specific immunotherapy improves the progression of allergic asthma. The current treatment is based on crude Alternaria extracts. Alt a 1 is the predominant allergen in Alternaria. However, the treatment efficacy of recombinant Alt a 1 (rAlt a 1) in an asthmatic animal model and its influence on Tfh and Breg cells are unknown.

Objective

To explore the therapeutic treatment effects of rAlt a 1 on the progress of an asthmatic mouse model and its effect on Tfh and Breg cells.

Methods

We synthesized and purified rAlt a 1. Alternaria-sensitized and challenged mice received subcutaneous immunotherapy (SCIT) with four different rAlt a 1 dosages (5, 50, 100, and 150 µg) or PBS only. Finally, lung and airway inflammation, mouse mast cell protease 1 (MMCP-1), serum immunoglobulin responses, Tfh and Breg cell levels, and the correlation between asthmatic features (inflammation grades and IL-4 and IL-10 levels) and these two cell types were measured after Alternaria rechallenge.

Results

High purity and allergenic potency of rAlt a 1 protein were obtained. Following treatment with four different rAlt a 1 dosages, both lung and airway inflammation ameliorated, including lung pathology, serum MMCP-1 levels, inflammatory cell numbers, and cytokine levels in bronchoalveolar lavage fluid (BALF). Additionally, rAlt a 1-SCIT increased the expression of Alternaria-sIgG1, rAlt a 1-sIgG1, rAlt a 1-sIgG2a, and rAlt a 1-sIgG2b in serum. Moreover, the number and percentage of CXCR5⁺PD-1⁺Tfh cells were increased in the PC control, while they decreased in the rAlt a 1-SCIT groups. Meanwhile, the absolute numbers and proportions of Breg cells were evaluated after administration of rAlt a 1. A positive correlation was observed between CXCR5⁺PD-1⁺Tfh cells and inflammation grades (r = 0.50, p = 0.01), as well as a slightly strong positive relationship with IL-4 (r = 0.55, p = 0.005) and IL-10 (r = 0.58, p = 0.003) levels; Breg cells showed an opposite correlation with the grades of inflammation (r = -0.68, p = 0.0003), along with a negative correlation to IL-4 (r = -0.61, p = 0.001) and IL-10 (r = -0.53, p = 0.008) levels.

Conclusions

We verified that treatment with rAlt a 1 can alleviate asthma progression and further have a regulatory effect on Tfh and Breg cells in an Alternaria-induced asthmatic mouse model.

Advances and highlights in allergic rhinitis

Allergic rhinitis (AR) is a growing public health, medical and economic problem worldwide. The current review describes the major discoveries related to AR during the past 2 years, including risk factors for the prevalence of AR, the corresponding diagnostic strategy, precise underlying immunological mechanisms, and efficient therapies for AR during the ongoing global "coronavirus disease 2019" (COVID-19) pandemic. The review further attempts to highlight future research perspectives. Increasing evidence suggests that environmental exposures, climate changes, and lifestyle are important risk factors for AR. Consequently, detailed investigation of the exposome and the connection between environmental exposures and health in the future should provide better risk profiles instead of single predictors, and also help mitigate adverse health outcomes in allergic diseases. Although patients with dual AR, a newly defined AR phenotype, display perennial and seasonal allergens-related nasal symptoms, they are only allergic to seasonal allergens, indicating the importance of measuring inflammation at the local sites. Herein, we suggest that a combination of precise diagnosis in local sites and traditional diagnostic methods may enhance the precision medicine-based approach for management of AR; however, this awaits further investigations. Apart from traditional treatments, social distancing, washing hands, and disinfection are also required to better manage AR patients in the ongoing global COVID-19 pandemic. Despite recent advances in understanding the immune mechanisms underlying the effects of allergen immunotherapy (AIT), further understanding changes of cell profiles after AIT and accurately evaluate the efficacy of AIT are required.

COVID-19 pandemic and allergen immunotherapy-an EAACI survey

BACKGROUND

As in many fields of medical care, the coronavirus disease 2019 (COVID-19) resulted in an increased uncertainty regarding the safety of allergen immunotherapy (AIT). Therefore, the European Academy of Allergy and Clinical Immunology (EAACI) aimed to analyze the situation in different countries and to systematically collect all information available regarding tolerability and possible amendments in daily practice of sublingual AIT (SLIT), subcutaneous AIT (SCIT) for inhalant allergies and venom AIT.

METHODS

Under the framework of the EAACI, a panel of experts in the field of AIT coordinated by the Immunotherapy Interest Group set-up a web-based retrospective survey (SurveyMonkey^® ) including 27 standardized questions on practical and safety aspects on AIT in worldwide clinical routine.

RESULTS

417 respondents providing AIT to their patients in daily routine answered the survey. For patients (without any current symptoms to suspect COVID-19), 60% of the respondents informed of not having initiated SCIT (40% venom AIT, 35% SLIT) whereas for the maintenance phase of AIT, SCIT was performed by 75% of the respondents (74% venom AIT, 89% SLIT). No tolerability concern arises from this preliminary analysis. 16 physicians reported having performed AIT despite (early) symptoms of COVID-19 and/or a positive test result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

CONCLUSIONS

This first international retrospective survey in atopic diseases investigated practical aspects and tolerability of AIT during the COVID-19 pandemic and gave no concerns regarding reduced tolerability under real-life circumstances. However, the data indicate an undertreatment of AIT, which may be temporary, but could have a long-lasting negative impact on the clinical care of allergic patients.

Role of nanostructures in allergy: Diagnostics, treatments and safety

Nanotechnology is science, engineering and technology conducted at the nanoscale, which is about 1-100 nm. It has led to the development of nanomaterials, which behave very differently from materials with larger scales and can have a wide range of applications in biomedicine. The physical and chemical properties of materials of such small compounds depend mainly on the size, shape, composition and functionalization of the system. Nanoparticles, carbon nanotubes, liposomes, polymers, dendrimers and nanogels, among others, can be nanoengineeried for controlling all parameters, including their functionalization with ligands, which provide the desired interaction with the immunological system, that is dendritic cell receptors to activate and/or modulate the response, as well as specific IgE, or effector cell receptors. However, undesired issues related to toxicity and hypersensitivity responses can also happen and would need evaluation. There are wide panels of accessible structures, and controlling their physico-chemical properties would permit obtaining safer and more efficient compounds for clinical applications goals, either in diagnosis or treatment. The application of dendrimeric antigens, nanoallergens and nanoparticles in allergy diagnosis is very promising since it can improve sensitivity by increasing specific IgE binding, mimicking carrier proteins or enhancing signal detection. Additionally, in the case of immunotherapy, glycodendrimers, liposomes, polymers and nanoparticles have shown interest, behaving as platforms of allergenic structures, adjuvants or protectors of allergen from degradation or having a depot capacity. Taken together, the application of nanotechnology to allergy shows promising facts facing important goals related to the improvement of diagnosis as well as specific immunotherapy.

Plasma-derived extracellular vesicles discriminate type-1 allergy subjects from non-allergic controls

Background

Allergies are on the rise globally, with an enormous impact on affected individuals’ quality of life as well as health care resources. They cause a wide range of symptoms, from slightly inconvenient to potentially fatal immune reactions. While allergies have been described and classified phenomenologically, there is an unmet need for easily accessible biomarkers to stratify the severity of clinical symptoms. Furthermore, biomarkers marking the success of specific immunotherapy are urgently needed.

Objectives

Plasma extracellular vesicles (pEV) play a role in coordinating the immune response and may be useful future biomarkers. A pilot study on differences in pEV content was carried out between patients with type I allergy, suffering from rhinoconjunctivitis with or without asthma, and voluntary non-allergic donors.

Methods

We examined pEV from 38 individuals (22 patients with allergies and 16 controls) for 38 chemokines, cytokines, and soluble factors using high-throughput data mining approaches.

Results

Patients with allergies had a distinct biomarker pattern, with 7 upregulated (TNF-alpha, IL-4, IL-5, IL-6, IL-17F, CCL2, and CCL17) and 3 downregulated immune mediators (IL-11, IL-27, and CCL20) in pEV compared to controls. This reduced set of 10 factors was able to discriminate controls and allergic patients better than the total array.

Conclusions

The content of pEV showed potential as a target for biomarker research in allergies. Plasma EV, which are readily measurable via blood test, may come to play an important role in allergy diagnosis. In this proof-of-principle study, it could be shown that pEV's discriminate patients with allergies from controls. Further studies investigating whether the content of pEVs may predict the severity of allergic symptoms or even the induction of tolerance to allergens are needed.

Dogmas, challenges, and promises in phase III allergen immunotherapy studies

The concept of treatment of an allergy with the offending allergen was introduced more than a century ago. Allergen immunotherapy (AIT) is the only disease modifying treatment of allergic diseases caused by inhalational allergens and insect venoms. Despite this, only few AIT products have reached licensure in the US or an official marketing authorization status in European countries. Moreover, most of these AIT products are provided on an individual patient basis as named patient products (NPP) in Europe, while individualized preparations of (mixed) allergenic extract vials for subcutaneous administration (compounding) is common practice in the US. AIT products are generally considered safe and well tolerated, but the major practical clinical development challenge is to define the optimal dose and prove the efficacy and safety of these products using state-of-the art Phase II and pivotal Phase III studies. In planning Phase II-III AIT studies, a thorough understanding of the study challenges is essential (e.g. variability and non-validated status of subjective primary endpoints, limitations of pollen season definitions) and dogmas of these products (e.g., for sublingual immunotherapy (SLIT) trials double-blinding conditions cannot be maintained, resulting in stronger placebo responses in the active treatment group and inflated treatment effects in Phase III). There is future promise for more objective biomarker endpoints (e.g. basophil activation (CD63 and CD203c), subsets of regulatory dendritic, T and B cells, IL-10–producing group 2 innate lymphoid cells; alone or in combination) to overcome several of these dogmas and challenges; innovation in AIT clinical trials can only progress with integral biomarker research to complement the traditional endpoints in Phase II-III clinical development. The aim of this paper is to provide an overview of these dogmas, challenges and recommendations based on published data, to facilitate the design of Phase III studies and improve the evidence basis of safe and effective AIT products.

Alternaria as an Inducer of Allergic Sensitization

Alternaria alternata is a saprophytic mold whose spores are disseminated in warm dry air, the typical weather of the Mediterranean climate region (from 30° to 45°), with a peak during the late summer and early autumn. Alternaria spores are known to be biological contaminants and a potent source of aeroallergens. One consequence of human exposure to Alternaria is an increased risk of developing asthma, with Alt a 1 as its main elicitor and a marker of primary sensitization. Although the action mechanism needs further investigation, a key role of the epithelium in cytokine production, TLR-activated alveolar macrophages and innate lymphoid cells in the adaptive response was demonstrated. Furthermore, sensitization to A. alternata seems to be a trigger for the development of co-sensitization to other allergen sources and may act as an exacerbator of symptoms and an elicitor of food allergies. The prevalence of A. alternata allergy is increasing and has led to expanding research on the role of this fungal species in the induction of IgE-mediated respiratory diseases. Indeed, recent research has allowed new perspectives to be considered in the assessment of exposure and diagnosis of fungi-induced allergies, although more studies are needed for the standardization of immunotherapy formulations.

Molecular allergology approach to allergic asthma

Allergic asthma is a frequently encountered and well described asthma phenotype. However, its precise mechanisms are less known. The tools for targeted selection of patients for an optimal response to intervention (prevention or treatment) are also lacking. Here we explore the potential of the molecular allergology approach to achieve a better understanding of allergic asthma mechanisms, a precise diagnosis and an optimal management of these patients.

Allergen immunotherapy against house dust mites in patients with local allergic rhinitis and asthma

METHODS

The study was a prospective, double-blind, placebo-controlled trial with patients diagnosed with LAR to HDMs and with concomitant asthma who underwent a 12-month treatment course of SLIT for HDM allergies. Seventeen patients were randomized to SLIT with the use of allergen extracts of D. pteronyssinus and D. farinae (50/50%) in SQ-HDM SLIT tablets and 15 patients were randomized to the placebo group. The total rhinitis score (TRSS), total asthma symptom score (TASS), combined total symptom score (TSS), total medication score (TMS), and FEV1 were analyzed.Results: In the final analysis, 16 patients who received SLIT and 14 who received placebo who completed the study protocol were included. Significant reductions in TRSS, TASS, TSS, and TMS after 12 months of treatment were observed in patients after SLIT (p < 0.05). A significant increase in the mean FEV1 between baseline and after 12 months of therapy was observed in the study, with p = 0.03 in the study group. Conclusion: SLIT can improve nasal and bronchial symptoms and reduce symptomatic treatment in patients with LAR and asthma and with hyperresponsiveness to HDMs.