International Consensus on Allergen Immunotherapy II: Mechanisms, standardization, and pharmacoeconomics

[Recombinant allergens, peptides, and virus-like particles for allergy immunotherapy]

Currently, extract-based therapeutic allergens from natural allergen sources (e.g., house dust mites, tree and grass pollen) are used for allergen-specific immunotherapy (AIT), the only causative therapy that can exhibit positive disease-modifying effects by tolerance induction and prevention of disease progression. Due to variations in the natural composition of the starting materials and different manufacturing processes, there are variations in protein content, allergen composition, and allergenic activity of similar products, which poses specific challenges for their standardization. The identification of the nucleotide sequences of allergenic proteins led to the development of molecular AIT approaches. This allows for the application of exclusively relevant structures as chemically synthesized peptides, recombinant single allergens, or molecules with hypoallergenic properties that potentially allow for an up-dosing with higher allergen-doses without allergic side effects leading more quickly to effective cumulative doses. Further modifications of AIT preparations to improve allergenic and immunogenic properties may be achieved, e.g., by including the use of virus-like particles (VLPs). To date, the herein described therapeutic approaches have been tested in clinical trials only. This article provides an overview of published molecular approaches for allergy treatment used in clinical AIT studies. Their added value and challenges compared to established therapeutic allergens are discussed. The aim of these approaches is to develop highly effective and well-tolerated AIT preparations with improved patient acceptance and adherence.

Intradermal Phleum pratense allergoid immunotherapy. Double-blind, randomized, placebo-controlled trial

Background

In allergology, the intradermal approach is generally used to establish an aetiological diagnosis, with limited experience in specific allergen immunotherapy.

Objective

To evaluate the efficacy and safety of immunotherapy with an allergen extract of glutaraldehyde‐polymerized Phleum pratense, administered intradermally, in patients with rhinoconjunctivitis sensitized to grass pollen.

Methods

Multicentre, randomized, double‐blind, placebo‐controlled clinical trial in patients from 12 to 65 years of age with rhinitis or rhinoconjunctivitis, with or without asthma, due to grass pollen allergy. Patients were divided into three groups and received a total of six doses in a weekly interval, of either placebo; 0.03 or 0.06 μg of protein per dose of P pratense allergoid. The primary objective was to evaluate the combined symptoms and medication consumption score (CSMS). The secondary objectives were symptoms and medication, tolerance to the conjunctival provocation test, specific IgE and IgG4 antibodies and the safety profile according to the WAO scale.

Results

The dose of 0.06 μg of protein proved to be effective versus the placebo by significantly reducing CSMS and increasing tolerance to the allergenic extract in the conjunctival provocation test, after the first pollen season. This group showed a significant reduction in specific IgE after the second pollen season relative to the baseline. There were no variations in IgG4 levels. Only one grade 2 systemic reaction was recorded.

Conclusion & Clinical Relevance

Intradermal immunotherapy with P pratense allergoid has been shown to be effective and safe, reducing CSMS, increasing tolerance to the conjunctival provocation test and reducing IgE levels.

Use of Sublingual Immunotherapy for Aeroallergens in Children with Asthma

Asthma is a heterogeneous disease that in children is often allergen-driven with a type 2 inflammation. Sublingual immunotherapy represents an important progress in the use of personalized medicine in children with allergic asthma. It is a viable option for house dust mite-driven asthma and in subjects with the asthma associated with allergic rhinitis. The use and indications for isolated asthma caused by other allergens are still controversial owing to heterogeneity of commercially available products and methodological limitations of studies in children. Nevertheless, most studies and meta-analyses found the efficacy of sublingual immunotherapy. Sublingual immunotherapy is safe but cannot be recommended in children with uncontrolled asthma.

[Allergic immunotherapy in children and adolescents]

L’immunothérapie spécifique allergénique nécessite l’administration répétée d’allergènes dans le but de provoquer une tolérance clinique et immunologique. C’est la seule thérapeutique à visée étiologique qui permet de modifier l’évolution de la maladie en assurant une rémission après l’interruption de la procédure. La prévention de nouvelles sensibilisations par l’immunothérapie reste discutée. Nous envisagerons dans cette revue les principaux mécanismes immunologiques et les indications de l’immunothérapie chez l’enfant et l’adolescent.

A 300 IR sublingual tablet is an effective, safe treatment for house dust mite-induced allergic rhinitis: An international, double-blind, placebo-controlled, randomized phase III clinical trial

BACKGROUND

Allergic rhinitis induced by house dust mites (HDMs) is a highly prevalent but often underdiagnosed and undertreated/untreated chronic disease. It often has a negative impact on sleep, work, leisure activities, and health-related quality of life. Allergen immunotherapy is a proven, safe treatment for respiratory allergies.

OBJECTIVE

We sought to assess the efficacy and safety of a 300 index of reactivity (IR) sublingual tablet formulation of Dermatophagoides pteronyssinus:Dermatophagoides farinae 1:1 extract in adolescents (aged ≥12) and adults with moderate to severe HDM-induced allergic rhinitis.

METHODS

In a phase III, international, double-blind, placebo-controlled, randomized clinical trial, participants received approximately 12 months of treatment with placebo or the 300 IR tablet. The primary end point was the average total combined score during 4 weeks at the end of the treatment period.

RESULTS

A total of 1607 participants were randomized, and 1476 (including 555 [37.6%] with concomitant mild controlled asthma at inclusion) comprised the full analysis set. Over the primary evaluation period, the least squares mean average total combined score in the 300 IR group (3.62) was significantly lower (P < .0001) than in the placebo group (4.35), with a relative least squares mean difference of -16.9% (95% CI, -24.0% to -9.2%). All prespecified secondary end points were consistently improved in the 300 IR group, relative to placebo. The 300 IR tablet was generally well tolerated. Treatment-related adverse events (mainly mild or moderate local reactions) were reported for 51.0% of the patients in the 300 IR group and 14.9% in the placebo group.

CONCLUSIONS

The 300 IR sublingual HDM tablet is an effective, safe treatment for HDM-induced allergic rhinitis.

[Study on expression and mechanism of serum differential proteins after rush immunotherapy of allergic rhinitis]

Objective:To detect the expression of differentially expressed proteins in serum of patients with allergic rhinitis who were allergic to dust mites before and after 6-day rush immunotherapy. The three differentially expressed proteins, CRP, CTHRC1 and WDR89, were detected and identified. The immunoregulatory effects and significance of these three differentially expressed proteins in rush immunotherapy of allergic rhinitis were analyzed and discussed. Method:The serum samples of 15 patients with allergic rhinitis, 15 patients with rush immunotherapy and 10 patients with healthy control group were collected. The samples were studied by isobaric tags for relative and absolute quantitation（iTRAQ） technique. The related differential proteins were determined by two-dimensional gel electrophoresis and mass spectrometry, and the rationality of the screened differential proteins was tested and verified by Cluster3.0 software and Java TreeView software. Finally, the selected CRP, CTHRC1 and WDR89 proteins were identified by enzyme-linked immunosorbent assay（ELISA）. Result:In this study, 893 proteins were detected and 53 differential proteins were identified. Compared with healthy control group, 24 proteins which was statistically significant were found in allergic rhinitis group, which were closely related to the occurrence of allergic rhinitis, including 10 up-regulated proteins and 14 down-regulated proteins. Compared with the allergic rhinitis group, patients with allergic rhinitis underwent 6 days of rush immunotherapy. There were 29 proteins whose expression of proteins with a difference of P value of less than 0.05 and 1.2 times higher, which were related to the effect after the incremental phase of rush immunotherapy was completed, of which 12 were up-regulated and 17 were down-regulated. Compared with healthy control group, the expression of up-regulated of allergic rhinitis group and the expression of down-regulated protein after 6 days of rush immunotherapy were CTHRC1, WDR89; Compared with healthy control group, AR group was down-regulated and the expression of up-regulated protein after 6 days of rush immunotherapy was CRP. CRP, CTHRC1 and WDR89 proteins were identified by enzyme linked immunosorbent assay（ELISA）, and it was found that the differential expression of CTHRC1 and WDR89 in AR and RIT was statistically significant（P<0.05）, but the differential expression of serum CRP in AR and RIT was not statistically significant（P>0.05）. Conclusion:Serum protein CTHRC1 and WDR89 are closely related to the pathogenesis of allergic rhinitis, and played a role in the regulation of rush immunotherapy, while serum protein CRP has no significant effect on AR and RIT.

Association between biomarkers and house dust mite sublingual immunotherapy in allergic asthma

BACKGROUND

House dust mite (HDM) sublingual immunotherapy (SLIT) has demonstrated efficacy in clinical trials of patients with asthma. Airway inflammation is a characteristic of respiratory allergy, but its relationship to SLIT remains unclear.

OBJECTIVE

We evaluate the association between clinical outcomes with pulmonary function and biomarkers in before and after HDM SLIT (UMIN Number 000022390).

METHODS

One hundred twelve patients with asthma sensitized to HDM were randomized to add-on 6 standardized quality (SQ)-HDM SLIT to pharmacotherapy or pharmacotherapy alone for 48 weeks. At baseline and end of study, biomarkers, blood eosinophils, serum IgE, serum periostin, fractional exhaled nitric oxide (FeNO), and spirometry and clinical symptoms were measured. Association between biomarkers and an increase in FEV₁ of 120 mL or greater were analysed.

RESULTS

Sublingual immunotherapy (SLIT) demonstrated a significant reduction of serum periostin (P < .001), FeNO (P < .01), and increase in HDM-specific IgE (P < .05), FEV₁ (P < .001) and improvement of clinical symptom scores, when compared to pharmacotherapy. The change in FEV₁ correlated with the changes in serum periostin (r = .696, P < .001) and the changes in FeNO (r = .682, P < .001). The independent predictor of improvement in airflow limitation was changed in serum periostin (r²  = .753, P = .013) and FeNO (P = .038). Based on cut-off values derived by receiver operating characteristic analysis (periostin 30.9 ng/mL, FeNO 28.0 ppb), patients were distinguished responders from non-responders, but with no predictive value for blood eosinophils or total IgE. The proportion of patients with both high periostin and FeNO levels was significantly higher in responder than in non-responder (P = .026).

CONCLUSIONS AND CLINICAL RELEVANCE

Adding HDM SLIT to pharmacotherapy resulted in reduced serum periostin and FeNO, and improved pulmonary function. Serum periostin and FeNO may be useful biomarkers for prediction of SLIT.

Sublingual Versus Subcutaneous Immunotherapy for Allergic Rhinitis: What Are the Important Therapeutic and Real-World Considerations?

PURPOSE OF REVIEW

Allergen immunotherapy has been used for over 100 years in the treatment of allergic rhinitis. With two major options for administering this disease-modifying therapy, SCIT, and SLIT, what is our current understanding of the efficacy and safety of each one? How do we determine who is the appropriate candidate for each one in the real world?

RECENT FINDINGS

SCIT and SLIT show significant improvement in clinical symptoms and need for medication in the treatment of allergic rhinitis. In recent meta-analyses, there is no significant difference in the efficacy between the two treatments, but SLIT has more local side effects though less systemic ones. Shared decision-making should be instituted to determine which treatment should be started in a patient with allergic rhinitis. This review provides up-to-date information on the efficacy and safety of SCIT vs SLIT in the care of children and adults with allergic rhinitis in the real world and the role of shared decision-making in the use of these modalities.

TRIAL REGISTRATIONS

Clinicaltrials.gov: NCT04145219 and NCT02478398.

Production of allergen-specific immunotherapeutic agents for the treatment of food allergy

Allergen-specific immunotherapy (IT) is emerging as a viable avenue for the treatment of food allergies. Clinical trials currently investigate raw or slightly processed foods as therapeutic agents, as trials using food-grade agents can be performed without the strict regulations to which conventional drugs are subjected. However, this limits the ability of standardization and may affect clinical trial outcomes and reproducibility. Herein, we provide an overview of methods used in the production of immunotherapeutic agents for the treatment of food allergies, including processed foods, allergen extracts, recombinant allergens, and synthetic peptides, as well as the physical and chemical processes for the reduction of protein allergenicity. Commercial interests currently favor producing standardized drug-grade allergen extracts for therapeutic use, and clinical trials are ongoing. In the near future, recombinant production could replace purification strategies since it allows the manufacturing of pure, native allergens or sequence-modified allergens with reduced allergenicity. A recurring issue within this field is the inadequate reporting of production procedures, quality control, product physicochemical characteristics, allergenicity, and immunological properties. This information is of vital importance in assessing therapeutic standardization and clinical safety profile, which are central parameters for the development of future therapeutic agents.

Allergen Immunotherapy in Pediatric Asthma: A Pragmatic Point of View

To date, the only disease-modifying treatment strategy for allergic rhinitis and asthma is allergen immunotherapy (AIT). There is evidence that AIT improves allergic rhinitis and asthma, such as reducing symptom severity and medication use and improving of quality of life, with a long-lasting effect after the end of the course. The recent clinical trials evidenced AIT effectiveness and safety in allergic asthma. Consequently, the current version of the GINA (Global Initiative for Asthma) guidelines recommend AIT as an add-on therapy for asthma. There is also evidence that AIT may exert preventive activity on the possible progression from allergic rhinitis to asthma in children and the onset of new sensitizations. The present review provides a pragmatic summary of the clinical indications of AIT in pediatric asthma, including the immunological mechanisms, the predictive biomarkers, and the safety issues in clinical practice.

Allergen immunotherapy in the current COVID-19 pandemic: A position paper of AeDA, ARIA, EAACI, DGAKI and GPA: Position paper of the German ARIA GroupA in cooperation with the Austrian ARIA GroupB, the Swiss ARIA GroupC, German Society for Applied Allergology (AEDA)D, German Society for Allergology and Clinical Immunology (DGAKI)E, Society for Pediatric Allergology (GPA)F in cooperation with AG Clinical Immunology, Allergology and Environmental Medicine of the DGHNO-KHCG and the European Academy of Allergy and Clinical Immunology (EAACI)H

No abstract available.

Nanoparticle-based immunotherapy: state of the art and future perspectives

INTRODUCTION

For several years now, medicine has been benefiting from the contribution of nanoparticles (NPs) technology for both diagnosis and therapy. They can be used as adjuvants, being capable per se of immune-modulating activity, or as carriers for molecules to be transported to a specific target, eventually loaded with specific ligands favoring specific uptake.

AREAS COVERED

The review focuses on experimental use of NPs as adjuvants/carriers for allergen immunotherapy (AIT). Human clinical trials conducted so far are discussed.

EXPERT OPINION

Results of experimental studies and recent clinical trials support the use of NPs as carrier/adjuvant in AIT. Comparisons between NP-based and classical AIT are needed, to show the usefulness of the NP-based approach. However, there are still unsolved problems: the persistence of non-degradable NPs with possible toxicological consequences, and the formation of the protein corona around the NPs, which could alter their activity and fate. Virus-like particles seem the most promising NPs for allergy treatment, as for other vaccines. Over the next decade, NP-based AIT will be largely used to treat allergic disorders.

EAACI Allergen Immunotherapy User's Guide

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

Clinical trials in allergen immunotherapy in the age group of children and adolescents: current concepts and future needs

Allergen immunotherapy (AIT) is the only treatment option available for allergic patients with disease-modifying intention. Both efficacy and safety has been demonstrated for multiple trials in children, adolescents and adults. Though regulatory requirements for marketing authorization have been clearly outlined and an increasing number of high quality trials has been initiated, multiple concepts and details in study design may be further elaborated, harmonized and improved. An international group of experts in the field of AIT has thoroughly reviewed and discussed current concepts and provided an outlook on further improvement especially in the age group of children and adolescents. Emphasis of the group's discussion as a basis for this article was put on (i) the regulatory background of marketing authorization of AIT products including the 'Pediatric Investigational Plan', (ii) patient reported outcomes and endpoints in AIT trials, (iii) considerations regarding the 'minimal clinically important difference', (iv) the role of placebo effects in AIT clinical trials and clinical routine and (v) the potential of mobile Health for future development of AIT. Current concepts in AIT have been optimized throughout the recent decades, but there remains room for improvement e.g., in the topics outlined in this article.

Immunotherapy in allergic diseases - improved understanding and innovation for enhanced effectiveness

Allergen immunotherapy leads to tolerance through multiple mechanisms that include tolerogenic dendritic cells and T and B regulatory cells. These induced cellular populations produce mediators to skew the immune response to a tolerogenic milieu that, among others, results in IgG4 blocking antibodies formation and lowered FcE receptors. All lead in decreased effector responses from mast cells, eosinophils, and basophils thus limiting the allergic inflammation. Clinically, this results in better allergic rhinitis control and, of importance, asthma prevention. Newer approaches include modified allergens, second generation adjuvants/carriers and routes of administration, all aiming to increased efficacy with parallel no compromise of safety.

State-of-the-art in marketed adjuvants and formulations in Allergen Immunotherapy: A position paper of the European Academy of Allergy and Clinical Immunology (EAACI)

Since the introduction of allergen immunotherapy (AIT) over 100 years ago, focus has been on standardization of allergen extracts, with reliable molecular composition of allergens receiving the highest attention. While adjuvants play a major role in European AIT, they have been less well studied. In this Position Paper, we summarize current unmet needs of adjuvants in AIT citing current evidence. Four adjuvants are used in products marketed in Europe: aluminium hydroxide (Al(OH)₃ ) is the most frequently used adjuvant, with microcrystalline tyrosine (MCT), monophosphoryl lipid A (MPLA) and calcium phosphate (CaP) used less frequently. Recent studies on humans, and using mouse models, have characterized in part the mechanisms of action of adjuvants on pre-existing immune responses. AIT differs from prophylactic vaccines that provoke immunity to infectious agents, as in allergy the patient is presensitized to the antigen. The intended mode of action of adjuvants is to simultaneously enhance the immunogenicity of the allergen, while precipitating the allergen at the injection site to reduce the risk of anaphylaxis. Contrasting immune effects are seen with different adjuvants. Aluminium hydroxide initially boosts Th2 responses, while the other adjuvants utilized in AIT redirect the Th2 immune response towards Th1 immunity. After varying lengths of time, each of the adjuvants supports tolerance. Further studies of the mechanisms of action of adjuvants may advise shorter treatment periods than the current three-to-five-year regimens, enhancing patient adherence. Improved lead compounds from the adjuvant pipeline are under development and are explored for their capacity to fill this unmet need.

Molecular diagnosis for allergen immunotherapy

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

Allergen-specific immunotherapy for patients with atopic dermatitis sensitized to animal dander

Introduction

Atopic dermatitis (AD) is a chronic inflammatory skin disease, and AD patients are commonly sensitized to house dust mite (HDM). Of the several treatment options available, allergen‐specific immunotherapy (AIT) has been recognized as an effective treatment modality that is directed toward the immunoglobulin E (IgE)‐mediated nature of AD, and subcutaneous administration using HDM is most commonly used for AIT in AD. For patients sensitized to animal (dog or cat) dander, the treatment may not be easy, especially when avoiding the allergen is not possible.

Methods

This study enrolled patients with AD who were sensitized to cat and/or dog dander and underwent AIT (n = 19). Patients’ medical information was obtained, including past treatment history, treatment duration of AIT, and the progress of treatment. Also, the specific IgE levels and IgG4 levels were measured before and after AIT.

Results

A total of 19 patients with AD underwent AIT using cat and/or dog dander. The patients consisted of 4 males and 15 females with an average age of 31.74 ± 9.71. Only two patients had AD only, and the other 17 patients had one or more concomitant allergic diseases, such as allergic rhinitis, allergic asthma, or allergic conjunctivitis. Seven patients were not sensitized to HDMs and only sensitized to cat and/or dog dander. The duration of AIT ranged from 2 to 58 months. The symptoms of 17 patients were well‐controlled, requiring only topical treatment and/or oral antihistamines. One patient required systemic cyclosporine, but only of low dose (25 mg/day). The specific IgE levels were decreased (P = .005) and IgG4 levels showed the tendency of increasing after AIT. No adverse events were observed in these patients.

Conclusion

Although a larger number of patients for a longer follow‐up period are needed to precisely assess the treatment efficacy, AIT using cat and/or dog dander may be an effective treatment option for AD patients, especially for severe AD patients with other respiratory allergic comorbidities who cannot completely avoid the exposure to animal dander.

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

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

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

Alum impairs tolerogenic properties induced by allergoid-mannan conjugates inhibiting mTOR and metabolic reprogramming in human DCs

Background

Polymerized allergoids conjugated to mannan (PM) are suitable vaccines for allergen‐specific immunotherapy (AIT). Alum remains the most widely used adjuvant in AIT, but its way of action is not completely elucidated. The better understanding of the mechanisms underlying alum adjuvanticity could help to improve AIT vaccine formulations.

Objective

We sought to investigate the potential influence of alum in the tolerogenic properties imprinted by PM at the molecular level.

Methods

Flow cytometry, ELISAs, cocultures, intracellular staining and suppression assays were performed to assess alum and PM effects in human dendritic cells (DCs). BALB/c mice were immunized with PM alone or adsorbed to alum. Allergen‐specific antibodies, splenocyte cytokine production and splenic forkhead box P3 (FOXP3)⁺ regulatory T (Treg) cells were quantified. Metabolic and immune pathways were also studied in human DCs.

Results

Alum decreases PD‐L1 expression and IL‐10 production induced by PM in human DCs and increases pro‐inflammatory cytokine production. Alum impairs PM‐induced functional FOXP3⁺ Treg cells and promotes Th1/Th2/Th17 responses. Subcutaneous immunization of mice with PM plus alum inhibits in vivo induction of Treg cells promoted by PM without altering the capacity to induce functional allergen‐specific blocking antibodies. Alum inhibits mTOR activation and alters metabolic reprogramming by shifting glycolytic pathways and inhibiting reactive oxygen species (ROS) production in PM‐activated DCs, impairing their capacity to generate functional Treg cells.

Conclusion

We uncover novel mechanisms by which alum impairs the tolerogenic properties induced by PM, which might well contribute to improve the formulation of novel vaccines for AIT.

Adherence to Allergen Subcutaneous Immunotherapy is Increased by a Shortened Build-Up Phase: A Retrospective Study

Introduction. The poor long-term adherence is known to affect the efficacy of allergen immunotherapy (AIT). In the case of injection AIT (SCIT), one of the main determinants is the inconvenience for patients to undergo prolonged build-up phases. Thus, simplifying the time schedule of the induction protocol could be effective in increasing the adherence to SCIT.

Methods

We backtracked the SCIT renewal orders, thanks to the cooperation of the manufacturing company, and we compared the long-term adherence of 152 patients, who were prescribed with an abbreviated build-up schedule (4 injections, allergoid) with that of 302 patients treated with the same product, but with the traditional build-up protocol (7 injections).

Results

According to the patient-named refills, those patients on the abbreviated build-up were significantly more compliant at the 2nd and 3rd year of treatment compared to the other group (p=0.0001). The drop-out rate after one year was also significantly lower between the two groups (p=0.0001). The drop-out rate after one year was also significantly lower between the two groups (p=0.0001). The drop-out rate after one year was also significantly lower between the two groups (.

Conclusions

Abbreviating the build-up phase by reducing the number of injections significantly improves patients' adherence to SCIT.

Vaccination against Allergy: A Paradigm Shift?

Since the discovery that IgE antibodies mediate allergy, decades of research have unraveled complex mechanisms associated with conventional immunotherapy and the vital protagonists that shape 'immune tolerance' to allergens. Debate exists on what should constitute the dominant effector mechanism in driving rational drug designs for next-generation immunotherapies. As vaccine technology continues to advance, the development of novel vaccines in this area of continued medical need might stand on a threshold of breakthrough inspired by experiments by Dunbar on the passive vaccination of allergic animals more than 100 years ago. In this opinion article, we discuss both novel insights into IgG antibodies as the principle effector modality induced by specific immunotherapy and advances in antigen-carrier design that may catapult allergy treatment into our modern world.

Safety evaluation of a multiallergen immunotherapy treatment in polyallergic patients. APOLO observational study

Aim: Assessment of safety, tolerability and changes in global clinical impression with an multiallergen immunotherapy treatment without dilutional effect in polyallergic patients. Patients & methods: This observational prospective study included patients with allergic rhinitis-rhinoconjunctivitis with or without asthma between 5 and 60 years old receiving immunotherapy treatment with a mixture of two allergenic sources. All adverse events were recorded. Global clinical impression, tolerability subjective assessment and satisfaction were also assessed. Results: 130 patients were analyzed. Nine clinically relevant local adverse reactions were reported in six patients (4.6%). Six systemic reactions (grades 0-I) occurred in four patients (3.1%). Patients improved significantly in their global clinical impression. Good tolerability subjective assessment and satisfaction values were also observed. Conclusion: This multiallergen immunotherapy treatment without dilutional effect can be considered as a potential therapeutic alternative for polyallergic patients suffering from allergic rhinitis.

CD23 provides a noninflammatory pathway for IgE-allergen complexes

BACKGROUND

Type I hypersensitivity is mediated by allergen-specific IgE, which sensitizes the high-affinity IgE receptor FcεRI on mast cells and basophils and drives allergic inflammation upon secondary allergen contact. CD23/FcεRII, the low-affinity receptor for IgE, is constitutively expressed on B cells and has been shown to regulate immune responses. Simultaneous binding of IgE to FcεRI and CD23 is blocked by reciprocal allosteric inhibition, suggesting that the 2 receptors exert distinct roles in IgE handling.

OBJECTIVE

We aimed to study how free IgE versus precomplexed IgE-allergen immune complexes (IgE-ICs) target the 2 IgE receptors FcεRI and CD23, and we investigated the functional implications of the 2 pathways.

METHODS

We performed binding and activation assays with human cells in vitro and IgE pharmacokinetics and anaphylaxis experiments in vivo.

RESULTS

We demonstrate that FcεRI preferentially binds free IgE and CD23 preferentially binds IgE-ICs. We further show that those different binding properties directly translate to distinct biological functions: free IgE initiated allergic inflammation through FcεRI on allergic effector cells, while IgE-ICs were noninflammatory because of reduced FcεRI binding and enhanced CD23-dependent serum clearance.

CONCLUSION

We propose that IgE-ICs are noninflammatory through reduced engagement by FcεRI but increased targeting of the CD23 pathway.

Mechanisms of food allergy

Although oral tolerance is the normal physiologic response to ingested antigens, a breakdown in this process appears to have occurred in the past 2 decades, leading to an increasing prevalence of sensitization to food allergens. Over the past decade, basic research has intensified in an attempt to better understand the mechanisms leading to sensitization and disease versus desensitization and short- and long-term tolerance. In this review we assess various factors that can influence tissue and immune responses to food antigens, the current understanding of immune tolerance development, the role of the gastrointestinal microbiota, and current knowledge regarding immunologic mechanisms involved in desensitization and sustained unresponsiveness, although perhaps the latter is more appropriately termed remission.

Responders and nonresponders to pharmacotherapy and allergen immunotherapy

Allergen immunotherapy (AIT) is a very useful therapy for allergic rhinitis. However, some patients do not achieve the expected results. The aim of the study was to investigate the potential factors that could affect the result, either good or poor, from AIT.Methods: A retrospective analysis of 1624 patients with allergic rhinitis who underwent AIT and 1519 matched patients who underwent only symptomatic therapy (without AIT) was performed. Symptoms, medications scores and quality of life related to allergic diseases before and after therapy were recorded. Cluster analysis on all of the patients was performed to find any associations between responsiveness to therapy and the analyzed parameters. Responsiveness to therapy was assessed by the Mailing criteria.Results: A total of 1266 (77.8%) patients from the AIT group met the criterion of 30% or greater improvement, and 1061 (65.2%) of these patients met the threshold of 60% or greater improvement according to the Mailing criteria. Patients who had a frequently better response to AIT were highly represented in the two clusters. There were subjects with a short history of allergic rhinitis and concomitant allergy to grass pollen or house dust mites. Patients with a prolonged duration of allergic rhinitis before therapy and with polysensitization were more frequently worse responders to AIT.Conclusion: Responsiveness to therapy, including that to AIT, is difficult to assess. However, there were associations suggesting that short-term allergic rhinitis and monovalent allergies to grass pollen or mites could correspond to a better response to AIT.

Long-term effects of allergen sublingual immunotherapy

Introduction

Allergen-specific immunotherapy (AIT) is a crucial therapy for allergic rhinitis. However, the long-term effectiveness of AIT remains to be explored.

Aim

To evaluate clinical and immunological long-term effects of sublingual allergen immunotherapy (SLIT) for common inhalant allergens in elderly patients with allergic rhinitis.

Material and methods

This trial was a prospective follow-up observation of patients with allergic rhinitis who completed SLIT for grass pollen or house dust mites (HDM). After 3 years of SLIT, 115 patients were compared to a placebo group during an additional 5 years of observation. The combined symptom medication score (SMS), quality of life and concentration of IgG₄ for Phleum pratense or Dermatophagoides pteronyssinus were monitored during the study.

Results

Five years after SLIT was discontinued, a significant clinical effect based on SMS was still observed compared with the baseline, just after SLIT and 5 years later as follows: 7.53 ±2.09 vs. 2.45 ±0.72 vs. 3.09 ±1.07 (p < 0.05) for HDM and 8.19 ±2.41 vs. 3.05 ±1.62 vs. 4.47 ±2.31 (p < 0.05) for grass pollen. Quality of life based on the Rhinoconjunctivitis Quality of Life Questionnaire was significantly improved in patients who received SLIT and remained at a good level after 5 years of observation. During the 5 years of observation after SLIT, there were no significant changes between specific IgG₄ levels and the analysed allergens compared to results just after SLIT.

Conclusions

The positive effect obtained after SLIT for grass pollen or house dust mites was sustained for a long period after AIT.

Der p 1-specific regulatory T-cell response during house dust mite allergen immunotherapy

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only available treatment for allergic diseases that can induce specific immune tolerance to allergens. The key mechanisms involved in this process include changes in allergen-specific regulatory T (Treg) cells.

METHODS

We studied 25 allergic rhinitis patients undergoing subcutaneous house dust mite-specific immunotherapy. Peripheral blood mononuclear cells were studied before and after 10, 30 weeks, and 3 years of AIT. Der p 1-specific T regulatory cell responses were investigated by characterization of Der p 1-MHC class II tetramer-positive cells and correlated with nasal symptom score.

RESULTS

Twelve of 25 AIT patients matched with their MHC class II expression to the Der p 1 peptide-MHC class II tetramers. A significant increase in the numbers of Der p 1-specific FOXP3⁺ Helios⁺ CD25⁺ CD127^- Treg cells after 30 weeks was observed, which slightly decreased after 3 years of AIT. In contrast, Der p 1-specific immunoglobulin-like transcript 3 (ILT3)⁺ CD25⁺ Treg cells decreased substantially from baseline after 3 years of AIT. ILT3⁺ Treg cells displayed compromised suppressive function and low FOXP3 expression. In addition, Der p 1-specific IL-10 and IL-22 responses have increased after 30 weeks, but only IL-10⁺ Der p 1-specific Treg cells remained present at high frequency after 3 years of AIT. Increased number of FOXP3⁺ Helios⁺ and IL-10⁺ and decreased ILT3⁺ Treg cell responses correlated with improved allergic symptoms.

CONCLUSION

The results indicate that AIT involves upregulation of the activated allergen-specific Treg cells and downregulation of dysfunctional allergen-specific Treg cell subset. Correction of dysregulated Treg cells responses during AIT is associated with improved clinical response.

EAACI Guidelines on Allergen Immunotherapy: House dust mite-driven allergic asthma

Allergen immunotherapy (AIT) has been in use for the treatment of allergic disease for more than 100 years. Asthma treatment relies mainly on corticosteroids and other controllers recommended to achieve and maintain asthma control, prevent exacerbations, and improve quality of life. AIT is underused in asthma, both in children and in adults. Notably, patients with allergic asthma not adequately controlled on pharmacotherapy (including biologics) represent an unmet health need. The European Academy of Allergy and Clinical Immunology has developed a clinical practice guideline providing evidence-based recommendations for the use of house dust mites (HDM) AIT as add-on treatment for HDM-driven allergic asthma. This guideline was developed by a multi-disciplinary working group using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. HDM AIT was separately evaluated by route of administration and children and adults: subcutaneous (SCIT) and sublingual AIT (SLIT), drops, and tablets. Recommendations were formulated for each. The important prerequisites for successful treatment with HDM AIT are (a) selection of patients most likely to respond to AIT and (b) use of allergen extracts and desensitization protocols of proven efficacy. To date, only AIT with HDM SLIT-tablet has demonstrated a robust effect in adults for critical end points (exacerbations, asthma control, and safety). Thus, it is recommended as an add-on to regular asthma therapy for adults with controlled or partially controlled HDM-driven allergic asthma (conditional recommendation, moderate-quality evidence). HDM SCIT is recommended for adults and children, and SLIT drops are recommended for children with controlled HDM-driven allergic asthma as the add-on to regular asthma therapy to decrease symptoms and medication needs (conditional recommendation, low-quality evidence).

What you should not miss from the systematic reviews and meta-analyses on allergen-specific immunotherapy in 2017

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is a well recognized and extensively studied therapeutic intervention for some allergic diseases. Every year new systematic reviews and meta-analysis provide the most powerful source of evidence to orient decision making on prevention or efficacy of AIT. We here discuss systematic reviews and meta-analyses on AIT (published January 2017 to February 2018).

RECENT FINDINGS

We identified 4 systematic reviews and 10 meta-analyses. Subcutaneous and sublingual AIT (SCIT/SLIT) significantly reduced the development of asthma in children-adolescents with moderate/severe allergic rhinitis, but evidence for a short-term, preventive effect for new allergic sensitizations was nonconclusive. SCIT/SLIT proved to significantly improve symptom and medication scores versus placebo or active comparators in respiratory allergy, with various effect sizes. Oral immunotherapy for IgE-mediated food allergy resulted in substantial benefit in desensitization rates. Data on venom AIT and latex AIT, although limited in quantity and quality, respectively, suggest a large and discrete beneficial effect.

SUMMARY

Although current evidence extracted from meta-analyses and systematic reviews support AIT as an effective, relatively safe, and well tolerated alternative for some allergic diseases, heterogeneity and some methodological inconsistencies represent matters of concern as they may affect the validity and applicability of their results, especially in the context of individual, real-life settings.

The use of biologics for immune modulation in allergic disease

The rising prevalence of allergies represents an increasing socioeconomic burden. A detailed understanding of the immunological mechanisms that underlie the development of allergic disease, as well as the processes that drive immune tolerance to allergens, will be instrumental in designing therapeutic strategies to treat and prevent allergic disease. Improved characterization of individual patients through the use of specific biomarkers and improved definitions of disease endotypes are paving the way for the use of targeted therapeutic approaches for personalized treatment. Allergen-specific immunotherapy and biologic therapies that target key molecules driving the Th2 response are already used in the clinic, and a wave of novel drug candidates are under development. In-depth analysis of the cells and tissues of patients treated with such targeted interventions provides a wealth of information on the mechanisms that drive allergies and tolerance to allergens. Here, we aim to deliver an overview of the current state of specific inhibitors used in the treatment of allergy, with a particular focus on asthma and atopic dermatitis, and provide insights into the roles of these molecules in immunological mechanisms of allergic disease.

Glycosylated nanostructures in sublingual immunotherapy induce long-lasting tolerance in LTP allergy mouse model

An effective specific immunotherapy should contain elements to generate specific recognition (T-cell peptides) and to modulate the immunological response towards a Th1/Treg pattern by enhancing dendritic cells (DCs). We propose a novel sublingual immunotherapy for peach allergy, using systems, that combine Prup3-T-cell peptides with mannose dendrons (D₁ManPrup3 and D₄ManPrup3). Peach anaphylactic mice were treated 1, 2 and 5 nM concentrations. Tolerance was assessed one/five weeks after finishing treatment by determining in vivo/in vitro parameters after challenge with Prup3. Only mice receiving D₁ManPrup3 at 2 nM were protected from anaphylaxis (no temperature changes, decrease in Prup3-sIgE and -sIgG1 antibody levels, and secreting cells) compared to PBS-treated mice. Moreover, an increase of Treg-cells and regulatory cytokines (IL-10⁺/IFN-γ⁺) in CD4⁺-T-cells and DCs were found. These changes were maintained at least five weeks after stopping treatment. D₁ManPrup3 is an effective new approach of immunotherapy inducing protection from anaphylaxis which persists after finishing treatment.

Validation of Patient-Reported Outcomes for Clinical Trials in Allergic Rhinitis: A Systematic Review

Although regulatory authorities have recently recommended the use of a combined symptom-medication score as a primary efficacy end point, none has been psychometrically validated. Here, we sought to determine to what extent allergic rhinitis (AR)-related patient-reported outcomes (symptom scores, medication scores, disease control scores, and satisfaction or quality-of-life scales) have been assessed for construct, content, and/or criterion validity, reliability, responsiveness, and the minimal clinically important difference. We searched the PubMed database from January 1997 to June 2018 with logical combinations of key words related to validation, AR, and patient-rated outcomes and scales. From a total of 1705 potentially relevant publications, 55 were reviewed. Despite the current emphasis on a combined symptom-medication score for evaluating the efficacy of allergen immunotherapy in AR, symptom scores have not been extensively validated, and we did not find any publications describing the validation of a medication score. Disease control scales (mainly the Rhinitis Control Assessment Test, the Control of Allergic Rhinitis and Asthma Test, and the Allergic Rhinitis Control Test) and health-related quality-of-life scales (mainly the Rhinoconjunctivitis Quality of Life Questionnaire [RQLQ] and the mini-RQLQ) have been extensively validated in AR but have some practical disadvantages as primary efficacy criteria in clinical trials.

Role of whole saliva in the efficacy of sublingual immunotherapy in seasonal allergic rhinitis

BACKGROUND

The development of methods to predict the clinical effectiveness of sublingual immunotherapy (SLIT) for allergic diseases is a crucial matter. We sought to determine whether whole saliva, which is the first body component that contacts allergen extracts during SLIT, is associated with the clinical effectiveness of SLIT in Japanese cedar pollinosis.

METHODS

Blood monocytes or monocytic THP-1 cells were cultured in the presence or absence of either whole saliva or pure saliva with or without treatments including filtration and blockade of TLR2 and/or TLR4 signaling. IL-10 levels in the supernatants were then measured. Whole saliva-induced IL-10 production by THP-1 cells was compared between asymptomatic and disease-onset patients during peak pollen dispersal after SLIT.

RESULTS

Both monocytes and THP-1 cells produced substantial amounts of IL-10 in response to whole saliva. IL-10 production was significantly reduced in response to pure saliva and 0.2 μm-filtered saliva. Simultaneous treatment with polymyxin B and TL2.1, a neutralizing antibody against TLR2, also reduced IL-10 production. IL-10 levels produced by THP-1 cells in response to whole saliva collected prior to SLIT were significantly higher in asymptomatic patients determined by symptom-medication scores than disease-onset patients following SLIT. Such differences were not seen in saliva collected 3 months after the initiation of SLIT or saliva collected during peak pollen dispersal.

CONCLUSIONS

Our results provide a basis for why the sublingual route is effective and preferable in allergen immunotherapy. Saliva-induced IL-10 levels produced by THP-1 cells may be a predictive marker for clinical remission after SLIT.

Intranasal administration of probiotic Lactobacillus rhamnosus GG prevents birch pollen-induced allergic asthma in a murine model

BACKGROUND

There is an increasing interest in targeted application of probiotic bacteria for prevention and treatment of airway diseases, including allergies. Here, we investigated the beneficial effects of preventive intranasal treatment with probiotics Lactobacillus rhamnosus GG and L. rhamnosus GR-1 in a mouse model of allergic asthma.

METHODS

Lactobacillus rhamnosus was administered intranasally eight times on days 1-4 and 8-11 at 5 × 10⁸  CFU/dose, followed by a 2-week asthma induction protocol with birch pollen extract on alternating days. Effects of preventive treatment were analyzed based on serum antibody levels, bronchoalveolar lavage cell counts, lung histology, lung cytokine levels, and airway hyperreactivity. Colonization and translocation of L. rhamnosus were assessed by bacterial cell counts in nasal mucosa, fecal samples, cervical lymph nodes, and blood. Binding of fluorescent L. rhamnosus to fixed murine nasal mucosal cells and airway macrophages was visualized by fluorescence microscopy.

RESULTS

Transient colonization of the murine upper airways by L. rhamnosus GG was demonstrated and was approximately ten times higher compared to L. rhamnosus GR-1. Marked binding of fluorescent L. rhamnosus GG to murine nasal mucosal cells and airway macrophages was visualized. Preventive treatment with L. rhamnosus GG (but not L. rhamnosus GR-1) resulted in a significant decrease in bronchoalveolar lavage eosinophil counts, lung interleukin-13 and interleukin-5 levels, and airway hyperreactivity. A tendency toward a decrease in serum Bet v 1-specific immunoglobulin G1 was likewise observed.

CONCLUSION

Intranasally administered L. rhamnosus GG prevents the development of cardinal features of birch pollen-induced allergic asthma in a strain-specific manner.

Role of Der p 1-specific B cells in immune tolerance during 2 years of house dust mite-specific immunotherapy

BACKGROUND

Long-term follow-up of allergen-specific B cells in terms of immunoglobulin isotype expression, plasmablast differentiation, and regulatory B (Breg) cell development during allergen-specific immunotherapy (AIT) has not been reported.

OBJECTIVE

Allergen-specific B-cell responses during 2 years of house dust mite AIT were compared between responder and nonresponder patients.

METHODS

B cells specific for Der p 1 were detected by using the fluorochrome-labeled allergen method. The frequency of IgA-, IgG₁- and IgG₄-switched Der p 1-specific B cells, plasmablasts, and IL-10- and IL-1 receptor antagonist (IL-1RA)-producing Breg cells were investigated and correlated to clinical response to AIT.

RESULTS

Sixteen of 25 patients completed the 2-year study. Eleven responder patients showed a successful response to AIT, as measured by a decrease in symptom-medication scores from 13.23 ± 0.28 to 2.45 ± 0.24 (P = .001) and a decrease in skin prick test reactivity to house dust mite from 7.0 ± 1.3 to 2.7 ± 0.5 mm (P = .001). IgG₄⁺ and IgA⁺ Der p 1-specific B cells showed a significant increase after AIT, with a significantly greater frequency in responders compared with nonresponders in the IgG₄⁺ but not the IgA⁺ fraction. The frequency of plasmablasts and IL-10- and/or IL-1RA-producing Breg cells was greater among responders compared with nonresponders after 2 years. The increased frequency of Der p 1-specific IgG4⁺ B cells, plasmablasts, and IL-10⁺ and dual-positive IL-10⁺IL-1RA⁺ Breg cells significantly correlated with improved clinical symptoms over the course of AIT.

CONCLUSION

Allergen-specific B cells in patients responding to AIT are characterized by increased numbers of IgA- and IgG₄-expressing Der p 1-specific B cells, plasmablasts, and IL-10⁺ and/or IL-1RA⁺ Breg cells.

Recent developments and highlights in allergen immunotherapy

Allergen immunotherapy (AIT) is the only disease-modifying treatment option for patients with IgE-mediated inhalant allergies. Though used in clinical practice for more than 100 years, most innovations in AIT efficacy and safety have been developed in the last two decades. This expert review aimed to highlight the recent progress in AIT for both application routes, the sublingual (SLIT) and subcutaneous (SCIT) forms. As such, it covers recent aspects regarding efficacy and safety in clinical trials and real-life data and outlines new concepts in consensus and position papers as well as in guidelines for AIT. Potential clinical and nonclinical biomarkers are discussed. This review also focuses on potential future perspectives in AIT, such as alternative application routes, immune-modulating adjuvants, and recombinant vaccines. In conclusion, this state of the art review provides a comprehensive overview of AIT and highlights unmet needs for the future.

Sublingual allergen immunotherapy with a liquid birch pollen product in patients with seasonal allergic rhinoconjunctivitis with or without asthma

BACKGROUND

Sublingual allergen immunotherapy (SLIT) has been demonstrated to be both clinically efficacious and safe. However, in line with the current regulatory guidance from the European Medicines Agency, allergen immunotherapy (AIT) products must demonstrate their efficacy and safety in pivotal phase III trials for registration.

OBJECTIVE

We sought to investigate the efficacy and safety of sublingual high-dose liquid birch pollen extract (40,000 allergy units native [AUN]/mL) in adults with birch pollen allergy.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group multicenter trial was conducted in 406 adult patients with moderate-to-severe birch pollen-induced allergic rhinoconjunctivitis with or without mild-to-moderate controlled asthma. Treatment was started 3 to 6 months before the birch pollen season and continued during the season in 40 clinical study centers in 5 European countries. For primary end point assessment, the recommended combined symptom and medication score of the European Academy of Allergy and Clinical Immunology was used. Secondary end points included quality-of-life assessments, immunologic parameters, and safety.

RESULTS

Primary efficacy results demonstrated a significant (P < .0001) and clinically relevant (32%) reduction in the combined symptom and medication score compared with placebo after 3 to 6 months of SLIT. Significantly better rhinoconjunctivitis quality-of-life scores (P < .0001) and the patient's own overall assessment of his or her health status, including the visual analog scale score (Euro Quality of Life Visual Analogue Scale; P = .0025), were also demonstrated. In total, a good safety profile of SLIT was observed.

CONCLUSION

This study confirmed both the clinical efficacy and safety of a sublingual liquid birch pollen extract in adults with birch pollen allergy in a pivotal phase III trial (EudraCT: 2013-005550-30; ClinicalTrials.gov: NCT02231307).

Preparation allergenic pollen extracts; the points should be considered to make high-quality products

Atopic diseases have an increasing trend worldwide during the last two decades. Determining the main cause of allergic diseases, allergens, is the first step in managing and improving the issue, usually is done by Skin Prick tests (SPTs). Having allergenic extract in high quality is desired to perform a reliable SPT. Several parameters of extracts are considered including composition, stability, potency, preservation conditions, and unit definition. In this review, these factors have been explained pointing to factors might have profitable points or harmful drawback in the quality of allergen extracts.