Update on allergy immunotherapy: American Academy of Allergy, Asthma & Immunology/European Academy of Allergy and Clinical Immunology/PRACTALL consensus report

Impact of liquid sublingual immunotherapy on asthma onset and progression in patients with allergic rhinitis: a nationwide population-based study (EfficAPSI study)

Background

The only disease-modifying treatment currently available for allergic rhinitis (AR) is allergen immunotherapy (AIT). The main objective of the EfficAPSI real-world study (RWS) was to evaluate the impact of liquid sublingual immunotherapy (SLIT-liquid) on asthma onset and evolution in AR patients.

Methods

An analysis with propensity score weighting was performed using the EfficAPSI cohort, comparing patients dispensed SLIT-liquid with patients dispensed AR symptomatic medication with no history of AIT (controls). Index date corresponded to the first dispensation of either treatment. The sensitive definition of asthma event considered the first asthma drug dispensation, hospitalisation or long-term disease (LTD) for asthma, the specific one omitted drug dispensation and the combined one considered omalizumab or three ICS ± LABA dispensation, hospitalisation or LTD. In patients with pre-existing asthma, the GINA treatment step-up evolution was analysed.

Findings

In this cohort including 112,492 SLIT-liquid and 333,082 controls, SLIT-liquid exposure was associated with a significant lower risk of asthma onset vs. control, according to all definitions (combined: HR [95% CI] = 0.62 [0.60-0.63], sensitive: 0.77 [0.76-0.78], and specific: 0.67 [0.61-0.72]). Exposure to SLIT was associated with a one-third reduction in GINA step-up regardless baseline steps.

Interpretation

In this national RWS with the largest number of person-years of follow-up to date in the field of AIT, SLIT-liquid was associated with a significant reduction in the risk of asthma onset or worsening. The use of three definitions (sensitive or specific) and GINA step-up reinforced the rigorous methodology, substantiating SLIT-liquid evidence as a causal treatment option for patients with respiratory allergies.

Funding

Stallergenes Greer.

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

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

A successful linkage of a named patient products of sublingual immunotherapy-dispensing registry to French healthcare insurance database (SNDS): methodological constitution of the EfficAPSI cohort

BACKGROUND

The only causal treatment for allergic rhinitis (AR) is allergen immunotherapy (AIT) including personalized liquid sublingual AIT (SLIT). We present the methodology for establishing the EfficAPSI cohort to further evaluate the real-life effectiveness and use of SLIT liquid.

RESEARCH DESIGN AND METHODS

The EfficAPSI cohort was constituted by deterministic linkage of Stallergenes Greer dispensing and nationwide French healthcare insurance system (SNDS) databases. Data from 2006 to 2018 were extracted. All patients who initiated Stallergenes Greer SLIT liquid between 2010 and 2013 were considered as exposed and those dispensed with AR symptomatic treatment only as control. To limit the impact of confounding, the models will be weighted using the inverse probability of treatment weighting (IPTW).

RESULTS

A total of 445,574 patients were included; median age was 38 years; 59.1% were female. Exposed patients (n = 112,492) were significantly younger, more frequently males, and less likely to have comorbidities than controls (n = 333,082). After IPTW, patients' characteristics from both groups were similar.

CONCLUSIONS

To date, the EfficAPSI cohort has the largest number of person-years of follow-up in the field of AIT. The completeness of the data allows to evaluate SLIT liquid effectiveness with rigorous methodology, leading to important insights on personalized medicine in real-life.

Self-Assembling Allergen Vaccine Platform Raises Therapeutic Allergen-Specific IgG Responses without Induction of Systemic Allergic Responses

Allergen immunotherapies are often successful at desensitizing allergic patients but can require life-long dosing and suffer from frequent adverse events including instances of systemic anaphylaxis, leading to poor patient compliance and high cost. Allergen vaccines, in turn, can generate more durable immunological allergen desensitization with far fewer doses. However, like immunotherapies, allergen vaccines are often highly reactogenic in allergic patients, hampering their use in therapeutic settings. In this work, we utilize a peptide-based self-assembling nanofiber platform to design allergen vaccines against allergen B-cell epitopes that do not elicit systemic anaphylaxis when administered subcutaneously to allergic mice. We show that, in contrast to protein vaccines, nanofiber vaccines prevent leakage of allergen material into the vascular compartment, a feature that likely underpins their reduced systemic reactogenicity. Further, we show that our allergen vaccine platform elicits therapeutic IgG antibody responses capable of desensitizing allergic mice to allergen-induced Type I hypersensitivity reactions. Finally, we have demonstrated a proof-of-concept for the therapeutic potential of nanofiber-based peanut allergen vaccines directed against peanut allergen-derived epitopes.

Quality control of allergen products with mass spectrometry part I: Positioning within the EU regulatory framework

Mass spectrometry (MS) has advanced greatly and many of its applications are ready for utilization within regulatory procedures and could significantly contribute to overcome challenges in standardization of allergen products. It seems sensible to discuss MS within the regulatory framework, before addressing technical questions. While the application to purified proteins is well established from product development to manufacturer's release analytics, its application to complex products such as allergen products is still under development. It needs to be determined where it can complement or replace established methods or where MS offers limited improvement. Despite its technical appeal and versatility, currently MS is mentioned in regulatory guidelines only as one possible measurement method. For example, no specific MS method is given in the European Pharmacopoeia. We discuss applications of MS within the EU regulatory framework. This includes their advantages and disadvantages and their positioning between research, characterization, manufacturer's release analytics and official batch testing. We discuss the qualitative detection of single and multiple allergens as proof of identity, qualitative to semi-quantitative protein profiles for batch to batch consistency testing, and quantification of allergens to state mass units of allergens. MS may also facilitate standardization of allergen products, reference products and reference standards.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

The Art of Immunotherapy

Selection of a patient with rhinitis/conjunctivitis or asthma for allergy immunotherapy (AIT) requires several decisions. First, does the patient's sensitization, pattern of exposure to an allergen, and degree of exposure to that allergen reasonably suggest a causal relationship? Does the level and duration of symptoms warrant the cost and inconvenience of immunotherapy, or is the patient motivated by the disease-modifying potential of AIT? If AIT is selected, is the choice to be greater safety and convenience with sublingual immunotherapy (SLIT) tablets, but with treatment probably limited to 2 or 3 allergens, or for subcutaneous immunotherapy where multiple allergen therapy is the rule and efficacy may be somewhat greater, at least initially, or does the physician go off-label into the unknowns of liquid SLIT? Are there extracts of sufficient potency to achieve likely effective doses? How does the physician deal with large local or systemic reactions, with gaps in treatment, with pollen seasons, and the use of premedication or cautionary prescription of epinephrine autoinjectors? How can adherence to AIT be improved? These and other questions are addressed in this paper.

Efficacy and safety of subcutaneous immunotherapy in asthmatic children allergic to house dust mite: a meta-analysis and systematic review

Background

Subcutaneous immunotherapy (SCIT) has been proved to be effective and safe in adult asthma. But it is still controversial in children.

Object

To evaluate the efficacy and safety of SCIT in asthmatic children with allergy to house dust mite.

Method

We searched the databases of Cochrane Library, EMBASE and MEDLINE (from 1 January 1990 to 1 December 2022). Two reviewers independently screened studies, extracted data and critically appraised the risk of bias. We used the Revman 5 to synthesize the effect sizes.

Results

We finally selected 38 eligible studies including 21 randomized controlled trials to evaluate the efficacy and safety of SCIT and 17 observational studies to assess the safety. The results revealed that short-term asthma symptom scores were declined with a standardized mean difference (SMD) of -1.19 (95% CI: -1.87, -0.50) in 12 researches with high heterogeneity. Short-term asthma medication scores were decreased with SMD -1.04 (95% CI: -1.54, -0.54) in 12 heterogeneous researches. One study showed no significant reduction in combined symptom and medication scores without providing details. No studies we reviewed reported long-term efficacy. SCIT resulted in an obviously increased risk of adverse reactions compared with placebo. For secondary outcomes, SCIT improved life quality and reduced the numbers of annual asthma attacks and allergen-specific airway hyperreactivity, but without significant improvement in pulmonary function, asthma control or hospitalization.

Conclusions

SCIT can reduce the short-term symptom scores and medication scores regardless of different treatment duration or mono/polysensitization, but with an increased incidence of local and systemic adverse effects. Further studies on pediatric asthma are needed to evaluate the long-term efficacy, and clarify the effectiveness of SCIT in specific population using mix allergen extracts or with severe asthma. Overall, it is recommended for children with mild-moderate HDM-driven allergic asthma.

Mechanisms of Allergen Immunotherapy and Potential Biomarkers for Clinical Evaluation

Allergen-immunotherapy (AIT) is an efficacious and disease-modifying treatment option for IgE-mediated diseases. Among these allergic rhinitis, insect venom allergy, food allergy, and allergic asthma are the most common candidates for AIT. AIT gives rise to clinical immunotolerance which may last for years after the treatment cessation. Mechanisms of AIT include suppression of allergic inflammation in target tissues and stimulation of the production of blocking antibodies, especially IgG4 and IgA. These mechanisms are followed by a reduction of underlying allergen-specific Th2 cell-driven responses to the allergens. Tolerance induction takes place through the desensitization of effector cells and stimulation of regulatory T cells that show their effects by mechanisms involving cell-cell cross-talk, but also other mechanisms, e.g., by the production of immunomodulatory cytokines such as, e.g., IL-10 and TGF-beta. From a personalized medical perspective, there is a need for clinical biomarkers of value in selecting responders and optimizing patient care during AIT. Also, a deeper understanding of underlying mechanistic processes will improve AIT's future outcomes. In this paper, the current knowledge of mechanisms in AIT is reviewed with a special focus on biomarkers of this therapy.

Clinical and experimental treatment of allergic asthma with an emphasis on allergen immunotherapy and its mechanisms

Allergen immunotherapy (AIT) is currently the only form of treatment that modifies allergic asthma. Pharmacotherapy alone seeks to control the symptoms of allergic asthma, allergic rhinitis, and other atopic conditions. In contrast, AIT can induce long-term physiological modifications through the immune system. AIT enables individuals to live improved lives many years after treatment ends, where they are desensitized to the allergen(s) used or no longer have significant allergic reactions upon allergen provocation. The leading forms of treatment with AIT involve injections of allergen extracts with increasing doses via the subcutaneous route or drops/tablets via the sublingual route for several years. Since the initial attempts at this treatment as early as 1911 by Leonard Noon, the mechanisms by which AIT operates remain unclear. This literature-based review provides the primary care practitioner with a current understanding of the mechanisms of AIT, including its treatment safety, protocols, and long-term efficacy. The primary mechanisms underlying AIT include changes in immunoglobulin classes (IgA, IgE, and IgG), immunosuppressive regulatory T-cell induction, helper T cell type 2 to helper T cell type 1 cell/cytokine profile shifts, decreased early-phase reaction activity and mediators, and increased production of IL-10, IL-35, TGF-β, and IFN-γ. Using the databases PubMed and Embase, a selective literature search was conducted searching for English, full-text, reviews published between 2015 and 2022 using the keywords (with wildcards) "allerg*," "immunotherap*," "mechanis*," and "asthma." Among the cited references, additional references were identified using a manual search.

Allergic rhinitis behavioral changes after Indonesian house dust mites allergenic extract administration as immunotherapy

Background: Allergy is a hypersensitivity reaction that is generally mediated by Immunoglobulin E (IgE). More than 25% of the world’s population is suspected of having these various diseases, and the prevalence and progression of these diseases have continued to increase significantly in recent years. Among these allergy-related diseases, allergic rhinitis and food allergy are the types of allergies with the highest prevalence. Clinical manifestations of allergic rhinitis include sneezing, rhinorrhea, nasal itching, and nasal congestion. Objective: This study aimed to determine the behavioral changes of allergic rhinitis after Indonesian House Dust Mites (IHDM) allergenic extract administration as an immunotherapy. Methods: Eight male BALB/c mice aged 6-8 weeks in each group were treated for seven groups. The sensitization phase is given intraperitoneal, the desensitization phase is given by subcutaneous, and the challenge phase is given intranasal. The allergic parameters were observed, such as nose rubbing and sneezing. The parameters were observed for 15 minutes after the challenge administration. Results: The results showed that the administration of Indonesian House Dust Mites as immunotherapy decreased the frequency of nose rubbing and sneezing after the administration of immunotherapy compared to the allergic rhinitis model. Conclusions: The administration of the Indonesia House Dust Mites as immunotherapy decreased the allergic rhinitis immune response by altering the behavioral parameter.

A review on aero-allergen induced allergy in India

Allergic diseases such as bronchial asthma, rhinitis and eczema are an important public health issue globally in 21st century. Their prevalence and impact in India is high, in terms of total numbers of people affected. Due to diverse climate and lifestyle, the Indian population is exposed to a rich and varied range of aerobiological particles. In the last two decades in India, 83 pollens, 34 fungi, six dust mite and 19 insect species were reported as allergenic, often contributing to heavy allergenic exposure in indoor and outdoor environments. There are currently few practitioners who offer allergy diagnosis and treatment in India, but there is active basic and molecular research aiming to improve the health of allergic patients. This review explores the field of aero-allergy in India during the last two decades, with special emphasis on prevalence across various centres and relevant scientific advances such as genetic associations and new therapeutics. This review will be helpful for clinicians to select aero-allergens for sensitisation testing in patients suffering from symptoms in different regions of India, and to support patients undertaking prophylaxis of allergic symptoms in India according to local environmental conditions. This study also helps to define patient selection for allergy testing and the role of test results in guiding allergic disease management in the Indian context. Finally, we summarize genetic findings relevant to aero-allergy in India and discuss the development of novel therapeutics for investigation and management of aero-allergy in India.

Effects of subcutaneous immunotherapy in allergic rhinitis children sensitive to dust mites

BACKGROUND

Subcutaneous immunotherapy (SCIT) is now the only treatment that can modify the natural course of allergic rhinitis (AR). However, not all children with AR benefit from SCIT.

OBJECTIVE

To evaluate the efficacy of SCIT in dust-mites-induced AR children and explore correlative factors predicting treatment response to SCIT.

METHODS

225 children aged 4-17 years old with AR were recruited from January 2016 to September 2019, and monitored at baseline, 4, 12, and 24 months after the start of SCIT treatment. The visual-analogue-score (VAS) was used to assess the clinical symptoms. Multivariate binary logistic regression analyses and receiver operating characteristic curves were used to explore correlative factors in predicting the efficacy of SCIT.

RESULTS

The significant declines in VAS started after 4 months of SCIT and continued to improve throughout the study compared with baseline. An increase in children's age (OR=0.688, 95%CI: 0.479-0.988) and those with allergic history (OR=0.097, 95%CI: 0.009-1.095) were negatively associated with the risk of poor efficacy. Polysensitized children were more likely to suffer poor efficacy (OR=15.511 95%CI: 1.319-182.355). The clinical response at month 4 (r=0.707) and month 12 (r=0.925) was related to that at month 24. The area under the curve (AUC) for improvement at month 4 and month 12 was 0.746 and 0.860, respectively.

CONCLUSION

Our study confirmed the clinical efficacy of SCIT in AR children. Children with younger age, negative allergic history, and multiple allergens may predict a worse efficacy. The onset of action and the clinical response to SCIT in the second year can be predicted as early as by month 4.

Omalizumab in IgE-Mediated Food Allergy: A Systematic Review and Meta-Analysis

BACKGROUND

A growing number of studies have shown encouraging results with omalizumab (OMA) as monotherapy and as an adjunct to oral immunotherapy (OMA+OIT) in patients with single/multiple food allergies.

OBJECTIVES

To evaluate the efficacy and safety of OMA or OMA+OIT in patients with immunoglobulin E (IgE)-mediated food allergy.

METHODS

An extensive literature search (inception to December 31, 2020) was performed to identify randomized, controlled, and observational studies that assessed OMA as monotherapy or OMA+OIT in patients with IgE-mediated food allergy. The outcomes were an increase in tolerated dose of foods, successful desensitization, sustained unresponsiveness, immunological biomarkers, severity of allergic reactions to food, quality of life (QoL), and safety. A P less than .05 was considered significant.

RESULTS

In total, 36 studies were included. The OMA monotherapy (vs pre-OMA) significantly increased the tolerated dose of multiple foods; increased the threshold of tolerated dose for milk, egg, wheat, and baked milk; improved QoL; and reduced food-induced allergic reactions (all P < .01). The OMA+OIT significantly increased the tolerated dose of multiple foods (vs placebo and pre-OMA), desensitization (vs placebo+OIT and pre-OMA) (all P ≤ .01), and improved QoL (vs pre-OMA) and immunoglobulin G4 levels (both P < .01). No major safety concerns were identified.

CONCLUSIONS

In IgE-mediated food allergy, OMA can help patients consume multiple foods and allow for food dose escalation. As an adjunct to OIT, OMA can also support high-dose desensitization and higher maintenance doses. Further studies are warranted to empirically evaluate the effect of OMA and confirm these findings.

Molecular Mechanisms Underlying the Effects of Bimin Kang Mixture on Allergic Rhinitis: Network Pharmacology and RNA Sequencing Analysis

Background

Allergic rhinitis (AR) is a highly prevalent chronic inflammatory disease of the respiratory tract. Previous studies have demonstrated that Bimin Kang Mixture (BMK) is effective in alleviating AR symptoms and reducing the secretion of inflammatory factors and mucin; however, the precise mechanisms underlying these effects remain unclear.

Methods

We built target networks for each medication component using a network pharmacology technique and used RNA-seq transcriptome analysis to screen differentially expressed genes (DEGs) for AR patients and control groups. The overlapping targets in the two groups were assessed using PPI networks, GO, and KEGG enrichment analyses. The binding ability of essential components to dock with hub target genes was investigated using molecular docking. Finally, we demonstrate how BMK can treat AR by regulating the NF-κB signaling pathway through animal experiments.

Results

Effective targets from network pharmacology were combined with DEGs from RNA-seq, with 20 intersections as key target genes. The construction of the PPI network finally identified 5 hub target genes, and all hub target genes were in the NF-κB signaling pathway. Molecular docking suggests that citric acid, deoxyandrographolide, quercetin, luteolin, and kaempferol are structurally stable and can spontaneously attach to IL-1β, CXCL2, CXCL8, CCL20, and PTGS2 receptors. Animal experiments have shown that BMK inhibits NF-κB transcription factor activation, reduces the expression of proinflammatory cytokines and chemokines IL-1β, CXCL2, IL-8, and COX-2, and exerts anti-inflammatory and anti-allergic effects.

Conclusion

BMK by regulating the NF-κB signaling pathway improves inflammatory cell infiltration, regulates mucosal immune balance, and reduces airway hypersensitivity. These findings provide theoretical support for the clinical efficacy of BMK for AR treatment.

Efficacy and safety of sublingual allergen immunotherapy

Sublingual immunotherapy (SLIT)-tablets represent a new allergen immunotherapy option for clinicians. In North America, there are five SLIT-tablets approved for the treatment of allergic rhinoconjunctivitis (ARC). No SLIT-drops products are currently approved in the United States or Canada. This work reviewed the efficacy of the timothy grass SLIT-tablet, five-grass SLIT-tablet, ragweed SLIT-tablet, house-dust mite SLIT-tablet, and tree SLIT-tablet in patients with ARC. All the SLIT-tablets showed consistent clinical efficacy for the treatment of ARC in large, double-blind, placebo-controlled trials, including for both patients who were monosensitized and those who were polysensitized. Treatment with house-dust mite SLIT-tablet has shown efficacy in patients who are pollen sensitized during their respective pollen seasons. In contrast to SLIT-tablets, efficacy studies of SLIT-drops show high heterogeneity of treatment effect. Although data are scarce, data that compared the efficacy of SLIT-tablets versus ARC pharmacotherapy generally indicated that SLIT-tablets had a greater benefit than pharmacotherapy when compared with placebo, particularly for perennial ARC. When compared with subcutaneous immunotherapy, analysis of these data indicated that SLIT-tablets had a benefit over subcutaneous immunotherapy in regard to safety but somewhat less benefit in regard to efficacy. The safety of SLIT-tablets has been well documented, and a U.S. Food and Drug Administration class label with safety considerations is present in the prescribing information for all SLIT-tablets. No new safety signals have been observed after reinitiating SLIT-tablets after a short treatment interruption.

A review of allergen immunotherapy in asthma

Asthma is one of the most common chronic diseases worldwide. Besides symptomatic treatments, allergen immunotherapy (AIT) is a possible add-on treatment for asthmatic patients. In case of an immunologically proven allergen-driven mechanism of asthma, AIT represents the only etiologic treatment for allergic symptoms. AIT has proven both its efficacy and effectiveness in reducing asthma symptoms and asthma medications. It is still debated whether its prescription in severe asthmatic patients is allowed and safe. As for uncontrolled asthma, such a condition should be considered temporary, and AIT may be started as asthma becomes at least partially controlled after treatment adjustment. Finally, randomized trials and real-life studies in recent years have proven that AIT could be administered as a preventive strategy to reduce the risk of developing asthma in patients suffering from allergic rhinitis. More studies are needed to provide more precise indications on the role in clinical practice of AIT in asthmatic patients. Nevertheless, present data are already strong enough to highlight its role as a therapeutic option for allergic asthma and as a preventive strategy to stop or at least decelerate the allergic march.

Immunotherapy for Asthma

Asthma represents one of the biggest global health concerns with increasing prevalence and influence on global health. Several distinct asthma phenotypes have been identified with one of the most common, earliest recognized, and described being the allergic asthma phenotype, in which allergens trigger asthma through mechanisms involving allergen-specific immunoglobulin E (IgE). Allergen-specific immunotherapy (AIT), in the forms of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), has been used for many decades as a tool for reducing IgE-mediated sensitization and controlling symptoms of allergic disease, most commonly for allergic rhinitis, and it remains the only currently available disease modifying therapy in atopic patients. AIT has been studied for use in mild to moderate allergic asthma. While the data are often inconsistent, and utilize a multitude of different methods, antigens, and outcome measures, in general, AIT may have several beneficial effects on asthma disease control, quality of life, and requirement for medication. These benefits are notable when immunotherapy is used as an adjunct to pharmacologic treatment in carefully selected and monitored patients with mild to moderate persistent asthma. Patients with severe asthma are excluded from these trials. Importantly, patients with asthma, and in particular severe asthma, may have a higher rate of systemic adverse reactions to SCIT, including anaphylaxis, however, these events are overall rare. Future research in the area is needed to definitively assess the benefit of SCIT and SLIT for patients with asthma, comparing outcomes with different methods, addressing the role of AIT in severe asthma, significance of multiallergen AIT in allergic asthma, and safety concerns in asthma.

CD44 is critical for the enhancing effect of hyaluronan in allergen-specific sublingual immunotherapy in a murine model of chronic asthma

Allergen-specific sublingual immunotherapy (SLIT) is a potentially effective disease-modification treatment for patients with allergic asthma. Because CD44 signaling enhances regulatory T (Treg) cell-induction, administering CD44 ligands such as hyaluronan (HA) with allergen-specific SLIT may enhance the therapeutic effects. We evaluated the role of CD44 in Treg cell-induction in T helper type 2 (Th2)-mediated chronic airway inflammation using CD44-/- mice and the efficacy of HA on SLIT in a Dermatophagoides farinae (Df)-induced murine model of chronic asthma. Th2 responses and Treg cell induction were evaluated in CD44-/- mice. We devised a new SLIT model of Df-induced chronic asthma utilizing HA as an adjuvant. The effects of HA added to the new SLIT model were evaluated by the early asthmatic response (EAR) and airway hyperresponsiveness (AHR), eosinophilic airway inflammation, and serum Df-specific IgE levels. Th2-mediated chronic eosinophilic airway inflammation was worse in CD44-/- mice compared with Df-sensitized wild-type (WT) mice. HA enhanced the effect of Df-induced Treg cells in a CD44-dependent manner. Sublingual Df treatment in combination with HA, but not alone, normalized EAR and AHR, and significantly reduced the serum IgE levels and the bronchoalveolar lavage fluid (BALF) eosinophil number. HA also induced Treg cells in a Df-sensitized spleen cell culture in a CD44-dependent manner. The treatment-enhancing effects of HA in this SLIT model were diminished in CD44-/- mice. CD44 is a key contributor to Treg cell induction and critical for the enhancing effects of HA in a Df-induced murine model of chronic asthma.

Linear Epitope Binding Patterns of Grass Pollen-Specific Antibodies in Allergy and in Response to Allergen-Specific Immunotherapy

Allergic diseases affect many individuals world-wide and are dependent on the interaction between allergens and antibodies of the IgE isotype. Allergen-specific immunotherapy (AIT) can alter the development of the disease, e.g., through induction of allergen-specific IgG that block allergen-IgE interactions. The knowledge of epitopes recognized by allergy-causing and protective antibodies are limited. Therefore, we developed an allergome-wide peptide microarray, aiming to track linear epitope binding patterns in allergic diseases and during AIT. Here, we focused on immune responses to grass pollen allergens and found that such epitopes were commonly recognized before initiation of AIT and that AIT commonly resulted in increased antibody production against additional epitopes already after 1 year of treatment. The linear epitope binding patterns were highly individual, both for subjects subjected to and for individuals not subjected to AIT. Still, antibodies against some linear epitopes were commonly developed during AIT. For example, the two rigid domains found in grass pollen group 5 allergens have previously been associated to a diversity of discontinuous epitopes. Here, we present evidence that also the flexible linker, connecting these domains, contains regions of linear epitopes against which antibodies are developed during AIT. We also describe some commonly recognized linear epitopes on Phl p 2 and suggest how antibodies against these epitopes may contribute to or prevent allergy in relation to a well-defined stereotyped/public IgE response against the same allergen. Finally, we identify epitopes that induce cross-reactive antibodies, but also antibodies that exclusively bind one of two highly similar variants of a linear epitope. Our findings highlight the complexity of antibody recognition of linear epitopes, with respect to both the studied individuals and the examined allergens. We expect that many of the findings in this study can be generalized also to discontinuous epitopes and that allergen peptide microarrays provide an important tool for enhancing the understanding of allergen-specific antibodies in allergic disease and during AIT.

Allergen-Specific IgE and IgG4 as Biomarkers for Immunologic Changes during Subcutaneous Allergen Immunotherapy

(1) Background: Biomarkers of efficacy for subcutaneous immunotherapy (SCIT) on allergic rhinitis have not been evaluated in details. The present study aims to assess the relevance of measuring of sIgE, sIgG4 and IgE/IgG4 ratio during SCIT in patients with allergic rhinitis; (2) Methods: 20 patients, 13 men and 7 women aged 19 to 58 years, with clinically manifested seasonal and perennial allergic rhinitis were studied. At the initiation and in the end of the three-year course of SCIT serum allergen-specific IgE and IgG4 were measured with ImmunoCAP system. The sIgE/sIgG4 ratio was calculated as a biomarker for immunologic effectiveness; (3) Results: There was a significant increase of sIgG4 antibodies (p < 0.05), while at the end of SCIT for the sIgE levels no significant changes were seen (p > 0.05). Moreover, 90% of patients showed a decrease of the IgE/IgG4 ratio; (4) Conclusions: In most of treated patients with AR, SCIT with Bulgarian allergen products leads to clear immunological changes. After a 3-year of SCIT there is a significant increase in allergen specific IgG4 levels and both decrease of sIgE and IgE/IgG4 ratio. sIgE, sIgG4 and IgE/IgG4 ratio can be used as a substantial biomarker for predicting immunological effectiveness of SCIT.

Review of current and future therapeutics in ABPA

Allergic bronchopulmonary aspergillosis is an allergic pulmonary condition caused by hypersensitivity to antigens of Aspergillus sp. found most commonly in patients with underlying asthma or cystic fibrosis. Host factors which alter the innate and adaptive immune responses to this abundant airborne fungus contribute to the development of chronic airway inflammation, bronchiectasis, and fibrosis. Traditionally, treatment has focussed on reducing fungal burden and immune response to fungal antigens. However, a significant proportion of patients continue to suffer recurrent exacerbations with progressive lung damage, and the side effect burden of existing treatments is high. New treatments including novel antifungal agents, monoclonal antibodies against aspects of the adaptive immune response as well as targeted immunotherapies may be better tolerated and achieve improved outcomes but have not yet been studied in large-scale randomised control trials.

Tolerogenic Nanoparticles Impacting B and T Lymphocyte Responses Delay Autoimmune Arthritis in K/BxN Mice

Current treatments for unwanted antibody responses largely rely on immunosuppressive drugs compromising overall immunity. New approaches to achieve antigen-specific tolerance are desirable to avoid unwanted side effects. Several nanoparticle-based approaches that utilize different mechanisms to tolerize the B or T cell arms of the humoral immune response have shown promise for induction of antigen-specific tolerance, raising the possibility that they could work synergistically if combined. Earlier we showed that Siglec-engaging tolerance-inducing antigenic liposomes (STALs) that display both an antigen (Ag) and glycan ligands of the inhibitory co-receptor CD22 (CD22L) lead to robust antigen-specific B cell tolerance to protein antigens in naive mice. In another approach, administration of free Ag with poly(lactic-co-glycolic acid)-rapamycin nanoparticles (PLGA-R) induced robust antigen-specific tolerance through production of regulatory T cells. Here we illustrate that coadministration of STALs together with PLGA-R to naive mice induced more robust tolerance to multiple antigen challenges than either nanoparticle alone. Moreover, in K/BxN mice that develop spontaneous autoimmune arthritis to the self-antigen glucose-6-phosphate-isomerase (GPI), co-delivery of GPI-LP-CD22L and PLGA-R delayed onset of disease and in some mice prevented the disease indefinitely. The results show synergy between B cell-tolerizing STALs and T cell-tolerizing PLGA-R and the potential to induce tolerance in early stage autoimmune disease.

Effectiveness of Sublingual Immunotherapy in the Treatment of HDM-Induced Nasobronchial Allergies: A 3-Year Randomized Case-Control Study From Kashmir

Allergen immunotherapy (AIT) is the only disease-modifying treatment for allergic disorders that induces immunological tolerance through administration of specific allergens. Studies on AIT for subcutaneous route are in abundance; however, the efficacy of AIT in tablet form through sublingual route has not been well elucidated. The present prospective, parallel-group, controlled study sought to compare the efficacy of sublingual immunotherapy (SLIT) tablets with pharmacotherapy (PT) in 332 house dust mite (HDM)-specific allergic asthma and/or rhinitis patients over a period of 3 years. Patients were followed up for a 6-month run-in period and then randomly stratified as those who would receive SLIT, SLIT in addition to PT (SLIT+PT), and PT alone. AIT was administered in the form of sublingual tablets. Symptom and medication scores were measured every 3 months. In vitro evaluation of serum total and HDM specific immunoglobulin E (HDM sIgE) levels was carried out every 3 months, whereas in vivo skin prick test was performed annually for 3 years. Our study demonstrated sustained clinical improvement, reduction in inhaled corticosteroid (ICS) dose and duration as well as prevention from development of neosensitization to other aero allergens in HDM-allergic asthmatics and/or rhinitis patients treated with 3 years SLIT. Despite a remarkable clinical improvement with AIT, we observed that SLIT did not significantly change the skin reactivity to HDM at 3 years and there was no significant change in the ratio of serum total and HDM sIgE. Given the immune and disease modifying effects of AIT in allergic diseases, the present study supports the notion of its sublingual mode being an effective long-term immunomodulator in HDM-sensitized nasobronchial allergies.

Differential induction of allergen-specific IgA responses following timothy grass subcutaneous and sublingual immunotherapy

INTRODUCTION

There is no detailed comparison of allergen-specific immunoglobulin responses following sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT).

OBJECTIVE

We sought to compare nasal and systemic timothy grass pollen (TGP)-specific antibody responses during 2 years of SCIT and SLIT and 1 year after treatment discontinuation in a double-blind, double-dummy, placebo-controlled trial.

METHODS

Nasal fluid and serum were obtained yearly (per-protocol population, n = 84). TGP-specific IgA₁, IgA₂, IgG₄, IgG, and IgE were measured in nasal fluids by ELISA. TGP-specific IgA₁, IgA₂, and Phleum pratense (Phl p)1, 2, 4, 5b, 6, 7, 11, and 12 IgE and IgG₄ were measured in sera by ELISA and ImmunoCAP, respectively.

RESULTS

At years 2 and 3, TGP-IgA_1/2 levels in nasal fluid were elevated in SLIT compared with SCIT (4.2- and 3.0-fold for IgA₁, 2.0- and 1.8-fold for IgA₂, respectively; all P < .01). TGP-IgA₁ level in serum was elevated in SLIT compared with SCIT at years 1, 2, and 3 (4.6-, 5.1-, and 4.7-fold, respectively; all P < .001). Serum TGP-IgG level was higher in SCIT compared with SLIT (2.8-fold) at year 2. Serum TGP-IgG₄ level was higher in SCIT compared with SLIT at years 1, 2, and 3 (10.4-, 27.4-, and 5.1-fold, respectively; all P < .01). Serum IgG₄ levels to Phl p1, 2, 5b, and 6 were increased at years 1, 2, and 3 in SCIT and SLIT compared with placebo (Phl p1: 11.8- and 3.9-fold; Phl p2: 31.6- and 4.4-fold; Phl p5b: 135.5- and 5.3-fold; Phl p6: 145.4- and 14.7-fold, respectively, all at year 2 when levels peaked; P < .05). IgE to TGP in nasal fluid increased in the SLIT group at year 2 but not at year 3 compared with SCIT (2.8-fold; P = .04) and placebo (3.1-fold; P = .02). IgA to TGP and IgE and IgG₄ to TGP components stratified participants according to treatment group and clinical response.

CONCLUSIONS

The observed induction of IgA_1/2 in SLIT and IgG₄ in SCIT suggest key differences in the mechanisms of action.

Serum Concentrations of Antigen-Specific IgG4 in Patients with Japanese Cedar Pollinosis

Purpose: To elucidate the usefulness of Japanese cedar pollen (JCP)-specific antigen-specific immunoglobulin (IgG) 4 as a biomarker for predicting the efficacy of sublingual immunotherapy for cedar pollen-induced allergic rhinitis. Methods: We divided a total of 105 cases with Japanese cedar pollinosis into three groups: “SLIT Successful,” SLIT Unsatisfactory,” and “SCIT” groups. The SLIT group patients were treated with JCP Droplet (Torii Pharmaceutical Co. Ltd., Tokyo, Japan) for one year from 2015 and were divided into two groups, the SLIT Successful group or the SLIT Unsatisfactory group. The SLIT Successful group (n = 16) were subjects treated by SLIT only, who were able to experience control of their naso-ocular symptoms without the need for antiallergic rescue agents during the peak season of atmospheric pollen. The SLIT Unsatisfactory group (n = 76) comprised subjects treated with SLIT only, who did not respond successfully, and were administered with rescue agents to control their naso-ocular symptoms. The SCIT group had been treated with standardized JCP extract (Torii Pharmaceutical Co., Ltd., Tokyo, Japan) for three years from 2012, and were also able to experience control of their symptoms during the peak pollen season without the need for antiallergic rescue agents. We determined the serum level of JCP-specific immunoglobulin E (IgE), IgG, and IgG4 used in the 3gAllergy-specific IgE assay (3gAllergy). The serum levels of periostin and SCCA2 were measured using established ELISA procedures (clones SS18A and SS17B; Shino-Test, Japan) following the manufacturer’s instructions. We then made ROC curves for each group and assessed which index was best able to predict the efficacy of sublingual immunotherapy. Results: Serum JCP-specific IgE was significantly lower in the SCIT group than in the SLIT Successful group and the SLIT Unsatisfactory group (p < 0.05). Serum JCP-specific IgG was significantly higher in the SCIT group and the SLIT Successful group than in the SLIT Unsatisfactory group (p < 0.05). Serum JCP-specific IgG4 was also significantly higher in the SCIT group and the SLIT Successful group than in the SLIT Unsatisfactory group (p < 0.05). There was no significant difference among serum levels of periostin in the SCIT group, the SLIT Successful group, or the SLIT Unsatisfactory group. There was also no significant difference in SCCA2 among the three groups. In terms of ROC curves, a serum JCP-specific IgG4 value greater than 989.5 UA/mL showed the best sensitivity (93.3%) and specificity (94.7%) (p < 0.05) among other parameters. Conclusions: The serum JCP-specific IgG4 level is significantly correlated with the clinical efficacy of SLIT. Serum JCP-specific IgG4 cutoff levels greater than 989.5 UA/mL were correlated with an effective clinical response to SLIT, with a sensitivity of 93.3% and a specificity of 94.7%.

Systemic reactions to subcutaneous allergen immunotherapy: real-world cause and effect modelling

Background

Subcutaneous immunotherapy (SCIT) is an effective treatment for allergic rhinoconjunctivitis. However, adverse events, including life-threatening systemic reactions, may occur. The purpose of this project is to identify risk factors for systemic reactions to SCIT and to provide practice-based solutions using a quality improvement (QI) framework.

Methods

A QI initiative was performed in a hospital-based, Canadian Allergy clinic administering SCIT in a 12-month period.

Results

A total of 4242 injections of SCIT were performed over a period of 12 months. Of these, 10 injections resulted in a systemic reaction requiring epinephrine administration (i.e., an incidence of 1 in 424 injections, or 0.24%). Eight patients had at least one documented risk factor for a systemic reaction, and six had multiple risk factors. Major risk factors included seasonal exacerbation of allergic rhinitis, uncontrolled asthma, and an error in route of administration. All reactions occurred with the highest allergen extract concentration.

Conclusion

This QI initiative highlights the need for improved patient and health care practitioner education and pre-administration screening. We suggest several considerations for SCIT administration: provide patients with written information on safety; screen patients before injections, including a review of treatment plan adherence and asthma control; adjust dosing to slow down buildup of the most concentrated immunotherapy extract, particularly in high risk patients; and apply additional safety measures in patients with multiple risk factors.

Real-world evidence costs of allergic rhinitis and allergy immunotherapy in the commercially insured United States population

OBJECTIVE

To assess total and allergic rhinitis (AR)-related healthcare costs among AR patients residing in the United States with a focus on patients persisting with AIT.

METHODS

AR patients were identified in the IBM MarketScan database between 1 January 2014 to 31 March 2017. Patients receiving allergy immunotherapy (AIT) were identified with relevant billing codes (earliest AIT claim = index date); non-AIT patients were identified with claims containing a diagnosis code for AR (earliest AR claim = index date). AIT patients reaching 25+ injection claims were analyzed as a separate maintenance cohort. All patients were required to have continuous enrollment for 12 months preceding and following index.

RESULTS

A total of 2,334,530 AR patients were included; 103,207 had at least 1 AIT claim, with 45,279 (43.9%) of these patients reaching maintenance, and 24,640 AIT patients (23.9%) never presenting a single injection claim. Compared to non-AIT patients, patients initiating AIT presented higher rates of baseline comorbidities, including asthma (30.1% vs. 7.5%) and conjunctivitis (21.7% vs. 4.4%). During the follow-up period, patients reaching the maintenance phase of AIT incurred lower total costs than the overall AIT cohort ($10,431±$16,606 vs. $11,612±$24,797), and also presented lower follow-up hospitalization costs ($698±$7,248 vs. $1,281±$12,991) and total medical costs ($7950±$13,844 vs. $8989±$22,019).

CONCLUSIONS

Continued efforts are needed to increase patient awareness of available options and adherence to AIT, along with reducing wastage. Despite AIT patients presenting fairly progressed disease at the time of treatment initiation, this therapy remains an economical treatment option, as it was not accompanied by substantial increases in overall healthcare expenditure, and may promote positive societal impacts beyond the direct medical costs.What is known on this topicThe prevalence of allergic diseases has increased over the past 50 years and affects between 10-30% of the world population.Allergic rhinitis (AR) poses a significant economic burden in the form of both direct and indirect costsAllergy immunotherapy (AIT) is the only treatment option able to modify the underlying course of the disease.What this study addsSpecific all-cause and AR-related healthcare costs decreased following the initiation of AIT among patients diagnosed with AR, with the largest decreases observed among AIT patients reaching the maintenance phase of treatment, while non-AIT patients showed increases in all categories assessed over a similar follow-up period.Cost decreases among AIT patients were observed despite increased levels of comorbidities compared to non-AIT patients, as the AIT cohort presented elevated rates of atopic dermatitis (7.1% vs. 2.7%), conjunctivitis (21.7% vs. 4.4%), asthma (30.1% vs. 7.5%), and chronic sinusitis (22.6% vs. 4.9%).An analysis of patients' index subcutaneous AIT consultation revealed substantial variability in the initial treatment costs, with nearly 20% of paid amounts exceeding $1,000; given nearly 1 in 4 AIT patients who get AIT mixed never came back for their first injection, this highlights an opportunity to target frontloaded billing practices and the timing of mixing/injection as an area to minimize healthcare waste.

A Retrospective Nationwide Non-Interventional Study of an Aqueous Sublingual Immunotherapy Formulation Administered with a 200-µL Dosing Pump

Background

Convenient dosing is a key component of treatment adherence and thus efficacy and safety. Aqueous sublingual immunotherapy (SLIT) formulations can be administered with a dosing pump that delivers 200 µL of volume per actuation.

Objective

The objective of this study was to describe the use of Staloral^® 300 Rapid in its new dosing pump presentation and to evaluate the safety and satisfaction from both the patient and doctor.

Patients and Methods

We performed a retrospective non-interventional study in a population (aged 5 years or over) of individuals with allergic rhinitis or allergic asthma who were being treated with aqueous 300 index of reactivity SLIT formulations of various allergens (grass pollen, tree pollen, house dust mites). Based on a detailed, SLIT-specific, patient self-questionnaire (Quartis^®) and the inspection of medical records, we assessed the characteristics of the SLIT, safety, patient satisfaction and willingness to continue SLIT. The physician’s satisfaction with the treatment was measured on a 0–100 visual analogue scale. Adverse events were coded with the Medical Dictionary for Regulatory Activities.

Results

A total of 801 valid patients were included (52.4% male; mean ± standard deviation age: 25.9 ± 17.2 years; mean time since diagnosis: 4.56 ± 4.68 years; mean time using the previous dosing pump: 19.2 ± 13.0 months; time using the 200-µL dosing pump: 14.95 ± 3.80 months). Among the study population, 317 subjects comprised the paediatric subgroup (57%: male; mean age: 9.8 ± 2.5 years). Overall, 54 patients (6.7%) reported a total of 68 adverse events (including 51 gastrointestinal adverse events). The large majority of adverse events were mild, local and transient and did not require treatment. There were no severe adverse events. The level of patient satisfaction with the ease of SLIT administration was high (84.3% overall, and 82.6% in the paediatric subgroup). The mean ± standard deviation visual analogue scale score for physician satisfaction with the treatment was 70.6 ± 25.1 out of 100.

Conclusions

Administration of 300 index of reactivity SLIT with a 200-µL dosing pump is safe, well tolerated and associated with good levels of patient satisfaction.

Real-world mapping of allergy immunotherapy in the United States: The argument for improving adherence

Background: There is a dearth of real-world evidence studies focused on allergy immunotherapy (AIT) use among patients with allergic rhinitis (AR). Objective: This study examined claims data of AR patients residing in the United States to assess patient characteristics and health outcomes. Methods: AR patients were identified in the IBM MarketScan database between January 1, 2014, and March 31, 2017. Patients receiving AIT were identified with relevant billing codes (earliest AIT claim for vaccine as the index date); patients without AIT were identified with claims that contained a diagnosis code for AR (earliest AR claim as the index date). All the patients were required to have continuous enrollment 12 months prior to and following their index date. AIT patients reaching 25+ injection claims were analyzed as a separate maintenance cohort. Patients were assessed for demographic characteristics, comorbid conditions, and health care utilization. Results: A total of 2,334,530 AR patients were included; 103,207 had at least one AIT claim, with 45,279 (43.9%) of these patients reaching maintenance. Patients who reached AIT maintenance presented higher rates of baseline comorbidities than both the full AIT cohort and the patients with no AIT claims, including asthma (34.6% versus 30.1% versus 7.5%) and upper respiratory tract infections (63.1% versus 60.3% versus 34.2%). From baseline to follow-up, maintenance AIT patients demonstrated reductions in all AR-related comorbidities assessed, along with reductions in all-cause and AR-related service utilization. Conclusion: Patients initiating AIT presented the greatest need for therapeutic intervention, as evidenced by higher allergy-related comorbidities; those who reached maintenance demonstrated improved outcomes following the initiation of therapy. Continued efforts to increase patient awareness and adherence to AIT are needed.

Compliance, efficacy, and safety of subcutaneous and sublingual immunotherapy in children with allergic rhinitis

BACKGROUND

Although previous studies had confirmed the effectiveness and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), respectively, direct head-to-head comparison of SCIT vs SLIT is sparse. We aimed to compare the efficacy, safety, and compliance of SCIT and SLIT in allergic rhinitis (AR) children.

METHODS

This study is a prospective, open-label, and single-center study performed between June 2017 and June 2018. A total of 325 children were grouped into SLIT, Alutard (SCIT1), and NovoHelisen Depot (NHD) (SCIT2) according to the parents' wishes. The adherence and reasons for dropout were recorded. The efficacy of SLIT and SCIT was evaluated by a combined symptom medication score. Adverse events (AEs) were recorded and graded during the whole treatment.

RESULTS

The compliance rate was higher in the SCIT group compared with the SLIT group (P < .05). The total nasal symptom score (TNSS), rescue medication score (RMS), and symptom medication score (SMS) after 6-month, 12-month, and 2-year treatment were lower in the SCIT group compared with the SLIT group (P < .05). But the scores between the Alutard and NHD groups were not significantly different. The occurrence of AEs in the SCIT group was significantly higher compared with the SLIT group (P < .05).

CONCLUSION

Our results suggested SCIT is more effective compared with SLIT to a certain degree, whereas SLIT had less AEs compared with SCIT. The AIT routes can be chosen according to personal specific conditions.

Mechanisms of Allergen Immunotherapy in Allergic Rhinitis

PURPOSE OF REVIEW

Allergic rhinitis (AR) is a chronic inflammatory immunoglobulin (Ig) E-mediated disease of the nasal mucosa that can be triggered by the inhalation of seasonal or perennial allergens. Typical symptoms include sneezing, rhinorrhea, nasal itching, nasal congestion and symptoms of allergic conjunctivitis. AR affects a quarter of the population in the United States of America and Europe.

RECENT FINDINGS

AR has been shown to reduce work productivity in 36-59% of the patients with 20% reporting deteriorated job attendance. Moreover, 42% of children with AR report reduced at-school productivity and lower grades. Most importantly, AR impacts the patient's quality of life, due to sleep deprivation. However, a proportion of patients fails to respond to conventional medication and opts for the allergen immunotherapy (AIT), which currently is the only disease-modifying therapeutic option. AIT can be administered by either subcutaneous (SCIT) or sublingual (SLIT) route. Both routes of administration are safe, effective, and can lead to tolerance lasting years after treatment cessation. Both innate and adaptive immune responses that contribute to allergic inflammation are suppressed by AIT. Innate responses are ameliorated by reducing local mast cell, basophil, eosinophil, and circulating group 2 innate lymphoid cell frequencies which is accompanied by decreased basophil sensitivity. Induction of allergen-specific blocking antibodies, immunosuppressive cytokines, and regulatory T and B cell phenotypes are key pro-tolerogenic adaptive immune responses.

CONCLUSION

A comprehensive understanding of these mechanisms is necessary for optimal selection of AIT-responsive patients and monitoring treatment efficacy. Moreover, it could inspire novel and more efficient AIT approaches.

The evolution of allergy immunotherapy

OBJECTIVE

The objective of this review is to trace the evolution of the art and science of allergy immunotherapy (AIT).

DATA SOURCES

Original reports relating to the evolution of the concept of respiratory allergy and its specific treatment were identified by following references in journal articles, review articles, and allergy textbooks from the mid-20th century to the present.

STUDY SELECTIONS

Studies highlighting substantial milestones in the evolution of the practice of allergy immunotherapy were included.

RESULTS

The story of AIT begins with the recognition of hay fever as a distinct entity and subsequent studies that established grass pollen as one of the causes. This knowledge led several investigators, most notable Leonard Noon and John Freeman who worked at St. Mary's Hospital in London, to attempt to induce tolerance giving grass pollen extract by injection to their patients. After the publication of the work of Noon and Freeman in 1911, the practice of AIT spread rapidly and was applied to many other pollen allergens besides grass and for perennial rhinitis and asthma. The early studies were largely anecdotal, but over the past 60 to 70 years, studies of AIT have been conducted with increasingly sophisticated scientific methods. Nowadays, not only is the practice of AIT based on carefully conducted studies, but the underlying immunologic basis of allergy and the response to AIT have also been and still are being firmly established.

CONCLUSION

Both the art and the science behind the practice of AIT have been established by a solid base of clinical and immunologic studies.

Genetically engineered fusion of allergen and viral-like particle induces a more effective allergen-specific immune response than a combination of them

Chimeric virus-like particles (VLPs) were developed as a candidate for allergen-specific immunotherapy. In this study, hepatitis B core antigen (HBcAg) that genetically fused to Chenopodium album polcalcin (Che a 3)-derived peptide was expressed in E. coli BL21, purified, and VLP formation was evaluated using native agarose gel electrophoresis (NAGE) and transmission electron microscopy (TEM). Chimeric HBc VLPs were characterized in terms of their reactivity to IgE, the induction of blocking IgG and allergen-specific IgE, basophil-activating capacity, and Th1-type immune responses. Results from IgE reactivity and basophil activation test showed that chimeric HBc VLPs lack IgE-binding capacity and basophil degranulation activity. Although chimeric HBc VLPs induced the highest level of efficient polcalcin-specific IgG antibody in comparison to those induced by recombinant Che a 3 (rChe a 3) mixed either with HBc VLPs or alum, they triggered the lowest level of polcalcin-specific IgE in mice following immunization. Furthermore, in comparison to the other antigens, chimeric HBc VLPs produced a polcalcin-specific Th1 cell response. Taken together, genetically fusion of allergen derivatives to HBc VLPs, in comparison to a mix of them, may be a more effective way to induce appropriate immune responses in allergen-specific immunotherapy. KEY POINTS: • The insertion of allergen-derived peptide into major insertion region (MIR) of hepatitis B virus core (HBc) antigen resulted in nanoparticles displaying allergen-derived peptide upon its expression in prokaryotic host. • The resultant VLPs (chimeric HBc VLPs) did not exhibit IgE reactivity with allergic patients' sera and were not able to degranulate basophils. • Chimeric HBc VLPs dramatically improved protective IgG antibody response compared with those induced by allergen mixed either with HBc VLPs or alum. • Chimeric HBc VLPs induced Th1 responses that were counterparts of Th2 responses (allergic). • Chimeric HBc VLPs increased IgG2a/ IgG1 ratio and the level of IFN-γ compared to those induced by allergen mixed with either HBc VLPs or alum. Graphical Abstract.

Specific sublingual immunotherapy in children with perennial rhinitis: a systemic review and meta-analysis

BACKGROUND

Allergic rhinitis (AR) is a major public health problem and is increasing worldwide. AR affects children's learning efficiency, sleep quality, and other major aspects of life. Sublingual immunotherapy (SLIT) is effective and safe for children with seasonal AR, but for children with perennial allergic rhinitis (PAR) caused by house dust mites (HDM), its effectiveness and safety is less convincing.

METHODS

Medical literature databases up to 2019 were searched for published and unpublished pieces of evidence. Studies were individually screened by 2 reviewers against the eligibility criteria. Primary outcomes were total nasal symptoms scores (TNSS) and total medication scores (TMS). The secondary outcomes were total ocular symptoms scores and adverse events (AEs). Random effect models and fixed-effect models were used to calculate the standard mean difference (SMD) and risk ratio (RR), respectively.

RESULTS

We identified 3772 abstracts, of which only 16 studies met our established criteria. SLIT significantly reduced TNSS (SMD -1.73; 95% CI, -2.62 to -0.84; p = 0.0001) and TMS (SMD -1.21; 95% CI, -1.75 to -0.67; p < 0.00001). Compared with children taking placebo, children taking SLIT were 1.08 (95% CI, 1 to 1.17; p = 0.05), 1.15 (95% CI, 0.87 to 1.51; p = 0.32), and 1.68 (95% CI, 0.68 to 4.11; p = 0.26) times more likely to develop mild, moderate, and severe AEs, respectively.

CONCLUSION

HDM SLIT can effectively alleviate TNSS and TMS in children with PAR, but care should be taken to avoid harm due to possible adverse drug reactions.

Probiotics function and modulation of the immune system in allergic diseases

Allergic diseases have been a global problem over the past few decades. The effect of allergic diseases on healthcare systems and society is generally remarkable and is considered as one of the most common causes of chronic and hospitalized disease. The functional ability of probiotics to modulate the innate/acquired immune system leads to the initiation of mucosal/systemic immune responses. Gut microbiota plays a beneficial role in food digestion, development of the immune system, control/growth of the intestinal epithelial cells and their differentiation. Prescribing probiotics causes a significant change in the intestinal microflora and modulates cytokine secretion, including networks of genes, TLRs, signaling molecules and increased intestinal IgA responses. The modulation of the Th1/Th2 balance is done by probiotics, which suppress Th2 responses with shifts to Th1 and thereby prevent allergies. In general, probiotics are associated with a decrease in inflammation by increasing butyrate production and induction of tolerance with an increase in the ratio of cytokines such as IL-4, IL-10/IFN-γ, Treg/TGF-β, reducing serum eosinophil levels and the expression of metalloproteinase-9 which contribute to the improvement of the allergic disease's symptoms. Finally, it can be said that the therapeutic approach to immunotherapy and the reduction of the risk of side effects in the treatment of allergic diseases is the first priority of treatment and the final approach that completes the first priority in maintaining the condition and sustainability of the tolerance along with the recovery of the individual.

Tyrophagus putrescentiae group 4 allergen allergenicity and epitope prediction

INTRODUCTION AND OBJECTIVES

Allergen-specific immunotherapy (ASIT) is the only allergic disease-modifying therapy available for children and adults, and recombinant allergens are an interesting approach to improve allergy diagnosis and ASIT. Tyrophagus putrescentiae is a common storage mite that produces potent allergens. The aim of this study was to express and characterize recombinant group 4 allergen protein of T. putrescentiae (Tyr p 4), and to further investigate allergenicity and potential epitopes of Tyr p 4.

MATERIALS AND METHODS

The cDNA encoding Tyr p 4 was generated by RT-PCR and subcloned into pET-28a(+) plasmid. The plasmid was then transformed into E. coli cells for expression. After purification by nickel affinity chromatography and identification by SDS-PAGE, recombinant Tyr p 4 protein was used for a skin prick test and an ELISA to determine the allergic response.

RESULTS

Study participants' allergic response rate to Tyr p 4 protein was 13.3% (16/120). Eight B-cell epitopes and three T-cell epitopes of Tyr p 4 were predicted.

CONCLUSIONS

Similar to group 4 allergens of other species of mite, allergenicity of Tyr p 4 is weak. The expression, characterization and epitope prediction of recombinant Tyr p 4 protein provide a foundation for further study of this allergen in the diagnosis and ASIT of storage mite allergy.

Tolerance mechanisms in allergen immunotherapy

PURPOSE OF REVIEW

Allergen immunotherapy is the only treatment modality which alters the natural course of allergic diseases by restoring immune tolerance against allergens. Deeper understanding of tolerance mechanisms will lead to the development of new vaccines, which target immune responses and promote tolerance.

RECENT FINDINGS

Successful allergen immunotherapy (AIT) induces allergen-specific peripheral tolerance, characterized mainly by the generation of allergen-specific Treg cells and reduction of Th2 cells. At the early phase, AIT leads to a decrease in the activity and degranulation of mast cells and basophils and a decrease in inflammatory responses of eosinophils in inflamed tissues. Treg cells show their effects by secreting inhibitory cytokines including interleukin (IL)-10, transforming growth factor-β, interfering with cellular metabolisms, suppressing antigen presenting cells and innate lymphoid cells (ILCs) and by cytolysis. AIT induces the development of regulatory B cells producing IL-10 and B cells expressing allergen-specific IgG4. Recent investigations have demonstrated that AIT is also associated with the formation of ILC2reg and DCreg cells which contribute to tolerance induction.

SUMMARY

Research done so far, has shown that multiple molecular and cellular factors are dysregulated in allergic diseases and modified by AIT. Studies should now focus on finding the best target and ideal biomarkers to identify ideal candidates for AIT.

Effectiveness and adverse events of topical and allergen immunotherapy for atopic dermatitis: a systematic review and network meta-analysis protocol

BACKGROUND

Atopic dermatitis (AD) is an inflammatory chronic condition that affects the skin of children and adults and has an important impact on the quality of life. Treatments for AD are based on environmental controls, topical and systemic therapies, and allergen-specific immunotherapy (AIT). However, it remains unclear the effectiveness and adverse events of AIT and all conventional topical treatments compared with placebo and each other for AD.

METHODS

We will search five electronic databases [Central Cochrane register of controlled trials (CENTRAL), MEDLINE, EMBASE, CINAHL, and LILACS] from inception until November 2019 with no language restriction, and we will include experimental studies [randomized controlled trials (RCTs), and quasi-RCTs]. The primary outcome is global and specific skin symptoms assessment. Secondary outcomes are hospital length of stay, quality of life, and adverse events. Reviewers independently will extract data from the studies that meet our inclusion criteria and will assess the risk of bias of individual primary studies. We will conduct random effects pairwise meta-analyses for the observed pairwise comparisons with at least two trials. Then, we will perform random-effects Bayesian network meta-analysis (NMA) to obtain treatment effects for all possible comparisons and to provide a hierarchy of all interventions for each outcome. Possible incoherence between direct and indirect sources of evidence will be investigated locally (if possible) and globally. To investigate sources of statistical heterogeneity, we will perform a series of meta-regression analyses based on pre-specified important effect modifiers. Two authors will appraise the certainty of the evidence for each outcome applying the GRADE's framework for NMA.

DISCUSSION

The findings of this systematic review will shed the light on the effectiveness and adverse events of all possible comparisons for treating AD and on the quality of the collated evidence for recommendations. It will also provide critical information to health care professionals to comprehend and manage this disease at different age stages, treatment type, duration, and severity of atopic dermatitis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO Protocol ID CRD42019147106.

[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.

Sublingual dendritic cells targeting by aptamer: Possible approach for improvement of sublingual immunotherapy efficacy

The efficacy improvement of current sublingual immunotherapy (SLIT) for preventing and treating respiratory airway allergic diseases is the main purpose of many investigations. In this study, we aimed to assess whether ovalbumin (Ova) encapsulated poly (lactic-co-glycolic) acid nanoparticles (PLGA NPs) decorated with dendritic cells (DCs)-specific aptamer could be applied for this purpose.The nanoparticles containing Ova were synthesized by emulsion/solvent evaporation method and attached to DCs-specific aptamer. Ova-sensitized BALB/c mice have been treated in five ways: subcutaneously with free Ova (SCIT), sublingually either with free Ova, Ova-PLGA NPs (two doses), Apt-Ova-PLGA NPs (two doses) and placebo/control Apt-Ova-PLGA NPs. For assessment of immunologic responses, IL-4, IFN-γ, IL-17, IL10, and TGF-β and IgE antibody levels were measured by ELISA and T cell proliferation were evaluated by MTT. In addition, lung and nasal histological examinations, NALF cells counting were carried out. Results declared that the lowest IgE and IL- 4 levels were observed in Apt-Ova-PLGA NPs (both doses). In the other hands, Apt-Ova-PLGA NPs (high dose) showed the highest increase of IFN- γ and TGF- β, decrease of IL-17 levels, total cell count and T-cell proliferation. IL-10 levels showed more decrease in SCIT, Apt-Ova-PLGA NPs (high dose) and Ova-PLGA NPs (high dose) than other groups. Histopathological examinations also confirmed in vitro results. Our findings suggest SLIT with this functionalized delivery system could be a promising approach for promoting the SLIT efficiency by decreasing the required allergen doses through specific delivery of allergen to sublingual DCs and enhancing the suppression of allergic responses.

Allergen Immunotherapy for Local Respiratory Allergy

PURPOSE OF REVIESW

Local respiratory allergy (LRA) is an eosinophilic phenotype of chronic airway disease. Three entities have been described within the LRA spectrum: local allergic rhinitis (LAR) and local allergic asthma (LAA) in non-atopic patients, and dual allergic rhinitis (DAR) in atopic patients (coexistence of LAR and allergic rhinitis). In this article, we aim to review the current evidence on the therapeutic options for LRA.

RECENT FINDINGS

No controlled study has assessed the effect of standard therapy (oral antihistamines, intranasal or inhaled corticosteroids, bronchodilators) in LRA subjects. Three randomized clinical trials and one observational study demonstrated that allergen immunotherapy (AIT) is able to control nasal and ocular symptoms, decrease the need for rescue medication, and improve quality of life in LAR individuals. Nasal or inhaled steroids can be expected to improve eosinophilic inflammation in LRA patients but cannot change the natural course of the disease. Moreover, the long-term and disease-modifying effects of AIT in LRA subjects need to be investigated.

Clinical Practice of Allergen Immunotherapy for Allergic Rhinoconjunctivitis and Asthma: An Expert Panel Report

Allergen immunotherapy (AIT) reduces symptoms and medication use associated with allergic rhinitis with or without conjunctivitis and allergic asthma. Although several AIT guidelines exist, there remain unanswered questions about AIT that are relevant to everyday practice. Our objective was to prepare an evidence-based overview addressing the practical aspects of AIT in clinical practice based on published evidence and the experience of international experts in the field. Topics covered include interpretation and translation of clinical trial data into everyday clinical practice (eg, allergen doses and treatment duration), assessment of risk and treatment of local and systemic allergic reactions, recommendations for improvement of AIT guidelines, and identification of appropriate data for seeking regulatory approval, to name a few. Many informational gaps in AIT practice need further evaluation as products and practices evolve.

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.