Allergen immunotherapy for allergic asthma: a systematic overview of systematic reviews

Efficacy and safety of subcutaneous immunotherapy combined with omalizumab in children with dust mite-induced asthma

OBJECTIVE

To evaluate the benefits of combining omalizumab with specific immunotherapy (SCIT) in the treatment of children with bronchial asthma.

METHODS

In this study, 83 children with asthma were treated at the Allergy Department of Qingdao University from January 2019 to February 2020. Participants were divided into three groups: SCIT, combination (omalizumab + SCIT), and control (standard asthma medications). We assessed Asthma Control Questionnaire (ACQ) scores, Visual Analogue Scale (VAS) scores, and lung function at baseline, 24 wk, and 48 wk. Additionally, asthma medication scores were compared at 24 and 48 wk. Adverse reactions were monitored in both the SCIT and combination groups.

RESULTS

The combination group demonstrated lower ACQ scores at both 24 and 48 wk, and improved VAS scores at 48 wk compared to the other groups. Additionally, lung function parameters (FEV1 and FEF50) showed significant improvement in the combination group. Reduced asthma medication scores were noted in the combination group at 24 and 48 wk. Local adverse reactions were fewer in the combination group, and no systemic adverse reactions were reported.

CONCLUSION

Combining omalizumab with SCIT provides quicker asthma control, lowers medication requirements, and enhances lung function with fewer adverse effects, making it a safe and effective treatment for children with bronchial asthma.

The combination of allergen immunotherapy and biologics for inhalant allergies: Exploring the synergy

The development of monoclonal antibodies that selectively target IgE and type 2 immunity has opened new possibilities in the treatment of allergies. Although they have been used mainly as single therapies found to have efficacy in the management of asthma and other T2-mediated diseases, there is a growing interest in using these monoclonal antibodies in combination with allergen immunotherapy (AIT). AIT has transformed the treatment of allergic diseases by aiming to modify the underlying immune response to allergens rather than just providing temporary symptom relief. Despite the proven efficacy and safety of AIT, unmet needs call for further research and innovation. Combination strategies involving biologics and AIT exhibit potential in improving short-term efficacy, reducing adverse events, and increasing immunologic tolerance. Anti-IgE emerges as the most promising therapeutic strategy, not only enhancing AIT's safety and tolerability but also providing additional evidence of efficacy compared with AIT alone. Anti-interleukin-4 receptor offers a reduction in adverse effects and an improved immunologic profile when combined with AIT; however, its impact on short-term efficacy seems limited. The combination of cat dander subcutaneous immunotherapy with anti-thymic stromal lymphopoietin was synergistic with enhanced efficacy and altered immune responses that persisted for 1 year after discontinuation compared with AIT alone. Long-term studies are needed to evaluate the sustained benefits and safety profiles of combination strategies.

House dust mite SCIT reduces asthma risk and significantly improves long-term rhinitis and asthma control-A RWE study

BACKGROUND

The German Therapy Allergen Ordinance (TAO) triggered an ongoing upheaval in the market for house dust mite (HDM) allergen immunotherapy (AIT) products. Three HDM subcutaneous AIT (SCIT) products hold approval in Germany and therefore will be available after the scheduled completion of the TAO procedure in 2026. In general, data from clinical trials on the long-term effectiveness of HDM AIT are rare. We evaluated real-world data (RWD) in a retrospective, observational cohort study based on a longitudinal claims database including 60% of all German statutory healthcare prescriptions to show the long-term effectiveness of one of these products in daily life. Aim of this analysis was to provide a per product analysis on effectiveness of mite AIT as it is demanded by international guidelines on AIT.

METHODS

Subjects between 5 and 70 years receiving their first (index) prescription of SCIT with a native HDM product (SCIT group) between 2009 and 2013 were included. The exactly 3:1 matched control group received prescriptions for only symptomatic AR medication (non-AIT group); the evaluation period for up to 6 years of follow-up ended in February 2017. Study endpoints were the progression of allergic rhinitis (AR) and asthma, asthma occurrence and time to the onset of asthma after at least 2 treatment years.

RESULTS

In total, 892 subjects (608 adults and 284 children/adolescents) were included in the SCIT group and 2676 subjects (1824 adults and 852 children/adolescents) in the non-AIT group. During the follow-up period after at least 2 years of SCIT, the number of prescriptions in the SCIT group was reduced by 62.8% (p < .0001) for AR medication and by 42.4% for asthma medication (p = .0003). New-onset asthma risk was significantly reduced in the SCIT vs non-AIT group by 27.0% (p = .0212). The asthma-preventive effect of SCIT occurred 15 months after start of the treatment. In the SCIT group, the time to onset of asthma was prolonged compared to the non-AIT group (p = .0010).

CONCLUSION

In this first product based RWD analysis on SCIT with a native HDM product, patients aged 5 to 70 years benefited from AIT in the long term in terms of reduced progression of AR and asthma after at least 2 years of treatment. The effects seemed to last for up to 6 years after treatment termination. A significantly reduced risk of asthma onset was observed, starting after 15 months of treatment.

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

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

One-pot preparation of mannan-coated antigen nanoparticles using human serum albumin as a matrix for tolerance induction

Nanoparticles (NPs) for allergen immunotherapy have garnered attention for their high efficiency and safety compared with naked antigen proteins. In this work, we present mannan-coated protein NPs, incorporating antigen proteins for antigen-specific tolerance induction. The heat-induced formation of protein NPs is a one-pot preparation method and can be applied to various proteins. Here, the NPs were formed spontaneously via heat denaturation of three component proteins: an antigen protein, human serum albumin (HSA) as a matrix protein, and mannoprotein (MAN) as a targeting ligand for dendritic cells (DCs). HSA is non-immunogenic, therefore suitable as a matrix protein, while MAN coats the surface of the NP. We applied this method to various antigen proteins and found that the self-disperse after heat denaturation was a requirement for incorporation into the NPs. We also established that the NPs could target DCs, and the incorporation of rapamycin into the NPs enhanced the induction of a tolerogenic phenotype of DC. The MAN coating provided steric hindrance and heat denaturation destroyed recognition structures, successfully preventing anti-antigen antibody binding, indicating the NPs may avoid anaphylaxis induction. The MAN-coated NPs proposed here, prepared by a simple method, have the potential for effective and safe allergies treatment for various antigens.

Effectiveness of sublingual immunotherapy with house dust mite drops in asthmatic children at different ages

Background

Respiratory allergies in children, such as asthma and rhinitis, are becoming progressively common every year. Recent studies found that pediatric patients with asthma receiving regular medication and specific immunotherapy (SIT) had improved therapeutic outcomes in a wide age range. However, there are few studies that have examined the effectiveness of SIT treatment in children with allergic asthma at different ages in terms of the degree of asthma control, improvements in lung function, and changes in exhaled nitric oxide (FeNO).

Method

A total of 200 asthmatic pediatric patients who had been receiving regular treatment for at least a year were split into the observation and the control groups, which depended on whether sublingual immunotherapy was added based on conventional treatment medicines. The children who were divided by an age cut-off of 6 years old in these two groups were compared before and after therapy based on the exhaled levels of FeNO, pulmonary function, visual analog scale, medication scores, daytime and nighttime ratings of asthma symptom, and rhinitis symptom scores.

Results

Before treatment, there was no significant difference between the observation group and the control group in various indicators of the patients under 6 years old; and in the older children (6-16 years old) group, the scores of FVC, FEV1, and FEF25 in the observation group were significantly lower than those in the control group (P < 0.05). The FEF75, FEF50, FEF25, and MMEF75/MMEF25 indexes in the observation group were significantly higher than those in the control group after treatment (P < 0.05), but there was no statistical significance in other indexes (P > 0.05). The scores of ACT, FEF75, FEF50, MMEF72/MMEF25, and FeNO in the observation group were all higher than those in the control group after treatment (P < 0.05), and the differences in other indexes were not statistically significant (P > 0.05). Between the young-age group and the elder group, there was no significant difference in all indexes in the observation group before and after treatment (P > 0.05).

Conclusion

Children with asthma of all ages can considerably benefit from sublingual immunotherapy. Specifically, younger patients showed greater tendency on the improvement of small airway resistance, whereas school-age children with asthma significantly improved their small airway resistance as well as their asthma control and inflammation alleviation.

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

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

Immunotherapy in the Treatment of Allergic Rhinitis in Children

Allergic rhinitis (AR) is an inflammation of the nasal membranes characterized by multiple allergic symptoms. It is a widespread health problem that affects patients' ability to engage in social and physical activity, which lowers their quality of life. The pathophysiology of AR is complex and requires sensitization and the development of a specific immune response to the allergen. Allergen-specific immunotherapy (AIT) is a therapeutic method that induces specific immune tolerance to allergens. The objectives of this review are to demonstrate the mechanism of action of immunotherapy, explain how it alleviates clinical symptoms of allergic rhinitis, list the indications and contraindications of immunotherapy in the treatment of allergic rhinitis, and identify different modalities of allergen immunotherapy, their disease-modifying effects, as well as their potential risks and benefits. The review of the literature highlights that T-cell and B-cell responses to inhaled allergens are altered by AIT, which decreases both early and late reactions to allergen exposure. To induce clinical and immunologic tolerance, especially in the pediatric age, escalating dosages of the causing allergen are administered subcutaneously or sublingually. AIT is indicated for severe persistent AR when avoidance measures and medications are inadequate to control the symptoms. To conclude, AIT is a disease-modifying therapy that is safe and effective for the treatment of allergic rhinitis. It is indicated when the symptoms are uncontrolled or when there are undesirable effects from pharmacotherapy.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Pterostilbene suppresses oxidative stress and allergic airway inflammation through AMPK/Sirt1 and Nrf2/HO-1 pathways

Introduction

Pterostilbene (Pts) may be used for allergic asthma treatment. The AMPK/Sirt1 and Nrf2/HO‐1 pathways are potential targets for asthma treatement. However, the relationship between Pts and AMPK/Sirt1 and Nrf2/HO‐1 pathways in asthma is unclear. Herein, we aim to explore the pharmacological effects of Pts on oxidative stress and allergic inflammatory response as well as the mechanism involving AMPK/Sirt1 and Nrf2/HO‐1 pathways.

Methods

Asthma model was established in mice with ovalbumin (OVA). The model mice were treated by different concentrations of Pts. Lung pathological changes were observed through histological staining. In vitro, lipopolysaccharide (LPS)‐stimulated 16HBE cells were treated with Pts. The siAMPKα2, siSirt1 and siNrf2 knockdown, and treatment with compound C, EX‐527 or ML385 were also performed in 16HBE cells. Enzyme‐linked immunosorbent assay was used to detect interleukin‐4 (IL‐4), IL‐13, IL‐5, total and OVA specific immunoglobulin E (IgE), and interferon γ (IFN‐γ). Pneumonography was used to measure the airway hyperreactivity (AHR). Superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) levels were also detected. Immunohistochemistry, Western blot and immunofluorescence were used to measure protein levels.

Results

Pts significantly attenuated lung inflammatory cell infiltration and goblet cell proliferation. Meanwhile, Pts treatment could reduce IL‐4, IL‐13, IL‐5, and IgE (total and OVA specific) levels in the asthma model mice. However, IFN‐γ in bronchoalveolar lavage fluid was elevated. In addition, Pts reduced AHR. We also found that Pts treatment promoted serum SOD and CAT, and reduced MDA. In vitro results showed that Pts treatment promoted iNOS, TNF‐α, COX‐2, IL‐1β, and IL‐6 expressions in 16HBE cells, prolonged G0/G1 phase of the cell cycle, and resulted in a shortened G2M phase. Moreover, we found that Pts promoted the phosphorylation of AMPK in 16HBE, and meanwhile inhibited the increase of ROS induced by LPS. Additionally, Pts treatment inhibited p‐AMPK, Sirt1, Nrf2 and HO‐1, which in turn leads to the alleviation of AMPK/Sirt1 and Nrf2/HO‐1 pathways.

Conclusion

Pts alleviated oxidative stress and allergic airway inflammation via regulation of AMPK/Sirt1and Nrf2/HO‐1 signaling pathways.

Benefit Effect of Sublingual Dust Mite Drops on the Control of Asthma in Children

AIM

To evaluate the effect of sublingual dust mite drops on inhaled corticosteroid replacement and its effect on asthma control level.

METHODS

Two hundred children with asthma who had received regular treatment for one year or more were divided into the observation group (71 cases) and control group (89 cases) according to whether sublingual dust mite drops were added on the basis of conventional treatment drugs. After treatment, C-ACT score, VAS score, drug score, lung function, exhaled nitric oxide level, and "ICS avoidance" were compared between the two groups.

RESULTS

Before treatment, FVC and PEF25 scores in the observation group were lower than those in the control group, and the difference was statistically significant. There was no significant difference in other indicators between the two groups. There was no statistical significance in each index between the single allergic group and the multiple allergic group. Both the observation group and the control group showed statistically significant differences in each index before and after treatment. C-ACT score, FVC, FEV1, PEF, PEF75, PEF50, PEF25, MMEF75/MMEF25 after treatment were all higher than before treatment in both groups; VAS score, drug score and FeNO after treatment were all lower than before treatment. Except PEF, the difference between the observation group and the control group before and after treatment was statistically significant. Among them, after treatment, the increased values of C-ACT, FVC, FEV1, PEF75, PEF50, PEF25, MMEF75/MMEF25 in the observation group were higher than those in the control group, while the decreased values of VAS score, drug score and FeNO were higher than those in the control group. The differences were statistically significant. After treatment, the increased value of FEV1 in the single allergic group was higher than that in the multiple allergic group, and the difference was statistically significant. There was no statistical significance in the changes in other indexes between the two groups before and after treatment. The ICS avoidance rate in the observation group was 57.4% (58/100), higher than that in the control group (17.0%, 17/100), and the difference was statistically significant (χ2=35.108, P < 0.01). The ICS avoidance rate was 55.6% (15/27) in the single allergic group and 58.1% (43/74) in the multiple allergic group, and there was no significant difference between the two groups (χ2=0.053, P=0.818).

CONCLUSION

Sublingual dust mite drops can significantly improve the asthma control levels in children with asthma and have the effect of inhaled corticosteroid replacement.

Allergen immunotherapy for pediatric asthma: current evidence and knowledge gaps

PURPOSE OF REVIEW

The introduction of high-quality and standardized extracts for immunotherapy has renewed the interest in the treatment of pediatric allergic asthma that represents a high-prevalence disease.

RECENT FINDINGS

In addition to clinical trials, several systematic reviews and metaanalyses were published, confirming overall the clinical efficacy of allergen immunotherapy in pediatric asthma. In addition, new data on the preventive effect of the treatment on asthma onset were published. Despite this, many intriguing questions emerged, in parallel to the development of knowledge.

SUMMARY

Allergen immunotherapy is overall effective for the treatment of asthma in children, but a class-effect should not be claimed, rather the efficacy of each single product. According to the recent findings, the challenge for the future research will be to clarify: when to start immunotherapy in children, which are (if they exist) the predictive biomarkers for efficacy in the single individual, the magnitude of the preventive effect and the optimal duration of the treatment.

Allergen immunotherapy for respiratory allergy: Quality appraisal of observational comparative effectiveness studies using the REal Life Evidence AssessmeNt Tool. An EAACI methodology committee analysis

Background

Observational comparative effectiveness studies in allergen immunotherapy (AIT) represent an important evidence source answering research questions that can be challenging to obtain from randomized controlled trials (RCTs), such as long-term benefits of AIT, the effects on asthma prevention and the onset of new allergen sensitizations. However, observational studies are prone to several sources of bias, which limit their reliability.The REal Life Evidence AssessmeNt Tool (RELEVANT) was recently developed to assist in quality appraisal of observational comparative research to enable identification of useful nonrandomized studies to be considered within guideline development.

Objective

To systematically appraise the quality of published observational comparative AIT studies using RELEVANT.

Methods

Observational studies comparing AIT to pharmacotherapy for respiratory allergies, assessing as outcome measures reduction of symptoms and/or medication use reduction, were retrieved by computerized bibliographic searches. According to RELEVANT, a failure to meet any one of primary items (background, design, measures, analysis, results, discussion/interpretation, and conflict of interest) represents a critical flaw, significantly undermining the validity of the study results.

Results

The 14 studies identified supported the benefit of AIT in real-life, which persists after treatment discontinuation. However, none of them met all the 7 primary RELEVANT criteria. The main defects were reported in the design (28.6% of studies), measures and analysis (64.3% of studies), and results (78.6% of studies) items, due to selection bias and lack of methods for adjusting controls. Half of the studies did not report on conflict of interest.

Conclusion

There is a need for more robust observational research in AIT. RELEVANT appears as an easy-to-use and sensitive tool for quality appraisal in AIT studies.

Allergic Endotypes and Phenotypes of Asthma

Allergic asthma is defined as asthma associated with sensitization to aeroallergens, which leads to asthma symptoms and airway inflammation. Allergic asthma is the most common asthma phenotype. The onset of allergic asthma is most often in childhood and is usually accompanied by other comorbidities including atopic dermatitis and allergic rhinitis. It is often persistent although there is a wide variation in disease severity. It is a T_H2-driven process. Biomarkers have been identified to distinguish patients with allergic asthma, particularly serum IgE levels, tests to indicate sensitization to aeroallergens such as specific IgE or skin prick test positivity, blood and sputum eosinophil levels, fraction of exhaled nitric oxide, and periostin. Treatments for allergic asthma include environmental control measures, allergen immunotherapy, and glucocorticoids. Biologics, targeting the T_H2 pathway, have been shown to be effective in the treatment of allergic asthma.

Recent Advances in Allergen-Specific Immunotherapy as Treatment for Allergic Asthma: A Practical Overview

The Global Initiative for Asthma Report updated in 2019 stated that potential benefits of allergen immunotherapy (AIT), compared to pharmacological and avoidance options, must be weighed against the risk of adverse effects and the inconvenience and cost of the prolonged course of therapy in asthma. Thus, with the aim of clarifying some aspects with regard to the possible use of AIT in allergic asthma treatment armamentarium, a group of expert allergists from the Spanish Allergy and Clinical Immunology Scientific Society (SEAIC), particularly from the Immunotherapy and Asthma Interest Groups developed a frequently asked questions in clinical practice. This document updates relevant topics on the use of AIT in asthma and could facilitate physician clinical decisions and improve health outcomes for individual patients.

Physiopathologie de la dermatite atopique et des autres maladies atopiques : une approche globale est-elle possible ?

Atopy is defined by the propensity to develop an exaggerated type-2 inflammatory response to environmental molecules. Clinically, atopy is diagnosed when atopic disease occurs: atopic dermatitis, food allergy, atopic asthma and allergic rhinitis and conjunctivitis. Whereas the classical "atopic march" is increasingly challenged through epidemiological studies, type-2 cellular inflammation is a characteristic shared by the atopic diseases. This inflammation can be innate (non-specific: eosinophils, mast cells, dendritic cells, innate lymphoid cells [ILC]), or adaptive (antigen-specific, involving T cells). Interleukins (IL-)4, 5 and 13 are major actors of type-2 inflammation and are mainly produced by ILC and T cells. The efficacy of treatments targeting these type-2 cytokines highlight the importance of type-2 inflammation in atopic diseases. However, several patients do not respond to type-2 targeting treatments, highlighting the presence of other actors in pathophysiology of atopic diseases: alteration of epithelial barrier, IgE-mediated allergic responses, type-17 inflammation. Thus, the term "endotype" can illustrate this diversity in pathophysiology. Finally, a global approach of atopic diseases, as type-2 inflammatory diseases, is fundamental, but not sufficient. An approach by endotype is advisable, in a personalized medicine perspective. © 2020 Elsevier Masson SAS. All rights reserved.

Sublingual immunotherapy for asthma

BACKGROUND

Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. Fifty-two studies were identified and synthesised in the original Cochrane Review in 2015, but questions remained about the safety and efficacy of sublingual immunotherapy for people with asthma.

OBJECTIVES

To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma.

SEARCH METHODS

The original searches for trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov, WHO ICTRP, and reference lists of all primary studies and review articles found trials up to 25 March 2015. The most recent search for trials for the current update was conducted on 29 October 2019.

SELECTION CRITERIA

We included parallel randomised controlled trials, irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma. We selected outcomes to reflect recommended outcomes for asthma clinical trials and those most important to people with asthma. Primary outcomes were asthma exacerbations requiring a visit to the emergency department (ED) or admission to hospital, validated measures of quality of life, and all-cause serious adverse events (SAEs). Secondary outcomes were asthma symptom scores, exacerbations requiring systemic corticosteroids, response to provocation tests, and dose of inhaled corticosteroids (ICS).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results for included trials, extracted numerical data, and assessed risk of bias, all of which were cross-checked for accuracy. Any disagreements were resolved by discussion. We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We considered the strength of evidence for all primary and secondary outcomes using the GRADE approach.

MAIN RESULTS

Sixty-six studies met the inclusion criteria for this update, including 52 studies from the original review. Most studies were double-blind and placebo-controlled, varied in duration from one day to three years, and recruited participants with mild or intermittent asthma, often with comorbid allergic rhinitis. Twenty-three studies recruited adults and teenagers; 31 recruited only children; three recruited both; and nine did not specify. The pattern of reporting and results remained largely unchanged from the original review despite 14 further studies and a 50% increase in participants studied (5077 to 7944). Reporting of primary efficacy outcomes to measure the impact of SLIT on asthma exacerbations and quality of life was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence; 16 studies did not contribute any data, and a further six studies could only be included in a post hoc analysis of all adverse events. Allocation procedures were generally not well described; about a quarter of the studies were at high risk of performance or detection bias (or both); and participant attrition was high or unknown in around half of the studies. The primary outcome in most studies did not align with those of interest to the review (mostly asthma or rhinitis symptoms), and only two small studies reported our primary outcome of exacerbations requiring an ED or hospital visit; the pooled estimate from these studies suggests SLIT may reduce exacerbations compared with placebo or usual care, but the evidence is very uncertain (OR 0.35, 95% confidence interval (CI) 0.10 to 1.20; n = 108; very low-certainty evidence). Nine studies reporting quality of life could not be combined in a meta-analysis and, whilst the direction of effect mostly favoured SLIT, the effects were often uncertain and small. SLIT likely does not increase SAEs compared with placebo or usual care, and analysis by risk difference suggests no more than 1 in 100 people taking SLIT will have a serious adverse event (RD -0.0004, 95% CI -0.0072 to 0.0064; participants = 4810; studies = 29; moderate-certainty evidence). Regarding secondary outcomes, asthma symptom and medication scores were mostly measured with non-validated scales, which precluded meaningful meta-analysis or interpretation, but there was a general trend of SLIT benefit over placebo. Changes in ICS use (MD -17.13 µg/d, 95% CI -61.19 to 26.93; low-certainty evidence), exacerbations requiring oral steroids (studies = 2; no events), and bronchial provocation (SMD 0.99, 95% CI 0.17 to 1.82; low-certainty evidence) were not often reported. Results were imprecise and included the possibility of important benefit or little effect and, in some cases, potential harm from SLIT. More people taking SLIT had adverse events of any kind compared with control (OR 1.99, 95% CI 1.49 to 2.67; high-certainty evidence; participants = 4251; studies = 27), but events were usually reported to be transient and mild. Lack of data prevented most of the planned subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Despite continued study in the field, the evidence for important outcomes such as exacerbations and quality of life remains too limited to draw clinically useful conclusions about the efficacy of SLIT for people with asthma. Trials mostly recruited mixed populations with mild and intermittent asthma and/or rhinitis and focused on non-validated symptom and medication scores. The review findings suggest that SLIT may be a safe option for people with well-controlled mild-to-moderate asthma and rhinitis who are likely to be at low risk of serious harm, but the role of SLIT for people with uncontrolled asthma requires further evaluation.

Mesenchymal Stem Cells in Asthma

Asthma is one of the worldwide respiratory health problem that affect children and adult. Current treatment strategies such as conventional and allergen immunotherapy still fall behind. Mesenchymal stem cells (MSCs) have wide regenerative capacity and immunoregulatory activity with their wide range of secretions and contact dependent manner. In this review, we focus on the current treatment strategies for asthma and MSCs as a new therapeutic tool.

Astragali Radix (Huangqi): A promising edible immunomodulatory herbal medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali Radix (AR, Huangqi in Chinese), the dried root of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or A. membranaceus (Fisch.) Bge., possesses diverse therapeutic effects against fatigue, dyspepsia, diarrhea, heart diseases, hepatitis, and anemia. In recent years, increasing evidence has indicated the multiple immunomodulatory activities of AR in preclinical and clinical studies.

AIM OF THE REVIEW

This review attempts to elaborate the immunomodulatory effects of AR and its potential application in the treatment of immune related diseases.

MATERIALS AND METHODS

A comprehensive literature search AR was carried out using multiple internationally recognized databases (including Web of Science, Google Scholar, PubMed, ScienceDirect, Wiley, ACS, Springer, Taylor & Francis, and CNKI).

RESULTS

The immunomodulatory effects of AR are closely attributed to its active constituents such as polysaccharides, saponins, and flavonoids. We also demonstrate that AR can be used as a potential therapeutic intervention for immune related diseases through regulating immune organs, mucosal immune, and immune system (innate immunity and acquired immunity).

CONCLUSION

AR promotes the development of immune organs, enhances mucosal immune function, increases the quantity and phagocytic capacity of innate immunity, promotes the maturation and differentiation of acquired immunity cells, and improves the expression of antibodies in acquired immunity. We believe that AR has a broad research space in the adjuvant treatment of immune related diseases, which could be a breakthrough point to improve the application value of AR.

Allergen Immunotherapy in children with respiratory allergic diseases

Allergen immunotherapy (AIT) is a well-established treatment for allergic respiratory diseases. It represents a cornerstone in the clinical management of allergic children since it is the only curative option to date able to modify the natural history of Ig-E mediated allergic diseases. Through a well-defined immunologic mechanism, AIT promotes regulatory T cells and cuts down the immune response induced by allergens. According to current guidelines based on up-to-date evidence, AIT should be offered to children with moderate-severe allergic rhinitis and/or controlled asthma starting from 5 years of age, further to an adequate risk-benefit assessment which includes patient's adherence to the treatment and a proper selection of the right product. Younger age and mild disease could be considered based on an individual evaluation. Both subcutaneous (SCIT) and sublingual (SLIT) routes of administration have a good efficacy and safety profile with safer outcomes for SLIT compared to SCIT. Only standardized products with documented evidence of clinical efficacy should be used. Although AIT is used worldwide, there are still gaps and limitations, including the lack of reliable biomarkers predictive of the clinical outcome. Novel adjuvants are currently under investigations to boost the strength and efficiency of the immune response, as well as new formulations with better efficacy and better patient's adherence to the treatment. Herein, we aim to provide an overview of current key evidence with major regard to clinical practice as well as knowledge gaps and future research needs in the context of AIT in children with respiratory allergic diseases.

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.

Asthma immunotherapy and treatment approaches with mesenchymal stem cells

Asthma is a chronic inflammatory disease of the airways where exaggerated T helper 2 immune responses and inflammatory mediators play a role. Current asthma treatment options can effectively suppress symptoms and control the inflammatory process; however, cannot modulate the dysregulated immune response. Allergen-specific immunotherapy is one of the effective treatments capable of disease modification. Injecting allergens under the skin in allergen-specific immunotherapy can reduce asthma and improve the sensitivity of the lungs, however, has a risk of severe reactions. Mesenchymal stem cells have immunoregulatory activity with their soluble mediators and contact dependent manner. In this review, we focus on the current treatment strategies with mesenchymal stem cells in asthma as a new therapeutic tool and compare those with immunotherapy.

30 years of sublingual immunotherapy

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

Effect of Dermatophagoides pteronyssinus Immunotherapy on Upper and Lower Airway Eosinophilic Inflammatory Response to Nasal Allergen Challenge

Purpose

It remains unknown whether allergen-specific immunotherapy (AIT) could attenuate airway inflammatory response triggered by allergen exposure.

Methods

We performed Dermatophagoides pteronyssinus (Der-p) nasal provocation tests (NPTs) in allergic rhinitis (AR) and/or asthma patients without AIT (non-AIT), or at 16, 52, 104, or 156 weeks after Der-p AIT. Rhinitis and asthma visual analog scale (VAS; VAS of nasal symptoms [VAS-NS], VAS of asthma symptoms), the rhinoconjunctivitis quality of life questionnaire (RQLQ), nasal lavage, sputum induction, fractional exhaled nitric oxide (FeNO), nasal airway resistance, pulmonary function, and airway hyperresponsiveness were performed before and after NPT.

Results

Non-AIT subjects demonstrated significantly higher VAS-NS before and after NPT compared to AIT subjects (P < 0.05). NPT response was positive in 14 (100%) non-AIT, 7 (70%) 16 weeks-AIT, 6 (60%) 52 weeks-AIT, 6 (60%) 104 weeks-AIT, and 2 (20%) 156 weeks-AIT subjects. The NPT grade significantly correlated with AIT duration and baseline RQLQ score (r = −0.561, P < 0.001 and r = 0.525, P < 0.001, respectively). Sputum and nasal lavage eosinophil count, and FeNO in non-AIT subjects were significantly increased 6 hours after NPT (P < 0.05). AIT subjects did not change their sputum or nasal lavage eosinophil count before and after NPT. Subjects with 156 weeks-AIT demonstrated significantly lower levels of sputum and nasal lavage eosinophil count before and after NPT when compared with non-AIT patients (P < 0.05). Sputum eosinophil counts positively correlated with nasal lavage eosinophil counts at baseline and 6 hours after NPT (r = 0.719, P = 0.006 and r = 0.823, P < 0.001, respectively) in non-AIT patients.

Conclusion

Our results show that AIT can attenuate both upper and lower airway immune response to nasal allergen exposure in patients with AR and/or asthma.

Efficacy of Allergen Immunotherapy for Allergic Asthma in Real World Practice

Purpose

Allergen immunotherapy (AIT) induces immunological tolerance, and there is increasing evidence of the clinical efficacy of AIT in the treatment of allergic asthma. However, the optimal parameters for asthma control in clinical trials are still unclear. We investigated the efficacy of AIT with respect to changes in the inhaled corticosteroid (ICS) dose in patients with allergic asthma.

Methods

A total of 117 adults with allergic asthma who had used ICS for more than 1 year in a single tertiary hospital in Korea were included in this retrospective study. We compared the clinical parameters and outcomes between the AIT group (ICS with AIT, n = 48) and the non-AIT group (ICS without AIT, n = 69) by applying an inverse probability of treatment weighting method. The patients in the AIT group had received subcutaneous AIT monthly as a maintenance treatment for more than 1 year. The changes in the ICS dose from baseline were evaluated in the 2 groups for 3 years.

Results

The proportion of responders who discontinued or decreased in the ICS dose with achieving control status of asthma was significantly higher in the AIT group than in the non-AIT group throughout the study period (at 6 months, 52.1% vs. 24.6%; at 1 year, 70.8% vs. 34.7%; at 2 years, 89.5% vs. 35.6%; at 3 years, 96.3% vs. 51.2%). Treatment responses did not differ significantly by type of allergen (single- or multi-allergens or 3 different products) used throughout the study period.

Conclusions

Irrespective of the type of allergen, long-term maintenance AIT helps to spare ICS dose and achieve better control in patients with allergic asthma in real-world clinical practice.

Resolution of allergic asthma

Allergic asthma is an inflammatory disease of the airways characterized by recurrent episodes of wheezing and bronchoconstriction. Chronic inflammation may finally lead to structural damage followed by airway remodeling. Various studies in recent years contributed to unravel important aspects of the immunopathogenesis of asthma and adapted new pharmaceutical developments. Here, I consider some novel insights into the immunopathogenesis of asthma and the protective and pathogenic roles of some innate and adaptive immune cells as well as the function of soluble mediators such as cytokines. Particular attention will be given to new concepts on resolution of chronic airway inflammation for prevention of airway structural damage.

Options of immunotherapeutic treatments for children with asthma

Introduction: Asthma is the most common chronic disease in children. Avoiding triggers, and pharmacologic treatment with short acting beta-agonist, inhaler corticosteroids and anti-leukotriene are often enough to obtain symptoms control. Nevertheless, there is a subset of children with severe asthma and poor symptom control despite maximal therapy. In these patients, anti-IgE and anti-IL5 monoclonal antibodies are suggested as the fifth step of Global Initiative for Asthma guidelines. Area covered: Immunotherapeutic treatments are now suggested for asthma management. This article will discuss the available evidence on allergen immunotherapy and biologic drugs in pediatric asthma treatment. Expert opinion: Previously published studies demonstrated a good efficacy and safety profile of Allergen Immunotherapy in patients with mild-moderate asthma and sensitization to one main allergen. New understanding of mechanisms underlying severe asthma inflammation has allowed the identifications of specific biomarkers guiding the clinician in the choice of patient specific drug. Among the suggested immunotherapeutic options, omalizumab (blocking IgE) remains the first choice for atopic 'early onset' asthma in patients aged over 6 years. Instead, mepolizumab (blocking the IL5 ligand) should be considered for 'eosinophilic' asthma. Other biologic drugs are under consideration but data on the pediatric population are still lacking.

Novel therapeutic targets for allergic airway disease in children

The aim of precision medicine is setting up targeted therapies for selected patients that would ideally have high effectiveness and few side effects. This is made possible by targeted therapy drugs that selectively act on a specific pathway. Precision medicine is spreading to many medical specialties, and there is increasing interest in the context of allergic airway diseases, such as allergic rhinitis, chronic rhinosinusitis, and asthma. This review is an update of new targets in the treatment of childhood allergic upper airway diseases and asthma, including the most recent biologic drugs that have already been licensed or are in the pipeline to be tested with children.

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.

Does evidence support the use of cat allergen immunotherapy?

PURPOSE OF REVIEW

Cat allergy can manifest as allergic rhinitis, conjunctivitis and/or asthma. With widespread cat ownership and exposure, cat allergy has emerged as a major cause of morbidity. Cat allergen immunotherapy is a potential disease modifying treatment for patients with cat allergy. We examine evidence on the effectiveness, cost-effectiveness and safety of cat allergen immunotherapy and consider the clinical contexts in which it should be prescribed.

RECENT FINDINGS

The European Association of Allergy and Clinical Immunology systematic reviews on allergic rhinitis and asthma along with the accompanying guidelines on allergic rhinitis were used as primary sources of evidence. Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are most common routes of administration for allergen immunotherapy (AIT). A limited number of high-quality studies related to cat dander have shown mixed results in improvements in ocular and nasal symptoms, asthma symptoms, peak expiratory flow rate and medication use scores with subcutaneous immunotherapy. Two studies examining cat dander and cat-related allergy response with sublingual immunotherapy have shown mixed results in terms of symptomatic response. One randomized trial examining intralymphatic immunotherapy has shown a positive symptom response and a favourable safety profile. Although studies have reported mixed results regarding safety of SCIT, adverse events have been reported more commonly with SCIT than SLIT.

SUMMARY

There is a limited body of high-quality evidence on the effectiveness and safety of cat AIT and no high-quality data on its cost-effectiveness. The available evidence on effectiveness is mixed based on studying a limited array of immunological, physiological and patient-reported outcome measures. Based on this evidence and extrapolating on the wider evidence base in AIT, it is likely that some patients may benefit from this modality of treatment, particularly those with moderate-to-severe disease who are inadequately controlled on allergen avoidance measures and pharmacotherapy and those who are monosensitized to Felix Domesticus 1. Further evidence is, however, required from larger trials before more definitive advice can be offered.

Retrospective analysis of aeroallergen's sensitization patterns in Edmonton, Canada

Background

Sensitization to common environmental aeroallergens plays a significant role in the pathogenesis and severity of respiratory allergic disorders, specifically asthma and allergic rhinitis. Understanding sensitization patterns helps clinicians tailor care more effectively. This study examines patterns of sensitization to aeroallergens in subjects suspected of having an allergic disease in Edmonton and catchment area.

Methods

Retrospective chart review of skin prick test (SPT) results to 11 environmental aeroallergens performed between January 1st and June 30th 2014 at a University-based clinic, where patients are referred for SPT by allergists, respirologists, otolaryngologists, internists and general practitioners. Potential differences in aeroallergen sensitization patterns were evaluated.

Results

A total of 623 patients (36.9% males; 63.1% females), aged 4–84 years (mean age 38.6 years) had SPT done, of which 438 (70.3%) had a positive test for at least one aeroallergen (atopy). There were no significant sex differences in the frequency of atopy (males: 71.3% versus females: 69.7%; p = 0.373). The frequency of sensitivity to particular allergens among atopic subjects was: cat (53.1%), house dust mites (50.3%), grass (39.2%), birch (23.7%), alternaria (23.7%), dog (17.3%), poplar (12.1%), cedar (9.6%), aspergillus (9.6%), hormodendrum (8%), and penicillium (6.2%). Of 438 atopic patients, 110 (25.1%) were mono sensitized, 199 (45.4%) oligosensitized (2–3 allergens), and 129 (29.5%) polysensitized (≥ 4 allergens). There were no significant differences between males and females in the odds of being oligo-sensitized (OR: 0.95; 95% CI 0.58, 1.57). Polysensitization was significantly more frequent in males 37.2% than in females 24.8%; (OR: 0.95; 95% CI 0.58, 1.57).

Conclusion

Cat is the most frequent perennial allergen and timothy grass pollen the most frequent seasonal allergen in Edmonton and catchment area. There was no significant difference in the frequency of atopy between males and females. However, males were more likely to be polysensitized compared to females.

Highlights and recent developments in airway diseases in EAACI journals (2017)

The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. There was substantial progress in 2017 in the identification of basic mechanisms of allergic and respiratory disease and the translation of these mechanisms into clinics. Better understanding of molecular and cellular mechanisms, efforts for the development of biomarkers for disease prediction, novel prevention and intervention studies, elucidation of mechanisms of multimorbidies, entrance of new drugs in the clinics as well as recently completed phase three clinical studies and publication of a large number of allergen immunotherapy studies and metaanalyses have been the highlights of the last year.

Anti-Inflammatory Activities of Pentaherbs formula and Its Influence on Gut Microbiota in Allergic Asthma

Allergic asthma is a highly prevalent airway inflammatory disease, which involves the interaction between the immune system, environmental and genetic factors. Co-relation between allergic asthma and gut microbiota upon the change of diet have been widely reported, implicating that oral intake of alternative medicines possess a potential in the management of allergic asthma. Previous clinical, in vivo, and in vitro studies have shown that the Pentaherbs formula (PHF) comprising five traditional Chinese herbal medicines Lonicerae Flos, Menthae Herba, Phellodendri Cortex, Moutan Cortex, and Atractylodis Rhizoma possesses an anti-allergic and anti-inflammatory potential through suppressing various immune effector cells. In the present study, to further investigate the anti-inflammatory activities of PHF in allergic asthma, intragastrical administration of PHF was found to reduce airway hyperresponsiveness, airway wall remodeling and goblet cells hyperplasia in an ovalbumin (OVA)-induced allergic asthma mice model. PHF also significantly suppressed pulmonary eosinophilia and asthma-related cytokines IL-4 and IL-33 in bronchoalveolar lavage (BAL) fluid. In addition, PHF modulated the splenic regulatory T cells population, up-regulated regulatory interleukin (IL)-10 in serum, altered the microbial community structure and the short chain fatty acids content in the gut of the asthmatic mice. This study sheds light on the anti-inflammatory activities of PHF on allergic asthma. It also provides novel in vivo evidence that herbal medicines can ameliorate symptoms of allergic diseases may potentially prevent the development of subsequent atopic disorder such as allergic asthma through the influence of the gut microbiota.

Frontline Science: RIP2 promotes house dust mite-induced allergic airway inflammation

House dust mites (HDMs) are one of the most significant environmental allergens in the establishment of the so-called "Atopic March." It is known that the immune response to HDM is Th2 dominant, but the innate mechanisms leading to HDM-induced type 2 responses are still not completely understood. A number of innate immune receptors have been implicated in the response to HDM including toll-like receptors, C-type lectin receptors, and protease activated receptors. NOD2 is a member of the NOD-like receptor family, which has been reported to be involved in the establishment of type 2 immunity and in blocking respiratory tolerance. NOD2 mediates its effects through its downstream effector kinase, receptor interacting protein (RIP2). It has not been shown if RIP2 is involved in the innate response to HDM and in the resulting generation of type 2 immunity. Furthermore, the role of RIP2 in modulating allergic airway inflammation has been controversial. In this study, we show that RIP2 is activated in airway epithelial cells in response to HDM and is important for the production of CCL2. Using a murine HDM asthma model, we demonstrate that lung pathology, local airway inflammation, inflammatory cytokines, HDM-specific IgG1 antibody production, and HDM-specific Th2 responses are all reduced in RIP2 knockout mice compared to WT animals. These data illustrate that RIP2 can be activated by a relevant allergic stimulus and that such activation can contribute to allergic airway inflammation. These findings also suggest that RIP2 inhibitors might have some efficacy in down-regulating the inflammatory response in type 2 dominated diseases.

Phenotype analyses of IL-10-producing Foxp3- CD4+ T cells increased by subcutaneous immunotherapy in allergic airway inflammation

INTRODUCTION

The mechanisms of allergen immunotherapy are not fully elucidated. Here, we sought to develop a murine model to demonstrate the effectiveness of subcutaneous immunotherapy (SCIT) for allergic responses. As excessive antigen dosages may induce immune tolerance in sensitized mice, the effects of SCIT were assessed by varying the antigen dosage. The mechanisms of SCIT were analyzed by focusing on the induction of Foxp3⁺ Treg cells and IL-10-producing Foxp3^- CD4⁺ T cells, as well as on the phenotype of the latter cells.

METHODS

Ovalbumin (OVA) + Al(OH)₃-sensitized mice received subcutaneous dosages of OVA at 0.01, 0.1 or 1 mg/animal for SCIT, followed by intratracheal challenges with OVA at 5, 50 or 500 μg/animal.

RESULTS

The maximum effects of SCIT were observed with 1 mg/animal of OVA for airway inflammation induced by 5 μg/animal of OVA, in which airway eosinophilia and Th2 cytokine production were markedly suppressed. The increase in the OVA-specific IgE level was significantly suppressed by SCIT. The development of bronchial epithelial thickening and mucus accumulation were also suppressed by SCIT. Concomitantly, IL-10-producing Foxp3^- CD4⁺ T cells were increased in the lungs by SCIT, but Foxp3⁺ Treg cells were not. Most of the induced IL-10-producing Foxp3^- CD4⁺ T cells were negative for either IL-5 or LAG-3, but positive for CD49b.

CONCLUSION

We successfully developed an airway allergic model for SCIT. It was suggested that most of IL-10-producing Foxp3^- CD4⁺ regulatory T cells increased by SCIT in the lungs were CD49b⁺ CD4⁺ regulatory T cells, but neither Th2 cells nor Tr1 cells.

Immunotherapy for pet allergies

Allergic diseases compose a serious challenge for modern societies. Their individual, medical and economical burden is large. As humans spend most of their time indoors, exposure to indoor allergens is a significant contributor to the development of allergic sensitization and respiratory allergies, such as allergic rhinoconjunctivitis and asthma. One important source of indoor allergens are pets, in particular cats and dogs. Allergens from these and other mammals spread effectively and they are encountered widely in public places. If patient education, allergen avoidance and pharmacotherapy do not suffice for controlling the symptoms of pet allergy, allergen immunotherapy can be a treatment option. Current information on allergen immunotherapy in pet allergy suggests that it can be effective in reducing allergic symptoms. However, the low number of high-quality randomized controlled trials of allergen immunotherapy in pet allergy warrants for further investigations.

Impact of allergen immunotherapy in allergic asthma

Although traditional pharmacological approaches improve outcomes in disease management for allergic asthma, these fail to modify the underlying immune responses. Allergen immunotherapy remains the only etiological therapy for the treatment of respiratory allergies for which clinical efficacy has been demonstrated through several well-controlled studies. In this review, we examine evidence from the past 5 years regarding the impact of allergen immunotherapy on allergic asthma to inform practitioners and stimulate further discussion and research.

Immunotherapy and Asthma in Children

Allergen immunotherapy (AIT) is still the only disease-modifying treatment strategy for IgE-mediated allergic diseases, with consolidated evidence both in adults and children. AIT is effective in determining clinical improvement of allergic rhinitis and asthma, such as reduced symptoms, medication use, and improvement of quality of life, with a long-lasting effect after cessation of treatment. Results from recent clinical studies have implemented the evidence of effectiveness and safety of allergen immunotherapy for the treatment of allergic asthma, so that the current asthma guidelines now recommend sublingual immunotherapy as an add-on therapy for asthma in adults and adolescents with house dust mite allergy, allergic rhinitis, and exacerbations despite low-to-moderate dose ICS, with forced expiratory volume in 1 second more than 70% predicted. AIT may also reduce the risk of progression from allergic rhinitis to asthma in children and prevent the onset of new sensitizations, thus representing a potentially preventive method of treatment. The aim of this review is to present an updated overview of the clinical indications of AIT, with particular reference to pediatric asthma, of the mechanisms of clinical and immunological tolerance to allergens, and of the potential biomarkers predicting clinical response.