Cluster subcutaneous allergen specific immunotherapy for the treatment of allergic rhinitis: a systematic review and meta-analysis

A meta-analysis investigating the efficacy and safety of allergen-specific immunotherapy in the management of respiratory allergies

BACKGROUND

This meta-analysis aimed to evaluate the effectiveness and adverse effects of specific immunotherapy (SIT) in the management of respiratory allergens, including allergic asthma, rhinitis, and related disorders, based on a review of current literature up to November 8, 2022.

METHODS

We conducted a search of databases, including PubMed, Embase, Cochrane, and Web of Science, to identify relevant randomized controlled trials (RCTs) assessing respiratory allergy-specific immunotherapy. We employed the Consolidated Standards of Reporting Trials (CONSORT) Statement to select RCTs that adhered to rigorous reporting standards. Specifically, we focused on double-blind placebo-controlled (DBPC) trials and open studies involving both adults and children, considering factors such as dosage, inclusion criteria, allergens, and primary outcome measurements.

RESULTS

A total of 25 meta-analyses were included in this study. Among them, 14 evaluated sublingual-specific allergen immunotherapy (SLIT), 4 assessed subcutaneous allergen immunotherapy (SCIT), 4 explored both sublingual and subcutaneous immunotherapy, and 3 investigated intralymphatic immunotherapy. The outcomes of these meta-analyses indicated a reduction in medication scores in 20 cases and a decrease in symptom scores in 23 cases. Additionally, six studies reported on changes in IgE levels, seven studies focused on IgG4, four studies examined FEV1 (forced expiratory volume in 1 s), and eight studies reported on symptom and medication scores. Furthermore, 11 studies reported on differences in adverse reactions.

CONCLUSION

The results of our meta-analysis suggest that specific immunotherapy, while associated with some adverse effects, effectively reduces the symptoms of asthma and rhinitis. Therefore, we recommend its use in the treatment of respiratory allergies.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Risk of anaphylaxis in cluster vs standard subcutaneous multiallergen immunotherapy

BACKGROUND

Cluster schedules for subcutaneous allergen immunotherapy (AIT) require significantly fewer injections, but there have been conflicting reports regarding the risk of systemic reactions (SR).

OBJECTIVE

To compare the incidence of SRs during the build-up stages of multiallergen standard vs cluster immunotherapy.

METHODS

Data on SRs were collected prospectively from 91 urban adult patients who underwent either standard or cluster AIT at the Johns Hopkins Allergy and Asthma Center from 2014 to 2022. The SRs were recorded during the build-up phase and compared for both protocols using Pearson's χ², Fisher exact test, and multivariate logistic regression models.

RESULTS

Overall, SR rates were 21% for patients in the standard schedule and 37% for patients in the cluster immunotherapy schedule, which was not statistically different (P = .08). However, the SR rate for each injection was 0.69% per injection in the standard protocol and 2.29% per injection in the cluster schedule (incident rate ratio = 3.3). All SRs (100%) in both groups occurred in the second half of the build-up phase. Multivariate regression revealed that the target prescription protein nitrogen units and the number of allergens in the treatment vial did not influence SR rates (odds ratio = 1.00 and 1.06, respectively).

CONCLUSION

The overall incidence of SR was not statistically different for cluster and standard AIT protocols. However, because cluster patients received approximately half the number of injections, the risk for SR per individual injection is more than 3-fold higher than that of standard immunotherapy.

Chinese Guideline on Allergen Immunotherapy for Allergic Rhinitis: The 2022 Update

In the last few decades, there has been a progressive increase in the prevalence of allergic rhinitis (AR) in China, where it now affects approximately 250 million people. AR prevention and treatment include allergen avoidance, pharmacotherapy, allergen immunotherapy (AIT), and patient education, among which AIT is the only curative intervention. AIT targets the disease etiology and may potentially modify the immune system as well as induce allergen-specific immune tolerance in patients with AR. In 2017, a team of experts from the Chinese Society of Allergy (CSA) and the Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G) produced the first English version of Chinese AIT guidelines for AR. Since then, there has been considerable progress in basic research of and clinical practice for AIT, especially regarding the role of follicular regulatory T (TFR) cells in the pathogenesis of AR and the use of allergen-specific immunoglobulin E (sIgE) in nasal secretions for the diagnosis of AR. Additionally, potential biomarkers, including TFR cells, sIgG4, and sIgE, have been used to monitor the incidence and progression of AR. Moreover, there has been a novel understanding of AIT during the coronavirus disease 2019 pandemic. Hence, there was an urgent need to update the AIT guideline for AR by a team of experts from CSA and C2AR2G. This document aims to serve as professional reference material on AIT for AR treatment in China, thus improving the development of AIT across the world.

Allergic Rhinitis: What Do We Know About Allergen-Specific Immunotherapy?

Allergic rhinitis (AR) is an IgE-mediated disease that is characterized by Th2 joint inflammation. Allergen-specific immunotherapy (AIT) is indicated for AR when symptoms remain uncontrolled despite medication and allergen avoidance. AIT is considered to have been effective if it alleviated allergic symptoms, decreased medication use, improved the quality of life even after treatment cessation, and prevented the progression of AR to asthma and the onset of new sensitization. AIT can be administered subcutaneously or sublingually, and novel routes are still being developed, such as intra-lymphatically and epicutaneously. AIT aims at inducing allergen tolerance through modification of innate and adaptive immunologic responses. The main mechanism of AIT is control of type 2 inflammatory cells through induction of various functional regulatory cells such as regulatory T cells (Tregs), follicular T cells (Tfr), B cells (Bregs), dendritic cells (DCregs), innate lymphoid cells (IL-10⁺ ILCs), and natural killer cells (NKregs). However, AIT has a number of disadvantages: the long treatment period required to achieve greater efficacy, high cost, systemic allergic reactions, and the absence of a biomarker for predicting treatment responders. Currently, adjunctive therapies, vaccine adjuvants, and novel vaccine technologies are being studied to overcome the problems associated with AIT. This review presents an updated overview of AIT, with a special focus on AR.

Subcutaneous Allergen-Specific Immunotherapy Is Safe in Pediatric Patients with Allergic Rhinitis

INTRODUCTION

Subcutaneous allergen-specific immunotherapy (SCIT) is one of the main cornerstones in the treatment of allergic rhinitis in pediatric patients. It has demonstrated symptoms and quality of life improvement, but it is not exempt from adverse reactions (ADVrs). Nevertheless, there are a few reports that have evaluated their safety. Our objective was to evaluate the ADVr to SCIT in pediatric patients.

METHODS

We reviewed 786 clinical records with SCIT from 2005 to 2018, comparing the clinical characteristics of patients with ADVrs with SCIT versus a group of a similar number of patients who completed SCIT (control group, CG). The analysis of ADVrs was according to the World Allergy Organization (WAO) 2010 grading system by frequency analysis, survival curve, and log rank.

RESULTS

Of 786 patients, 106 (13.4%) presented ADVrs, and the patients with ADVr had sensitivity and immunotherapy with at least 2 allergens versus CG p < 0.001, containing a combination of standardized and nonstandardized allergens (p = 0.003). The ADVrs were in the buildup phase (p < 0.001). The survival curve showed that 50% had some reaction at 12 weeks of SCIT. The most frequent ADVr was grade 1 in 73/106 patients (68.8%) and grade 2 in 33/106 (31.1%). The log-rank analysis between the grades of the WAO grading system showed a statistically significant difference (p = 0.02).

CONCLUSIONS

The SCIT is safe in pediatric patients. The ADVrs are infrequent, grade 1 being the most reported; however, at >12 weeks, the risk of ADVrs that involve 2 organs systems increases.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Twenty years' observation of subcutaneous pollen allergoid immunotherapy efficacy in adults

INTRODUCTION

It is valuable to determine the long-term efficacy of allergen-specific immunotherapy (SIT) and whether it can cure allergy.

AIM

For this study, patients were prospectively observed for 20 years after completion of SIT to determine its effectiveness.

MATERIAL AND METHODS

A total of 1006 patients who underwent SIT for pollen allergy were observed for 20 years to assess the efficacy of SIT. The rhinitis symptom score (RSS) and asthma symptom score (ASS) were measured after SIT completion. The possibility of allergy cure was estimated based on three sets of criteria: group A - neither symptoms nor intake of medication during the analysis period, group B - no symptoms during the analysis period (but possible medication intake), and group C - at most one mild symptom during the analysis period.

RESULTS

After SIT, approximately 25% of patients showed complete relief of allergy symptoms and had no need for symptomatic drug treatment during the pollen season. The level of effectiveness of SIT was similar throughout the treatment period. During the observation period after SIT, RSS ranged from 1.51 to 1.82, and ASS ranged from 1.22 to 1.29. The treatment effect at 10 and 20 years after SIT was comparable, regardless of whether criterion A or B was used. However, the effect of SIT using criterion C was lower than those using criteria A and B for the analyzed time points.

CONCLUSIONS

For this study cohort, SIT had a long-term effect that did not depend significantly on the duration of immunotherapy against pollen.

Chinese Guideline on allergen immunotherapy for allergic rhinitis

The present document is based on a consensus reached by a panel of experts from Chinese Society of Allergy (CSA) and Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G). Allergen immunotherapy (AIT), has increasingly been used as a treatment for allergic rhinitis (AR) globally, as it has been shown to provide a long-term effect in improving nasal and ocular symptoms, reducing medication need, and improving quality of life. AIT is currently the only curative intervention that can potentially modify the immune system in individuals suffering from AR and prevent the development of new sensitization and the progression of disease from AR to asthma. Although the use of AIT is becoming more acceptable in China, to date no AR immunotherapy guideline from China is available for use by the international community. This document has thus been produced and covers the main aspects of AIT undertaken in China; including selection of patients for AIT, the allergen extracts available on the Chinese market, schedules and doses of allergen employed in different routes of AIT, assessment of effect and safety, patients' administration and follow-up, and management of adverse reactions. The Chinese guideline for AR immunotherapy will thus serve as a reference point by doctors, healthcare professionals and organizations involved in the AIT of AR in China. Moreover, this guideline will serve as a source of information for the international community on AIT treatment strategies employed in China.

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

Background

The European Academy of Allergy and Clinical Immunology (EAACI) is developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis (ARC). To inform the development of recommendations, we sought to critically assess the systematic review evidence on the effectiveness, safety and cost-effectiveness of AIT for ARC.

Methods

We undertook a systematic overview, which involved searching nine international biomedical databases from inception to October 31, 2015. Studies were independently screened by two reviewers against pre-defined eligibility criteria and critically appraised using the Critical Appraisal Skills Programme (CASP) Systematic Review Checklist for systematic reviews. Data were descriptively synthesized.

Results

Our searches yielded a total of 5932 potentially eligible studies, from which 17 systematic reviews met our inclusion criteria. Eight of these were judged to be of high, five moderate and three low quality. These reviews suggested that, in carefully selected patients, subcutaneous (SCIT) and sublingual (SLIT) immunotherapy resulted in significant reductions in symptom scores and medication requirements. Serious adverse outcomes were rare for both SCIT and SLIT. Two systematic reviews reported some evidence of potential cost savings associated with use of SCIT and SLIT.

Conclusions

We found moderate-to-strong evidence that SCIT and SLIT can, in appropriately selected patients, reduce symptoms and medication requirements in patients with ARC with reassuring safety data. This evidence does however need to be interpreted with caution, particularly given the heterogeneity in the populations, allergens and protocols studied. There is a lack of data on the relative effectiveness, cost-effectiveness and safety of SCIT and SLIT. We are now systematically reviewing all the primary studies, including recent evidence that has not been incorporated into the published systematic reviews.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0159-6) contains supplementary material, which is available to authorized users.

Allergen immunotherapy for the treatment of allergic rhinitis and/or asthma: an umbrella review

BACKGROUND

Allergic rhinitis and asthma are important public health concerns, yet there is no consensus about the benefits and harms of allergen-specific immunotherapy to treat these conditions. We performed an umbrella review of systematic reviews summarizing the current evidence for the benefits and harms of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT).

METHODS

We searched MEDLINE, Embase, the Cochrane Library and the grey literature from Jan. 1, 2010 to Nov. 20, 2016 for systematic reviews of randomized controlled trials or prospectively controlled studies involving children or adults with allergic rhinitis or asthma. Outcomes were summarized narratively (benefits: total combined symptom-medication score, symptom score, medication score, disease-specific quality of life, adherence; harms: anaphylaxis, death, local and systemic reactions).

RESULTS

Twenty-three systematic reviews were included. SCIT and SLIT were more effective than placebo for most outcomes. SCIT was better than SLIT at improving medication and symptom scores, with no differences in quality of life; however, data were limited for this comparison. Anaphylaxis and death were infrequently reported. Few reviews assessed benefits or harms among children.

INTERPRETATION

Allergen immunotherapy appears to be effective among patients with allergic rhinitis and asthma. The safety of allergen immunotherapy is not conclusively established, although death and anaphylaxis appear to be rare. PROSPERO no.: CRD42015024590.

Semi-depot house-dust mite allergen extract for Chinese with allergic rhinitis and asthma

BACKGROUND

Real-world data of the subcutaneous immunotherapy (SCIT) with semi-depot house-dust mite (HDM) allergen extract (a HDM allergen extract that contains a 50%-50% mixture of Dermatophagoides pteronyssinus and Dermatophagoides farina) for allergic rhinitis and asthma was unavailable in China until recently.

AIM

To investigate the effectiveness and safety of a HDM-SCIT for allergic rhinitis and asthma in Chinese patients.

METHODS

A multicenter, single-arm, open-label, self-controlled study. Chinese patients with allergic rhinitis or allergic asthma and with a history of symptoms from HDM exposure were included and received allergen-specific immunotherapy for 1 year by subcutaneous injection of HDM-SCIT. The primary outcome measure was the percentage of patients with an improvement in symptom severity assessed at 12 months after initiation of the treatment. The occurrence of adverse events and compliance of treatment were also evaluated.

RESULTS

A total of 272 outpatients were included for effectiveness analysis. The subject-evaluated improvement rate in the visual analog scale (VAS) was 76.1% and 71.3% at 6 and 12 months, respectively; corresponding values for investigator-evaluated VAS were 77.9% and 71.7%, respectively (p < 0.0001). Symptom score changes were -2.43 and -3.79 at 6 and 12 months, respectively (both p < 0.0001); the VAS improvement rate and symptom score change did not differ significantly between children and adolescents and/or adults. Good injection schedule adherence was found in 98.8% of the patients. No study drug-related serious adverse events or serious systemic allergic reactions occurred.

CONCLUSION

HDM-SCIT was safe and effective in the treatment of allergic rhinitis and asthma in a Chinese population, with good compliance.

Evidence in immunotherapy for paediatric respiratory allergy: Advances and recommendations

Allergic respiratory diseases are major health problems in paediatric population due their high level of prevalence and chronicity, and to their relevance in the costs and quality of life. One of the most important risk factors for the development of airway diseases in children and adolescents is atopy. The mainstays for the treatment of these diseases are avoiding allergens, controlling symptoms, and preventing them through sustained desensitization by allergen immunotherapy (AIT). AIT is a treatment option that consists in the administration of increasing amounts of allergens to modify the biological response to them, inducing long-term tolerance even after treatment has ended. This treatment approach has shown to decrease symptoms and improve quality of life, becoming cost effective for a large number of patients. In addition, it is considered the only treatment that can influence the natural course of the disease by targeting the cause of the allergic inflammatory response. The aim of this publication is to reflect the advances of AIT in the diagnosis and treatment of allergic respiratory diseases in children and adolescents reviewing articles published since 2000, establishing evidence categories to support the strength of the recommendations based on evidence. The first part of the article covers the prerequisite issues to understand how AIT is effective, such as the correct etiologic and clinical diagnosis of allergic respiratory diseases. Following this, the article outlines the advancements in understanding the mechanisms by which AIT achieve immune tolerance to allergens. Administration routes, treatment regimens, dose and duration, efficacy, safety, and factors associated with adherence are also reviewed. Finally, the article reviews future advances in the research of AIT.

Analysis of T-cell epitopes of Der f3 in Dermatophagoides farina

House dust mites (HDM) are most important indoor allergens for humans. Der f3, one of the potent allergens with allergenicity, is derived from Dermatophagoides farina (D. farinae), and exhibits strong allergenicity that was confirmed in our previous work. The current study was undertaken to determine the localization of T-cell epitope of Der f3. We initially developed the T-cell fraction from BALB/c mice sensitized with recombinant Der f3 to determine the T-cell epitopes in the murine models, and performed T cell proliferation assay with 25 synthetic overlapping peptides of Der f3. The results indicated that T-cell reactive region of murine were assigned on amino acid range 41-60, 101-120, 161-180 and 201-220, respectively. In addition, we did T-cell proliferation experiment, respectively using the 4 murine T-cell epitope peptide and the human T-cell lines from three patients allergic to mite allergens in order to verify homogenous T-cell epitopes in humans. The results indicated that the amino acid sequences of 41-60, 101-120 and 161-180 had induced T cell proliferation in humans, yet 201-220 failed to. These findings suggest that T-cell epitope in Der f3 is located in the amino acid sequences of 41-60, 101-120 and 161-180, respectively. T-cell epitope localization detected in our study may provide a basis for development of animal therapeutic model and peptide vaccine for asthma.