Advances in allergen immunotherapy in 2015

The long-term efficacy of intra-cervical lymphatic immunotherapy on adults with allergic rhinitis: A randomized controlled study

BACKGROUND

The efficacy and safety of the novel immunotherapy method, intra-cervical lymphatic immunotherapy (ICLIT), need to be investigated. Comparing it with subcutaneous immunotherapy (SCIT), we clarified the long-term efficacy and safety of intra-cervical lymphatic immunotherapy on allergic rhinitis (AR), and investigated the improvement of clinical efficacy of the booster injection at 1 year after ICLIT treatment.

METHODS

Ninety adult patients with dust mite allergy were randomly divided into 3 groups: 30 in the SCIT group, 30 in the ILCLIT group, and 30 in ICLIT booster group. Changes in total symptom score (TSS), nasal symptom score (TNSS), ocular symptom score (TOSS) and total medication score (TMS) were evaluated in the three groups. Adverse reactions were recorded, and serum dust mite specific IgE (sIgE) and specific IgG4 were assessed in the ICLIT group and ICLIT booster group.

RESULTS

TSS, TNSS, TOSS, and TMS scores were significantly lower in the three groups at 36 months after treatment (p < 0. 05). And at 36 months the ICLIT-booster group showed results similar to SCIT and superior to ICLIT (p < 0. 05). Serum specific IgE decreased in all three groups at 12 and 36 months after treatment, p < 0.01. The ICLIT group and the ICLIT booster group showed a significant increase in sIgG4, p < 0.01. None of the patients in the three groups had any serious systemic adverse effects during the 3-year follow-up.

CONCLUSION

The ICLIT treatment is effective and safe on AR. One booster injection of allergens at 1 year can greatly improve its long-term efficacy.

TRIAL REGISTRY

Clinical trial registration number: ChiCTR1800017130.

Intra-cervical lymphatic immunotherapy for dust mite-induced allergic rhinoconjunctivitis in children: a 3-year prospective randomized controlled trial

Background

Pediatric allergic rhinoconjunctivitis has become a public concern with an increasing incidence year by year. Conventional subcutaneous immunotherapy (SCIT) has long treatment time, high cost and poor compliance. The novel immunotherapy significantly shortens the course of treatment by directly injecting allergens into cervical lymph nodes, which can perform faster clinical benefits to children.

Objective

By comparing with SCIT, this study aimed to evaluate the long-term efficacy and safety of intra-cervical lymphatic immunotherapy (ICLIT).

Methods

This is a prospective randomized controlled study. A total of 50 allergic rhinoconjunctivitis children with dust mite allergy was randomly divided into ICLIT group and SCIT group, receiving three cervical intralymphatic injections of dust mite allergen or three years of subcutaneous injection, separately. Primary outcomes included total nasal symptom scores (TNSS), total ocular symptom scores (TOSS), total symptom scores (TSS), total medication scores (TMS), and total quality of life score. Secondary outcomes included pain perception and adverse reactions during treatment. Other secondary outcome was change in Dermatophagoides pteronyssinus (Derp) and Dermatophagoides farina (Derf) -specific IgE level.

Results

Both groups had significantly decreased TNSS, TOSS, TSS, TMS, and total quality of life score after 36 months of treatment (p<0.0001). Compared with SCIT, ICLIT could rapidly improve allergic symptoms (p<0.0001). The short-term efficacy was consistent between the two groups (p=0.07), while the long-term efficacy was better in SCIT group (p<0.0001). The pain perception in ICLIT group was lower than that in SCIT group (p<0.0001). ICLIT group was safer. Specifically, the children had only 3 mild local adverse reactions without systemic adverse reactions. The SCIT group had 14 systemic adverse reactions. At last, the serum Derp and Derf-specific IgE levels in ICLIT and SCIT groups decreased 3 years later (p<0.0001).

Conclusion

ICLIT could ameliorate significantly the allergic symptoms in pediatric patients with an advantage in effectiveness and safety, besides an improved life quality including shortened period of treatment, frequency of drug use and pain perception.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR1800017130.

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.

Structure-based prediction of the IgE epitopes of the major dog allergen Can f 1

Allergy to dogs has become increasingly prominent worldwide. Seven dog allergens have been identified, including Canis familiaris allergen 1-7 (Can f 1-7). Although Can f 1 is a major dog allergen sensitized to 50-75% of dog-allergic subjects, its IgE epitopes have not been identified. The structural analysis of an allergen is important to identify conformational epitopes. In this study, we generated a recombinant Can f 1 protein and determined its crystal structure using X-ray crystallography. Can f 1 had a typical lipocalin fold, which is composed of an eight-stranded β-barrel and α-helix, and has high similarity to Can f 2, Can f 4, and Can f 6 in overall structure. However, the localizations of surface charges on these proteins were quite different. Based on sequence alignment and tertiary structure, we predicted five critical residues (His86, Glu98, Arg111, Glu138, and Arg152) for the IgE epitopes. The relevance of these residues to IgE reactivity was assessed by generating Can f 1 mutants with these residues substituted for alanine. Although the effects of the mutation on IgE binding depended on the sera of dog-allergic patients, H86A and R152A mutants showed reduced IgE reactivity compared with wild-type Can f 1. These results suggest that Can f 1 residues His86 and Arg152 are candidates for the IgE conformational epitope.

Similar localization of conformational IgE epitopes on the house dust mite allergens Der p 5 and Der p 21 despite limited IgE cross-reactivity

BACKGROUND

Due to high IgE recognition frequency and high allergenic activity, Der p 5 and Der p 21 are clinically important house dust mite (HDM) allergens. The objective of this study was to characterize the immunodominant IgE epitopes of Der p 5 and Der p 21 responsible for their high allergenic activity.

METHODS

A panel of 12 overlapping peptides spanning the Der p 5 and Der p 21 sequence were synthesized to search for sequential IgE epitopes by direct testing for allergic patients' IgE reactivity. Peptide-specific antibodies raised in rabbits were used in inhibition studies for localizing conformational IgE epitopes which were visualized on the surfaces of the allergen structures by molecular modelling. IgE cross-reactivity between the allergens was investigated by IgE inhibition studies.

RESULTS

Immunodominant IgE epitopes defined by allergic patients' IgE on Der p 5 and Der p 21 were primarily of the conformational, discontinuous type including N- and C-terminal portions of the protein. They could be located on each allergen on one area with similar localization, but despite similar structure of the allergens, no relevant IgE cross-reactivity could be detected.

CONCLUSION

Our study shows that Der p 5 and Der p 21 contain a major conformational IgE epitope-containing area located on similar portions of their structure, but they lack relevant IgE cross-reactivity. These data are important for the development of modern allergy vaccines based on defined molecules for allergen-specific immunotherapy of HDM allergy.

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.

Human dendritic cells activated with MV130 induce Th1, Th17 and IL-10 responses via RIPK2 and MyD88 signalling pathways

Recurrent respiratory tract infections (RRTIs) are the first leading cause of community- and nosocomial-acquired infections. Antibiotics remain the mainstay of treatment, enhancing the potential to develop antibiotic resistances. Therefore, the development of new alternative approaches to prevent and treat RRTIs is highly demanded. Daily sublingual administration of the whole heat-inactivated polybacterial preparation (PBP) MV130 significantly reduced the rate of respiratory infections in RRTIs patients, however, the immunological mechanisms of action remain unknown. Herein, we study the capacity of MV130 to immunomodulate the function of human dendritic cells (DCs) as a potential mechanism that contribute to the clinical benefits. We demonstrate that DCs from RRTIs patients and healthy controls display similar ex vivo immunological responses to MV130. By combining systems biology and functional immunological approaches we show that MV130 promotes the generation of Th1/Th17 responses via receptor-interacting serine/threonine-protein kinase-2 (RIPK2)- and myeloid-differentiation primary-response gene-88 (MyD88)-mediated signalling pathways under the control of IL-10. In vivo BALB/c mice sublingually immunized with MV130 display potent systemic Th1/Th17 and IL-10 responses against related and unrelated antigens. We elucidate immunological mechanisms underlying the potential way of action of MV130, which might help to design alternative treatments in other clinical conditions with high risk of recurrent infections.

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.

Recent advances in the use of nanoparticles for allergen-specific immunotherapy

The number of patients suffering from allergic asthma and rhinoconjunctivitis has increased dramatically within the last decades. Allergen-specific immunotherapy (AIT) is the only available cause-oriented therapy so far. AIT reduces symptoms, but has also a disease-modifying effect. Disadvantages are a long-lasting procedure, and in a few cases potential systemic adverse reactions. Encapsulation of allergens or DNA vaccines into nanostructures may provide advantages compared to the conventional AIT with noncapsulated allergen extracts: The protein/DNA molecule can be protected from degradation, higher local concentrations and targeted delivery to the site of action appear possible, and most importantly, recognition of encapsulated allergen by the immune system, especially by IgE antibodies, is prevented. AIT with nanoparticles (NPs) may offer a safer and potentially more efficient way of treatment for allergic diseases. In this review, we summarize the use of biodegradable NPs consisting of synthetic or natural polymers, liposomes, and virus-like particles as well as nonbiodegradable NPs like dendrimers, and carbon- or metal-based NPs for AIT. More or less successful applications of these NPs in prophylactic as well as therapeutic vaccination approaches in rodents or other animals as well as first human clinical trials are discussed in detail.

Clustering of conformational IgE epitopes on the major dog allergen Can f 1

Immunoglobulin E (IgE)-associated allergy affects more than 25% of the population. Can f 1 is the major dog allergen associated with respiratory symptoms but the epitopes recognized by allergic patients IgE on Can f 1 are unknown. To characterize IgE epitopes of Can f 1 recognized by dog allergic patients, six overlapping peptides spanning the Can f 1 sequence were synthesized. In direct IgE epitope mapping experiments peptides were analyzed for IgE reactivity by dot blot and Enzyme-linked immunosorbent assay (ELISA) with sera from dog allergic patients. For indirect epitope-mapping, rabbits were immunized with the peptides to generate specific IgG antibodies which were used to inhibit allergic patients’ IgE binding to Can f 1. IgE binding sites were visualized on a model of the Can f 1 three-dimensional structure. We found that Can f 1 does not contain any relevant sequential IgE epitopes. However, IgE inhibition experiments with anti-peptide specific IgGs showed that Can f 1 N- and C-terminal portion assembled a major conformational binding site. In conclusion, our study is the first to identify the major IgE epitope-containing area of the dog allergen Can f 1. This finding is important for the development of allergen-specific treatment strategies.

Advances and highlights in allergen immunotherapy: On the way to sustained clinical and immunologic tolerance

Allergen immunotherapy (AIT) is an effective treatment strategy for allergic diseases and has been used for more than 100 years. In recent years, however, the expectations on concepts, conduct, statistical evaluation, and reporting have developed significantly. Products have undergone dose-response and confirmative studies in adults and children to provide evidence for the optimal dosage, safety, and efficacy of AIT vaccines using subcutaneous and sublingual delivery pathways in large patient cohorts, ensuring solid conclusions to be drawn from them for the advantage of patients and societies alike. Those standards should be followed today, and products answering to them should be preferred over others lacking optimization and proof of efficacy and safety. Molecular and cellular mechanisms of AIT include early mast cell and basophil desensitization effects, regulation of T- and B-cell responses, regulation of IgE and IgG₄ production, and inhibition of responses from eosinophils, mast cells, and basophils in the affected tissues. There were many developments to improve vaccination strategies, demonstration of new molecules involved in molecular mechanisms, and demonstration of new biomarkers for AIT during the last few years. The combination of probiotics, vitamins, and biological agents with AIT is highlighting current advances. Development of allergoids and recombinant and hypoallergenic vaccines to skew the immune response from IgE to IgG₄ and regulation of dendritic cell, mast cell, basophil, innate lymphoid cell, T-cell, and B-cell responses to allergens are also discussed in detail.