Allergen Immunotherapy: Past, Present, and Future

Clinical Trial With a Depigmented, Polymerized Mite Mixture Extract at Maximum Concentrations

BACKGROUND

Efficacy of allergen immunotherapy is dose-dependent; however, high doses of allergen may imply a greater risk of adverse reactions.

OBJECTIVE

To assess the safety and tolerability of subcutaneous immunotherapy (SCIT) with mixtures of mite allergen extracts, Dermatophagoides pteronyssinus/Blomia tropicalis (Dpt/Bt) and Dermatophagoides pteronyssinus/Lepidoglyphus destructor (Dpt/Ld) at maximum concentrations, in adult patients with allergic rhinitis or rhinoconjunctivitis, and controlled allergic asthma due to a clinically relevant sensitisation to these mites.

METHODS

An open-label, noncontrolled, nonrandomised, phase IIb clinical trial was carried out in three hospitals in Spain between September 2014 and May 2018. Patients received SCIT of either Dpt/Bt (100/1000 DPP/mL) or Dpt/Ld (100/100 DPP/mL) in two phases: a rush build-up phase on the first day (0.2 mL and 0.3 mL with a 30-min interval) and a monthly maintenance phase administration (0.5 mL) up to 48 months.

RESULTS

Forty patients were recruited for the study, seven allocated to the Dpt/Bt group and 33 to the Dpt/Ld. None experienced immediate or delayed systemic Grade ≥ 2 reactions (EAACI classification) (systemic reactions were mostly Grade 1) nor died during the study. Local reactions were mostly mild (0‒10 cm). Thirty-nine patients (97.5%) experienced at least one adverse event (AE). Of the 283 reported AEs, eight (2.8%) were systemic reactions experienced by six (15%) subjects and 14 (4.9%) were local reactions sustained by ten (25%) subjects.

CONCLUSIONS

SCIT treatment of patients with allergic rhinitis or rhinoconjunctivitis and controlled asthma with mixtures of Dpt/Bt and Dpt/Ld allergen extracts at maximum concentrations showed a favourable safety profile.

The SQ tree sublingual immunotherapy tablet is effective and well tolerated in children-A pivotal phase III trial

BACKGROUND

Allergic rhinitis and/or conjunctivitis (AR/C) induced by tree pollen is common and negatively impacts quality of life in children and adolescents. This phase III trial investigated the efficacy and safety of the SQ tree SLIT-tablet in a paediatric population (5-17 years) with moderate-to-severe AR/C induced by pollen from birch and trees in the birch homologous group.

METHODS

Nine hundred and fifty-two subjects were randomized (1:1) to daily treatment with SQ tree SLIT-tablet or placebo for up to 52 weeks and had free access to AR/C symptom-relieving medications. The primary endpoint was the average total combined score (TCS); sum of average daily symptom score (DSS) and average daily medication score (DMS) during the birch pollen season (BPS). Key secondary endpoints included average DSS and DMS during BPS and average TCS, DSS and DMS during tree pollen season (TPS).

RESULTS

SQ tree SLIT-tablet demonstrated a statistically significant and clinically relevant treatment effect compared with placebo for the TCS during BPS with an absolute treatment difference of 1.29 (95% CI: 0.58, 2.00; p = .0004) and a relative reduction of 21.9% (95% CI: 10.6, 31.9). Results were substantiated by reductions in both DSS and DMS versus placebo during the BPS and in DSS, DMS and TCS during the TPS. Treatment was generally well tolerated. Most treatment-related adverse events were mild or moderate local administration site reactions.

CONCLUSION

This is the first paediatric trial to provide robust evidence of efficacy and safety of the SQ tree SLIT-tablet in tree pollen-induced AR/C in a paediatric population (5-17 years).

Management of Allergic Rhinitis in the United Arab Emirates: Expert Consensus Recommendations on Allergen Immunotherapy

Allergic rhinitis (AR) is a chronic inflammatory condition of the upper airways caused by a type I hypersensitivity reaction triggered by environmental allergens. AR is associated with significant morbidity and affects patients' quality of life, emotional well-being, productivity, and cognitive functioning. As AR prevalence and morbidity have increased significantly worldwide, similar observations have been noted in the United Arab Emirates (UAE) with AR becoming a potential public health issue. Management of AR in the UAE is mainly provided by non-allergy specialists relying on first-line treatments such as intranasal steroids and antihistamines, with often suboptimal and short-term efficacy. Allergen Immunotherapy (AIT) is the only currently available disease-modifying treatment option in the form of either subcutaneous or sublingual allergen immunotherapy that has been proven to have long-term benefits. This article aims to provide recommendations regarding the use of AIT for managing AR in the UAE, considering both the current landscape in the Emirati healthcare system and local experience.

Construction by artificial intelligence and immunovalidation of hypoallergenic mite allergen Der f 36 vaccine

Background

The house dust mite (HDM) is widely recognized as the most prevalent allergen in allergic diseases. Allergen-specific immunotherapy (AIT) has been successfully implemented in clinical treatment for HDM. Hypoallergenic B-cell epitope-based vaccine designed by artificial intelligence (AI) represents a significant progression of recombinant hypoallergenic allergen derivatives.

Method

The three-dimensional protein structure of Der f 36 was constructed using Alphafold2. AI-based tools were employed to predict B-cell epitopes, which were subsequently verified through IgE-reaction testing. Hypoallergenic Der f 36 was then synthesized, expressed, and purified. The reduced allergenicity was assessed by enzyme-linked immunosorbent assay (ELISA), immunoblotting, and basophil activation test. T-cell response to hypoallergenic Der f 36 and Der f 36 was evaluated based on cytokine expression in the peripheral blood mononuclear cells (PBMCs) of patients. The immunogenicity was evaluated and compared through rabbit immunization with hypoallergenic Der f 36 and Der f 36, respectively. The inhibitory effect of the blocking IgG antibody on the specific IgE-binding activity and basophil activation of Der f 36 allergen was also examined.

Results

The final selected non-allergic B-cell epitopes were 25-48, 57-67, 107-112, 142-151, and 176-184. Hypoallergenic Der f 36 showed significant reduction in IgE-binding activity. The competitive inhibition of IgE-binding to Der f 36 was investigated using the hypoallergenic Der f 36, and only 20% inhibition could be achieved, which is greatly reduced when compared with inhibition by Der f 36 (98%). The hypoallergenic Der f 36 exhibited a low basophil-stimulating ratio similar to that of the negative control, and it could induce an increasing level of IFN-γ but not Th2 cytokines IL-5 and IL-13 in PBMCs. The vaccine-specific rabbit blocking IgG antibodies could inhibit the patients' IgE binding and basophil stimulation activity of Derf 36.

Conclusion

This study represents the first application of an AI strategy to facilitate the development of a B-cell epitope-based hypoallergenic Der f 36 vaccine, which may become a promising immunotherapy for HDM-allergic patients due to its reduced allergenicity and its high immunogenicity in inducing blocking of IgG.

The dichotomy of regulatory B cells in cancer versus allergic disease

Regulatory B cells (Bregs) are an immunosuppressive cell phenotype that affects the immune system by limiting the inflammatory cascade. Dysregulation of Bregs can interestingly play a dichotomous role in the pathophysiology of many diseases and is especially highlighted when examining cancer pathology compared to allergic disease. This study reviews the existing literature on Bregs and compares their role in allergic disease in contrast to cancer development. Upregulation of Bregs in cancer states has been associated with poor prognostic outcomes across various cancer types, and Breg proliferation was associated with chronic interferon signaling, activation of the BCR-BTK (B cell receptor-Bruton's tyrosine kinase) pathway, and release of C-X-C motif ligand 13. In contrast, Breg dysfunction has been identified as a key mechanism in many allergic diseases, such as allergic asthma, allergic rhinitis, atopic dermatitis, and contact dermatitis. Development of Breg-targeted immunotherapies is currently at the preclinical level, but strategies differentially focus on Breg depletion in cancer versus Breg stimulation in allergy. Our review highlights the divergent functions that Bregs play in cancer compared to allergy. We conclude that natural homeostasis hinges on a fine balance between the dichotomous role of Bregs-over or underactivation can result in a pathological state.

A randomised, double-blinded comparison between subcutaneous rush and intralympathic allergen immunotherapy induction in atopic dogs

BACKGROUND

Atopic dermatitis (AD) is one of the most common skin diseases in small animal practice. Allergen immunotherapy (AIT) is the only curative treatment for the disease, and oral, subcutaneous and intralymphatic administration of allergens are commonly employed.

OBJECTIVES

To compare the efficacy of AIT following an induction phase with intralymphatic injections (ILIT) or rush immunotherapy (RIT).

ANIMALS

Fifty privately owned dogs with AD.

MATERIALS AND METHODS

In a double-blinded study, dogs were randomly assigned to either four monthly ILIT of allergen extract or RIT with five injections administered subcutaneously at hourly intervals on the first day. They were assessed by validated scores; Canine Atopic Dermatitis Lesion Index (CADLI) and pruritus Visual Analog Scale (PVAS) at the beginning of the study and after 1, 3, 6 and 12 months. The latter were performed daily for 7 days before each revisit. Medication scores and a total clinical score were calculated and compared between each group and time point.

RESULTS

There was no significant difference in CADLI and PVAS scores, or CADLI and medication scores between groups at any of the time points. A significant improvement with both ILIT and RIT was seen in total and pruritus scores, respectively. An owner global assessment of good-to-excellent treatment efficacy was seen in 40% of the dogs; total scores improved by 27% and 35% in the RIT and ILIT group, respectively. Adverse effects were not seen.

CONCLUSIONS AND CLINICAL RELEVANCE

Induction of AIT can be conducted either as RIT or ILIT with no loss in efficacy.

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.

Antiallergic Effects of Callerya atropurpurea Extract In Vitro and in an In Vivo Atopic Dermatitis Model

(1) Background: Callerya atropurpurea is found in Laos, Thailand, and Vietnam. Although the anti-inflammatory action of C. atropurpurea has been investigated, the functions of this plant in allergic responses are not understood. Here, we explored the antiallergic mechanism of C. atropurpurea ethanol extract (Ca-EE) using in vitro assays and an in vivo atopic model. (2) Methods: The constituents of Ca-EE were analyzed using GC/MS. Inhibition of lipoxygenase and β-hexosaminidase activity was examined, and the expression of inflammatory genes was measured by quantitative real-time PCR. The regulatory roles of Ca-EE in IgE/FcεRI signaling were examined by Western blotting. The DNCB-induced atopic dermatitis mouse model was performed with histological analysis. (3) Results: Ca-EE comprised cis-raphasatin, lupeol, some sugars, and fatty acids. In RBL-2H3 cells, treatment with Ca-EE significantly reduced the activities of lipoxygenase and β-hexosaminidase, as well as cytokine gene expression. IgE-mediated signaling was downregulated by blocking Lyn kinases. Moreover, Ca-EE effectively inhibited allergic symptoms in the DNCB-induced atopic dermatitis model without toxicity. (4) Conclusions: Ca-EE displayed antiallergic activities through regulating IgE/Lyn signaling in RBL-2H3 cells and a contact dermatitis model. These results indicate that Ca-EE could be effective for allergic disease treatment.

Molecular Aspects of Allergen-Specific Immunotherapy in Patients with Seasonal Allergic Rhinitis

A systematic review and narrative synthesis of publications was undertaken to analyze the role of component-resolved diagnosis technology in identifying polysensitization for the provision of allergen-specific immunotherapy to patients with seasonal allergic rhinitis. A search of publications was carried out in electronic databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search helped to identify 568 publications, 12 of which were included in this review. Overall, 3302 patients were enrolled. The major finding was that component-resolved diagnostics change the choice of relevant allergens for allergen-specific immunotherapy in at least 50% of cases. Sensitization to allergen components differs with age, type of disease, and overall disease duration. Patients who had both bronchial asthma and allergic rhinitis were sensitized to a larger number of allergens than patients who had bronchial asthma alone.

Recent Updates of Immunotherapy for Allergic Rhinitis in Children

Purpose of Review

Allergen immunotherapy (AIT) is a novel treatment approach with disease-modifying and preventative benefits that are not shared with other strategies for treating allergic illnesses. It has been demonstrated to be safe and effective in children. This review provides the most recent information on AIT in children as well as any pertinent updates.

Recent Findings

Although there is not a standard way to begin AIT, there are clear indications for AIT. Each case needs to be evaluated on its own by weighing the pros and downsides. AIT has been proven to significantly improve symptoms and quality of life in children with allergic illness, reduce medication use, stop the development of new allergen sensitizations, and stop the progression of allergic rhinitis to asthma. Novel approaches are under investigation to overcome some known AIT disadvantages.

Summary

This review provides a thorough summary of the most recent research and updates on AIT in children.

Effectiveness and safety of allergen immunotherapy in patients with allergic rhinitis complicated by rheumatic autoimmune diseases: a case series study

Background

Allergen immunotherapy (AIT) is the only treatment that has modified the natural history of allergic diseases. However, since its overall effect on the immune system has not been elucidated, AIT is either absolutely or relatively contraindicated in patients with rheumatic autoimmune diseases (RADs). Therefore, there have been no long-term observations of patients with RADs receiving AIT; thus, the effectiveness and safety of AIT in these patients remain unclear.

Methods

This was a single-center retrospective observational study. RAD patients receiving AIT for allergic rhinitis at our institution were selected. Changes in the activity of RAD patients were investigated for 2 years from baseline, including those who discontinued AIT. The effectiveness of AIT was also investigated using the Japan Allergic Rhinitis Standard Quality of Life Questionnaire.

Results

Thirteen patients with RADs were enrolled in the study. All patients received sublingual immunotherapy, of which four discontinued AIT owing to adverse events. Among all patients, the symptoms of RADs in three patients worsened during the observation period; however, none of them were causally related to AIT. Most of the adverse events associated with AIT were mild, in which only one patient required drug intervention due to worsening rhinitis symptoms. In the nine patients who were able to continue AIT, their eye and nasal symptom scores showed a significant improvement from 1.67 (1.5–2.0) at baseline to 0.67 (0–1.17) in the 2nd year of treatment (p = 0.0141).

Conclusions

AIT is a safe and effective treatment modality for patients with allergic rhinitis complicated by RADs.

Cytokine and Lymphocyte Profiles in Dogs with Atopic Dermatitis after Allergen-Specific Immunotherapy

Canine atopic dermatitis (cAD) is a chronic and recurrent inflammatory and pruritic skin disease in dogs. Currently, allergen-specific immunotherapy (ASIT) is the only identified disease-modifying intervention for allergic diseases. It decreases the symptoms triggered by allergens and prevents recurrence of the disease in the long-term. The aim of our research was to determine how immunotherapy changes the proportion of lymphocyte subsets in dog peripheral blood and the levels of cytokines secreted by these cells during therapy. ASIT was applied for 6 months. Blood samples for further analyses were collected from patients in the third and sixth month of immunotherapy. Six out of seven dogs receiving ASIT showed a positive effect. A reduction in cytokine levels (IL-13, TNF-α) in peripheral blood of cAD patients and changes in the number of specific T cell subpopulations—reduction of Tc cells (CD8+) and increase of activated T cells (CD3+CD25+)—confirmed the beneficial effect of the applied ASIT. In addition, a significantly higher percentage of Treg cells (CD4+CD25+FOXP3+) was noted in cAD patients before treatment compared to healthy dogs. After 3 months of therapy, the percentage of Tregs significantly decreased, and after 6 months, it increased significantly again.

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

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

A Real-World Effectiveness of Subcutaneous Immunotherapy on the Cost of Medication, Allergic Rhinitis, and Asthma Exacerbations, as well as Upper Respiratory Tract Infection in Subjects with Allergic Rhinitis with or without Asthma: A Retrospective Pilot Study

Background and Objectives: Real-world studies are limited regarding the effectiveness of SCIT on allergic rhinitis (AR) with and without asthma and the cost of medication in Thailand. Moreover, limited data exist regarding the effectiveness of SCIT on worldwide upper respiratory tract infection (URTI). Therefore, the objective of this study was to compare the medication costs, rate of AR and asthma exacerbations, and rate of URTI in AR with or without asthma subjects before and during three years after receiving the maintenance phase of SCIT, compared with a standard usual care (SUC) group. Materials and Methods: A real-world retrospective study was conducted in AR subjects with or without asthma. From January 2001 to December 2018, 24 subjects with or without asthma received SCIT added to SUC, and 16 subjects were treated with SUC only at the Allergy and Chest Clinic of Chiang Mai Ram Hospital, Chiang Mai, Thailand. The cost of medication was recorded. AR and asthma exacerbations and URTI events were also collected. Results: From between-group comparisons, the cost of medication (THB) in the SCIT group at the one-, two-, and three-year follow up was significantly lower (587.4 (348.3–1374.6) vs. 1562.4 (1315.1–1857.3), p < 0.001, 501.2 (302.9–839.0) vs. 1728.3 (1190.0–2236.1), p < 0.001, and 372.4 (284.8–752.4) vs. 1500.3 (1217.9–1748.9), p < 0.001, respectively)), and AR and asthma exacerbations were significantly reduced at the three-year follow-up. From within-group comparisons, the cost of medication (THB) and AR and asthma exacerbations were significantly lower in the SCIT group at the one-, two-, and three-year follow-up. The URTI event was significantly reduced in the SCIT group at the two- and three-year follow-up. Conclusions: SCIT in subjects with AR with or without asthma was associated with a significantly reduced cost of medication, rates of AR and asthma exacerbations, and URTI events in the long term.

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.

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

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

Comprehensive mapping of immune tolerance yields a regulatory TNF receptor 2 signature in a murine model of successful Fel d 1-specific immunotherapy using high-dose CpG adjuvant

Background

The prevalence of allergy to cat is expanding worldwide. Allergen‐specific immunotherapy (AIT) has advantages over symptomatic pharmacotherapy and promises long‐lasting disease control in allergic patients. However, there is still a need to improve cat AIT regarding efficacy, safety, and adherence to the treatment. Here, we aim to boost immune tolerance to the major cat allergen Fel d 1 by increasing the anti‐inflammatory activity of AIT with the established immunomodulatory adjuvant CpG, but at a higher dose than previously used in AIT.

Methods

Together with CpG, we used endotoxin‐free Fel d 1 as therapeutic allergen throughout the study in a BALB/c model of allergy to Fel d 1, thus mimicking the conditions of human AIT trials. Multidimensional immune phenotyping including mass cytometry (CyTOF) was applied to analyze AIT‐specific immune signatures.

Results

We show that AIT with high‐dose CpG in combination with endotoxin‐free Fel d 1 reverts all major hallmarks of allergy. High‐dimensional CyTOF analysis of the immune cell signatures initiating and sustaining the AIT effect indicates the simultaneous engagement of both, the pDC‐Treg and B‐cell axis, with the emergence of a systemic GATA3⁺ FoxP3^hi biTreg population. The regulatory immune signature also suggests the involvement of the anti‐inflammatory TNF/TNFR2 signaling cascade in NK and B cells at an early stage and in Tregs later during AIT.

Conclusion

Our results highlight the potential of CpG adjuvant in a novel formulation to be further exploited for inducing allergen‐specific tolerance in patients with cat allergy or other allergic diseases.

Vaccines as therapies for food allergies

Food allergy is a growing public health epidemic with few available treatments beyond allergen avoidance and rescue medications for accidental exposures. A major focus of therapeutic development for food allergies is allergen-specific immunotherapy (AIT) in which patients are exposed to increasing amounts of allergen in controlled dosing to induce desensitization or tolerance. The work of the past few decades has culminated in the recent FDA approval of a peanut product for oral AIT for peanut allergies. Despite these advances, current AIT protocols are cumbersome, take a long time to reach clinical benefit and often have significant side effects. Therefore, there is a great need to develop new therapeutics for food allergy. One area of research aims to improve AIT through the use of adjuvants which are substances traditionally added to vaccines to stimulate or direct a specific immune response. Adjuvants that induce Th1-polarized and regulatory immune responses while suppressing Th2 immunity have shown the most promise in animal models. The addition of adjuvants to AIT may reduce the amount and frequency of allergen required to achieve clinical benefit and may induce more long-lasting immune responses. In this chapter, we highlight examples of adjuvanted AIT and vaccines in development to treat food allergies.

Oral administration of Hsp65-producing Lactococcus lactis attenuates allergic asthma in a murine model

AIMS

Allergic asthma is a chronic inflammatory lung disease characterized by a Th2-type immune response pattern. The development of nonspecific immunotherapy is one of the primary goals for the control of this disease.

METHODS AND RESULTS

In this study, we evaluated the therapeutic effects of Lactococcus lactis-producing mycobacterial heat shock protein 65 (LLHsp65) in an ovalbumin (OVA)-induced allergic asthma model. OVA-challenged BALB/c mice were orally administrated with LLHsp65 for 10 consecutive days. The results demonstrate that LLhsp65 attenuates critical features of allergic inflammation, like airway hyperresponsiveness and mucus production. Likewise, the treatment decreases the pulmonary eosinophilia and the serum level of OVA-specific IgE. In addition to deviating immune responses towards Th1-cytokine profile, increase regulatory T cells, and cytokine levels, such as IL-6 and IL-10.

CONCLUSIONS

Our results reveal that the mucosal immunotherapy of LLHsp65 significantly reduces the overall burden of airway allergic inflammation, suggesting a promising therapeutic strategy for allergic asthma treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research reveals new perspectives on nonspecific immunotherapy based on the delivery of recombinant proteins by lactic acid bacteria to treat of allergic disorders.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Artemisia annua-sublingual immunotherapy for seasonal allergic rhinitis: A randomized controlled trial

BACKGROUND

Artemisia annua is an important autumnal pollen allergen for seasonal allergic rhinitis (SAR) in northern China. To date, no study has investigated allergen immunotherapy with A annua. We aimed to investigate the efficacy and mechanisms underlying A annua-sublingual immunotherapy (SLIT).

METHODS

This was a randomized, double-blind, placebo-controlled phase III clinical trial involving 71 SAR patients, randomized to SLIT with A annua extract (n = 47) or placebo (n = 24) for 32 weeks. Total nasal symptom score (TNSS; primary clinical end point) was evaluated at baseline (peak pollen phase (PPP) in the previous year), initiation of A annua-SLIT, 1st PPP during SLIT, end of SLIT and 2nd PPP during follow-up. Blood samples and nasal secretions were collected at beginning and after SLIT for assessment of T cells and inflammatory mediators. Safety was assessed according to adverse events (AEs) reported.

RESULTS

Artemisia annua-SLIT significantly reduced TNSS to a greater level from baseline (from 9.45 ± 1.68 to 6.16 ± 2.27) than placebo (from 9.29 ± 2.09 to 9.05 ± 2.40) at the 1st PPP (P < .001) and sustained the improvement in symptoms throughout to the 2nd PPP. Preseasonal A annua-SLIT for 16 weeks significantly decreased Th2 cells, increased nTreg and Tr1 cells in blood; and increased cystatin 1 (CST1) in nasal secretion after 16 and 32 weeks compared with pretreatment. Overall, 17/47 patients experienced mild local AEs and 2 patients mild systemic AEs, after A annua-SLIT.

CONCLUSION

Artemisia annua-SLIT is an efficacious and safe treatment in patients with A annua SAR.

A non-stationary Markov model for economic evaluation of grass pollen allergoid immunotherapy

Introduction

Allergic rhino-conjunctivitis (ARC) is an IgE-mediated disease that occurs after exposure to indoor or outdoor allergens, or to non-specific triggers. Effective treatment options for seasonal ARC are available, but the economic aspects and burden of these therapies are not of secondary importance, also considered that the prevalence of ARC has been estimated at 23% in Europe. For these reasons, we propose a novel flexible cost-effectiveness analysis (CEA) model, intended to provide healthcare professionals and policymakers with useful information aimed at cost-effective interventions for grass-pollen induced allergic rhino-conjunctivitis (ARC).

Methods

Treatments compared are: 1. no AIT, first-line symptomatic drug-therapy with no allergoid immunotherapy (AIT). 2. SCIT, subcutaneous immunotherapy. 3. SLIT, sublingual immunotherapy. The proposed model is a non-stationary Markovian model, that is flexible enough to reflect those treatment-related problems often encountered in real-life and clinical practice, but that cannot be adequately represented in randomized clinical trials (RCTs). At the same time, we described in detail all the structural elements of the model as well as its input parameters, in order to minimize any issue of transparency and facilitate the reproducibility and circulation of the results among researchers.

Results

Using the no AIT strategy as a comparator, and the Incremental Cost Effectiveness Ratio (ICER) as a statistic to summarize the cost-effectiveness of a health care intervention, we could conclude that:

Conclusions

Even though there is a considerable evidence that SCIT outperforms SLIT, we could not state that both SCIT and SLIT (or only one of these two) can be considered cost-effective for ARC, as a reliable threshold value for cost-effectiveness set by national regulatory agencies for pharmaceutical products is missing. Moreover, the impact of model input parameters uncertainty on the reliability of our conclusions needs to be investigated further.

Linking autoantigen properties to mechanisms of immunity

Antigen-specific immunotherapies (ASIT) present compelling potential for introducing precision to the treatment of autoimmune diseases where nonspecific, global immunosuppression is currently the only treatment option. Central to ASIT design is the delivery of autoantigen, which parallels allergy desensitization approaches. Clinical success in tolerizing allergen-specific responses spans longer than a century, but autoimmune ASITs have yet to see an FDA-approved breakthrough. Allergens and autoantigens differ substantially in physicochemical properties, and these discrepancies influence the nature of their interactions with the immune system. Approved allergen-specific immunotherapies are typically administered as water soluble, neutrally charged protein fractions from 10 to 70 kDa. Conversely, autoantigens are native proteins that exhibit wide-ranging sizes, solubilities, and charges that render them susceptible to immunogenicity. To translate the success of allergen hyposensitization to ASIT, delivery strategies may be necessary to effectively format autoantigens, guide biodistribution, and engage appropriate immune mechanisms.

Determining the Effect of Amino Acids on the Allergenic Activity of Pollen Extracts

BACKGROUND

The diagnosis and treatment of allergic diseases require high quality pollen allergen extracts for reliable test results and effective treatments. The quality of the pollen allergen extracts is influenced by pharmacologically inert ingredients, such as stabilizers which are added to prevent the degradation of the allergenic activity. This study was conducted to develop a stabilizer formulation in order to protect the allergenic activity of the pollen's extracts.

METHODS

Pine and orchard grass pollen allergen extracts were incubated for 40 days at 37 °C. The effects of chemicals were examined via inhibition ELISA on days 7, 14, 21, 28, and 40 to evaluate the ability of the pollen allergen extracts to inhibit specific IgE in the sera of sensitized patients.

RESULTS

Our findings showed that the pine pollen and orchard grass allergen extracts treated with Lys/Glu had the best stabilizing effect resulting in a 97% IgE inhibition following the 40 days of incubation. In the non-treatment group, the IgE inhibition decreased to 23% at the end of the 40 days. The orchard grass pollen allergen extracts receiving no treatment decreased to 12% IgE inhibition following the 40-day incubation.

CONCLUSION

Amino acids are able to act as an effective stabilizer for pollen allergen extracts and prevent the degradation of their activity over time. Particularly applying Lys/ Glu in pollen allergenic extracts can protect allergenic activity and potency of the pollen extracts to inhibit specific IgE in human sera.

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.

Safety of Ultra-rush Schedule of Subcutaneous Allergen Immunotherapy With House Dust Mite Extract Conducted in an Outpatient Clinic in Patients With Atopic Dermatitis and Allergic Rhinitis

PURPOSE

Ultra-rush schedule of subcutaneous allergen immunotherapy (UR-SCIT) administering maximum maintenance dose of allergen extract within one day can save time and effort for allergen immunotherapy in patients with allergic disease. However, UR-SCIT is associated with an increased risk of systemic reaction (SR) and typically has been conducted in a hospital admission setting. To overcome disadvantages of UR-SCIT, we evaluated the safety of UR-SCIT conducted in an outpatient clinic in patients with atopic dermatitis (AD) and allergic rhinitis (AR).

METHODS

UR-SCIT was performed in 538 patients with AD and/or AR sensitized to house dust mite (HDM). A maximum maintenance dose of tyrosine-adsorbed HDM extract (1 mL of maintenance concentration) was divided into 4 increasing doses (0.1, 0.2, 0.3, and 0.4 mL) and administered to the patients by subcutaneous injection at 2-hour intervals for 8 hours in an outpatient clinic. SRs associated with UR-SCIT were classified according to the World Allergy Organization grading system.

RESULTS

SR was observed in 12 of 538 patients (2.2%) with AD and/or AR during UR-SCIT. The severity grades of the observed SRs were mild-to-moderate (grade 1 in 7 patients, grade 2 in 4 patients, and grade 3 in 1 patient). The scheduled 4 increasing doses of HDM extract could be administered in 535 of 538 patients (99.4%) except 3 patients who experienced SR before administration of the last scheduled dose. SR was observed within 2 hours in 11 patients after administration of the scheduled doses of HDM extract except one patient who experienced a grade 2 SR at 5.5 hours after administration of the last scheduled dose.

CONCLUSIONS

UR-SCIT with tyrosine-adsorbed HDM extract conducted in an outpatient clinic was tolerable in patients with AD and AR. UR-SCIT can be a useful method to start a SCIT in patients with AD and AR.

Der p2‑A20 DNA vaccine attenuates allergic inflammation in mice with allergic rhinitis

Allergic rhinitis (AR) is a common disease that requires more convenient, safe and effective antigen-specific immunotherapies. The present study aimed to investigate the therapeutic effect of intranasal administration of a eukaryotic expression vector co-expressing Der p2 and A20 protein (pVAX1-Der p2-A20) on mice with allergic rhinitis. The pVAX1-Der p2-A20 vaccine was prepared and encapsulated into poly(L-lactide-co-glycolide) (PLGA) nanoparticles. An allergic rhinitis Balb/c mouse model was established through intraperitoneal sensitization with recombinant Der p2 and cholera toxin followed by intranasal challenge with recombinant Der p2. The treatment effect of the DNA vaccine on nasal allergic inflammation was evaluated, and serum IgE, sIgE, IgG and cytokine levels were determined by ELISA. The percentage of CD4⁺CD25⁺Foxp3⁺Tregs in the spleen was detected by flow cytometry. The DNA vaccine co-expressing Der p2 and A20 was successfully constructed and encapsulated into PLGA nanoparticles. Der p2-A20 DNA vaccine intranasal administration markedly ameliorated Der p2-induced nasal allergic inflammation. The serum Der p2-specific IgE, IL-4 and IL-13 expression levels were inhibited, while the Der p2-specific IgG1, IgG2a and IFN-γ expression levels in the serum and splenic CD4⁺CD25⁺Foxp3⁺Treg population were significantly increased after Der p2-A20 DNA vaccine treatment. These results indicated that the Der p2-A20 DNA vaccine alleviates nasal allergic inflammation and promotes splenic Treg population in mice with allergic rhinitis.

Effects of allergen-specific immunotherapy on peripheral blood regulatory T cells and serum concentrations of cytokines and immunoglobulins in horses with allergic dermatitis

The aim of this study was to assess the effect of allergen-specific immunotherapy (ASIT) on the immunological responses of horses. Blood samples were taken from thirty-two horses with allergic dermatitis treated with ASIT and 10 healthy control horses at 0, 3, 6, 9 and 12 months to investigate the evolution of the percentage of regulatory T cells (Treg) in the peripheral blood and the serum levels of cytokines and immunoglobulins. Clinical improvement was appreciated by the majority of the horses' owners (56.6%). No effect of ASIT on CD4⁺CD25^High Treg cells was found during the one year treatment period. No differences in the percentage of CD4⁺ T cells were observed between the groups, and no effects of ASIT over time were observed. The percentage of CD25⁺ T cells was always higher in the ASIT group (17.9 ± 11.3%) than in the control group (7.3 ± 4.4%, p < 0.001). We did not detect any effect of ASIT on the serum levels of TGF-β, IL-10 and IFN-γ or on the serum concentrations of IgA and IgG4. A reduction in the serum levels of total IgE in the horses with allergic dermatitis was observed at the 6th month (p < 0.05), but increased again at the end of the study. The results indicate that immunotherapy was insufficient to induce significant changes that could indicate T cell tolerance, a shift in cytokine production to more protective Th1 cells. More studies are needed with new vaccine compositions and administration protocols to improve the immunological responses of the horses with allergic dermatitis.

Factors Associated with Adherence to Allergen Specific Subcutaneous Immunotherapy

PURPOSE

Allergen-specific immunotherapy (AIT) is known to be the only therapeutic modality to alter the natural course of allergic diseases. However, at least 3 years of treatment is recommended for achieving long-term disease modifying effect. This study aimed to investigate factors associated with immunotherapy non-adherence in real practice.

MATERIALS AND METHODS

We retrospectively reviewed medical records of patients who were diagnosed with allergic rhinitis, asthma, or atopic dermatitis, and received AIT to common allergens such as house dust mite and/or pollens from January 2007 to August 2014. In this study, non-adherence was defined as not completing 3 years of AIT.

RESULTS

Among 1162 patients enrolled, 228 (19.6%) failed to complete 3 years of AIT. In multivariate analysis, age less than 20 years [odds ratio (OR) 3.11, 95% confidence interval (CI) 1.70-5.69] and 20 to 40 years (OR 2.01, 95% CI 1.17-3.43), cluster build-up (OR 1.78, 95% CI 1.05-3.02) and ultra-rush build-up schedules (OR 5.46, 95% CI 2.40-12.43), and absence of visit to other departments in the same hospital (OR 1.87, 95% CI 1.05-3.32) were independently associated with immunotherapy non-adherence. Disease duration of 5-10 years was negatively associated with non-adherence compared to shorter disease duration of less than 5 years (OR 0.61, 95% CI 0.40-0.94). Although male sex and commercial product of AIT, Tyrosine S®, compared to Novo-Helisen® were non-adherent factors in univariate analysis, no statistical significances were identified in multivariate analysis.

CONCLUSION

Various factors are associated with immunotherapy adherence affecting the utility of immunotherapy. Clinicians should be aware of factors associated with adherence to maximize the utility of allergen-specific subcutaneous immunotherapy.

An overview of tolerogenic immunotherapies based on plant-made antigens

INTRODUCTION

Over the last two decades, genetically engineered plants became attractive and mature platforms for producing vaccines and other relevant biopharmaceuticals. Autoimmune and inflammatory disorders demand the availability of accessible treatments, and one alternative therapy is based on therapeutic vaccines able to downregulate immune responses that favor pathology progression.

AREAS COVERED

The current status of plant-made tolerogenic vaccines is presented with emphasis on the candidates under evaluation in test animals. Nowadays, this concept has been assessed in models of food and pollen allergies, autoimmune diabetes, asthma, arthritis, and prevention of blocking antibodies induction against a biopharmaceutical used in replacement therapies.

EXPERT OPINION

According to the current evidence generated at the preclinical level, plant-made tolerogenic therapies are a promise to treat several immune-related conditions, and the beginning of clinical trials is envisaged for the next decade. Advantages and limitations for this technology are discussed.

Allergen-specific IgE and IgG4 patterns among patients with different allergic diseases

Background

In addition to allergen-specific IgE (sIgE), allergen-specific IgG4 (sIgG4) antibodies are also involved in the immune response resulting from an allergen exposure. The aim of our study was to analyze sIgE and sIgG4 patterns in the most common allergic disorders: bronchial asthma, upper airway disorders and atopic dermatitis.

Methods

In this study a screening analysis of blood serum samples from 673 patients aged from 6 months to 17 years with different allergic entities was performed on microarrays. sIgE and sIgG4 levels to the most common allergens were estimated.

Results

sIgE response to most pollen allergens is more strongly associated with respiratory diseases than with atopic dermatitis, while sIgE responses to cat and dog dander are more strongly associated with bronchial asthma than with atopic dermatitis and upper airway disorders such as rhinosinusitis and allergic rhinitis. A lower prevalence of sIgG4 to pollen allergens in cases of atopic dermatitis is observed compared with that in cases of asthma and upper airway disorders. Analyzing all the allergic disorders, one can see that sIgG4 response to inhalant allergens is strongly associated with sensitization to the corresponding allergen.

Conclusion

Allergen-specific IgE and IgG4 patterns that are relevant to concrete allergic diseases differ by sIgE and sIgG4 prevalences to defined allergens.

Electronic supplementary material

The online version of this article (10.1186/s40413-018-0220-5) contains supplementary material, which is available to authorized users.

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

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

An unexpected protective role of low-affinity allergen-specific IgG through the inhibitory receptor FcγRIIb

BACKGROUND

Induction of allergen-specific IgG antibodies is a critical parameter for successful allergen-specific immunotherapy. IgG antibodies can inhibit IgE-mediated mast cell activation through direct allergen neutralization or through the inhibitory receptor FcγRIIb. The affinity of IgE antibodies to the allergen has been shown to be critical for cellular activation.

OBJECTIVE

Here we addressed the question of affinity thresholds of allergen-specific IgG antibodies for inhibition of mast cell activation using 2 different mAbs against the major cat allergen Fel d 1 both in vitro and in vivo in mice.

METHODS

Sequences of the 2 high-affinity mAbs were back-mutated to germline, resulting in low-affinity (10-7 mol/L) antibodies of the exact same specificity.

RESULTS

Using these newly generated recombinant antibodies, we demonstrate that low-affinity antibodies are still able to inhibit mast cell activation through FcγRIIb but do not neutralize the allergen.

CONCLUSION

Antibody affinity dictates the mechanism of mast cell inhibition, and IgG antibodies triggering the inhibitory FcγRIIb pathway can show a broader cross-reactivity pattern than previously thought. This indicates that allergen-specific immunotherapy generates a larger protective umbrella of inhibitory IgG antibodies than previously appreciated.

Efficacy and Safety of Sublingual Immunotherapy in Elderly Rhinitis Patients Sensitized to House Dust Mites

PURPOSE

This study aims to determine the efficacy and safety of house dust mite (HDM)-sublingual immunotherapy (SLIT) in elderly patients with AR.

METHODS

A total of 45 patients aged ≥ 60 years with HDM-induced AR who had ≥ 3 A/H ratio on skin prick test and/or ≥ 0.35 IU/L to both Dermatophagoides farinae and Dermatophagoides pteronyssinus by ImmunoCAP were enrolled in 4 university hospitals. To evaluate additional effects of HDM-SLIT, they were randomized to the SLIT-treated group (n = 30) or control group (n = 15). Rhinoconjunctivitis total symptom score (RTSS), rhinoscopy score, Korean rhinoconjunctivitis quality of life questionnaire, rhinitis control assessment test, asthma control test scores, and adverse reactions, were assessed at the first visit (V1) and after 1 year of treatment (V5); for immunological evaluation, serum levels of HDM-specific immunoglobulin A/IgE/IgG1/IgG4 antibodies and basophil response to HDMs were compared between V1 and V5 in both groups.

RESULTS

There were no significant differences in demographics, RTSS, skin reactivity to HDMs, or serum total/specific IgE levels to HDMs (P < 0.05, respectively) between the 2 groups. Nasal symptom score and RTSS decreased significantly at year 1 in the 2 groups (P < 0.05). There were no significant differences in percent decrease in nasal symptom score and RTSS at year 1 between the 2 groups (P < 0.05); however, rhinoscopic nasal symptom score decreased significantly in the SLIT-treated group (P < 0.05). Immunological studies showed that serum specific IgA levels (not specific IgE/IgG) and CD203c expression on basophils decreased significantly at V5 in the SLIT-treated group (P = 0.011 and P = 0.001, respectively), not in the control group. The control group required more medications compared to the treatment group, but there were no differences in adverse reactions.

CONCLUSIONS

It is suggested that HDM-SLIT for 1 year could induce symptom improvement and may induce immunomodulation in elderly rhinitis patients.

Birch pollen-specific subcutaneous immunotherapy reduces ILC2 frequency but does not suppress IL-33 in mice

BACKGROUND

The underlying mechanism of allergen-specific subcutaneous immunotherapy (SCIT) is not yet fully understood, but suppression of allergen-specific Th2 cells and production of allergen-specific IgG4 antibodies are two hallmarks. The impact on the innate arm of the immune system is far less clear.

OBJECTIVE

The aim of this study was to investigate the effect of birch pollen (BP) SCIT on the innate immune response in a BP SCIT mouse model.

METHODS

Mice with birch pollen-induced allergic airway inflammation received weekly subcutaneous immunotherapy injections with birch pollen extract (BPE) adsorbed to alum. The effect of the BP SCIT on innate cytokine levels in lung, the number and the functionality of ILC2s and the airway inflammation was determined.

RESULTS

Mice with BP allergy had an increased level of the innate cytokines IL-33, IL-25, GM-CSF and IL-5⁺ ILC2s in the lungs. BP SCIT suppressed the number of IL-5⁺ ILC2s, mast cell tryptase release, Th2 cytokine production, eosinophil recruitment and peribronchial inflammatory infiltrates. In contrast, innate cytokine production and collagen deposition in the airways were not affected.

CONCLUSION AND CLINICAL RELEVANCE

BP SCIT is able to suppress the adaptive and part of the innate immune response, but this is not sufficient to inhibit collagen deposition and the IL-33 expression in the airways in mice.

Salivary Immunoglobulin A, E, and G4 Levels Specific to Dermatophagoides pteronyssinus in Allergic Rhinitis Patients Treated With Subcutaneous Immunotherapy

BACKGROUND

Allergen-specific immunotherapy (AIT) is an effective treatment for allergic rhinitis (AR). During the course of AIT, many biomarkers in body fluids change. It is necessary to find effective indicators of AIT.

OBJECTIVE

To examine levels of salivary immunoglobulin A, E, and G4 (IgA, IgE, and IgG4, respectively) specific to Dermatophagoides pteronyssinus (Dp-IgA, Dp-IgE, and Dp-IgG4, respectively) and their changes in AR patients undergoing subcutaneous immunotherapy (SCIT).

METHODS

This study included 82 patients with AR sensitized only to Dp and 14 healthy controls. Among patients with AR, 30 patients were not treated with specific immunotherapy (group A), while the remainder (n = 52) received house dust mite SCIT in the up-dosing phase (n = 27; group B) or the maintenance treatment phase (n = 25; group C). Dp-IgA, Dp-IgE, and Dp-IgG4 levels in the saliva were measured using the enzyme-linked immunosorbent assay. Clinical symptoms, concomitant medication, and the Rhinoconjunctivitis Quality of Life Questionnaire score were recorded and correlated with immunoglobulin levels.

RESULTS

Salivary Dp-IgG4 and Dp-IgA levels were significantly lower in AR patients than in healthy controls ( P < .001 for both), while Dp-IgE levels were significantly higher ( P < .001). SCIT resulted in sustained increases in Dp-IgG4 and Dp-IgA in the maintenance phase compared to the up-dosing phase ( P < .001 for both), whereas Dp-IgE only increased in the up-dosing phase ( P = .004, P < .0125). There was no correlation between the different salivary immunoglobulins and clinical scores during SCIT.

CONCLUSIONS

This study shows that allergen-specific IgE levels are increased in the saliva of sensitized patients, suggesting that measuring salivary IgE testing should be further considered for the diagnosis of AR. Moreover, allergen-specific IgA and IgG4 in the saliva, which may play protective roles against allergy, may serve as objective indicators for evaluating treatment response to SCIT. However, none of the immunoglobulin reflects subjective symptoms.

Efficacy and tolerability of a house dust mite allergoid in allergic bronchial asthma: a randomized dose-ranging trial

AIM

This multicenter randomized placebo-controlled double-blind clinical trial investigated which maintenance dose shows the optimal benefit-risk ratio for subcutaneous immunotherapy with a Dermatophagoides pteronyssinus allergoid preparation.

OBJECTIVE

To evaluate four maintenance doses of the allergoid preparation versus placebo.

METHODS

The late-phase reaction of the intracutaneous test was chosen as efficacy parameter and minimal dose of fluticasone required for asthma control.

RESULTS

A total of 146 adults with bronchial asthma were randomized. After subcutaneous immunotherapy, reductions in swelling size were greatest with 10,000 therapeutic units (TU). The 18,000 TU group showed the highest percentage of patients with fluticasone dose reduced to 0 μg/day.

CONCLUSION

The optimal dose of allergoid for the investigation in a confirmatory trial with inhaled corticosteroid reduction is 18,000 TU.

Sublingual immunotherapy for pediatric allergic conjunctivitis: a meta-analysis of randomized controlled trials

BACKGROUND

Allergic conjunctivitis (AC) is a common chronic condition, especially in children. Ocular symptoms are often overlooked during treatment of allergic rhinoconjunctivitis (ARC). Pediatric ARC can be effectively treated using sublingual immunotherapy (SLIT), which is a guideline-recommended safe treatment approach. However, the therapeutic efficacy of SLIT in terms of ameliorating eye symptoms has not been effectively evaluated.

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) evaluating the use of SLIT for infants, children, and adolescents (aged from 3 to 18 years) with AC or ARC. We searched the Cochrane Library database, EMBASE, and Medline from November 1990 to 2017 to find papers dealing with the effects of SLIT on pediatric AC or ARC. We used standardized mean differences (SMDs) to assess therapeutic effects, employing a random effects model. Subgroup and sensitivity analyses were also conducted. The I² metric was used to evaluate heterogeneity.

RESULTS

In total, 13 clinical RCTs were included in our meta-analysis. SLIT reduced ocular symptoms to a level below that of controls (SMD = -0.21; 95% confidence interval [CI], -0.41 to -0.01; p = 0.04; I² = 55%). Notably, on subgroup analysis, SLIT clearly reduced pollen-induced pediatric AC (SMD = -0.36; 95% CI, -0.53 to -0.19; p < 0.0001; I² = 25%) but not mite-induced AC (SMD = 0.20; 95% CI, -0.20 to 0.60; p = 0.34; I² = 46%).

CONCLUSION

SLIT relieved ocular symptoms in children with ARC or AC. To confirm these results, future meta-analyses should evaluate high-quality, large-scale population-based trials.

Allergen immunotherapy for the treatment of respiratory allergies in the elderly

PURPOSE OF REVIEW

Respiratory allergies, including asthma and allergic rhinitis can also occur in the elderly. Allergen immunotherapy for allergic diseases is the only disease-modifying treatment for patients with allergies available thus far. Here, we review current evidence supporting the use of allergen immunotherapy in the elderly and discuss its efficacy and utility for the treatment of respiratory allergic diseases in this setting.

RECENT FINDINGS

Subcutaneous and/or sublingual immunotherapy are effective therapeutic options in not only young but also older patients. Allergen immunotherapy reduces medication and symptom scores in the elderly and can thus be safely prescribed in this population.

SUMMARY

Elderly individuals with proven, clinically relevant immunoglobulin E sensitization to inhalant allergens may benefit from allergen immunotherapy for respiratory allergic diseases. Older patients without contraindications should therefore be considered for treatment, with the additional benefit of reduced medication and symptom scores.

Rhinosinusitis and Allergies in Elderly Patients

The sinonasal tract plays important roles in respiration, olfaction, and defense against external pathogens. Like many organ systems, the nose and sinuses undergo several changes with advancing age that can play a role in the development of disease. This article discusses the physiology of the aging sinonasal tract and reviews the common diseases affecting older patients, such as rhinitis and rhinosinusitis.

Protein corona-mediated targeting of nanocarriers to B cells allows redirection of allergic immune responses

BACKGROUND

Nanoparticle (NP)-based vaccines are attractive immunotherapy tools because of their capability to codeliver antigen and adjuvant to antigen-presenting cells. Their cellular distribution and serum protein interaction ("protein corona") after systemic administration and their effect on the functional properties of NPs is poorly understood.

OBJECTIVES

We analyzed the relevance of the protein corona on cell type-selective uptake of dextran-coated NPs and determined the outcome of vaccination with NPs that codeliver antigen and adjuvant in disease models of allergy.

METHODS

The role of protein corona constituents for cellular binding/uptake of dextran-coated ferrous nanoparticles (DEX-NPs) was analyzed both in vitro and in vivo. DEX-NPs conjugated with the model antigen ovalbumin (OVA) and immunostimulatory CpG-rich oligodeoxynucleotides were administered to monitor the induction of cellular and humoral immune responses. Therapeutic effects of this DEX-NP vaccine in mouse models of OVA-induced anaphylaxis and allergic asthma were assessed.

RESULTS

DEX-NPs triggered lectin-induced complement activation, yielding deposition of activated complement factor 3 on the DEX-NP surface. In the spleen DEX-NPs targeted predominantly B cells through complement receptors 1 and 2. The DEX-NP vaccine elicited much stronger OVA-specific IgG_2a production than coadministered soluble OVA plus CpG oligodeoxynucleotides. B-cell binding of the DEX-NP vaccine was critical for IgG_2a production. Treatment of OVA-sensitized mice with the DEX-NP vaccine prevented induction of anaphylactic shock and allergic asthma accompanied by IgE inhibition.

CONCLUSIONS

Opsonization of lectin-coated NPs by activated complement components results in selective B-cell targeting. The intrinsic B-cell targeting property of lectin-coated NPs can be exploited for treatment of allergic immune responses.

A Retrospective Study of Clinical Response Predictors in Subcutaneous Allergen Immunotherapy With House Dust Mites for Allergic Rhinitis

Purpose

House dust mites (HDM) are major allergens that cause allergic rhinitis (AR). Allergen-specific subcutaneous immunotherapy (SCIT) has been shown to be clinically beneficial in many clinical trials. Such trials, however, are not reflective of all patient populations. The aim of this study was to describe the efficacy and safety of SCIT in routine clinical practice in Korean adults with AR sensitized to HDM.

Methods

We reviewed medical records of 304 patients with AR treated at an allergy clinic of a tertiary hospital using SCIT with aluminum hydroxide-adsorbed allergen extract targeting HDM alone or with pollens for at least 1 year from 2000 to 2012. Patients with asthma were excluded. Rates of remission, defined as no further requirement of maintenance medication, over time were determined by means of life tables and extension of survival analysis. Specific immunoglobulin E (IgE) levels to HDM were categorized into 6 classes.

Results

The mean time until achieving remission was 4.9±0.1 years, and the cumulative incidence of remission from AR was 76.6%. Severe AR (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.23-0.69; P=0.001), specific IgE levels to HDM ≥17.5 kU/L (OR, 1.85; 95% CI, 1.01-3.37; P=0.045), and duration of immunotherapy ≥3 years (OR, 7.37; 95% CI, 3.50-15.51; P<0.001) were identified as significant predictors of clinical remission during SCIT for patients with AR sensitized to HDM. Overall, 73 patients (24.0%) experienced adverse reactions to SCIT, and only 1 case of anaphylaxis (0.3%) developed.

Conclusions

SCIT with HDM was found to be effective and safe for patients with AR. Specific IgE levels to HDM and a duration of SCIT ≥3 years may be predictors of clinical responses to SCIT in AR patients.

Decreased CRTH2 Expression and Response to Allergen Re-stimulation on Innate Lymphoid Cells in Patients With Allergen-Specific Immunotherapy

Purpose

Group 2 innate lymphoid cells (ILC2s) have been implicated in the pathogenesis of allergic disease. However, the effect of allergen-specific immunotherapy (AIT) on ILCs remains to be clarified. The aim of this study was to evaluate the levels of ILC subsets in allergic rhinitis (AR) patients in response to house dust mite (HDM)-specific immunotherapy.

Methods

We enrolled 37 AR patients undergoing AIT (16 responders and 11 non-responders) for 2 years, 35 HDM AR patients and 28 healthy subjects. Peripheral blood mononuclear cells (PBMCs) were analyzed by flow cytometry to identify ILC subsets. Stimulation of ILC2s with recombinant allergen-specific protein was used to determine ILC2's activation (CD69 expression).

Results

Responder AIT patients and healthy subjects had a decreased frequency of circulating ILC2s compared to non-responder AIT and AR patients. Conversely, ILC1s from responder AIT patients and healthy subjects showed increased frequency compared to non-responder AIT and AR patients. The frequency of ILC3s natural cytotoxicity receptor (NCR)⁺ and NCR⁻ in responder AIT patients was significantly lower compared to AR patients and healthy subjects. The ILC1: ILC2 proportion in responder AIT patients was similar to that of healthy subjects. PBMCs from patients who were responders to AIT had a significantly lower expression of the activation marker CD69 on ILC2s in response to allergen re-stimulation compared to AR patients, but no difference compared to non-responder AIT patients and healthy subjects.

Conclusions

We propose that AIT might affect ILC responses. The activation of ILC2s was reduced in AR patients treated with AIT. Our results indicate that a relative ILC1/ILC2 skewed response is a possible key to successful AIT.

Microarray-Based Multivariate Analysis of the Effectiveness of Sublingual Immunotherapy for Cedar Pollinosis

Sublingual immunotherapy (SLIT) is an effective treatment for allergic diseases. However, the mechanism by which this therapy exhibits its efficacy has not been fully delineated. To elucidate the mechanisms of SLIT in the treatment of cedar pollinosis (CP), we performed a multivariate analysis of microarray data on mRNA expression in CD4⁺ T cells and basophils. Although 2-year treatment with SLIT using cedar extracts was effective in >70% of patients with CP, the remaining patients did not respond to this therapy. The mRNA expression levels in peripheral CD4⁺ T cells and basophils from both high- and non-responder patients before and after undergoing SLIT were comparatively studied using microarray analysis. By processing the data using serial multivariate analysis, an apoptosis pathway was extracted in both CD4⁺ T cells and basophils. Conclusively, the strong treatment effectiveness of SLIT in patients with CP may be caused by the induction of apoptosis in CD4⁺ T cells and basophils in these patients (Trial registry at University Hospital Medical Information Network Clinical Trials Registry Database, UMIN000016532).

Allergen immunotherapy in atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a chronic relapsing skin disease, characterized by flare-up due to the exposure to allergens in patients sensitized to them. Currently, therapy of AD is mainly based on symptomatic treatment and avoidance of irritating/allergenic factors, house dust mites being particularly important. Allergen immunotherapy (AIT) is suggested to be the only etiologic treatment, to modify the natural history of the disease. Areas covered: The aim of this review is investigating the putative role of AIT in AD through the evaluation of the most recent scientific literature. Several studies have been conducted since 1970, with promising results in improving the clinical outcome of AD, but they often lack the necessary scientific rigorousness. Moreover, heterogeneity of the studies makes it very difficult to compare and to analyze data in a systematic review or meta-analysis. Expert commentary: As a result of the above-mentioned limitations, the treatment of AD with causative aeroallergen can nowadays be suggested only as an add-on therapy in selected patients who are non-responsive to the traditional therapy.

Expression, purification and epitope analysis of Pla a 2 allergen from Platanus acerifolia pollen

Platanus acerifolia is one of the major sources of outdoor allergens to humans, and can induce allergic asthma, rhinitis, dermatitis and other allergic diseases. Pla a 2 is a polygalacturonase and represents the major allergen identified in P. acerifolia pollen. The aim of the present study was to express and purify Pla a 2, and to predict B and T cell epitopes of Pla a 2. The gene encoding Pla a 2 was cloned into the pET28a vector and subsequently transfected into ArcticExpress™ (DE3) Escherichia coli cells; purified Pla a 2 was analyzed by western blot analysis. The results of the present study revealed that the Pla a 2 allergen has the ability to bind immunoglobulin E within the sera of patients allergic to P. acerifolia pollen. In addition, the B cell epitopes of Pla a 2 were predicted using the DNAStar Protean system, Bioinformatics Predicted Antigenic Peptides and BepiPred 1.0 software; T cell epitopes were predicted using NetMHCIIpan ‑3.0 and ‑2.2. In total, eight B cell epitopes (15‑24, 60‑66, 78‑86, 109‑124, 232‑240, 260‑269, 298‑306 and 315‑322) and five T cell epitopes (62‑67, 86‑91, 125‑132, 217‑222 and 343‑350) were predicted in the present study. These findings may be used to improve allergen immunotherapies and reduce the frequency of pollen‑associated allergic reactions.