Engineering nanoparticle therapeutics for food allergy

Food allergy is a growing public health issue among children and adults that can lead to life-threatening anaphylaxis following allergen exposure. The criterion standard for disease management includes food avoidance and emergency epinephrine administration because current allergen-specific immunotherapy treatments are limited by adverse events and unsustained desensitization. A promising approach to remedy these shortcomings is the use of nanoparticle-based therapies that disrupt disease-driving immune mechanisms and induce more sustained tolerogenic immune pathways. The pathophysiology of food allergy includes multifaceted interactions between effector immune cells, including lymphocytes, antigen-presenting cells, mast cells, and basophils, mainly characterized by a TH2 cell response. Regulatory T cells, TH1 cell responses, and suppression of other major allergic effector cells have been found to be major drivers of beneficial outcomes in these nanoparticle therapies. Engineered nanoparticle formulations that have shown efficacy at reducing allergic responses and revealed new mechanisms of tolerance include polymeric-, lipid-, and emulsion-based nanotherapeutics. This review highlights the recent engineering design of these nanoparticles, the mechanisms induced by them, and their future potential therapeutic targets.

Novel adjuvants in allergen-specific immunotherapy: where do we stand?

Type I hypersensitivity, or so-called type I allergy, is caused by Th2-mediated immune responses directed against otherwise harmless environmental antigens. Currently, allergen-specific immunotherapy (AIT) is the only disease-modifying treatment with the potential to re-establish clinical tolerance towards the corresponding allergen(s). However, conventional AIT has certain drawbacks, including long treatment durations, the risk of inducing allergic side effects, and the fact that allergens by themselves have a rather low immunogenicity. To improve AIT, adjuvants can be a powerful tool not only to increase the immunogenicity of co-applied allergens but also to induce the desired immune activation, such as promoting allergen-specific Th1- or regulatory responses. This review summarizes the knowledge on adjuvants currently approved for use in human AIT: aluminum hydroxide, calcium phosphate, microcrystalline tyrosine, and MPLA, as well as novel adjuvants that have been studied in recent years: oil-in-water emulsions, virus-like particles, viral components, carbohydrate-based adjuvants (QS-21, glucans, and mannan) and TLR-ligands (flagellin and CpG-ODN). The investigated adjuvants show distinct properties, such as prolonging allergen release at the injection site, inducing allergen-specific IgG production while also reducing IgE levels, as well as promoting differentiation and activation of different immune cells. In the future, better understanding of the immunological mechanisms underlying the effects of these adjuvants in clinical settings may help us to improve AIT.

The pharmacotherapeutic management of allergic rhinitis in people with asthma

INTRODUCTION

Up to 90% of asthmatic patients have comorbid allergic rhinitis (AR). Although appropriate therapy of AR can improve asthma symptoms and management, AR is often underdiagnosed and under-treated in asthmatics.A non-systematic literature research was conducted on AR as a comorbidity and risk factor of asthma. Latest international publications in medical databases, international guidelines, and the Internet were reviewed.

AREAS COVERED

Based on the conducted literature research there is proved evidence of the necessity of diagnosis and treatment of AR in patients with asthma because it affects health care utilization. Therefore, it is recommended in national and global guidelines.

EXPERT OPINION

AR increases the risk of asthma development and contributes to the severity of an existing asthma. Early treatment of AR with drugs as intranasal steroids, antihistamines, leukotriene receptor antagonists, and especially allergen-specific immunotherapy can reduce the risk of asthma development and the concomitant medication use in addition to severity of symptoms in AR and asthma.

Treatment of Allergic Rhinitis in Clinical Practice

Allergic rhinitis is a prevalent condition among children, with its occurrence reaching up to 40% of the general population in some geographical areas. A type 2 immunity sustains allergic rhinitis. Consequently, type 2 inflammation leads to eosinophilic infiltrate of the nasal mucosa. Allergic inflammation causes the symptom occurrence. Typical nasal symptoms include nasal itching, sneezing, watery rhinorrhea, and nasal congestion. Nasal congestion depends on vasodilation and increased mucus production. These conditions result in nasal obstruction. Nasal obstruction is closely associated with type 2 inflammation. Allergic rhinitis usually occurs in association with other allergic conditions, in particular allergic conjunctivitis and asthma. The effective management of allergic rhinitis involves avoiding triggering allergens and employing pharmacological treatments as per ARIA guidelines. These treatments may include intranasal/oral antihistamines or/and nasal corticosteroids. In particular, antihistamines are particularly indicated for symptoms consequent to mediators' release, mainly concerning histamine. These histamine-dependent symptoms include itching, sneezing, and rhinorrhea. Nasal obstruction, being associated with inflammation, is responsive to corticosteroids, administered mostly intranasally. The fixed combination of a topical antihistamine plus a topical corticosteroid is very effective, but is indicated for adolescents only. However, nasal lavage is safe, cheap, and adequate, thus its use is prevalent. Namely, nasal lavage allows to remove secretions, allergens, mediators. In addition, hypertonic solutions exert a decongestant activity. On the other hand, the allergen-specific immunotherapy is still the only causal treatment. Nutraceuticals have also been used to relieve symptoms. The objective of this review is to explore and compare the traditional and new therapeutic approaches for pollen-induced allergic rhinitis in children.

Attenuation of allergen-specific immunotherapy for atopic dermatitis by ectopic colonization of Brevundimonas vesicularis in the intestine

Allergen-specific immunotherapy (AIT) has shown beneficial effects against atopic dermatitis (AD); however, the mechanisms and parameters underlying the efficacy of AIT remain unclear. Here, we report that the community structure and function of the oral and gut microbiota are changed in patients with AD undergoing AIT. Transplantation of fecal microbiota from patients who respond well to AIT improves AD-like dermatitis in mice. The abundance of Brevundimonas vesicularis in the gut of AD patients has been found to be positively correlated with disease severity and is decreased following AIT. Furthermore, we find that B. vesicularis from the oral cavity might ectopically colonize the gut of AD patients. In AD model mice, meanwhile, B. vesicularis promotes the skewing of the Treg/Th17 balance toward Th17 polarization and attenuates the efficacy of ovalbumin-specific immunotherapy. Our findings provide potential strategies for the optimization of AIT for AD via the modulation of the gut microbiota.

Efficacy and Safety of Subcutaneous Allergen-Specific Immuno-Therapy in Horses with Allergic Cutaneous and Respiratory Diseases-A Systematic Review

Allergen-specific immunotherapy (AIT) is the only current intervention that has the ability to modify the immune response toward a tolerogenic state. This study aimed to assess the efficacy and safety of AIT in horses with allergic diseases in a systematic manner. Three databases were searched to identify articles reporting clinical outcomes and adverse events associated with AIT. The articles were evaluated for beneficial responses to AIT, defined as a ≥50% reduction in clinical signs, and clinical remission. Horses with respiratory diseases, urticaria, and pruritic dermatitis receiving insect monotherapy or multi-allergen AIT were included. All adverse events were graded, and analytical and confounding biases were assessed. The results showed that multi-allergen AIT had a beneficial response in 75% of horses with respiratory diseases, 88% with urticaria, and 56% with pruritic dermatitis. However, horses treated solely with insect AIT for pruritic dermatitis had a lower response rate (36%). Self-limiting local reactions were the most common adverse events, with systemic reactions grade II accounting for 11% of reported events. Analytical and confounding biases were identified as major limitations in the available studies. Further research is needed to address these biases and provide stronger evidence on the efficacy and safety of AIT in horses with allergic diseases.

Allergen-specific immunotherapy improves alopecia totalis in a severe atopic dermatitis patient

House dust mite (HDM) is the most common allergen exacerbating atopic dermatitis (AD), and allergen-specific immunotherapy (AIT) using HDM exhibited significant improvements in previous studies. Alopecia can occur as a complication of AD. Alopecia totalis (AT), a severe form of alopecia areata (AA), does not respond well to treatment and the chance of full recovery is less than 10%. For extensive hair loss, topical immunotherapy such as diphenylcyclopropenone (DPCP) is used as the first-line treatment. However, since DPCP is a kind of contact allergen, it has the potential to exacerbate AD. A 38-year-old man with AD and AA visited our clinic with symptoms worsening from 3 months ago. Although taking oral methylprednisolone (8 mg/day) and cyclosporine (100 mg/day) for 3 months, he has lost over 90% of his hair and the Eczema Area and Severity Index (EASI) was 43. Total serum immunoglobulin E (IgE) levels were 4454 kU/L (normal <100 kU/L) and the specific IgE levels for Dermatophagoides pteronyssinus and Dermatophagoides farinae following ImmunoCAP® were 20.8 and 37.4 kU/L, respectively. This patient did not respond well to previous treatment and was reluctant to use long-term steroids, so subcutaneous AIT using HDM was administered along with oral cyclosporine (100 mg/day). Topical tacrolimus was also applied to the AD lesions throughout the body. To reduce itching, nonsedative antihistamines were used if necessary. Hair loss was almost completely improved 1 year after the AIT initiation and the skin lesions of AD also improved (EASI 2.4). The specific IgE levels for D. pteronyssinus and D. farinae were 3.73 and 7.16 kU/L, respectively. Herein, we report a patient with promising results following AIT for AT with severe AD. In severe alopecic patients with AD refractory to conventional treatment, including immunosuppressants, AIT could be considered as a treatment option.

Efficacy of short-term combination of intralymphatic allergen immunotherapy and lokivetmab treatment in canine atopic dermatitis: A double-blinded, controlled, randomised study

BACKGROUND

Allergen-specific immunotherapy (ASIT) is an effective therapy for canine atopic dermatitis (cAD). Intralymphatic immunotherapy (ILIT) is potentially beneficial in decreasing time to clinical effectiveness.

OBJECTIVE

To compare clinical efficacy of six monthly ILIT injections combined with three monthly injections of lokivetmab (LVM) with monthly LVM monotherapy at Day (D)168. To monitor dogs treated with ILIT for an additional six months of subcutaneous immunotherapy (SCIT).

ANIMALS

Thirty-six client-owned dogs with cAD.

MATERIALS AND METHODS

In this double-blinded, randomised study, dogs received either six monthly injections of ILIT combined with three monthly LVM injections (ILIT group) or six monthly LVM injections (LVM group). Monthly evaluations with pruritus Visual Analogue Scale (pVAS), Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) and medication scores (MS) were undertaken. Owners completed a Quality of Life (QoL) questionnaire. Treatment success was predefined as ≥50% reduction in pVAS and CADESI-04 score ≤ 10. After D168, the ILIT group continued with SCIT until subjective assessment at 12 months.

RESULTS

The treatment benchmark at D168 was achieved by 11.1% of the ILIT group and 11.8% of LVM group. A significant decrease in mean pVAS and CADESI scores was observed in both groups (p < 0.001). The ILIT group had a trend towards higher MS compared to LVM. QoL was better in LVM (p = 0.01). At 12 months subjective good-to-excellent response in 77.8% of dogs in the ILIT/SCIT group was seen.

CONCLUSION AND CLINICAL RELEVANCE

The efficacy of this ILIT protocol was comparable with LVM monotherapy at six months. When ILIT was continued with SCIT, a favourable response was seen.

Effect of Allergen-Specific Immunotherapy on Transcriptomic Changes in Canine Atopic Dermatitis

Canine atopic dermatitis (cAD) is a genetic, chronic, and recurrent inflammatory and pruritic skin disorder. Allergen-specific immunotherapy (ASIT) is presently recognized as the only clinically effective disease-modifying treatment for allergies. The aim of our study was to analyze the changes in gene expression observed in the peripheral blood nuclear cells of cAD patients subjected to ASIT. Blood samples designated for transcriptomic analyses were collected from AD dogs twice, before and six months after ASIT, and also from healthy dogs. Statistical analysis revealed 521 differentially expressed transcripts, among which 241 transcripts represented genes with well-described functions. Based on the available literature, we chose nine differentially expressed genes (RARRES2, DPP10, SLPI, PLSCR4, MMP9, NTSR1, CBD103, DEFB122, and IL36G) which may be important in the context of the dysregulated immune response observed in cAD patients. The expressions of five out of the nine described genes (DPP10, PLSCR4, NTSR1, DEFB122, and IL36G) changed after the application of ASIT. The expressions of three of these genes returned to the level observed in the healthy control group. The genes listed above need further investigation to determine details of their role in the molecular mechanism of immune tolerance induction in response to allergen-specific immunotherapy.

IgE Mediated Shellfish Allergy in Children-A Review

Shellfish is a leading cause of food allergy and anaphylaxis worldwide. Recent advances in molecular characterization have led to a better understanding of the allergen profile. High sequence homology between shellfish species and between shellfish and house dust mites leads to a high serological cross-reactivity, which does not accurately correlate with clinical cross-reactions. Clinical manifestations are immediate and the predominance of perioral symptoms is a typical feature of shellfish allergy. Diagnosis, as for other food allergies, is based on SPTs and specific IgE, while the gold standard is DBPCFC. Cross-reactivity between shellfish is common and therefore, it is mandatory to avoid all shellfish. New immunotherapeutic strategies based on hypoallergens and other innovative approaches represent the new frontiers for desensitization.

Updates in the diagnosis and practical management of allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is a widespread disease that can be associated with other conditions, including conjunctivitis, rhinosinusitis, asthma, food allergy, and atopic dermatitis. Diagnosis is based on the history and documentation of sensitization, such as the production of allergen-specific IgE, preferably using molecular diagnostics. Treatments are based on patient education, non-pharmacological and pharmacological remedies, allergen-specific immunotherapy (AIT), and surgery. Symptomatic treatments mainly concern intranasal/oral antihistamines and/or nasal corticosteroids.

AREAS COVERED

This review discusses current and emerging management strategies for AR, covering pharmacological and non-pharmacological remedies, AIT, and biologics in selected cases with associated severe asthma. However, AIT presently remains the unique causal treatment for AR.

EXPERT OPINION

The management of allergic rhinitis could include new strategies. In this regard, particular interest should be considered in the fixed association between intranasal antihistamines and corticosteroids, probiotics and other natural substances, and new formulations (tablets) of AIT.

Salivary IgG4 Levels Contribute to Assessing the Efficacy of Dermatophagoides pteronyssinus Subcutaneous Immunotherapy in Children with Asthma or Allergic Rhinitis

At present, there are no effective, non-invasive, and objective indicators to evaluate the efficacy of pediatric house dust mite (HDM)-specific allergen immunotherapy (AIT). A prospective, observational study was performed in children with Dermatophagoides pteronyssinus (Der p) asthma and/or allergic rhinitis (AR). Forty-four patients received subcutaneous Der p-AIT for 2 years, and eleven patients received only symptomatic treatment. The patients needed to finish their questionnaires at each visit. Serum and salivary Der p-specific IgE, IgG4, and IgE-blocking factors (IgE-BFs) were measured at 0, 4, 12, and 24 months during AIT. A correlation between them was also evaluated. Subcutaneous Der p-specific AIT improved the clinical symptoms of children with asthma and/or AR. The Der p-specific IgE-BF significantly increased at 4, 12, and 24 months after AIT treatment. Serum and salivary Der p-specific IgG4 significantly increased with the time of the AIT treatment, and significant correlations between them at different time points were observed (p < 0.05). Furthermore, there were significant correlations (R = 0.31-0.62) between the serum Der p-specific IgE-BF and Der p-specific IgG4 at the baseline, 4, 12, and 24 months after the AIT (p < 0.01). The salivary Der p-specific IgG4 levels also demonstrated a certain correlation with the Der p-specific IgE-BF. Der p-specific AIT is an effective treatment for children with asthma and/or AR. Its effect was associated with increased serum and salivary-specific IgG4 levels, as well as an increased IgE-BF. Non-invasive salivary-specific IgG4 may be useful for monitoring the efficacy of AIT in children.

Allergic March in Children: The Significance of Precision Allergy Molecular Diagnosis (PAMD@) in Predicting Atopy Development and Planning Allergen-Specific Immunotherapy

The allergic march is a progression of naturally occurring symptoms whose nature changes with age. The classic allergic march typically begins in infancy and manifests in the form of atopic dermatitis and food allergy. As immune tolerance develops over time, these conditions may resolve by the age of 3-5 years; however, they may evolve into allergic rhinitis and bronchial asthma. Traditional diagnostic assessments, such as skin prick testing or serum allergen-specific immunoglobulin E (sIgE) level testing, are conducted to introduce effective treatment. Recent years saw the emergence of precision allergy molecular diagnosis (PAMD@), which assesses sIgE against allergenic molecules. This new technology helps more accurately evaluate the patient's allergy profile, which helps create more precise dietary specifications and personalize allergen-specific immunotherapy. This review presents possible predictions regarding the allergic march and the means of controlling it based on PAMD@ results.

Recombinant T-cell epitope conjugation: A new approach for Dermatophagoides hypoallergen design

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only clinical approach that can potentially cure some allergic diseases by inducing immunological tolerance. Dermatophagoides pteronyssinus is considered as the most important source of mite allergens worldwide, with high sensitization rates for the major allergens Der p 1, Der p 2 and Der p 23. The aim of this work is to generate a hypoallergenic hybrid molecule containing T-cell epitopes from these three major allergens.

METHODS

The hybrid protein termed Der p 2231 containing T-cell epitopes was purified by affinity chromatography. The human IgE reactivity was verified by comparing those with the parental allergens. The hybrid was also characterized immunologically through an in vivo mice model.

RESULTS

The hybrid rDer p 2231 stimulated in peripheral blood mononuclear cells (PBMCs) isolated from allergic patients with higher levels of IL- 2, IL-10, IL-15 and IFN-γ, as well as lower levels of IL-4, IL-5, IL-13, TNF-α and GM-CSF. The use of hybrid molecules as a therapeutic model in D. pteronyssinus allergic mice led to the reduction of IgE production and lower eosinophilic peroxidase activity in the airways. We found increased levels of IgG antibodies that blocked the IgE binding to the parental allergens in the serum of allergic patients. Furthermore, the stimulation of splenocytes from mice treated with rDer p 2231 induced higher levels of IL-10 and IFN-γ and decreased the secretion of IL-4 and IL-5, when compared with parental allergens and D. pteronyssinus extract.

CONCLUSIONS

rDer p 2231 has the potential to be used in AIT in patients co-sensitized with D. pteronyssinus major allergens, once it was able to reduce IgE production, inducing allergen-specific blocking antibodies, restoring and balancing Th1/Th2 immune responses, and inducing regulatory T-cells.

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.

Analysis of factors influencing the determination of indications for allergen-specific immunotherapy

OBJECTIVE

To develop a questionnaire and a scoring system for evaluating physicians' knowledge of allergen immunotherapy (AIT).

METHODS

Questionnaire was designed using the Questionnaire Star tool. A total of 1024 physicians were assessed, and based on the score divided into accurate judgment and inaccurate judgment groups. Statistical analysis was done, and counting data were expressed as frequencies and percentage values. Chi-square test and multi-factor logistic analysis were used to determine influencing factors on the indications for AIT.

RESULTS

Physician's age, grade of the hospital, and pediatric specialty influenced the accurate judgment of AIT indication after adjustment for independent variables (P < 0.05). In all, 80.5% physicians exercised accurate assessment for allergic rhinitis. Allergic conjunctivitis was judged accurately by 47.0% physicians. Bronchial asthma was judged accurately by 71.0% physicians, and atopic dermatitis by 61.3% physicians, with a higher accuracy rate for pediatricians than nonpediatricians for all the mentioned conditions (P < 0.05). There was no significant difference in the accuracy of judgment between pediatricians and non-pediatricians in terms of AIT for food allergy and dust mite sensitization (P > 0.05).

CONCLUSION

The results of our study demonstrated a high accuracy judgment rate among clinicians for rhinitis, asthma, and dermatitis, and a low accuracy rate for desensitization of healthy people with allergic conjunctivitis, food allergies, and allergen sensitization.

Monitoring of molecular profiling of allergen-antibody responses in HDM-immunotherapy patients

Among the potential hazards of HDM immunotherapy (AIT) with HDM allergenic extracts is the possible initiation of de novosensitizations caused by a lack of complementarity between a given HDM vaccine's content and a patient's molecular sensitization profile. To investigate whether immunotherapy with HDM extracts affects changes in the profile of sensitizations to allergens contained in the extract and whether neosensitizations occur. Serum samples from patients with HDM allergies (N=63) who received 1 year of treatment with subcutaneous AIT were tested for allergen-specific IgE (sIgE) reactivity to 7 microarrayed HDM allergen molecules (Der p 1, 2,10,11,23; D far 1 and 2) with ImmunoCAP. The HDM non-AIT patients (N=22) who did not receive immunotherapy constituted the study's control group. The obtained data were analysed at baseline and after 6 and 12 months. In the HDM-AIT group, no neosensitizations after 6 and 12 months of immunotherapy were reported. Conversely, in the HDM non-AIT group, only neosensitizations to Der p 10 were observed. In the study group, sIgE levels against the HDM extract of D. pteronyssinus, D. farinae, rDer p 1, rDer p 2 and Der f 2 decreased after 12 months of AIT (p< .05). SIgE levels against Der f 1, Der p 10, 11 and 23 remained unchanged in the course of 12 months of immunotherapy. In patients with allergic rhinitis with or without concomitant HDM-induced asthma treated with HDM AIT for 12 months, no neosensitizations related to the examined HDM molecules were observed.

Sialic acid and food allergies: The link between nutrition and immunology

Food allergies (FA), a major public health problem recognized by the World Health Organization, affect an estimated 3%-10% of adults and 8% of children worldwide. However, effective treatments for FA are still lacking. Recent advances in glycoimmunology have demonstrated the great potential of sialic acids (SAs) in the treatment of FA. SAs are a group of nine-carbon α-ketoacids usually linked to glycoproteins and glycolipids as terminal glycans. They play an essential role in modulating immune responses and may be an effective target for FA intervention. As exogenous food components, sialylated polysaccharides have anti-FA effects. In contrast, as endogenous components, SAs on immunoglobulin E and immune cell surfaces contribute to the pathogenesis of FA. Given the lack of comprehensive information on the effects of SAs on FA, we reviewed the roles of endogenous and exogenous SAs in the pathogenesis and treatment of FA. In addition, we considered the structure-function relationship of SAs to provide a theoretical basis for the development of SA-based FA treatments.

A singleplex IgE test to a mixture of molecules from multiple airborne allergen sources: Innovating in vitro screening of respiratory allergies

BACKGROUND

In vitro immunoglobulin E (IgE) tests can be better standardized if based on molecules rather than extracts. However, singleplex screening tests for respiratory or food allergies are still based on extracts only.

TARGET

To validate a novel singleplex IgE screening test for respiratory allergies, based on a mix of major allergenic molecules Der p 1, Der p 2, Fel d 1, Can f 1, Can f 2, Can f 3, Can f 5, Bet v 1, Phl p 1, and Art v 1 (Molecular SX01, NOVEOS, HYCOR, USA), and requiring only four microliters (μl) of serum.

METHODS

We examined six subsets of sera from participants of the German Multicenter Allergy Study (MAS) birth cohort enrolling 1314 newborns during 1990: (1) monosensitized (n = 58); (2) polysensitized (n = 24); (3) nonsensitized, with total IgE levels above (n = 24) or (4) below (n = 24) 300 kU/L; (5) sensitized to milk and/or egg but not to airborne allergens (n = 24); and (6) sera of children aged ≤5 years at their earliest IgE monosensitization to airborne allergens (n = 41). Sera were analyzed with the novel molecular SX01 test (NOVEOS) and with three categories of comparators: ImmunoCAP Phadiatop SX01, extracts, and molecules of D. pteronyssinus, cat, dog, grass, and birch. Sensitivity, specificity, positive and negative predictive values were calculated. Quantitative interrelationships were determined using Spearman's rank-order correlation coefficient and Bland-Altmann plots.

RESULTS

The molecular SX01 test predicted the outcome of IgE tests based on molecules, extracts, or Phadiatop in 188 (96.4%), 171 (87.7%), and 171 (87.7%) of the 195 sera, respectively. Accordingly, sensitivity was 93.5%, 89.0%, and 82.4%, whereas specificity was 100%, 97.6%, and 96.1% when compared with molecular, extract, and Phadiatop tests, respectively. Inconsistent outcomes were largely confined to sera with IgE-Ab levels around the cutoff value of 0.35 kU/L, except for 5/195 (2.5%) sera, containing high levels of IgE to Phl p 5 and/or Alt a 1 only. IgE levels measured by the molecular SX01 test and with IgE tests to molecules, extracts, and Phadiatop were highly correlated (rho 0.90; p < .001), (rho 0.87, p < .001), (rho 0.84, p < .001), respectively. The novel molecular SX01 test detected IgE-Ab in 27/28 (sensitivity 96.4%) of the sera of preschool children at their earliest IgE sensitization to the same molecules.

DISCUSSION

Our study validates the prototype of a novel category of IgE test, based on molecular mixes. The test's rather good precision and accuracy in early screening IgE sensitization to airborne allergens in German children may be further improved by adding a few other molecules, such as Phl p 5 and Alt a 1.

Molecular reactivity profiling upon immunotherapy with a 300 IR sublingual house dust mite tablet reveals marked humoral changes towards major allergens

BACKGROUND

Molecular antibody reactivity profiles have not yet been studied in depth in patients treated by sublingual house dust mite (HDM) tablet immunotherapy. Humoral immune responses to a large panel of HDM mite allergens were studied using allergen microarray technology in a subset of clinically defined high and low responder patients from a double-blind placebo-controlled allergen-specific immunotherapy (AIT) trial using sublingual 300 IR HDM tablets.

METHODS

Serum levels of IgE, IgG and IgG₄ to 13 Dermatophagoides pteronyssinus molecules were measured at baseline and after 1-year AIT, using allergen microarrays in 100 subjects exhibiting high or low clinical benefit.

RESULTS

Der p 1, Der p 2 and Der p 23 were the most frequently recognized allergens in the study population. Patients with HDM-related asthma had significantly higher allergen-specific IgE levels to Der p 1 and Der p 23. No significant difference in the distribution of allergen sensitization pattern was observed between high and low responders. An increase in serum allergen-specific IgG and IgG₄ occurred upon AIT, in particular to allergens Der p 1, Der p 2 and Der p 23 (p < 0.0001).

CONCLUSIONS

We confirm for our study population that Der p 1- and Der p 23-specific IgE levels are associated with asthma. IgE reactivity profiles were not predicitive of sublingual AIT outcomes, with 300 IR tablets as efficacious in pauci- and multi-sensitized subjects. Our study is the first to demonstrate the induction of IgG and IgG₄  specific for the HDM allergens Der p 1, Der p 2 and Der p 23 by sublingual AIT.

Microneedle Transdermal Drug Delivery Systems for Allergen-Specific Immunotherapy, Skin Disease Treatment, and Vaccine Development

Transdermal drug delivery systems (TDDSs) overcome the hurdle of an intact skin barrier by penetrating the skin to allow molecules through. These systems reduce side effects associated with conventional hypodermic needles. Here, we introduce novel microneedle (MN) TDDSs that enhance drug delivery by creating micron-sized pores across the skin. Many MN TDDSs designed to deliver a diverse array of therapeutics, including allergen-specific immunotherapy, skin disease treatments, and vaccines, are under pre-clinical and clinical trials. Although epicutaneous approaches are emerging as new options for treating food allergy in many clinical trials, MN TDDSs could provide a more efficient and convenient route to deliver macromolecules. Furthermore, MN TDDSs may allow for safe vaccine delivery without permanent scars. MN TDDSs are a major emerging strategy for delivering novel vaccines and treatments for diseases, including skin diseases, allergic diseases, and so on.

Allergen-specific immunotherapy induces monocyte-derived dendritic cells but attenuates their maturation and cytokine production in the lesional skin of an atopic dermatitis mouse model

Atopic dermatitis (AD) is a common inflammatory skin disease, but current treatments for AD are mostly limited to the alleviation of symptoms and inhibition of inflammation. Allergen-specific immunotherapy (ASIT) is the only curative approach for allergic diseases and could be a promising way to cure AD. Although ASIT has been gradually applied to patients with AD, there are still few studies on its efficacy evaluation and mechanisms. Based on our previous established AD mouse model by dinitrofluorobenzene and an extract of Dermatophagoides farina, we performed ASIT on this AD model through subcutaneous injection of Dermatophagoides farina extracts to evaluate the efficacy of ASIT and study its underlying mechanisms. Our results showed that ASIT could not only alleviate skin lesions and scratching behaviors of AD mice but also inhibit their Th2-type immune responses. Furthermore, ASIT could increase the infiltration of monocyte-derived dendritic cells in skin lesions but attenuated their maturation and production of interleukin 1α and interleukin 12/23 p40. As immature and semi-mature dendritic cells preferentially induce tolerance, accumulation but inhibition of maturation of monocyte-derived dendritic cells after ASIT may indicate a novel mechanism of ASIT and a potential therapeutic target for AD.

Comparing available treatments for pollen-induced allergic rhinitis in children

INTRODUCTION

Pollen-induced allergic rhinitis (PIAR) is a widespread disease in children, and its prevalence is rapidly evolving. In addition, it may be associated with other atopic diseases, in particular asthma. In most cases, PIAR can be treated effectively by avoiding exposure to responsible allergens and using symptomatic treatments, including intranasal/oral antihistamines or/and nasal corticosteroids, according to ARIA guidelines. In recent decades, new medicines have been studied and developed: allergen-specific immunotherapy (AIT), anti-IgE antibodies, and probiotics. In addition, nutraceuticals have also been used as add-on treatments. This review aims to discuss and compare the old and new therapeutic strategies for PIAR in children.

AREAS COVERED

Allergic rhinitis is a type 2 inflammatory disease. The management of patients with PIAR entails medications, AIT, and ancillary therapies. In addition, children with PIAR and associated severe asthma may be inclusively treated with biologics. Namely, subjects with allergic comorbidities could benefit from biological agents. However, AIT presently remains the unique causal treatment for PIAR.

EXPERT OPINION

New strategies may include combined treatments, mainly concerning fixed associations with antihistamines and corticosteroids, nutraceutical products, and new AIT formulations.

Current Strategies to Modulate Regulatory T Cell Activity in Allergic Inflammation

Over the past decades, atopic diseases, including allergic rhinitis, asthma, atopic dermatitis, and food allergy, increased strongly worldwide, reaching up to 50% in industrialized countries. These diseases are characterized by a dominating type 2 immune response and reduced numbers of allergen-specific regulatory T (Treg) cells. Conventional allergen-specific immunotherapy is able to tip the balance towards immunoregulation. However, in mouse models of allergy adaptive transfer of Treg cells did not always lead to convincing beneficial results, partially because of limited stability of their regulatory phenotype activity. Besides genetic predisposition, it has become evident that environmental factors like a westernized lifestyle linked to modern sanitized living, the early use of antibiotics, and the consumption of unhealthy foods leads to epithelial barrier defects and dysbiotic microbiota, thereby preventing immune tolerance and favoring the development of allergic diseases. Epigenetic modification of Treg cells has been described as one important mechanism in this context. In this review, we summarize how environmental factors affect the number and function of Treg cells in allergic inflammation and how this knowledge can be exploited in future allergy prevention strategies as well as novel therapeutic approaches.

Art v 1 IgE epitopes of patients and humanized mice are conformational

BACKGROUND

Worldwide, pollen of the weed mugwort (Artemisiavulgaris) is a major cause of severe respiratory allergy, with its major allergen, Art v 1, being the key pathogenic molecule for millions of patients. Humanized mice transgenic for a human T-cell receptor specific for the major Art v 1 T-cell epitope and the corresponding HLA have been made.

OBJECTIVE

We sought to characterize IgE epitopes of Art v 1-sensitized patients and humanized mice for molecular immunotherapy of mugwort allergy.

METHODS

Four overlapping peptides incorporating surface-exposed amino acids representing the full-length Art v 1 sequence were synthesized and used to search for IgE reactivity to sequential epitopes. For indirect mapping, peptide-specific rabbit antibodies were raised to block IgE against surface-exposed epitopes on folded Art v 1. IgE reactivity and basophil activation studies were performed in clinically defined mugwort-allergic patients. Secondary structure of recombinant (r) Art v 1 and peptides was determined by circular dichroism spectroscopy.

RESULTS

Mugwort-allergic patients and humanized mice sensitized by allergen inhalation showed IgE reactivity and/or basophil activation mainly to folded, complete Art v 1 but not to unfolded, sequential peptide epitopes. Blocking of allergic patients' IgE with peptide-specific rabbit antisera identified a hitherto unknown major conformational IgE binding site in the C-terminal Art v 1 domain.

CONCLUSIONS

Identification of the new major conformational IgE binding site on Art v 1, which can be blocked with IgG raised against non-IgE reactive Art v 1 peptides, is an important basis for the development of a hypoallergenic peptide vaccine for mugwort allergy.

Allergen Content of Therapeutic Preparations for Allergen-Specific Immunotherapy of European Paper Wasp Venom Allergy

Allergy to Polistes dominula (European paper wasp) venom is of particular relevance in Southern Europe, potentially becoming a threat in other regions in the near future, and can be effectively cured by venom immunotherapy (VIT). As allergen content in extracts may vary and have an impact on diagnostic and therapeutic approaches, the aim was to compare five therapeutic preparations for VIT of P. dominula venom allergy available in Spain. Products from five different suppliers were analyzed by SDS-PAGE and LC-MS/MS and compared with a reference venom sample. Three products with P. dominula venom and one product with a venom mixture of American Polistes species showed a comparable band pattern in SDS-PAGE as the reference sample and the bands of the major allergens phospholipase A1 and antigen 5 were assignable. The other product, which consists of a mixture of American Polistes species, exhibited the typical band pattern in one, but not in another sample from a second batch. All annotated P. dominula allergens were detected at comparable levels in LC-MS/MS analysis of products containing P. dominula venom. Due to a lack of genomic information on the American Polistes species, the remaining products were not analyzed by this method. The major Polistes allergens were present in comparable amounts in the majority, but not in all investigated samples of venom preparations for VIT of P. dominula venom allergy.

Evaluation of a Novel Adjuvanted Vaccine for Ultrashort Regimen Therapy of Artemisia Pollen-Induced Allergic Bronchial Asthma in a Mouse Model

Wormwood (Artemisia) pollen is among the top 10 aeroallergens globally that cause allergic rhinitis and bronchial asthma. Allergen-specific immunotherapy (ASIT) is the gold standard for treating patients with allergic rhinitis, conjunctivitis, and asthma. A significant disadvantage of today's ASIT methods is the long duration of therapy and multiplicity of allergen administrations. The goal of this study was to undertake a pilot study in mice of a novel ultrashort vaccine immunotherapy regimen incorporating various adjuvants to assess its ability to treat allergic bronchial asthma caused by wormwood pollen. We evaluated in a mouse model of wormwood pollen allergy candidates comprising recombinant Art v 1 wormwood pollen protein formulated with either newer (Advax, Advax-CpG, ISA-51) or more traditional [aluminum hydroxide, squalene water emulsion (SWE)] adjuvants administered by the intramuscular or subcutaneous route vs. intranasal administration of a mucosal vaccine formulation using chitosan-mannose nanoparticle entrapped with Art v 1 protein. The vaccine formulations were administered to previously wormwood pollen-sensitized animals, four times at weekly intervals. Desensitization was determined by measuring decreases in immunoglobulin E (IgE), cellular immunity, ear swelling test, and pathological changes in the lungs of animals after aeroallergen challenge. Art v 1 protein formulation with Advax, Advax-CpG, SWE, or ISA-51 adjuvants induced a significant decrease in both total and Art v 1-specific IgE with a concurrent increase in Art v 1-specific IgG compared to the positive control group. There was a shift in T-cell cytokine secretion toward a Th1 (Advax-CpG, ISA-51, and Advax) or a balanced Th1/Th2 (SWE) pattern. Protection against lung inflammatory reaction after challenge was seen with ISA-51, Advax, and SWE Art v 1 formulations. Overall, the ISA-51-adjuvanted vaccine group induced the largest reduction of allergic ear swelling and protection against type 2 and non-type 2 lung inflammation in challenged animals. This pilot study shows the potential to develop an ultrashort ASIT regimen for wormwood pollen-induced bronchial asthma using appropriately adjuvanted recombinant Art v 1 protein. The data support further preclinical studies with the ultimate goal of advancing this therapy to human clinical trials.

Immunological effects of adjuvanted low-dose allergoid allergen-specific immunotherapy in experimental murine house dust mite allergy

BACKGROUND

Native allergen extracts or chemically modified allergoids are routinely used to induce allergen tolerance in allergen-specific immunotherapy (AIT), although mechanistic side-by-side studies are rare. It is paramount to balance optimal dose and allergenicity to achieve efficacy warranting safety. AIT safety and efficacy could be addressed by allergen dose reduction and/or use of allergoids and immunostimulatory adjuvants, respectively. In this study, immunological effects of experimental house dust mite (HDM) AIT were investigated applying high-dose HDM extract and low-dose HDM allergoids with and without the adjuvants microcrystalline tyrosine (MCT) and monophosphoryl lipid A (MPL) in a murine model of HDM allergy.

METHODS

Cellular, humoral, and clinical effects of the different AIT strategies were assessed applying a new experimental AIT model of murine allergic asthma based on physiological, adjuvant-free intranasal sensitization followed by subcutaneous AIT.

RESULTS

While low-dose allergoid and high-dose extract AIT demonstrated comparable potency to suppress allergic airway inflammation and Th2-type cytokine secretion of lung-resident lymphocytes and draining lymph node cells, low-dose allergoid AIT was less effective in inducing a potentially protective IgG1 response. Combining low-dose allergoid AIT with MCT or MCT and dose-adjusted MPL promoted Th1-inducing mechanisms and robust B-cell activation counterbalancing the allergic Th2 immune response.

CONCLUSION

Low allergen doses induce cellular and humoral mechanisms counteracting Th2-driven inflammation by using allergoids and dose-adjusted adjuvants. In light of safety and efficacy improvement, future therapeutic approaches may use low-dose allergoid strategies to drive cellular tolerance and adjuvants to modulate humoral responses.

TGF-β1 Drives Inflammatory Th Cell But Not Treg Cell Compartment Upon Allergen Exposure

TGF-β1 is known to have a pro-inflammatory impact by inducing Th9 and Th17 cells, while it also induces anti-inflammatory Treg cells (Tregs). In the context of allergic airway inflammation (AAI) its dual role can be of critical importance in influencing the outcome of the disease. Here we demonstrate that TGF-β is a major player in AAI by driving effector T cells, while Tregs differentiate independently. Induction of experimental AAI and airway hyperreactivity in a mouse model with inducible genetic ablation of the gene encoding for TGFβ-receptor 2 (Tgfbr2) on CD4⁺T cells significantly reduced the disease phenotype. Further, it blocked the induction of pro-inflammatory T cell frequencies (Th2, Th9, Th17), but increased Treg cells. To translate these findings into a human clinically relevant context, Th2, Th9 and Treg cells were quantified both locally in induced sputum and systemically in blood of allergic rhinitis and asthma patients with or without allergen-specific immunotherapy (AIT). Natural allergen exposure induced local and systemic Th2, Th9, and reduced Tregs cells, while therapeutic allergen exposure by AIT suppressed Th2 and Th9 cell frequencies along with TGF-β and IL-9 secretion. Altogether, these findings support that neutralization of TGF-β represents a viable therapeutic option in allergy and asthma, not posing the risk of immune dysregulation by impacting Tregs cells.

Effects of rAmb a 1-Loaded PLGA-PEG Nanoparticles in a Murine Model of Allergic Conjunctivitis

Ambrosia artemisiifolia (Amb a) contains many allergens. Allergic conjunctivitis caused by Ambrosia artemisiifolia and its related allergen-specific immunotherapy (AIT) are seldom studied at present. poly(DL-lactide-co-glycolide)-polyethylene glycol (PLGA-PEG) is a very good nano-carrier, which has been applied in the medical field. In this context, we studied the immunotherapy effect and potential mechanism of recombinant Amb a 1 (rAmb a 1)-loaded PLGA-PEG nanoparticles. A mouse allergic conjunctivitis model was established with Ambrosia artemisiifolia crude extract, and the nanoparticles were used for AIT through direct observation of conjunctival tissue, degranulation of mast cells in conjunctival tissue, serum-specific antibodies, cytokines and other assessment models. The treatment of nanoparticles enhanced the secretion of T-helper 1 (Th1) cytokine Interferon-gama (IFN-γ) and the production of immunoglobulin G (IgG)2a (IgG2a), inhibited the secretion of T-helper 2 (Th2) cytokine Interleukin (IL)-13 and IL-4 and the level of IgE. Especially, degranulation of mast cells and expression of mast cell protease-1 (MCP-1) in conjunctival tissue was reduced significantly. In this study, we proved that the nanoparticles prepared by rAmb a 1 and PLGA-PEG have an immunotherapy effect on allergic conjunctivitis in mice.

Morning Versus Evening Dosing of Sublingual Immunotherapy in Allergic Asthma: A Prospective Study

BACKGROUND

Sublingual immunotherapy (SLIT) has been proved to be an effective and safe treatment for allergic asthma (AS) in children. Nonetheless, several issues regarding SLIT remain to be resolved, including the information about optimal administration timing.

METHODS

A total of 163 AS children aged 4-13 years were enrolled and randomized into the morning dosing (MD) group and the evening dosing (ED) group. Participants received SLIT with Dermatophagoides farinae drops between 7:00 a. m. and 9:00 a.m. (for the MD group) or between 8:00 p. m. and 10:00 p.m. (for the ED group). The total asthma symptom score (TASS), total asthma medicine score (TAMS), Asthma Control Questionnaire (ACQ), forced expiratory volume in one second (FEV₁), FEV₁/forced volume vital capacity (FVC), fractional exhaled nitric oxide (FeNO) and adverse events (AEs) were assessed at baseline, 0.5 and 1 year during the 1-year SLIT.

RESULTS

After 1 year, 62 patients in the MD group and 63 patients in the ED group completed the entire study. The clinical efficacy, pulmonary function and FeNO in both groups improved significantly at 0.5 and 1 year (p < 0.001). Compared to the MD group, the ED group showed significant lower ACQ score at 0.5 year (p < 0.001) and lower FeNO at 1 year (p < 0.05). No significant difference between two groups was observed in AE rate (p > 0.05). All AEs occurred in the first month, with no systemic AEs reported.

CONCLUSION

1-year house dust mite (HDM) SLIT is effective and well-tolerated in AS children regardless of administration time. SLIT dosing in the evening might enhance the asthma control level and reduce FeNO level compared with SLIT dosing in the morning.

Preparation and Characterization of a Glycyrrhizic Acid-Based Drug Delivery System for Allergen-Specific Immunotherapy

The most effective method of treating allergic diseases, aimed not at relieving symptoms, but at eliminating the cause of the disease, is allergen-specific immunotherapy (AIT). To reduce the risk of side effects and improve the delivery of allergens to the mucosa, various delivery systems, such as liposomes, dendrimers, nanoparticles, etc., can be used. To date, there are data on the creation of delivery systems based on glycyrrhizic acid (GA) and its derivatives, but such a delivery system has not been used for allergen-specific therapy until now. It is also known that GA has an anti-inflammatory effect, shifts the balance towards Th1, and increases the number of Treg cells, meaning that it could potentially enhance the anti-allergic effect of AIT and reduce the risk of unwanted side effects. Thus, the study of the immunomodulatory effect of the supramolecular complexes (micelles) of GA with extracts of allergens holds promise for the development of new drugs for AIT.

Immunotherapy With Recombinant Alt a 1 Suppresses Allergic Asthma and Influences T Follicular Cells and Regulatory B Cells in Mice

Background

Alternaria is a major source of asthma-inducing allergens. Allergen-specific immunotherapy improves the progression of allergic asthma. The current treatment is based on crude Alternaria extracts. Alt a 1 is the predominant allergen in Alternaria. However, the treatment efficacy of recombinant Alt a 1 (rAlt a 1) in an asthmatic animal model and its influence on Tfh and Breg cells are unknown.

Objective

To explore the therapeutic treatment effects of rAlt a 1 on the progress of an asthmatic mouse model and its effect on Tfh and Breg cells.

Methods

We synthesized and purified rAlt a 1. Alternaria-sensitized and challenged mice received subcutaneous immunotherapy (SCIT) with four different rAlt a 1 dosages (5, 50, 100, and 150 µg) or PBS only. Finally, lung and airway inflammation, mouse mast cell protease 1 (MMCP-1), serum immunoglobulin responses, Tfh and Breg cell levels, and the correlation between asthmatic features (inflammation grades and IL-4 and IL-10 levels) and these two cell types were measured after Alternaria rechallenge.

Results

High purity and allergenic potency of rAlt a 1 protein were obtained. Following treatment with four different rAlt a 1 dosages, both lung and airway inflammation ameliorated, including lung pathology, serum MMCP-1 levels, inflammatory cell numbers, and cytokine levels in bronchoalveolar lavage fluid (BALF). Additionally, rAlt a 1-SCIT increased the expression of Alternaria-sIgG1, rAlt a 1-sIgG1, rAlt a 1-sIgG2a, and rAlt a 1-sIgG2b in serum. Moreover, the number and percentage of CXCR5⁺PD-1⁺Tfh cells were increased in the PC control, while they decreased in the rAlt a 1-SCIT groups. Meanwhile, the absolute numbers and proportions of Breg cells were evaluated after administration of rAlt a 1. A positive correlation was observed between CXCR5⁺PD-1⁺Tfh cells and inflammation grades (r = 0.50, p = 0.01), as well as a slightly strong positive relationship with IL-4 (r = 0.55, p = 0.005) and IL-10 (r = 0.58, p = 0.003) levels; Breg cells showed an opposite correlation with the grades of inflammation (r = -0.68, p = 0.0003), along with a negative correlation to IL-4 (r = -0.61, p = 0.001) and IL-10 (r = -0.53, p = 0.008) levels.

Conclusions

We verified that treatment with rAlt a 1 can alleviate asthma progression and further have a regulatory effect on Tfh and Breg cells in an Alternaria-induced asthmatic mouse model.

Effect of Medical Therapy in Allergic Rhinitis: A Systematic Review and Meta-Analysis

BACKGROUND

Intranasal corticosteroids (INCS), oral antihistamines (POAH), and allergen-specific immunotherapy (ASIT) are widely used in the treatment of allergic rhinitis (AR); however, appraisal of treatment effect has been heterogenous, and few studies have interpreted these outcomes in context with measures of nasal airflow.

OBJECTIVE

To provide a systematic review and meta-analysis of randomized placebo-controlled trials for common therapy classes for AR to assess standardized treatment effect on validated patient-reported outcomes and physiologic measures of airflow.

METHODS

A systematic search was performed in PubMed, Scopus, OVID, and Cochrane library databases to identify randomized controlled trials meeting inclusion criteria. Treatment effects of INCS, POAH, and ASIT on total nasal symptom score (TNSS), visual analog scale (VAS), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), and peak nasal inspiratory flow (PNIF) were analyzed by meta-analysis.

RESULTS

Twenty-two studies with 4673 AR patients were identified, with 5 INCS, 8 POAH, and 9 ASIT trials. INCS improved TNSS (mean difference [MD] 0.90; P = .002) and PNIF (MD 13.31 L/min [P = .0007]. POAH improved quality of life assessed by RQLQ [MD 0.36; P < .001], but no improvement was found in PNIF. ASIT improved RQLQ [MD 0.65; P < .001], with a trend toward improvement in TNSS.

CONCLUSION

Overall, INCS resulted in a clinically and statistically meaningful improvement in symptom scores and physiologic measures in AR. POAH and ASIT both improved symptom scores and quality of life, but their impacts upon nasal airflow are uncertain. There is a lack of studies assessing the effect of INCS on quality of life and the effect of POAH on symptom severity, particularly for mild AR. Future studies should assess the effect of treatment for each of these patient-reported measures.

Sputum microRNA-screening reveals Prostaglandin EP3 receptor as selective target in allergen-specific immunotherapy

BACKGROUND

Several microRNAs (miRs) have been described as potential biomarkers in liquid biopsies and in the context of allergic asthma, while therapeutic effects on the airway expression of miRs remain elusive. In this study, we investigated epigenetic miR-associated mechanisms in the sputum of grass pollen-allergic patients with and without allergen-specific immunotherapy (AIT).

METHODS

Induced sputum samples of healthy controls (HC), AIT-treated and -untreated grass pollen-allergic rhinitis patients with (AA) and without asthma (AR) were profiled using miR microarray and whole-transcriptome microarray analysis of the same samples. miR targets were predicted in silico and used to identify inverse regulation. Local PGE₂  levels were measured using ELISA.

RESULTS

Two hundred and fifty nine miRs were upregulated in the sputum of AA patients compared with HC, while only one was downregulated. The inverse picture was observed in induced sputum of AIT-treated patients: while 21 miRs were downregulated, only 4 miRs were upregulated in asthmatics upon AIT. Of these 4 miRs, miR-3935 stood out, as its predicted target PTGER3, the prostaglandin EP₃ receptor, was downregulated in treated AA patients compared with untreated. The levels of its ligand PGE₂ in the sputum supernatants of these samples were increased in allergic patients, especially asthmatics, and downregulated after AIT. Finally, local PGE₂  levels correlated with ILC2 frequencies, secreted sputum IL-13 levels, inflammatory cell load, sputum eosinophils and symptom burden.

CONCLUSIONS

While profiling the sputum of allergic patients for novel miR expression patterns, we uncovered an association between miR-3935 and its predicted target gene, the prostaglandin E₃ receptor, which might mediate AIT effects through suppression of the PGE₂ -PTGER3 axis.

IgE-cross-blocking antibodies to Fagales following sublingual immunotherapy with recombinant Bet v 1

BACKGROUND

Evidence has accumulated that birch pollen immunotherapy reduces rhinoconjunctivitis to pollen of birch homologous trees. Therapeutic efficacy has been associated with IgE-blocking IgG antibodies. We have recently shown that sera collected after 16 weeks of sublingual immunotherapy with recombinant Bet v 1 (rBet v 1-SLIT) display strong IgE-blocking bioactivity for Bet v 1. Here, we assessed whether rBet v 1-SLIT-induced IgG antibodies display cross-blocking activity to related allergens in Fagales pollen.

METHODS

IgE, IgG1 and IgG4 reactivity to recombinant Bet v 1, Aln g 1, Car b 1, Ost c 1, Cor a 1, Fag s 1, Cas s 1 and Que a 1 were assessed in pre- and post-SLIT samples of 17 individuals by ELISA. A basophil inhibition assay using stripped basophils re-sensitized with a serum pool containing high Bet v 1-specific IgE levels was established and used to assess CD63 expression in response to allergens after incubation with pre-SLIT or post-SLIT samples. IgG1 and IgG4 were depleted from post-SLIT samples to assess its contribution to IgE-cross-blocking.

RESULTS

Sublingual immunotherapy with recombinant Bet v 1 boosted cross-reactive IgE antibodies and induced IgG1 and IgG4 antibodies with inter- and intra-individually differing reactivity to the homologs. Highly variable cross-blocking activities of post-SLIT samples to the different allergens were found. IgG1 and IgG4 antibodies displayed cross-blocking activity with individual variance.

CONCLUSIONS

Our mechanistic approach suggested that immunotherapy with the reference allergen Bet v 1 induces individual repertoires of cross-reactive IgG1 and IgG4 antibodies. The cross-blocking bioactivity of these antibodies was also highly variable and neither predictable from protein homology nor IgE-cross-reactivity.

Allergen-specific immunotherapy induces the suppressive secretoglobin 1A1 in cells of the lower airways

BACKGROUND

While several systemic immunomodulatory effects of allergen-specific immunotherapy (AIT) have been discovered, local anti-inflammatory mechanisms in the respiratory tract are largely unknown. We sought to elucidate local and epithelial mechanisms underlying allergen-specific immunotherapy in a genome-wide approach.

METHODS

We induced sputum in hay fever patients and healthy controls during the pollen peak season and stratified patients by effective allergen immunotherapy or as untreated. Sputum was directly processed after induction and subjected to whole transcriptome RNA microarray analysis. Nasal secretions were analyzed for Secretoglobin1A1 (SCGB1A1) and IL-24 protein levels in an additional validation cohort at three defined time points during the 3-year course of AIT. Subsequently, RNA was extracted and subjected to an array-based whole transcriptome analysis.

RESULTS

Allergen-specific immunotherapy inhibited pro-inflammatory CXCL8, IL24, and CCL26mRNA expression, while SCGB1A1, IL7, CCL5, CCL23, and WNT5BmRNAs were induced independently of the asthma status and allergen season. In our validation cohort, local increase of SCGB1A1 occurred concomitantly with the reduction of local IL-24 in upper airways during the course of AIT. Additionally, SCGB1A1 was identified as a suppressor of epithelial gene expression.

CONCLUSIONS

Allergen-specific immunotherapy induces a yet unknown local gene expression footprint in the lower airways that on one hand appears to be a result of multiple regulatory pathways and on the other hand reveals SCGB1A1 as novel anti-inflammatory mediator of long-term allergen-specific therapeutic intervention in the local environment.

Dynamic Changes, Correlation of Basophils, and the Therapeutic Effect in Patients With Allergic Rhinitis During Allergen-specific Immunotherapy

BACKGROUND

The role of basophils in allergic rhinitis (AR) has been studied extensively; however, there are very few reports on changes in basophils after allergen-specific immunotherapy (SIT).

OBJECTIVE

To examine the changes and correlation of peripheral blood basophils and the therapeutic effect in patients with AR during allergen-SIT.

METHODS

A total of 77 patients with AR who were allergic only to house dust mites received allergen-SIT. At 3 time points, patients underwent testing for the percentage and activation rate of basophils in peripheral blood, skin index (SI) measurement, visual analog scale (VAS) assessment, and rhinoconjunctivitis quality of life questionnaire (RQLQ) evaluation. The results were compared to a control group with congenital preauricular fistula.

RESULTS

(1) Before treatment, the percentage and activation rate of basophils in patients with AR were significantly higher than those in controls. There was no significant difference in the percentages and activation rates of basophils at the 3 time points. (2) The SIs, VAS, and RQLQ scores of the patients immediately after treatment and 2 years posttreatment decreased significantly compared to those before treatment; the SI, VAS, and RQLQ scores of the patients 2 years posttreatment increased significantly compared with those immediately after treatment. (3) There was no correlation between the patients' basophil activation rate and percentage and the SI, VAS, and RQLQ scores at all time points.

CONCLUSION

The percentage and activation rate of basophils were higher in patients with AR than in controls. The values did not change significantly after allergen-SIT and showed no correlation with treatment effectiveness. Therefore, the frequency and activation rate of basophils cannot be used as criteria for assessing the effectiveness of allergen-SIT for house dust mites. Allergen-SIT is effective for the management of AR, but the effect declines after the completion of therapy.

Next-Generation Allergen-Specific Immunotherapy for Japanese Cedar Pollinosis Using Molecular Approaches

Japanese cedar (JC) pollinosis is the most major IgE-mediated type I allergic disease in Japan. Allergen-specific immunotherapy is the only curative treatment for allergic diseases. Subcutaneous immunotherapy and sublingual immunotherapy have been introduced in Japan for JC pollinosis, but do not avoid some adverse side effects, because the natural allergens used as tolerogens cross-link with specific IgE types on mast cells and basophils. To make immunotherapy for JC pollinosis safer, more effective and convenient, rice-based oral allergy vaccines using hybrid peptides composed of multiple T-cell epitopes or recombinant deconstructed hypoallergenic derivatives derived from major allergens — Cry j 1 and Cry j 2 — have been developed and their efficacy and safety evaluated by oral administration of transgenic rice seeds. Furthermore, recombinant modified JC allergens conjugated with various immunomodulatory molecules and DNA-based vaccines have been created and their efficacy assessed.

Peptide allergen-specific immunotherapy for allergic airway diseases-State of the art

Allergen-specific immunotherapy (AIT) is the only means of altering the natural immunological course of allergic diseases and achieving long-term remission. Pharmacological measures are able to suppress the immune response and/or ameliorate the symptoms but there is a risk of relapse soon after these measures are withdrawn. Current AIT approaches depend on the administration of intact allergens, often comprising crude extracts of the allergen. We propose that the challenges arising from current approaches, including the risk of serious side-effects, burdensome duration of treatment, poor compliance and high cost, are overcome by application of peptides based on CD4⁺ T cell epitopes rather than whole allergens. Here we describe evolving approaches, summarize clinical trials involving peptide AIT in allergic rhinitis and asthma, discuss the putative mechanisms involved in their action, address gaps in evidence and propose future directions for research and clinical development.

Adjuvants and Vaccines Used in Allergen-Specific Immunotherapy Induce Neutrophil Extracellular Traps

Aluminum hydroxide (alum) and monophosphoryl-lipid A (MPLA) are conventional adjuvants in vaccines for allergen-specific immunotherapy (AIT). Alum triggers the release of neutrophil extracellular traps (NETs) by neutrophils. NETs contain expelled decondensed chromatin associated with granular material and may act as danger-associated molecular patterns and activate antigen-presenting cells. We investigated whether adjuvant-induced NETs contribute to innate responses to AIT-vaccines. Human neutrophils were incubated with alum, MPLA and adjuvant-containing AIT-vaccine preparations. NETs were verified by time-lapse and confocal fluorescence microscopy and quantitatively assessed by DNA and elastase release and ROS production. In contrast to MPLA, alum represented a potent trigger for NET release. Vaccine formulations containing alum resulted in less NET release than alum alone, whereas the vaccine containing MPLA induced stronger NET responses than MPLA alone. NETs and alum alone and synergistically increased the expression of molecules involved in antigen presentation, i.e., CD80, CD86 and CD83, by peripheral blood monocytes. Monocyte priming with NETs resulted in individually differing IL-1β- and IL-6-responses. Thus, NETs induced by adjuvants in AIT-vaccines can provide autonomous and cooperative effects on early innate responses. The high diversity of individual innate responses to adjuvants and AIT-vaccines may affect their therapeutic efficacy.

CpG Adjuvant in Allergen-Specific Immunotherapy: Finding the Sweet Spot for the Induction of Immune Tolerance

Prevalence and incidence of IgE-mediated allergic diseases have increased over the past years in developed and developing countries. Allergen-specific immunotherapy (AIT) is currently the only curative treatment available for allergic diseases that has long-term efficacy. Although AIT has been proven successful as an immunomodulatory therapy since its beginnings, it still faces several unmet needs and challenges today. For instance, some patients can experience severe side effects, others are non-responders, and prolonged treatment schedules can lead to lack of patient adherence and therapy discontinuation. A common strategy to improve AIT relies on the use of adjuvants and immune modulators to boost its effects and improve its safety. Among the adjuvants tested for their clinical efficacy, CpG oligodeoxynucleotide (CpG-ODN) was investigated with limited success and without reaching phase III trials for clinical allergy treatment. However, recently discovered immune tolerance-promoting properties of CpG-ODN place this adjuvant again in a prominent position as an immune modulator for the treatment of allergic diseases. Indeed, it has been shown that the CpG-ODN dose and concentration are crucial in promoting immune regulation through the recruitment of pDCs. While low doses induce an inflammatory response, high doses of CpG-ODN trigger a tolerogenic response that can reverse a pre-established allergic milieu. Consistently, CpG-ODN has also been found to stimulate IL-10 producing B cells, so-called B regulatory cells (Bregs). Accordingly, CpG-ODN has shown its capacity to prevent and revert allergic reactions in several animal models showing its potential as both preventive and active treatment for IgE-mediated allergy. In this review, we describe how CpG-ODN-based therapies for allergic diseases, despite having shown limited success in the past, can still be exploited further as an adjuvant or immune modulator in the context of AIT and deserves additional attention. Here, we discuss the past and current knowledge, which highlights CpG-ODN as a potential adjuvant to be reevaluated for the enhancement of AIT when used in appropriate conditions and formulations.

Novel vaccines for allergen-specific immunotherapy

PURPOSE OF REVIEW

Allergen-specific immunotherapy (AIT) is a highly economic, effective and disease-modifying form of allergy treatment but requires accurate prescription and monitoring. New molecular approaches are currently under development to improve AIT by reducing treatment-related side effects, cumbersome protocols and patients' compliance. We review the current advances regarding refined diagnosis for prescription and monitoring of AIT and the development of novel molecular vaccines for AIT. Finally, we discuss prophylactic application of AIT.

RECENT FINDINGS

There is evidence that molecular allergy diagnosis not only assists in the prescription and monitoring of AIT but also allows a refined selection of patients to increase the likelihood of treatment success. New data regarding the effects of AIT treatment with traditional allergen extracts by alternative routes have become available. Experimental approaches for AIT, such as virus-like particles and cell-based treatments have been described. New results from clinical trials performed with recombinant hypoallergens and passive immunization with allergen-specific antibodies highlight the importance of allergen-specific IgG antibodies for the effect of AIT and indicate opportunities for preventive allergen-specific vaccination.

SUMMARY

Molecular allergy diagnosis is useful for the prescription and monitoring of AIT and may improve the success of AIT. Results with molecular allergy vaccines and by passive immunization with allergen-specific IgG antibodies indicate the importance of allergen-specific IgG capable of blocking allergen recognition by IgE and IgE-mediated allergic inflammation as important mechanism for the success of AIT. New molecular vaccines may pave the road towards prophylactic allergen-specific vaccination.

Past, present, and future of allergen immunotherapy vaccines

Allergen-specific immunotherapy (AIT) is an allergen-specific form of treatment for patients suffering from immunoglobulin E (IgE)-associated allergy; the most common and important immunologically mediated hypersensitivity disease. AIT is based on the administration of the disease-causing allergen with the goal to induce a protective immunity consisting of allergen-specific blocking IgG antibodies and alterations of the cellular immune response so that the patient can tolerate allergen contact. Major advantages of AIT over all other existing treatments for allergy are that AIT induces a long-lasting protection and prevents the progression of disease to severe manifestations. AIT is cost effective because it uses the patient´s own immune system for protection and potentially can be used as a preventive treatment. However, broad application of AIT is limited by mainly technical issues such as the quality of allergen preparations and the risk of inducing side effects which results in extremely cumbersome treatment schedules reducing patient´s compliance. In this article we review progress in AIT made from its beginning and provide an overview of the state of the art, the needs for further development, and possible technical solutions available through molecular allergology. Finally, we consider visions for AIT development towards prophylactic application.

Hungarian adaptation and launch of the 2019 ARIA care pathways of allergic rhinitis in Hungary

Összefoglaló. Az allergiás betegségekben szenvedő emberek száma világszerte, köztük Magyarországon is növekszik. Az egészségügyi ellátórendszerek azon dolgoznak, hogy minél hatékonyabban tudják felhasználni a rendelkezésre álló forrásokat. Az Allergic Rhinitis and its Impact on Asthma (ARIA) szervezet célja az allergiás náthában szenvedő betegek ellátásának javítása, szakmai ajánlások készítése, aktualizálása. Ennek egyik módja integrált betegellátási utak kidolgozása. Célunk ezek hazai elérhetővé tétele, az ajánlások széles körű elterjesztése az Európai Unió (EU) többi tagállamához hasonlóan Magyarországon is. Az ARIA más nemzetközi innovatív szervezetek bevonásával olyan integrált betegellátási utakat fejlesztett ki, amelyek allergiás nátha, esetleg társbetegsége, az asztma esetén támogatják a kezelést. Ezeket újgenerációs irányelvek kidolgozása útján alkották, amelyekhez felhasználták a mobiltechnológiából és pollenkamra-vizsgálatokból származó valós evidenciákat is. A gyógyszeres terápia optimalizálásához a vizuális analóg skálán alapuló, úgynevezett Mobil Légúti Figyelő Hálózat algoritmusát digitalizálták, és valós evidenciák felhasználásával tovább finomították. Allergén immunterápiára az ARIA a világon elsőként dolgozott ki integrált betegellátási utakat 2019-ben. A kezelési irányelvekhez való adherenciaszint alacsony, a betegek a tüneteik erőssége alapján módosítják a kezelést. A flutikazon-propionát-azelasztin kombináció hatása erősebb az intranasalis kortikoszteroidokénál, míg az utóbbi hatásosabb az oralis H1-antihisztaminoknál. A mobiltelefonokban tárolt elektronikus napló vagy más 'mobile health' (mHealth) eszközök használata segíti a betegek kiválasztását allergén immunterápiára. Az ARIA által javasolt algoritmus megfelelőnek mutatkozott az allergiás rhinitis kezelésére, ezért ezek az irányelvek bekerülnek integrált betegellátási utakba, és részét fogják képezni az EU Egészségügyi és Élelmiszer-biztonsági Főigazgatósága digitalizált, személyközpontú gondozási anyagainak. Az allergén immunterápia hatékony az inhalatív allergének által okozott allergiás betegségekben, alkalmazását azonban korlátozni kell gondosan válogatott betegekre. Orv Hetil. 2020; 161(49): 2059-2071. Summary. The number of allergic patients is increasing all over the world, also in Hungary. Delivering effective and cost-effective health care is essential for all health care systems. ARIA (Allergic Rhinitis and its Impact on Asthma) aims to improve the care of patients who suffer from allergic rhinitis by setting up guidelines and updating them. Development of ICPs (integrated care pathways) can play an essential role in attaining this goal. Our aim is to make ICP-s developed by ARIA available also in Hungary, as is already the case in other countries of the European Union (EU). Together with other international initiatives, ARIA has worked out digitally-enabled ICPs to support care in allergic rhinitis and comorbid asthma. ICPs are based on new-generation guidelines using RWE (real-world evidence) from chamber studies and mobile technology. The MASK (Mobile Airways Sentinel NetworK) algorithm - based on visual analogue scale - was digitalized to support pharmacotherapy, and was refined by using RWE. ARIA was the first to develop ICPs for allergen immunotherapy (AIT) in 2019. Based on MASK data, patients did not follow guidelines and their adherence to treatment was poor. Patients would modify their treatments, depending on the disease control. The effect of fluticasone propionate-azelastine combination is superior to intranasal corticosteroids which are superior to oral H1-antihistamines. Electronic diaries obtained from cell phones and other 'mobile health' (mHealth) devices help select patients for AIT. The ARIA algorithm for AR was found appropriate and no change is necessary. These guidelines will inform ICPs and will be included in the DG Santé digitally-enabled, person-centred care system. AIT is an effective treatment for allergic diseases caused by inhaled allergens. Its use should, however, be restricted to carefully selected patients. Orv Hetil. 2020; 161(49): 2059-2071.

Toll-Like Receptor Agonists as Adjuvants for Allergen Immunotherapy

Toll-like receptors (TLRs) are essential components of innate immunity and provide defensive inflammatory responses to invading pathogens. Located within the plasma membranes of cells and also intracellular endosomes, TLRs can detect a range of pathogen associated molecular patterns from bacteria, viruses and fungi. TLR activation on dendritic cells can propagate to an adaptive immune response, making them attractive targets for the development of both prophylactic and therapeutic vaccines. In contrast to conventional adjuvants such as aluminium salts, TLR agonists have a clear immunomodulatory profile that favours anti-allergic T lymphocyte responses. Consequently, the potential use of TLRs as adjuvants in Allergen Immunotherapy (AIT) for allergic rhinitis and asthma remains of great interest. Allergic Rhinitis is a Th2-driven, IgE-mediated disease that occurs in atopic individuals in response to exposure to otherwise harmless aeroallergens such as pollens, house dust mite and animal dander. AIT is indicated in subjects with allergic rhinitis whose symptoms are inadequately controlled by antihistamines and nasal corticosteroids. Unlike anti-allergic drugs, AIT is disease-modifying and may induce long-term disease remission through mechanisms involving upregulation of IgG and IgG4 antibodies, induction of regulatory T and B cells, and immune deviation in favour of Th1 responses that are maintained after treatment discontinuation. This process takes up to three years however, highlighting an unmet need for a more efficacious therapy with faster onset. Agonists targeting different TLRs to treat allergy are at different stages of development. Synthetic TLR4, and TLR9 agonists have progressed to clinical trials, while TLR2, TLR5 and TLR7 agonists been shown to have potent anti-allergic effects in human in vitro experiments and in vivo in animal studies. The anti-allergic properties of TLRs are broadly characterised by a combination of enhanced Th1 deviation, regulatory responses, and induction of blocking antibodies. While promising, a durable effect in larger clinical trials is yet to be observed and further long-term studies and comparative trials with conventional AIT are required before TLR adjuvants can be considered for inclusion in AIT. Here we critically evaluate experimental and clinical studies investigating TLRs and discuss their potential role in the future of AIT.