Short-term and long-term efficacy of sublingual immunotherapy in different courses for house dust mite-induced allergic rhinitis

PURPOSE

Sublingual immunotherapy (SLIT) has been proven to be an effective and safe treatment for patients with house dust mite (HDM)-induced allergic rhinitis (AR) to achieve short-term and long-term efficacy. This study aimed to investigate the relationship between SLIT duration and long-term efficacy.

MATERIALS AND METHODS

This study involved 134 patients who underwent SLIT between 2019 and 2021 (in the 2-year group), between 2018 and 2021(in the 3-year group), or between 2017 and 2021 (in the 4-year group). The total nasal symptoms score (TNSS), total medication score (TMS), visual analogue scale (VAS), the Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) and adverse events (AEs) were assessed at baseline, after treatment (2021) and one year after the treatment completion (2022). The correlation between MiniRQLQ and other indicators was also analyzed.

RESULTS

After SLIT, patients in all three groups showed significant improvements in TNSS, TMS, VAS and MiniRQLQ scores (all p < 0.001). These improvements were sustained even one year after SLIT. Patients who received 3-4 years of SLIT showed significant improvement compared with those who received 2 years of SLIT in all clinical outcomes (all p < 0.01). The analysis showed positive correlations between the MiniRQLQ and TNSS, TMS, and VAS (all p < 0.001). No significant difference was observed in the AE rate in all three groups (p > 0.05).

CONCLUSION

Different duration of HDM SLIT could generate various short-term and long-term clinical efficacy. The MiniRQLQ could be applied to evaluate SLIT efficacy in clinical practice.

Designing a T-cell epitope-based vaccine using in silico approaches against the Sal k 1 allergen of Salsola kali plant

Allergens originated from Salsola kali (Russian thistle) pollen grains are one of the most important sources of aeroallergens causing pollinosis in desert and semi-desert regions. T-cell epitope-based vaccines (TEV) are more effective among different therapeutic approaches developed to alleviate allergic diseases. The physicochemical properties, and B as well as T cell epitopes of Sal k 1 (a major allergen of S. kali) were predicted using immunoinformatic tools. A TEV was constructed using the linkers EAAAK, GPGPG and the most suitable CD4+ T cell epitopes. RS04 adjuvant was added as a TLR4 agonist to the amino (N) and carboxyl (C) terminus of the TEV protein. The secondary and tertiary structures, solubility, allergenicity, toxicity, stability, physicochemical properties, docking with immune receptors, BLASTp against the human and microbiota proteomes, and in silico cloning of the designed TEV were assessed using immunoinformatic analyses. Two CD4+ T cell epitopes of Sal k1 that had high affinity with different alleles of MHC-II were selected and used in the TEV. The molecular docking of the TEV with HLADRB1, and TLR4 showed TEV strong interactions and stable binding pose to these receptors. Moreover, the codon optimized TEV sequence was cloned between NcoI and XhoI restriction sites of pET-28a(+) expression plasmid. The designed TEV can be used as a promising candidate in allergen-specific immunotherapy against S. kali. Nonetheless, effectiveness of this vaccine should be validated through immunological bioassays.

The Role of Regulatory T Cells in Allergic Diseases: Collegium Internationale Allergologicum (CIA) Update 2024

BACKGROUND

Allergy represents a major health problem of increasing prevalence worldwide with a high socioeconomic impact. Our knowledge on the molecular mechanisms underlying allergic diseases and their treatments has significantly improved over the last years. The generation of allergen-specific regulatory T cells (Tregs) is crucial in the induction of healthy immune responses to allergens, preventing the development and worsening of allergic diseases.

SUMMARY

In the last decades, intensive research has focused on the study of the molecular mechanisms involved in Treg development and Treg-mediated suppression. These mechanisms are essential for the induction of sustained tolerance by allergen-specific immunotherapy (AIT) after treatment discontinuation. Compelling experimental evidence demonstrated altered suppressive capacity of Tregs in patients suffering from allergic rhinitis, allergic asthma, food allergy, or atopic dermatitis, as well as the restoration of their numbers and functionality after successful AIT.

KEY MESSAGE

The better understanding of the molecular mechanisms involved in Treg generation during allergen tolerance induction might well contribute to the development of novel strategies for the prevention and treatment of allergic diseases.

[Feeling analysis on allergen immunotherapy on Twitter using an unsupervised machine learning model]

OBJECTIVE

Analyze feelings about allergen-specific immunotherapy on Twitter using the VADER model VADER (Valence Aware Dictionary and sEntiment Reasoner) model.

METHODS

tweets related to specific allergen immunotherapy were obtained through the Twitter Application Programming Interface (API). The keywords "allergy shot" were used between January 1, 2012, and December 31, 2022. The data was processed by removing URLs, usernames, hashtags, multiple spaces, and duplicate tweets. Subsequently, a sentiment analysis was performed using the VADER model.

RESULTS

A total of 34,711 tweets were retrieved, of which 1928 were eliminated. Of the remaining 32,783 tweets, 32.41% expressed a negative sentiment, 31.11% expressed a neutral sentiment, and 36.47% expressed a positive sentiment, with an average polarity of 0.02751 (neutral) over the 11-year period.

CONCLUSIONS

The average polarity of tweets about allergen-specific immunotherapy is neutral over the 11 years analyzed. There was an annual increase in the average polarity over the years, with 2017, 2018, and 2022 having positive polarity averages. Additionally, the number of tweets decreased over time.

[Insect venom allergies-What will change in times of global change?]

BACKGROUND

In Germany, honeybees (Apis mellifera) and various Vespula species (wasps) are primarily relevant for hypersensitivity reactions to stings. Hornets (Vespa crabro), bumblebees, paper wasps (Polistes) and yellowjackets (Dolichovespula) less frequently cause sting reactions.

OBJECTIVE

What effects do intensive agricultural utilization and climate change have on the living conditions and occurrence of Hymenoptera and what consequences do they have for the diagnostics and treatment of hypersensitivity reactions to Hymenoptera stings.

MATERIAL AND METHODS

A literature search was carried out.

RESULTS

Honeybees and wild bees are endangered due to introduced diseases, invasive species and pesticides. The aim of widespread beekeeping activity is to protect honeybees, which is why no reduction in stings is to be expected despite increased bee mortality. In Germany, there is evidence of the spread of thermophilic Polistes species (paper wasps) from south to north and the immigration of Vespa velutina nigrithorax (Asian hornet). It is unlikely that these species will lead to a significant increase in sting reactions. Nests of the red fire ant (Solenopsis invicta), which was originally common in South America, were first detected in Sicily in 2022. Red fire ants are aggressive insects with a high potential for adverse sting reactions.

CONCLUSION

Invasive insects must be considered as a trigger in the anamnesis and diagnostics. Diagnostics are only available for the detection of Polistes sensitization. Therapeutic allergens can be obtained from other European countries for venom immunotherapy of a Polistes allergy. Due to cross-reactivity, diagnostic and therapeutic allergens from Vespula spp. are used for the diagnosis and treatment of suspected allergies to the Asian hornet.

Prevention Is Better than Cure: Impact of Allergen Immunotherapy on the Progression of Airway Disease

Allergen immunotherapy is highly effective for seasonal pollinosis. Three years of treatment results in long-term efficacy. This disease modification is accompanied by downregulation of allergen-specific Th2 responses and the induction of persistent specific IgG- and IgA-associated IgE-blocking activity. In children with seasonal rhinitis, both subcutaneous and sublingual pollen immunotherapy have been shown to reduce the development of asthma symptoms and asthma medication requirements. House dust mite tablet allergen immunotherapy has been shown to be effective for perennial mite-driven rhinitis in adults and children and may suppress asthma exacerbations, whereas its long-term efficacy has yet to be explored. The success of primary prevention of peanut allergy in childhood by introduction of peanut into the diet during infancy provides a strong rationale to explore whether primary prevention of inhalant allergies and asthma may also be possible. House dust mite allergy is a major risk factor for developing asthma. Preliminary data in at-risk children suggest that sublingual house dust mite immunotherapy initiated during infancy could reduce the onset of multiple allergen sensitizations and prevent the development of asthma at age 6 years. This possibility should now be explored in an adequately powered, prospectively randomized controlled trial.

Safe and efficient oral allergy immunotherapy using one-pot-prepared mannan-coated allergen nanoparticles

Allergen immunotherapy (AIT) is the only curative treatment for allergic diseases. However, AIT has many disadvantages related to efficiency, safety, long-term duration, and patient compliance. Dendritic cells (DCs) have an important role in antigen-specific tolerance induction; thus, DC-targeting strategies to treat allergies such as glutaraldehyde crosslinked antigen to mannoprotein (MAN) have been established. However, glutaraldehyde crosslinking may reduce the antigen presentation efficiency of DCs. To overcome this, we developed a MAN-coated ovalbumin (OVA) nanoparticle (MDO), which uses intermolecular disulfide bond to crosslink OVA and MAN. MDO effectively targeted DCs resulting in tolerogenic DCs, and promoted higher antigen presentation efficiency by DCs compared with OVA or glutaraldehyde crosslinked nanoparticles. In vitro and in vivo experiments showed that DCs exposed to MDO induced Treg cells. Moreover, MDO had low reactivity with anti-OVA antibodies and did not induce anaphylaxis in allergic mice, demonstrating its high safety profile. In a mouse model of allergic asthma, MDO had significant preventative and therapeutic effects when administered orally or subcutaneously. Therefore, MDO represents a promising new approach for the efficient and safe treatment of allergies.

Decreased Basophil Activation against House Dust Mite after Japanese Cedar Pollen Subcutaneous Immunotherapy: A Retrospective Study

BACKGROUND

Allergen-specific immunotherapy (AIT), an established treatment for allergic diseases, prevents the development of other allergic manifestations. Although the mechanisms remain unclear, AIT has been shown to reduce basophil activation (BA) against nontarget allergens.

OBJECTIVES

The aim of this study was to assess immunological changes in Dermatophagoides farinae (Der f) after Japanese cedar pollen (JCP)-based subcutaneous immunotherapy (SCIT) monotherapy.

METHOD

The data of 16 patients (age: 6-37 years) with JCP-induced allergic rhinitis who were sensitive to Der f (serum Der f-specific immunoglobulin E [IgE] level >0.34 kUA/L) and received JCP-based SCIT for 5 years were reviewed retrospectively. BA by Der f and JCP extracts and serum-specific IgE and immunoglobulin G4 (IgG4) levels against these allergens were evaluated before and after completing 5 years of JCP-based SCIT monotherapy.

RESULTS

The areas under the dose-response curves of BA by Der f and JCP extracts were significantly reduced (p = 0.02 and p = 0.002, respectively). JCP-specific IgE levels decreased and JCP-specific IgG4 levels increased significantly (p < 0.001 for both), whereas Der f-specific IgE and IgG4 levels did not change significantly.

CONCLUSIONS

JCP-based SCIT monotherapy reduced Der f-specific BA. These findings suggest that JCP-based SCIT has the potential to modulate immune response toward nontarget allergens.

The Role of IgA in the Manifestation and Prevention of Allergic Immune Responses

PURPOSE OF REVIEW

Immunoglobulin A (IgA) mediates immune exclusion of antigens in the gut. Notably, IgA plays also a role in the prevention of IgE-mediated allergies and induction of immune tolerance. The present review addresses the role of IgA in the manifestation of IgE-mediated allergies, including allergen-specific immunotherapy (AIT), the regulation of IgA production, and the mechanism of IgA in immune cell activation.

RECENT FINDINGS

The majority of studies report an association of IgA with the induction of immune tolerance in IgE-mediated allergies. However, reports on the involvement of humoral and mucosal IgA, IgA subtypes, monomeric and polymeric IgA, and the mechanism of IgA-mediated immune cell activation are confounding. Effects by IgA are likely mediated by alteration of microbiota, IgE-blocking capacity, or activation of inhibitory signaling pathways. However, the precise mechanism of IgA-regulation, the contribution of serum and/or mucosal IgA, and IgA1/2 subtypes, on the manifestation of IgE-mediated allergies, and the underlying immune modulatory mechanism are still elusive.

A 5-Year Open-Label Follow-up of a Randomized Double-Blind Placebo-Controlled Trial of Intralymphatic Immunotherapy for Birch and Grass Allergy Reveals Long-term Beneficial Effects

BACKGROUND

Intralymphatic immunotherapy (ILIT) is a novel, faster alternative to conventional allergen immunotherapy (AIT). Few previous studies have evaluated its long-term effects. The objective of the present study was to complete a 5-year follow-up of a randomized double-blind placebo-controlled trial of ILIT for a combination of birch and grass allergens.

METHODS

Fifty-eight patients with allergic rhinitis were treated with either placebo or a combination of ALK Alutard Birch and Grass 1000 SQ-U administered in 3 intralymphatic injections at 1-month intervals. A year after the vaccination, the symptoms induced by nasal provocation were significantly reduced. After 5-6 years, 20 out of 26 actively treated patients were followed up with a nasal provocation test (NPT) and seasonal registration of the combined symptom and medications score (CSMS), IgE and IgG4 levels in blood, and immunological markers in blood and lymph nodes and compared with 13 unvaccinated controls.

RESULTS

The reduction in the NPT response with ILIT at year 1 could not be convincingly reproduced at year 5. The new CSMS scores were markedly lower among the previously treated patients than among the control group. Furthermore, grass-specific IgG4 was increased, grass-specific IgE decreased, FcεR1 on basophils was reduced, and the fraction of memory T-cells in lymph nodes increased.

CONCLUSION

The combination of seasonal clinical data and immunological parameters supports the notion of a long-lasting effect of ILIT. These data support the concept of ILIT as a good alternative to traditional AIT in pollen-induced allergic rhinitis.

What Evidence-based Medicine (EBM) Doesn't Say About Allergen-specific Immunotherapy (AIT)

Evidence-based allergology for the treatment of allergic rhinitis with allergen-specific immunotherapy (AIT) has been used in publications by the companies manufacturing AIT. The purpose of randomized controlled trials (RCTs) is to provide physicians, health authorities, patients, and their families with the best evidence upon which to base treatment decisions. However, some RCT results may do more harm than good because they serve the commercial interests of the companies producing and marketing AIT more than the interests of patients. Allergic rhinitis is a trivial disease that is not life-threatening and is easily controlled by drugs. In this paper, we analyze some of the more controversial points underlying the EBM supporting the use of AIT. The paradox behind RCT-based practice is that AIT is based on the results of incorrectly interpreted RCTs. International scientific societies and drug regulatory bodies should analyze trials more carefully, considering potential conflicts of interest.

Development of an Oral Immunotherapy-Related Parental Burden Scale

INTRODUCTION

Oral immunotherapy (OIT) imposes a burden on parents and their children with food allergies (FAs). We already developed a questionnaire for OIT-related Parental Burden (OIT-PB) scale. However, the previous questionnaire had some problems. This study modified OIT-PB and verified its reliability and validity.

METHODS

A 20-item draft covering the physical and mental burdens caused by OIT was prepared jointly with multiple allergists. The Food Allergy Quality of Life Questionnaire-Parental Burden (FAQLQ-PB) and Stress Response Scale-18 (SRS-18) were used to verify concurrent validity. A questionnaire survey was administered during treatment to parents of FA children who had started OIT for the first time. An additional OIT-PB survey was performed at one specific institution 1 week after the posttreatment survey.

RESULTS

The responses of 64 of the 76 recruited parents were analyzed. Of the 20 questions, 1 item was excluded owing to the floor effect, 1 was excluded because its commonality was less than 0.2, and 2 were excluded because their factor loading values were less than 0.4. Factor analysis was used to classify the OIT-PB into the following 4 subscales: "burden caused by adherence to treatment plan," "anxiety about symptom-induced risk," "burden due to patient's eating behavior," and "anxiety about treatment effect." The Cronbach's α for all 16 items of the OIT-PB was 0.893; Cronbach's α for each subscale was 0.876, 0.898, 0.874, and 0.717. The re-test reliability coefficient was 0.864 (95% confidence interval [CI]: 0.720-0.937, p < 0.001). A significant positive correlation was found between the OIT-PB and FAQLQ-PB (R = 0.610 [95% CI: 0.422-0.747], p < 0.001) and the SRS-18 (R = 0.522 [95% CI: 0.306-0.687], p < 0.001). A significant negative correlation was found between the rate of increase in OIT food intake and the "anxiety about treatment effect" score (R = -0.355 [95% CI: -0.558-0.112], p < 0.001). Parents of children on the hen's egg OIT treatment scored higher on the "burden due to patient's eating behavior" subscale than did parents of children on the milk and wheat OIT treatment.

CONCLUSION

The burden of OIT experienced by parents can be broadly classified into four categories. The modified OIT-PB was able to evaluate them individually and was shown to have reliability and validity. This scale is expected to be useful in the development of OIT that considers not only therapeutic effect but also the burden experienced by FA children and their parents.

Identification of key genes and the pathophysiology associated with allergen-specific immunotherapy for allergic rhinitis

BACKGROUND

Allergen-specific immunotherapy (AIT) is a causative treatment in allergic rhinitis (AR), comprising long-term allergen administration and over three years of treatment. This study is carried out for revealing the mechanisms and key genes of AIT in AR.

METHODS

The present study utilized online Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE37157 and GSE29521 to analyze the hub genes changes related to AIT in AR. Based on limma package, differential expression analysis for the two groups (samples of allergic patients prior to AIT and samples of allergic patients undergoing AIT) was performed to obtain differentially expressed genes (DEGs). Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs were conducted using DAVID database. A Protein-Protein Interaction network (PPI) was built and a significant network module was acquired by using Cytoscape software (Cytoscape, 3.7.2). Utilizing the miRWalk database, we identified potential gene biomarkers, constructed interaction networks of target genes and microRNAs (miRNAs) using Cytoscape software, and explore the cell type-specific expression patterns of these genes in peripheral blood using publicly available single-cell RNA sequencing data (GSE200107). Finally, we are using PCR to detect changes in the hub genes that are screened using the above method in peripheral blood before and after AIT treatment.

RESULTS

GSE37157 and GSE29521 included 28 and 13 samples, respectively. A total of 119 significantly co-upregulated DEGs and 33 co-downregulated DEGs were obtained from two datasets. The GO and KEGG analyses demonstrated that protein transport, positive regulation of apoptotic process, Natural killer cell mediated cytotoxicity, T cell receptor signaling pathway, TNF signaling pathway, B cell receptor signaling pathway and Apoptosis may be potential candidate therapeutic targets for AIT of AR. From the PPI network, 20 hub genes were obtained. Among them, the PPI sub-networks of CASP3, FOXO3, PIK3R1, PIK3R3, ATF4, and POLD3 screened out from our study have been identified as reliable predictors of AIT in AR, especially the PIK3R1.

CONCLUSION

Our analysis has identified novel gene signatures, thereby contributing to a more comprehensive understanding of the molecular mechanisms underlying AIT in the treatment of AR.

Computational Vaccine Design for Common Allergens

In this chapter, the steps of designing candidate vaccine molecules for allergen-specific immunotherapy (AIT) using immunoinformatics are described. The most modern approach of AIT deals with carrier-bound B cell epitope and multi-epitope vaccine molecules. The strategy for designing these molecules and the bioinformatics tools and servers used for that are discussed in detail here.

Mechanisms and biomarkers of successful allergen-specific immunotherapy

Allergen-specific immunotherapy (AIT) is considered the only curative treatment for allergic diseases mediated by immunoglobulin E (IgE). Currently, the route of administration depends both on the different types of causal allergens and on its effectiveness and safety profile. Several studies have reported the mechanisms and changes in humoral and cellular response underlying AIT; however, the full picture remains unknown. Knowledge of who can benefit from this type of treatment is urgently needed due to the patient safety risks and costs of AIT. In vivo or in vitro biomarkers have become a strategy to predict clinical outcomes in precision medicine. There are currently no standardized biomarkers that allow determining successful responses to AIT, however, some studies have found differences between responders and nonresponders. In addition, different candidates have been postulated that may have the potential to become biomarkers. In this review, we aim to summarize the findings to date related to biomarkers in different IgE-mediated allergic diseases (respiratory, food, and venom allergy) with the potential to define who will benefit from AIT.

Exposure to Allergen-Specific Immunotherapy in Pregnancy and Risk of Congenital Malformations and Other Adverse Pregnancy Outcomes

BACKGROUND

Owing to insufficient data, current guidelines recommend against initiating allergen-specific immunotherapy (AIT) during pregnancy but suggest that well-tolerated ongoing immunotherapy may be continued.

OBJECTIVE

To evaluate the safety of AIT in pregnancy, especially the risk for congenital malformations.

METHODS

This nationwide Swedish cohort study identified pregnancies exposed to AIT, both subcutaneous and sublingual, through the Swedish Medical Birth register and the Prescribed Drug Register between 2005 and 2014. Information on congenital malformations in offspring was retrieved from the National Patient Register. Using the personal identity number, we linked data between registers. Using logistic regression, we calculated odds ratios (ORs) with 95% CIs for congenital malformations and other adverse pregnancy outcomes after adjusting for potential confounders.

RESULTS

From 2005 to 2014, we identified 924,790 singleton pregnancies. Among these, 743 pregnancies had been exposed to AIT 3 months before conception up until gestational week 22. Allergen-specific immunotherapy in pregnancy was not linked to congenital malformations (OR = 0.90; 95% CI, 0.63-1.27) or other adverse pregnancy outcomes (preterm birth: OR = 0.98; 95% CI, 0.71-1.35; stillbirth: OR = 0.79; 95% CI, 0.26-2.47; or cesarean delivery: OR = 0.91; 95% CI, 0.76-1.09). Stratification by route of immunotherapy, subcutaneous or sublingual, resulted in similar ORs. Restricting the pregnancy cohort to women with asthma or pulmonary disease, nulliparous women, births in 2012 to 2014, or Swedish-born women yielded similar results.

CONCLUSIONS

This nationwide study found no evidence of congenital malformations or other adverse pregnancy outcomes in women treated with AIT in pregnancy.

Current possibilities and future perspectives for improving efficacy of allergen-specific sublingual immunotherapy

Allergen-specific sublingual immunotherapy (SLIT), a safe and efficient route for treating type I hypersensitivity disorders, requires high doses of allergens. SLIT is generally performed without adjuvants and delivery systems. Therefore, allergen formulation with appropriate presentation platforms results in improved allergen availability, targeting the immune cells, inducing regulatory immune responses, and enhancing immunotherapy's efficacy while decreasing the dose of the allergen. In this review, we discuss the adjuvants and delivery systems that have been applied as allergen-presentation platforms for SLIT. These adjuvants include TLRs ligands, 1α, 25-dihydroxy vitamin D3, galectin-9, probiotic and bacterial components that provoke allergen-specific helper type-1 T lymphocytes (TH1), and regulatory T cells (Tregs). Another approach is encapsulation or adsorption of the allergens into a particulate vector system to facilitate allergen capture by tolerogenic dendritic cells. Also, we proposed strategies to increasing the efficacy of SLIT via new immunopotentiators and carrier systems in the future.

Alteration of Allergen Fold of Bos d 5 into a Hypoallergenic Vaccine for Immunotherapy of Cow's Milk Allergy

BACKGROUND

Cow's milk allergy (CMA) is the most common IgE-mediated food allergy and Bos d 5 is the major allergen in cow's milk proteins. More than 60% of the patients with CMA are sensitized to this protein.

METHODS AND RESULTS

A recombinant protein, encoded by a synthetic gene and consisting of reassembled Bos d 5 fragments, was expressed in E. coli strain BL21 (DE3) cells and purified to homogeneity. The B5M lacked relevant IgE-reactivity and allergenic activity compared with Bos d 5 in dot-blot and basophil activation assays. T-cell proliferation experiments demonstrated that B5M preserved the main T cell epitopes of Bos d 5. Immunization of rabbits with B5M induced protective IgG antibodies that blocked the binding of patients' IgE antibodies to the wild-type allergen and inhibited the degranulation of basophils induced by Bos d 5.

CONCLUSION

Thus, we developed a new strategy, which was based on rational molecular reassembly for allergen-specific immunotherapy (AIT) of CMA and food allergy.

A Dendritic Cells-Targeting Nano-Vaccine by Coupling Polylactic-Co-Glycolic Acid-Encapsulated Allergen with Mannan Induces Regulatory T Cells

BACKGROUND

The efficacy of allergen-specific immunotherapy (AIT) is mainly depended on the tolerogenic immune responses elicited. Properly conjugated nano-vaccine has the advantages of both specific targeting and continuous and on-demand release of allergen.

OBJECTIVES

The aim of this study is to investigate the effects of a dendritic cells (DCs)-targeting nano-vaccine for AIT.

METHODS

The nano-vaccine was produced by coupling polylactic-co-glycolic acid (PLGA)-encapsulated ovalbumin (OVA) with mannan. Allergen capture, human monocytes-derived DCs (hMoDCs) activation, and T cells responses were assessed by flow cytometry, confocal microscopy, quantitative real-time PCR, ELISA, and Cytometric Bead Array. Balb/c mice were immunized with the nano-vaccines, and the immune responses were analyzed.

RESULTS

OVA-PLGA nanoparticle (NP) displayed favorable safety profile. OVA-mannan-PLGA NP was captured more efficiently by hMoDCs than OVA-PLGA NP, which was mediated mainly through DC-specific intercellular adhesion molecule 3-grabbing nonintegrin. A tolerogenic phenotype of hMoDCs was induced by OVA-mannan-PLGA NP, but not OVA-PLGA NP, and increased number of regulatory T (Treg) cells was generated subsequently in in vitro coculture. Immunization of Balb/c mice with OVA-mannan-PLGA NP resulted in lower serum level of OVA-specific immunoglobulins and less production of pro-inflammatory cytokines in splenocytes culture than the mice immunized with OVA-PLAG NP, PLGA NP, or OVA, while the number of splenic Treg cells was higher in OVA-mannan-PLGA group than in other groups. Moreover, preimmunization with OVA-mannan-PLGA NP significantly inhibited the Th2 immune response induced by OVA sensitization.

CONCLUSIONS

The biocompatible PLGA-encapsulated OVA coupling with mannan has augmented ability for tolerance induction and could be developed as a novel vaccine for AIT.

Japanese cedar and cypress pollinosis updated: New allergens, cross-reactivity, and treatment

Pollen from many tree species in the Cupressaceae family is a well-known cause of seasonal allergic diseases worldwide. Japanese cedar pollinosis and Japanese cypress pollinosis, which are caused by pollen from Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa), respectively, are the most prevalent seasonal allergic diseases in Japan. Recently, the novel major Japanese cypress allergen Cha o 3 and the homologous Japanese cedar allergen Cry j cellulase were identified, and it was shown, for the first time, that cellulase in plants is allergenic. Although the allergenic components of pollen from both species exhibit high amino acid sequence identity, their pollinosis responded differently to allergen-specific immunotherapy (ASIT) using a standardized extract of Japanese cedar pollen. Pharmacotherapy and ASIT for Japanese cedar and cypress pollinosis have advanced considerably in recent years. In particular, Japanese cedar ASIT has entered a new phase, primarily in response to the generation of updated efficacy data and the development of new formulations. In this review, we focus on both Japanese cypress and cedar pollinosis, and discuss the latest findings, newly identified causative allergens, and new treatments. To manage pollinosis symptoms during spring effectively, ASIT for both Japanese cedar and Japanese cypress pollen is considered necessary.

Allergoid-mannan conjugates reprogram monocytes into tolerogenic dendritic cells via epigenetic and metabolic rewiring

BACKGROUND

Allergoid-mannan conjugates are novel vaccines for allergen-specific immunotherapy being currently assayed in phase 2 clinical trials. Allergoid-mannan conjugates target dendritic cells (DCs) and generate functional forkhead box P3 (FOXP3)-positive Treg cells, but their capacity to reprogram monocyte differentiation remains unknown.

OBJECTIVE

We studied whether allergoid-mannan conjugates could reprogram monocyte differentiation into tolerogenic DCs and the underlying molecular mechanisms.

METHODS

Monocytes from nonatopic and allergic subjects were differentiated into DCs under conventional protocols in the absence or presence of allergoid-mannan conjugates. ELISA, real-time quantitative PCR, coculture, flow cytometry, and suppression assay were performed. Metabolic and epigenetic techniques were also used.

RESULTS

Monocyte differentiation from nonatopic and allergic subjects into DCs in the presence of allergoid-mannan conjugates yields stable tolerogenic DCs. Lipopolysaccharide-stimulated mannan-tolDCs show a significantly lower cytokine production, lower TNF-α/IL-10 ratio, and higher expression of the tolerogenic molecules PDL1, IDO, SOCS1, SOCS3, and IL10; and they induce higher numbers of functional FOXP3⁺ Treg cells than conventional DC counterparts. Mannan-tolDCs shift glucose metabolism from Warburg effect and lactate production to mitochondrial oxidative phosphorylation. They also display epigenetic reprogramming involving specific histone marks within tolerogenic loci and lower expression levels of histone deacetylase genes. Mannan-tolDCs significantly increase the expression of the anti-inflammatory miRNA-146a/b and decrease proinflammatory miRNA-155.

CONCLUSIONS

Allergoid-mannan conjugates reprogram monocyte differentiation into stable tolerogenic DCs via epigenetic and metabolic reprogramming. Our findings shed light on the novel mechanisms by which allergoid-mannan conjugates might contribute to allergen tolerance induction during allergen-specific immunotherapy.

Treatment Approaches to Food Allergy

IgE-mediated food allergies affect both children and adults and are associated with dramatic decreases in the quality of life. In the majority of cases, food allergens have to be avoided which may be difficult, particularly in patients who suffer from life-threatening symptoms following the ingestion of minimal doses of food allergens. Several novel therapeutic approaches have been studied during the recent past and are summarized in this review. Therapies with novel therapeutic monoclonal antibodies, innovative allergen-specific immunotherapies using subcutaneous, sublingual, or epicutaneous routes, and oral immunotherapies leading to increases of individual thresholds of tolerable foods upon their continuous ingestion showed promising results which may change future management strategies in moderate to severe food allergy.

Accelerated Dose Escalation with 3 Injections of an Aluminum Hydroxide-Adsorbed Allergoid Preparation of 6 Grasses Is Safe for Children and Adolescents with Moderate to Severe Allergic Rhinitis

A high-dose, accelerated escalation schedule during subcutaneous allergen-specific immunotherapy (AIT) is safe and well-tolerated in adults. However, there are no data in children and adolescents. The aim of the present trial was to assess safety and tolerability of an accelerated dose escalation schedule of an AIT with a grass pollen allergoid in children and adolescents with moderate to severe seasonal rhinoconjunctivitis in a multicenter, open-label, randomized phase II trial. The dose escalation scheme for patients in the One Strength Group included 3 injections with 1 strength B (10,000 TU/mL), whereas the dose escalation scheme for the Standard group included 7 injections with 2 strengths A (1,000 TU/mL) and B (10,000 TU/mL) of an allergoid grass pollen preparation. Overall, n = 50 children (n = 25 in each group; mean age 8.9 + 1.54 years) and n = 37 adolescents (n = 20 and n = 17; 14.2 + 1.62 years) were randomized. For all patients, the mean treatment duration was 59.4 days in the One Strength group and 88.6 days in the Standard group. Treatment-emergent adverse events (TEAEs) related to AIT were reported in 52 and 40% in children and 35 and 35.3% in adolescents, respectively. Systemic allergic reactions occurred in about 5% of our patients and were reported in more patients of the One Strength group (6.7 vs. 2.4%). All systemic reactions were classified as WAO Grade 1. Accelerated high-dose escalation with an aluminum hydroxide-adsorbed grass pollen allergoid can be initiated with a safety and tolerability profile comparable to the standard dose escalation schedule in children and adolescents with allergic rhinitis with or without asthma.

[Allergic rhinitis' treatment in children in Argentina. Update]

Allergic rhinitis (AR) is the most frequent allergic disease. Prevalence in children and teenagers in Argentina ranges between 22.3% and 34.9%. Given this situation, members of the scientific committees of Pediatrics and Rhinitis of the Argentinian Association of Allergy and Clinical Immunology (AAAeIC) have reviewed scientific evidence in order to update the therapeutic regulations of this pathology in the pediatric population. The classification and categorization of AR are currently in full review all around the world. It is necessary to make a differential diagnosis with other non-allergic types of rhinitis in children, and to confirm AR based on the clinical history, physical examination, determination of bio-markers, and/or skin tests. Non-pharmacological treatment includes education and guidelines of environmental control for allergens such as dust mites, anemophilous fungi, animal epithelium, and pollens. Step pharmacological therapy is proposed according to the control of the disease. Second-generation, non-sedating anti-histamines are the first line of therapy. The association with oral decongestants is not recommended in children under 4 years of age. Inhaled corticosteroids are the first choice for both moderate and severe forms. This document warns pediatricians about the importance of an early diagnosis, the rational use of step pharmacological therapy, and specific immunotherapy in children.

Mechanisms of allergen-specific immunotherapy and allergen tolerance

Allergen-specific immunotherapy (AIT) is the mainstay treatment for the cure of allergic disorders, with depicted efficacy and safety by several trials and meta-analysis. AIT impressively contributes to the management of allergic rhinitis, asthma and venom allergies. Food allergy is a new arena for AIT with promising results, especially via novel administration routes. Cell subsets with regulatory capacities are induced during AIT. IL-10 and transforming growth factor (TGF)-β are the main suppressor cytokines, in addition to surface molecules such as cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) within the micro milieu. Modified T- and B-cell responses and antibody isotypes, increased activity thresholds for eosinophils, basophils and mast cells and consequent limitation of inflammatory cascades altogether induce and maintain a state of sustained allergen-specific unresponsiveness. Established tolerance is reflected into the clinical perspectives as improvement of allergy symptoms together with reduced medication requirements and evolved disease severity. Long treatment durations, costs, reduced patient compliance and risk of severe, even life-threatening adverse reactions during treatment stand as major limiting factors for AIT. By development of purified non-allergenic, highly-immunogenic modified allergen extracts, and combinational usage of them with novel adjuvant molecules via new routes may shorten treatment durations and possibly reduce these drawbacks. AIT is the best model for custom-tailored therapy of allergic disorders. Better characterization of disease endotypes, definition of specific biomarkers for diagnosis and therapy follow-up, as well as precision medicine approaches may further contribute to success of AIT in management of allergic disorders.

Differential DNA methylation profiles of peripheral blood mononuclear cells in allergic asthmatic children following dust mite immunotherapy

BACKGROUND/PURPOSE

Allergen-specific immunotherapy (SIT) is now considered curative to allergic diseases such as asthma. Mechanistically, our previous work showed DNA hypermethylation of cytokine genes, in T-helper cells, in allergic asthmatic children treated with allergen-SIT. In this study, we extended to work to assess possible changes in the DNA methylomes of peripheral blood mononuclear cells (PBMCs), isolated from mite allergen-SIT asthmatic children, to explore further the underlying methylation changes.

METHODS

Thirteen allergic asthmatic children who received Der p-SIT, 12 non-SIT allergic asthmatic controls, and 12 healthy controls were enrolled. Bisulfite-converted DNA from Der p-stimulated PBMCs was analyzed using Human Methylation 450 k BeadChip. Pyrosequencing and quantitative real-time PCR were used to validate the DNA methylation levels and the gene expression of individual samples.

RESULTS

We identified 108 significantly differentially methylated regions (DMRs) unique to Der p-treated PBMCs, with 53 probes linked to demethylated DMRs, and 55 probes linked to methylated DMRs. Three associated genes (BCL6, HSPG2, and HSP90AA1), of selected DMRs, were subjected to bisulfite pyrosequencing. Of these, BCL6 showed significant hypomethylation, while HSPG2 and HSP90AA1 were hypermethylated in SIT group, compared to the AA group. Furthermore, SIT group had significantly higher gene expression of BCL6 and lower gene expression of HSPG2. KEGG pathway analysis further revealed DMR genes involved in ECM-receptor interactions, asthma, and antigen processing and presentation pathways.

CONCLUSIONS

Several DNA regions showed DNA methylation altered by Der p specific immunotherapy, indicating desensitization-associated methylomes. Genes belonging to these SIT-altered pathways may represent therapeutic targets for better clinical management of asthma.

The Honeybee Venom Major Allergen Api m 10 (Icarapin) and Its Role in Diagnostics and Treatment of Hymenoptera Venom Allergy

PURPOSE OF REVIEW

In Hymenoptera venom allergy, the research focus has moved from whole venoms to individual allergenic molecules. Api m 10 (icarapin) has been described as a major allergen of honeybee venom (HBV) with potentially high relevance for diagnostics and therapy of venom allergy. Here, we review recent studies on Api m 10 characteristics as well as its role in component-resolved diagnostics and potential implications for venom-specific immunotherapy (VIT).

RECENT FINDINGS

Api m 10 is a major allergen of low abundance in HBV. It is an obviously unstable protein of unknown function that exhibits homologs in other insect species. Despite its low abundance in HBV, 35 to 72% of HBV-allergic patients show relevant sensitization to this allergen. Api m 10 is a marker allergen for HBV sensitization, which in many cases can help to identify primary sensitization to HBV and, hence, to discriminate between genuine sensitization and cross-reactivity. Moreover, Api m 10 might support personalized risk stratification in VIT, as dominant sensitization to Api m 10 has been identified as risk factor for treatment failure. This might be of particular importance since Api m 10 is strongly underrepresented in some therapeutic preparations commonly used for VIT. Although the role of Api m 10 in HBV allergy and tolerance induction during VIT is not fully understood, it certainly is a useful tool to unravel primary sensitization and individual sensitization profiles in component-resolved diagnostics (CRD). Moreover, a potential of Api m 10 to contribute to personalized treatment strategies in HBV allergy is emerging.

Towards definitive management of allergic rhinitis: best use of new and established therapies

BACKGROUND

Allergic rhinitis (AR) is an inflammatory disease of the nasal mucosa impacting up to 25% of Canadians. The standard of care for AR includes a treatment plan that takes into account patient preferences, the severity of the disease, and most essentially involves a shared decision-making process between patient and provider.

BODY

Since their introduction in the 1940s, antihistamines (AHs) have been the most utilized class of medications for the treatment of AR. First-generation AHs are associated with adverse central nervous system (CNS) and anticholinergic side effects. On the market in the 1980s, newer generation AHs have improved safety and efficacy. Compared to antihistamines, intranasal corticosteroids (INCS) have significantly greater efficacy but longer onset of action. Intranasal AH and INCS combinations offer a single medication option that offers broader disease coverage and faster symptom control. However, cost and twice-per-day dosing remain a major limitation. Allergen immunotherapy (AIT) is the only disease-modifying option and can be provided through subcutaneous (SCIT) or sublingual (SLIT) routes. While SCIT has been the definitive management option for many years, SLIT tablets (SLIT-T) have also been proven to be safe and efficacious.

CONCLUSION

There is a range of available treatment options for AR that reflect the varying disease length and severity. For mild to moderate AR, newer generation AHs should be the first-line treatment, while INCS are mainstay treatments for moderate to severe AR. In patients who do not respond to INCS, a combination of intranasal AH/INCS (AZE/FP) should be considered, assuming that cost is not a limiting factor. While SCIT remains the option with the most available allergens that can be targeted, it has the potential for severe systemic adverse effects and requires weekly visits for administration during the first 4 to 6 months. SLIT-T is a newer approach that provides the ease of being self-administered and presents a reduced risk for systemic reactions. In any case, standard care for AR includes a treatment plan that takes into account disease severity and patient preferences.

Allergic respiratory disease care in the COVID-19 era: A EUFOREA statement

Spring and Summer 2020 are unique in that the challenges of care for those suffering from pollen allergy coincide with the COVID-19 pandemic. Several considerations are important to allow optimal care of allergic rhinitis (AR) and asthma and hence prevention of coronavirus spread through sneezing, rhinorrhoea, and coughing. This compact overview of recommendations by the EUFOREA expert teams on allergic airway diseases and allergen-specific immunotherapy (AIT) is based on investigation of the current COVID-19 literature in association with the key words above and shared clinical experience of the experts involved. It deals with similarities and differences between AR and coronavirus infection, specific recommendations for allergic disease care in the COVID-19 era, including guidance on AIT.

Enhanced Efficacy of Dust Mite Sublingual Immunotherapy in Low-Response Allergic Rhinitis Patients after Dose Increment at 6 Months: A Prospective Study

BACKGROUND

Several studies have suggested that sublingual immunotherapy (SLIT) involves a dose-response relationship and inadequate dosage might not achieve a favorable clinical effect.

OBJECTIVE

The aim of this prospective study was to investigate the efficacy and safety of increasing SLIT dosage at 6 months in patients with house dust mite-induced allergic rhinitis (AR) who had low response to treatment.

METHODS

A total of 157 AR participants aged 4-60 years were enrolled and received SLIT with Dermatophagoides farinae drops. After 6 months of SLIT, patients were interviewed and then classified into a high-response (HR) group and a low-response (LR) group based on the combined symptom and medication score (CSMS) reduction rate. Patients with a CSMS reduction rate over 50% were defined as HR and continued the original dose, while patients with a CSMS reduction rate ranging from 20 to 50% were defined as LR and received an increased dose (percentage of dosage increment, 33.33% for patients aged <14 years and 50% for patients aged ≥14 years). Patients with a CSMS reduction rate below 20% were considered nonresponse (NR) and recommended to withdraw from SLIT. CSMS, visual analog scale (VAS), and adverse events were assessed at 0.5, 1, 2, and 3 years during the 3-year treatment.

RESULTS

A total of 54 and 56 patients completed the treatment in the HR and LR groups, respectively. The CSMS and VAS of both groups decreased significantly at 6 months (p < 0.05). Significant differences between the two groups were found in CSMS and VAS at 6 months and 1 year (p < 0.05), but not in later follow-ups (p > 0.05). The improvement of adults in the LR group was significantly lower than that of children at 6 months (p < 0.05), but there was no difference in later follow-ups (p > 0.05). There was no difference in CSMS or VAS in patients with monosensitization and polysensitization in the same treatment group at 1 year and in subsequent visits (p> 0.05). Overall, 47 patients withdrew from this study due to NR (n = 22) and other reasons (n = 25).

CONCLUSIONS

Six months might be a critical time point for efficacy assessment and dosage adjustment for AR patients after SLIT. In patients with low response, dosage enhancement within a certain range may enhance the effectiveness of SLIT.

Dermatophagoides spp. hypoallergens design: what has been achieved so far?

Introduction: Allergic illnesses are one of the most prevalent immunological disorders worldwide and house dust mites are important triggers of these diseases. Allergen-specific immunotherapy (AIT) is an alternative treatment to pharmacotherapy and among its technologies, recombinant hypoallergenic derivatives have shown promising features, turn them into safer and more efficient allergy vaccines.Areas covered: Patents and scientific publications referring to advances in the design of Dermatophagoides spp. hypoallergenic molecules. Data were obtained from the Espacenet® and PubMed websites, using different key terms, advanced tools and Boolean operators for searches. The retrieved data were then descriptively analyzed, taking into consideration clinical targets, geographical, temporal, collaborative, and different classification aspects of the productions.Expert opinion: Joint advances of molecular biology, genetic engineering, and bioinformatics technologies led to progresses in the design of Dermatophagoides spp. hypoallergenic derivatives. Collaborative networks seem to be an interesting way not only to improve technologies in AIT but also to boost the number of patents, publications, and grants for researchers. The observed trend for the use of hypoallergenic hybrid molecules was a fundamental AIT advance and this type of molecule appears to be a more attractive product for companies and more convenient, efficient, and safer allergy immunotherapy for patients.

Accelerated Dose Escalation with Three Injections of an Aluminum Hydroxide-Adsorbed Allergoid Preparation of Six Grasses Is Safe for Patients with Moderate to Severe Allergic Rhinitis

Only few data on safety during high-dose, accelerated escalation schedules during subcutaneous allergen immunotherapy (AIT) are available. The aim of this study was to assess the safety and tolerability of an accelerated dose escalation schedule of AIT in adult patients with moderate to severe seasonal rhinoconjunctivitis in a multicenter, open-label, randomized phase II trial. The dose escalation scheme for patients in Group I (1 strength) included 3 injections with 1 strength, B (10,000 TU/mL), whereas the dose escalation scheme for Group II (standard) included 7 injections with 2 strengths, A (1,000 TU/mL) and B (10,000 TU/mL), of an aluminum hydroxide-adsorbed allergoid grass pollen preparation. Overall, 72 of 87 randomized patients (83.7%) reported at least 1 treatment-emergent adverse event (TEAE; 82.2 [Group I] vs. 85.4% [Group II]); 58.8% of all reported TEAEs were assessed as being related to AIT (60.0 vs. 48.8%). The most frequently reported AIT-related TEAEs were swelling (46.7 vs. 34.1%), erythema (28.9 vs. 36.6%), and pruritus (31.1 vs. 17.1%) at the site of the injection. Systemic allergic reactions occurred in 5 (5.8%) patients overall, with more being reported in the 1-strength group (4 [8.9%] vs. 1 [2.4%]). All systemic allergic reactions were classified as World Allergy Organization (WAO) Grade 1 or Grade 2 reactions. Accelerated high-dose escalation with an aluminum hydroxide-adsorbed grass pollen allergoid can be initiated with a safety and tolerability profile comparable to the standard dose escalation schedule in patients with allergic rhinitis with or without asthma.

Principles of Allergen Immunotherapy and Its Clinical Application in China: Contrasts and Comparisons with the USA

Allergen immunotherapy (AIT) for allergic rhinitis (AR), asthma, and other allergic diseases has developed quickly. House dust mite (HDM), Artemisia (wormwood), Humulus japonicus (Japanese hop), Alternaria alternata, and Cladosporium herbarum are the five most common inhalant allergens in China. AIT has been performed in China for over 60 years. With the support of the Chinese Medical Association (CMA) and the Chinese Medical Doctors Association (CMDA), the Chinese College of Allergy and Asthma (CCAA) was established in 2016 as a specialized branch of CDMA and is the main certification authority for AIT. Chinese allergists and scientists have made tremendous progress in the development of AIT. There have been many publications by Chinese allergists and scientists worldwide encompassing original research studies, systematic reviews, case studies, and clinical trials. Currently, conventional subcutaneous immunotherapy (SCIT) is the preferred AIT in China, but sublingual immunotherapy (SLIT) is beginning to gain recognition. An increasing number of clinical trials have been conducted to investigate the clinical efficacy and side effects of SLIT and SCIT. In China, HDM is the only commercial standardized allergen extracts in clinical use, whereas the others are crude allergen extracts. Besides standardized allergen extracts, other forms of hypoallergenic extracts are still being investigated and developed in China. Immunotherapy in China is similar to that in the USA in which allergen extracts can be mixed for SCIT. However, allergen extracts cannot be mixed for SCIT in Europe.

Preventive effects of "ovalbumin-conjugated celastrol-loaded nanomicelles'' in a mouse model of ovalbumin-induced allergic airway inflammation

Allergies affect a significant proportion of the world's population, and existing vaccination strategies to restrict their adverse pathologies often render side-effects. The aim of this study was to design a new vaccine for allergen-specific immunotherapy (SIT), and to investigate its preventive effects during allergic inflammation. We constructed ovalbumin (OVA)-conjugated celastrol-loaded nanomicelles (OVA-NMs-celastrol), wherein celastrol (a bioactive anti-inflammatory compound) was loaded into carboxyl-functioned polymeric nanomicelles using a thin-film hydration method. OVA was used as a model allergen and conjugated on nanomicelles. The OVA-NMs-celastrol obtained were characterized based on particle size, morphology, drug encapsulation efficiency, and drug loading percentage. Further, the preventive effect of OVA-NMs-celastrol was evaluated in a mouse model of allergic asthma. Our results showed that OVA-NMs-celastrol possessed valuable characteristics such as small particle size (50.72 ± 0.98 nm) and spherical-like shape, with celastrol encapsulation efficiency of 99.89 ± 0.85% and a drug loading percentage of 4.76 ± 0.03%. Further, in vivo results showed that treatment with OVA-NMs-celastrol could decrease OVA specific IgE and histamine levels, Th2 cytokine (IL-4, IL-5) levels, and inflammatory cell infiltration in the lung tissues. Moreover, it could enhance the OVA specific IgG1 and IgG2a levels and decrease the IgE / IgG2a ratio. These results demonstrate the successful construction of OVA-NMs-celastrol as a potential vaccine candidate for use in SIT for allergic inflammation.

CRM197-Coupled Der p 2 Peptides Suppress Allergic Airway Inflammation in a Der p 2-Induced Asthma Mouse Model

Allergic diseases affect more than 25% of the global population. Der p 2 is the major allergen of the house dust mite (HDM) Dermatophagoides pteronyssinus. Allergen-specific immunotherapy is the only treatment to change the course of allergic diseases. In this study, two synthesized Der p 2 peptides coupled to cross-reacting material 197 (CRM197) showed reduced IgE reactivity and allergenic activity. CRM197-coupled Der p 2 peptides induced rDer p 2-specific IgG1 antibodies in mice, which could inhibit HDM-allergic patients' IgE binding to rDer p 2. The immunity effects of CRM197-coupled Der p 2 peptides were studied in an rDer p 2-induced asthma mouse model. CRM197-coupled Der p 2 peptides can suppress asthmatic airway inflammation in this model. Analysis of IL-4, IL-5, and IFN-γ levels in bronchoalveolar lavage fluid revealed that the suppression was associated with a shift from a Th2 to a Th1 response. Thus, CRM197-bound Der p 2 peptides exhibited less allergenic activity than the rDer p 2 allergen, which preserved immunogenicity and may be candidates for mite allergy vaccines.

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.

Food allergen-specific sublingual immunotherapy modulates peripheral T cell responses of dogs with adverse food reactions

Food allergen-specific sublingual immunotherapy (FA-SLIT) is a novel, safe and effective approach in dogs with adverse food reactions (AFR) to reduce their clinical symptoms. However, little is known about the specific immune components which mediate this reduction in clinical symptoms. In humans, regulatory T cells seem to play an important role in this desensitisation process. Here, we investigated changes in peripheral T cell responses of dogs with AFR upon FA-SLIT. Five dogs received a dose escalation of FA-SLIT over a six-month period. An oral food challenge was performed at the beginning and end of the study to assess the efficacy of the FA-SLIT. Using in vitro allergen-recall assays, we assessed the proliferation of T cell subsets before and at the end of the treatment. FA-SLIT significantly increased the percentage of proliferating CD4-CD8- double-negative (DN) T cells, while the percentage of allergen-specific CD4-CD8+ and CD4+CD8+ double-positive (DP) T cells decreased upon treatment. These findings indicate that sublingual immunotherapy in dogs activates DN T cells, which might be important for the desensitisation of dogs with adverse food reactions. However, further research is needed to corroborate these findings and to further elucidate the mechanism of action of FA-SLIT in dogs with AFR.

Will every child have allergic rhinitis soon?

OBJECTIVES

Given the increasing prevalence of AR amongst children, we aimed to review the literature regarding the future of AR in this population.

METHODS

We searched the PubMed, Google and Proquest Central databases at Kırıkkale University Library. Search terms used were: "allergic rhinitis", "children", "paediatric", "allergy", "future", "risk factors", "treatment", "pharmacotherapy" and/or "allergen - specific immunotherapy". With regard to risk factors for allergic rhinitis, the terms "Environmental factors", "Improved hygiene", "Increased indoor allergen exposure", "Farms, villages, worms, and other parasites", "Environmental toxicants", "Diet", "Lifestyle changes", "Air pollution" and "Climate factors" were searched for. "Prevention of allergic diseases" and "Allergen-specific immunotherapy in the future" were also included in the search.

RESULTS

AR has a high prevalence and causes considerable morbidity, has associated comorbidity and features specific complications. The principal treatments rely on avoiding the allergens responsible, and administering drug treatment or immunotherapy, which targets specific antigens. Genetic drift does not explain the rising prevalence of allergic disorders, but multifactorial environmental factors are likely culprits. Amongst such environmental factors to consider are the rise in caesarean births, decreases in breast feeding, dietary changes resulting in less fresh produce being consumed, the eradication of intestinal worm infestations, alterations in the way homes are aired and heated, children taking less exercise and being outdoors for shorter periods, whilst also having more contact with pollution.

CONCLUSION

Barring substantial lifestyle alterations, more and more children are likely to develop AR. It may prove feasible to stop allergy developing in the first place through manipulation of the microbiome, but the exact format such a modification should involve remains to be discovered. Molecular allergological techniques do offer the prospect of more precisely targeted immunotherapy, the sole disease modifier at present. However, at present the complexity and cost of such interventions prevents their widespread use and research in this area is still needed. The majority of children with AR are going to be managed using nasal saline sprays, since they are the most straightforward and least risky alternative for first line treatment.

Stepwise approach towards adoption of allergen immunotherapy for allergic rhinitis and asthma patients in daily practice in Belgium: a BelSACI-Abeforcal-EUFOREA statement

Allergic rhinitis (AR) affects 23–30% of the European population with equal prevalence reported in Belgium. Despite guidelines on the correct use of effective treatment, up to 40% of AR patients remain uncontrolled. Allergen immunotherapy (AIT) has been shown to improve the level of control up to 84% of patients being controlled by AIT. Recently, new guidelines for AIT have been published, supporting the clinical evidence for effectiveness of various subcutaneous and sublingual products for AIT in patients who are allergic to airborne allergens. AIT in AR patients not only reduces nasal and/or ocular symptoms but also induces tolerance and has preventive potential. Adoption of AIT into daily clinical practice in Belgium and other European countries is hampered primarily by reimbursement issues of each of the single products but also by several patient- and physician-related factors. Patients need to be better informed about the effectiveness of AIT and the different routes of administration of AIT. Physicians dealing with AR patients should inform patients on tolerance-inducing effects of AIT and are in the need of a harmonized and practical guide that supports them in selecting eligible patients for AIT, in choosing evidence-based AIT products and in following treatment protocols with proven efficacy. Therefore, a stepwise and holistic approach is needed for better adoption of AIT in the real-life setting in Belgium.

Role of Der p 1-specific B cells in immune tolerance during 2 years of house dust mite-specific immunotherapy

BACKGROUND

Long-term follow-up of allergen-specific B cells in terms of immunoglobulin isotype expression, plasmablast differentiation, and regulatory B (Breg) cell development during allergen-specific immunotherapy (AIT) has not been reported.

OBJECTIVE

Allergen-specific B-cell responses during 2 years of house dust mite AIT were compared between responder and nonresponder patients.

METHODS

B cells specific for Der p 1 were detected by using the fluorochrome-labeled allergen method. The frequency of IgA-, IgG₁- and IgG₄-switched Der p 1-specific B cells, plasmablasts, and IL-10- and IL-1 receptor antagonist (IL-1RA)-producing Breg cells were investigated and correlated to clinical response to AIT.

RESULTS

Sixteen of 25 patients completed the 2-year study. Eleven responder patients showed a successful response to AIT, as measured by a decrease in symptom-medication scores from 13.23 ± 0.28 to 2.45 ± 0.24 (P = .001) and a decrease in skin prick test reactivity to house dust mite from 7.0 ± 1.3 to 2.7 ± 0.5 mm (P = .001). IgG₄⁺ and IgA⁺ Der p 1-specific B cells showed a significant increase after AIT, with a significantly greater frequency in responders compared with nonresponders in the IgG₄⁺ but not the IgA⁺ fraction. The frequency of plasmablasts and IL-10- and/or IL-1RA-producing Breg cells was greater among responders compared with nonresponders after 2 years. The increased frequency of Der p 1-specific IgG4⁺ B cells, plasmablasts, and IL-10⁺ and dual-positive IL-10⁺IL-1RA⁺ Breg cells significantly correlated with improved clinical symptoms over the course of AIT.

CONCLUSION

Allergen-specific B cells in patients responding to AIT are characterized by increased numbers of IgA- and IgG₄-expressing Der p 1-specific B cells, plasmablasts, and IL-10⁺ and/or IL-1RA⁺ Breg cells.

Allergen immunotherapy for food allergy from the Asian perspective: key challenges and opportunities

Introduction: Prevalence of food allergy is rising in different regions of the world. Asia has not been spared from this epidemic, but epidemiological data have revealed a different pattern of food allergens in this continent. Allergen-specific immunotherapy (AIT) for food allergy, which has been revolutionary as the main focus of research in recent years, needs to be adapted for the different populations in Asia. Areas covered: Recent evidence shows increasing popularity and superiority of AIT over strict food avoidance as the cornerstone of food allergy management. Asia is a distinctive continent with specific food allergy triggers, in particular, seafood, and wheat. Peanut, on the contrary, is not a common food allergen in most parts of Asia. The common Asian food allergens, as well as the rapidly developing food-specific AIT in this region will be covered in this article. Expert commentary: Evidence on oral immunotherapy for wheat allergy and preclinical data on shellfish AIT are promising. Further work should be done on resolving cross-sensitization between environmental allergens with wheat and shellfish allergens, and a modified AIT approach to enhance the safety and effectiveness of food-specific immunotherapy.

Assessment of taste functions in allergic rhinitis patients undergoing allergen-specific immunotherapy

BACKGROUND

We evaluated taste functions of patients with perennial allergic rhinitis (AR) before and after allergen-specific immunotherapy (AIT).

METHODS

The study was designed as a prospective clinical study in our tertiary care hospital. Patients (n = 21) who were diagnosed with perennial AR on the basis of physical examination, skin prick test of at least 3* for HDM allergen and treated with AIT were enrolled in this study. A control group (n = 21) was selected from patients who were given intranasal steroids (INS) for perennial AR. Both groups had self-reported hyposmia and subjective loss of the sense of taste before treatment. Taste strips (Burghart, Wedel, Germany) were used for the taste identification scores before and after 6 months treatment.

RESULTS

A total of 42 subjects were included, with a mean age of 24.1 ± 7.9 years (range 15-43 years). Overall, the AIT group showed more of an improvement of taste function, observed in the total average test scores, compared to the INS group (p < 0.05), but no change was detected between the groups before treatment. No difference was found for the bitter taste scores between the study groups (p = 0.053).

CONCLUSION

Subcutaneous allergen immunotherapy resulted in more of an improvement in taste function than intranasal steroids. Further studies are needed.

Immune Basis of Allergic Reactions to Food

Food allergies are diseases where the normal tolerance response to oral antigens is altered. Recent advances have begun to uncover mechanisms that mediate sensitization to food allergens and maintenance of the disease. Production of alarmins by epithelial cells triggers a cascade that leads to allergen-specific IgE synthesis. IL-9 has also been shown to play a role in mast cell recruitment and amplification of the allergic response. In recent years, increasing evidence suggests that sensitization to food allergens can be developed via nonoral routes, in particular the skin, thus leading to the "dual exposure hypothesis". Environmental factors such as diet or microbiota can shape the immune system to promote tolerance or sensitization to food antigens. While the mechanism of primary tolerance to food antigens is quite clear, that leading to permanent tolerance in food-allergic individuals through immunotherapy is still under study. Understanding the mechanisms by which oral tolerance is suppressed and sensitization develops will help to identify new targets to develop combined therapies for the treatment of food allergies.

Design and evaluation of a hypoallergenic peptide-based vaccine for Salsola kali allergy

BACKGROUND

The Salsola kali (S. kali) pollen is one of the most important causes of allergic rhinitis in the deserts and semi-desert areas. Immunotherapy with allergen extracts remains the only available treatment addressing the underlying mechanism of allergy. However, given the low efficacy of this method, it is necessary to find more effective and alternative therapeutic interventions using molecular biology and bioinformatics tools. In this study, a hypoallergenic vaccine was designed on the basis of B-cell epitope approach for S. kali immunotherapy.

METHODS

Using the Immune Epitope Database (IEDB), a 35-mer peptide was selected and chemically conjugated to a keyhole limpet hemocyanin (KLH) molecule. Specific IgG and IgE from immunized BALB/c mice sera against the vaccine (Sal k 1-KLH), S. kali extract and the recombinant protein, rSal k 1, were measured using ELISA. Also, inhibition of IgE by mouse IgG was evaluated using an inhibitory ELISA. Finally, the IgE reactivity and T-cell reactivity of the designed vaccine were evaluated by dot blot assay and MTT assay.

RESULTS

Vaccination with the vaccine produced high levels of protective IgG in mice, which inhibited the binding of patients IgE to recombinant proteins. The result showed that the designed vaccine, unlike the recombinant protein and extract, did not induce T-cell lymphocytes response and also exhibited decreased IgE reactivity.

CONCLUSION

The designed vaccine can be considered as a promising candidate for therapeutic allergen-specific immunotherapy.

Adjuvants in Allergen-Specific Immunotherapy: Modulating and Enhancing the Immune Response

Allergen-specific immunotherapy (AIT) is the only treatment that can affect the natural course of allergic diseases such as allergic asthma, allergic rhinitis, and IgE-mediated food allergy. Adjuvants are used to induce a quicker, more potent, and longer-lasting immune response. Only 4 compounds are used as adjuvants in currently marketed AIT products: aluminum hydroxide, calcium phosphate, microcrystalline tyrosine (MCT), and monophosphoryl lipid A (MPL). The first 3 adjuvants are delivery systems with a depot effect, although they may also have immunomodulatory properties. These first-generation adjuvants are still widely used, especially aluminum hydroxide. However, aluminum is subject to limitations. MCT is the depot formulation of L-tyrosine; it enhances IgG production without inducing a significant increase in IgE, is biodegradable, and has good local and systemic tolerability. In turn, MPL is an immunostimulatory agent that is the only second-generation adjuvant currently used for AIT. In addition, multiple adjuvants are currently being studied, including immunostimulatory sequences (ISSs), nanoparticles (liposomes, virus-like particles, and biodegradable polymers), and phosphatidylserine derivatives. In a murine model of allergic bronchial inflammation by sensitization to olive pollen, the specific IgE level was significantly higher in sensitized mice treated with olive pollen and aluminum hydroxide. However, specific IgE levels were significantly reduced and bronchial hyperreactivity significantly improved in sensitized mice treated with olive pollen and bacterial derivatives (MPL or ISSs).

Intralymphatic Immunotherapy: Update and Unmet Needs

Allergen-specific immunotherapy (AIT) is the only allergy treatment that confers long-term symptom amelioration for patients suffering from allergy. The most frequently used allergen application route is subcutaneous injection (SCIT), commonly taken as the gold standard, followed by sublingual (SLIT) or oral (OIT) application of allergen preparations. This is an up-to-date review of the clinical evidence for a novel route of allergen application, i.e., directly into lymph nodes - intralymphatic immunotherapy (ILIT). The major advantages of ILIT over the current AIT approaches are its short duration and the low allergen doses administered. The whole treatment consists of merely 3 ultrasound-guided injections into inguinal lymph nodes 1 month apart. While the number of patients included in randomised controlled trials is still limited, the clinical results for ILIT are encouraging, but more clinical trials are needed, as well as more preclinical work for optimising formulations.

Oral immunotherapy with the ingestion of house dust mite extract in a murine model of allergic asthma

Background

Allergen-specific immunotherapy (ASIT) has the potential to modify allergic diseases, and it is also considered a potential therapy for allergic asthma. House dust mite (HDM) allergens, a common source of airborne allergen in human diseases, have been developed as an immunotherapy for patients with allergic asthma via the subcutaneous and sublingual routes. Oral immunotherapy with repeated allergen ingestion is emerging as another potential modality of ASIT. The aim of this study was to evaluate the therapeutic efficacy of the oral ingestion of HDM extracts in a murine model of allergic asthma.

Methods

BABL/c mice were sensitized twice by intraperitoneal injection of HDM extracts and Al(OH)₃ on day 1 and day 8. Then, the mice received challenge to induce airway inflammation by intratracheal instillation of HDM extracts on days 29–31. The treatment group received immunotherapy with oral HDM extracts ingestion before the challenge. All the mice were sacrificed on day 32 for bronchoalveolar inflammatory cytokines, mediastinal lymph node T cells, lung histology, and serum HDM-specific immunoglobulins analyses.

Results

Upon HDM sensitization and following challenge, a robust Th2 cell response and eosinophilic airway inflammation were observed in mice of the positive control group. The mice treated with HDM extracts ingestion had decreased eosinophilic airway inflammation, suppressed HDM-specific Th2 cell responses in the mediastinal lymph nodes, and attenuated serum HDM-specific IgE levels.

Conclusions

Oral immunotherapy with HDM extracts ingestion was demonstrated to have a partial therapeutic effect in the murine model of allergic asthma. This study may serve as the basis for the further development of oral immunotherapy with HDM extracts in allergic asthma.

IgE Test in Secretions of Patients with Respiratory Allergy

PURPOSE OF REVIEW

IgE is a key player in multiple inflammatory airway diseases. Ample literature demonstrates its presence in mucosa of patients with allergic rhinitis (AR), local allergic rhinitis (LAR), asthma, or chronic rhinosinusitis with nasal polyposis (CRSwNP).

RECENT FINDINGS

Current evidence shows that high-affinity IgE in blood stream of allergic individuals derives mainly from the mucosae. Also, mucosal synthesis of IgE can occur in the absence of systemic atopy, and may be relevant in atopic and non-atopic phenotypes of rhinitis as demonstrated in LAR. Specific IgE (sIgE) detection varies depending on technique used for sample collection and its measurement. sIgE detection is highly specific for diagnosis of LAR. Moreover, measurement of sIgE in secretions could be useful in monitoring response to allergen-specific immunotherapy in both AR and LAR phenotypes. This review will focus on recent developments in the role of IgE in respiratory diseases, and the clinical implications of its measurement in secretions.

Allergen Extracts for In Vivo Diagnosis and Treatment of Allergy: Is There a Future?

Today, in vivo allergy diagnosis and allergen-specific immunotherapy (AIT) are still based on allergen extracts obtained from natural allergen sources. Several studies analyzing the composition of natural allergen extracts have shown severe problems regarding their quality such as the presence of undefined nonallergenic materials, contaminants as well as high variabilities regarding contents and biological activity of individual allergens. Despite the increasing availability of sophisticated analytical technologies, these problems cannot be overcome because they are inherent to allergen sources and methods of extract production. For in vitro allergy diagnosis problems related to natural allergen extracts have been largely overcome by the implementation of recombinant allergen molecules that are defined regarding purity and biological activity. However, no such advances have been made for allergen preparations to be used in vivo for diagnosis and therapy. No clinical studies have been performed for allergen extracts available for in vivo allergy diagnosis that document safety, sensitivity, and specificity of the products. Only for very few therapeutic allergen extracts state-of-the-art clinical studies have been performed that provide evidence for safety and efficacy. In this article, we discuss problems related to the inconsistent quality of products based on natural allergen extracts and share our observations that most of the products available for in vivo diagnosis and AIT do not meet the international standards for medicinal products. We argue that a replacement of natural allergen extracts by defined recombinantly produced allergen molecules and/or mixtures thereof may be the only way to guarantee the supply of clinicians with state-of-the-art medicinal products for in vivo diagnosis and treatment of allergic patients in the future.