Mechanisms of allergen immunotherapy for inhaled allergens and predictive biomarkers

Safety and efficacy of epicutaneous immunotherapy with DBV712 (peanut patch) in peanut allergy

INTRODUCTION

DBV712 250 µg (also referred to as Viaskin Peanut or peanut patch; Viaskin is a trademark of DBV Technologies) is an innovative approach to epicutaneous immunotherapy (EPIT). The patch-based technology system facilitates peanut protein (allergen) absorption into the intact non-vascularized epidermis to promote desensitization to peanut while limiting systemic allergen exposure.

AREAS COVERED

Efficacy and safety in children have been evaluated in four completed phase 3 studies. Overall, the results from these studies have demonstrated the peanut patch to be superior in desensitization compared with placebo and safe for daily use over multiple years.

EXPERT OPINION

These findings, as well as supportive evidence from phase 2 studies, confirm the potential for an effective treatment of peanut allergy in children. The purpose of this review is to summarize the safety and efficacy of the peanut patch in the treatment of peanut allergy.

Allergen Immunotherapy: The Evidence Supporting the Efficacy and Safety of Subcutaneous Immunotherapy and Sublingual Forms of Immunotherapy for Allergic Rhinitis/Conjunctivitis and Asthma

Allergen immunotherapy (AIT) is a recognized key therapeutic modality for the treatment of allergic respiratory disease. Definitive studies have provided evidence-based data to demonstrate its effectiveness in allergic rhinitis and asthma due to the inhalation of proteinaceous allergic substances from specific seasonal pollens, dust mites, animal allergens, and certain mold spores. Over the ensuing decades, laboratory investigations have provided objective evidence to demonstrate immunologic changes, including production of protective IgG antibody, suppression of IgE antibody, upregulation of regulatory T cells, and induction of a state of immune tolerance to the offending allergen(s). Tangential to this work were carefully designed clinical studies that defined allergen dose and duration of treatment, established the importance of preparing extracts with standardized allergens (or well-defined extracts) based on major protein moieties, and used allergen provocation models to demonstrate efficacy superior to placebo. In the United States, the use of subcutaneous immunotherapy extracts for AIT was grandfathered in by the Food and Drug Administration based on expert literature review. In contrast, sublingual tablet immunotherapy underwent formal clinical development programs (phase I-III clinical trials) that provided the necessary clinical evidence for safety and efficacy that led to regulatory agency approvals for the treatment of allergic rhinitis in properly characterized patients with allergy. The allergy specialist's treatment options currently include traditional subcutaneous AIT and specific sublingual tablets approved for grass, ragweed, house dust mites, trees belonging to the birch-homologous group, and Japanese cedar. Tangential to this are sublingual drops that are increasingly being used off-label (albeit not approved by the Food and Drug Administration) in the United States. This article will review the evidence-based literature supporting the use of these forms of AIT, as well as focus on several current controversies and gaps in our knowledge base that have relevance for the appropriate selection of patients for treatment with specific AIT.

Acupoint Autohemotherapy Attenuates DNCB-Induced Atopic Dermatitis and Activates Regulatory T Cells in BALB/c Mice

Purpose

Acupoint autohemotherapy (A-AHT) has been proposed as an alternative and complementary treatment for atopic dermatitis (AD), yet the exact role of its blood component in terms of therapeutic efficacy and mechanism of action is still largely unknown.

Methods

This study aimed to evaluate the therapeutic efficacies and action mechanisms of intramuscular injections of autologous whole blood (AWB) and mouse immunoglobulin G (IgG) (autologous or heterologous) at acupoints on 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse models. Serum levels of total immunoglobulin E (IgE), IgG, interleukin-10 (IL-10), and interferon-gamma (IFN-γ) were measured, as well as mRNA expression levels of Forkhead box P3 (FoxP3), IL-10 and IFN-γ in dorsal skin lesions, and IL-10+, IFN-γ+ and FoxP3+CD4+T cells in murine spleen.

Results

It showed that repeated acupoint injection of AWB, autologous total IgG (purified from autologous blood in AD mice) or heterologous total IgG (purified from healthy blood in normal mice) effectively reduced the severity of AD symptoms and decreased epidermal and dermal thickness as well as mast cells in skin lesions. Additionally, AWB acupoint injection was found to upregulate FoxP3+, IL-10+ and IFN-γ+ CD4+T cells in murine spleen, suppressing the production of IgE antibodies and increasing that of IgG antibodies in the serum. Furthermore, both AWB and autologous total IgG administrations significantly elevated FoxP3 expression, mRNA levels of IL-10 and IFN-γ in dorsal skin lesions. However, acupoint injection of heterologous total IgG had no effect on regulatory T (Treg) and Th1 cells modulation.

Conclusion

These findings suggest that the therapeutic effects of A-AHT on AD are mediated by IgG-induced activation of Treg cells.

Intranasal PAMAM-G3 scavenges cell-free DNA attenuating the allergic airway inflammation

Allergic airway inflammation (AAI), including allergic rhinitis (AR) and allergic asthma, is driven by epithelial barrier dysfunction and type 2 inflammation. However, the underlying mechanism remains uncertain and available treatments are constrained. Consequently, we aim to explore the role of cell-free DNA (cfDNA) in AAI and assess the potential alleviating effects of cationic polymers (CPs) through cfDNA elimination. Levels of cfDNA were evaluated in AR patients, allergen-stimulated human bronchial epithelium (BEAS-2B cells) and primary human nasal epithelium from both AR and healthy control (HC), and AAI murine model. Polyamidoamine dendrimers-generation 3 (PAMAM-G3), a classic type of cationic polymers, were applied to investigate whether the clearance of cfDNA could ameliorate airway epithelial dysfunction and inhibit AAI. The levels of cfDNA in the plasma and nasal secretion from AR were higher than those from HC (P < 0.05). Additionally, cfDNA levels in the exhaled breath condensate (EBC) were positively correlated with Interleukin (IL)-5 levels in EBC (R = 0.4191, P = 0.0001). Plasma cfDNA levels negatively correlated with the duration of allergen immunotherapy treatment (R = -0.4297, P = 0.006). Allergen stimulated cfDNA secretion in vitro (P < 0.001) and in vivo (P < 0.0001), which could be effectively scavenged with PAMAM-G3. The application of PAMAM-G3 inhibited epithelial barrier dysfunction in vitro and attenuated the development of AAI in vivo. This study elucidates that cfDNA, a promising biomarker for monitoring disease severity, aggravates AAI and the application of intranasal PAMAM-G3 could potentially be a novel therapeutic intervention for AAI. Allergen stimulates the secretion of cell-free DNA (cfDNA) in both human and mouse airway. Intranasal polyamidoamine dendrimers-generation 3 (PAMAM-G3) scavenges cfDNA and alleviates allergic airway inflammation.

Long-term efficacy of house dust mite sublingual immunotherapy on clinical and pulmonary function in patients with asthma and allergic rhinitis

Background

A previous study reported that house dust mite (HDM) sublingual immunotherapy (SLIT) for 48 weeks was effective as add-on treatment for allergic asthma; however, data regarding its long-term efficacy are scarce.

Objective

We sought to evaluate the effect of HDM SLIT on asthma control, pulmonary function, and airway inflammation and remodeling throughout the 5-year treatment period.

Methods

A total of 140 patients with asthma and allergic rhinitis sensitized to HDM were randomized to receive either drugs alone or drugs plus SLIT for 5 years. The 5-item Asthma Control Questionnaire (ACQ-5), Asthma Quality of Life Questionnaire (AQLQ), Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), spirometry, quantitative computed tomography, and type 2 biomarkers were assessed.

Results

An improvement in the ACQ-5, AQLQ, and RQLQ scores was observed in the SLIT group compared with the control group. HDM SLIT increased lung function and reduced the percentage of airway wall area. The levels of fractional exhaled nitric oxide (Feno), blood eosinophil, serum specific IgE for HDM, and total IgE decreased and were sustained during the 5 years. The change in type 2 biomarkers correlated with change in the AQLQ score. On the basis of receiver-operating characteristic analysis for predicting responders, the area under the receiver-operating characteristic curve in FEV1% predicted, airway wall area, Feno, and specific IgE was high. Multivariate regression analysis showed that the strongest predictor of responders was Feno.

Conclusions

HDM SLIT continued to provide sustained efficacy, improve lung function, and prevent progression of airway inflammation and remodeling in asthma throughout the 5-year treatment period.

The Role of Extracellular Vesicles in Allergic Sensitization: A Systematic Review

Allergies affect approximately 10-30% of people worldwide, with an increasing number of cases each year; however, the underlying mechanisms are still poorly understood. In recent years, extracellular vesicles (EVs) have been suggested to play a role in allergic sensitization and skew to a T helper type 2 (Th2) response. The aim of this review is to highlight the existing evidence of EV involvement in allergies. A total of 22 studies were reviewed; 12 studies showed EVs can influence a Th2 response, while 10 studies found EVs promoted a Th1 or Treg response. EVs can drive allergic sensitization through up-regulation of pro-Th2 cytokines, such as IL-4 and IL-13. In addition, EVs from MRSA can induce IgE hypersensitivity in mice towards MRSA. On the other hand, EVs can induce tolerance in the immune system; for example, pre-exposing OVA-loaded EVs prevented OVA sensitization in mice. The current literature thus suggests that EVs play an essential role in allergy. Further research utilizing human in vitro models and clinical studies is needed to give a reliable account of the role of EVs in allergy.

Genetic and T2 biomarkers linked to the efficacy of HDM sublingual immunotherapy in asthma

BACKGROUND

Hypersensitivity to house dust mite (HDM) allergens is a common cause of allergic asthma symptoms and can be effectively treated with allergy immunotherapy (AIT).

OBJECTIVE

To investigate whether genetic and type 2 (T2) inflammatory biomarkers correlate with disease severity in subjects with allergic asthma, and whether this can be modified by AIT.

METHODS

MITRA (NCT01433523) was a phase III, randomised, double-blind, placebo-controlled trial of HDM sublingual immunotherapy (SLIT)-tablets in adults with HDM allergic asthma. Post hoc analyses of the study population (N=742) evaluated associations between T2 inflammatory (blood eosinophils, eosinophil cationic protein (ECP), total IgE and tryptase) and genetic (single-nucleotide polymorphisms, SNP) biomarkers (n=582) for the primary study endpoint (time to first moderate/severe asthma exacerbation). SNP associations were verified in HDM-positive subgroup from an independent 3-year Severe Asthma Research Programme (SARP3) subject cohort.

RESULTS

An increased asthma exacerbation risk in subjects homozygous for SNP rs7216389 (chromosomal locus 17q12-21) was reduced (p=0.037) by treatment with HDM SLIT (HR=0.37 (95% CI 0.22 to 0.64), p<0.001). The associations between exacerbation risk and 17q12-21 SNPs were replicated in the SARP3 HDM-positive subgroup. High levels of T2 biomarkers were associated with increased risk of asthma exacerbations in the placebo group. HDM SLIT-tablet treatment reduced this risk (blood eosinophils: HR=0.50 (95% CI 0.30 to 0.85); ECP: HR=0.45 (95% CI 0.29 to 0.87); tryptase: HR=0.45 (95% CI 0.25 to 0.80)). The treatment effect was higher (p=0.006) for subjects with a higher number of elevated T2 biomarkers.

CONCLUSIONS

HDM SLIT-tablet AIT is efficacious in HDM-sensitised asthma subjects with a genetic asthma predisposition and/or an underlying T2 endotype.

TRIAL REGISTRATION NUMBER

NCT01433523.

Clinical Practice Guideline: Immunotherapy for Inhalant Allergy

OBJECTIVE

Allergen immunotherapy (AIT) is the therapeutic exposure to an allergen or allergens selected by clinical assessment and allergy testing to decrease allergic symptoms and induce immunologic tolerance. Inhalant AIT is administered to millions of patients for allergic rhinitis (AR) and allergic asthma (AA) and is most commonly delivered as subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT). Despite its widespread use, there is variability in the initiation and delivery of safe and effective immunotherapy, and there are opportunities for evidence-based recommendations for improved patient care.

PURPOSE

The purpose of this clinical practice guideline (CPG) is to identify quality improvement opportunities and provide clinicians trustworthy, evidence-based recommendations regarding the management of inhaled allergies with immunotherapy. Specific goals of the guideline are to optimize patient care, promote safe and effective therapy, reduce unjustified variations in care, and reduce the risk of harm. The target patients for the guideline are any individuals aged 5 years and older with AR, with or without AA, who are either candidates for immunotherapy or treated with immunotherapy for their inhalant allergies. The target audience is all clinicians involved in the administration of immunotherapy. This guideline is intended to focus on evidence-based quality improvement opportunities judged most important by the guideline development group (GDG). It is not intended to be a comprehensive, general guide regarding the management of inhaled allergies with immunotherapy. The statements in this guideline are not intended to limit or restrict care provided by clinicians based on their experience and assessment of individual patients.

ACTION STATEMENTS

The GDG made a strong recommendation that (Key Action Statement [KAS] 10) the clinician performing allergy skin testing or administering AIT must be able to diagnose and manage anaphylaxis. The GDG made recommendations for the following KASs: (KAS 1) Clinicians should offer or refer to a clinician who can offer immunotherapy for patients with AR with or without AA if their patients' symptoms are inadequately controlled with medical therapy, allergen avoidance, or both, or have a preference for immunomodulation. (KAS 2A) Clinicians should not initiate AIT for patients who are pregnant, have uncontrolled asthma, or are unable to tolerate injectable epinephrine. (KAS 3) Clinicians should evaluate the patient or refer the patient to a clinician who can evaluate for signs and symptoms of asthma before initiating AIT and for signs and symptoms of uncontrolled asthma before administering subsequent AIT. (KAS 4) Clinicians should educate patients who are immunotherapy candidates regarding the differences between SCIT and SLIT (aqueous and tablet) including risks, benefits, convenience, and costs. (KAS 5) Clinicians should educate patients about the potential benefits of AIT in (1) preventing new allergen sensitizations, (2) reducing the risk of developing AA, and (3) altering the natural history of the disease with continued benefit after discontinuation of therapy. (KAS 6) Clinicians who administer SLIT to patients with seasonal AR should offer pre- and co-seasonal immunotherapy. (KAS 7) Clinicians prescribing AIT should limit treatment to only those clinically relevant allergens that correlate with the patient's history and are confirmed by testing. (KAS 9) Clinicians administering AIT should continue escalation or maintenance dosing when patients have local reactions (LRs) to AIT. (KAS 11) Clinicians should avoid repeat allergy testing as an assessment of the efficacy of ongoing AIT unless there is a change in environmental exposures or a loss of control of symptoms. (KAS 12) For patients who are experiencing symptomatic control from AIT, clinicians should treat for a minimum duration of 3 years, with ongoing treatment duration based on patient response to treatment. The GDG offered the following KASs as options: (KAS 2B) Clinicians may choose not to initiate AIT for patients who use concomitant beta-blockers, have a history of anaphylaxis, have systemic immunosuppression, or have eosinophilic esophagitis (SLIT only). (KAS 8) Clinicians may treat polysensitized patients with a limited number of allergens.

The implication of infection with respiratory syncytial virus in pediatric recurrent wheezing and asthma: knowledge expanded post-COVID-19 era

BACKGROUND

Respiratory syncytial virus (RSV) infection has been identified to serve as the primary cause of acute lower respiratory infectious diseases in children under the age of one and a significant risk factor for the emergence and development of pediatric recurrent wheezing and asthma, though the exact mechanism is still unknown.

METHODS AND RESULTS

In this study, we discuss the key routes that lead to recurrent wheezing and bronchial asthma following RSV infection. It is interesting to note that following the coronavirus disease 2019 (COVID-19) epidemic, the prevalence of RSV changes significantly. This presents us with a rare opportunity to better understand the associated mechanism for RSV infection, its effects on the respiratory system, and the immunological response to RSV following the COVID-19 epidemic. To better understand the associated mechanisms in the occurrence and progression of pediatric asthma, we thoroughly described how the RSV infection directly destroys the physical barrier of airway epithelial tissue, promotes inflammatory responses, enhances airway hyper-responsiveness, and ultimately causes the airway remodeling. More critically, extensive discussion was also conducted regarding the potential impact of RSV infection on host pulmonary immune response.

CONCLUSION

In conclusion, this study offers a comprehensive perspective to better understand how the RSV infection interacts in the control of the host's pulmonary immune system, causing recurrent wheezing and the development of asthma, and it sheds fresh light on potential avenues for pharmaceutical therapy in the future.

Atopic dermatitis (eczema) guidelines: 2023 American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters GRADE- and Institute of Medicine-based recommendations

BACKGROUND

Guidance addressing atopic dermatitis (AD) management, last issued in 2012 by the American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force, requires updating as a result of new treatments and improved guideline and evidence synthesis methodology.

OBJECTIVE

To produce evidence-based guidelines that support patients, clinicians, and other decision-makers in the optimal treatment of AD.

METHODS

A multidisciplinary guideline panel consisting of patients and caregivers, AD experts (dermatology and allergy/immunology), primary care practitioners (family medicine, pediatrics, internal medicine), and allied health professionals (psychology, pharmacy, nursing) convened, prioritized equity, diversity, and inclusiveness, and implemented management strategies to minimize influence of conflicts of interest. The Evidence in Allergy Group supported guideline development by performing systematic evidence reviews, facilitating guideline processes, and holding focus groups with patient and family partners. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed rating the certainty of evidence and strength of recommendations. Evidence-to-decision frameworks, subjected to public comment, translated evidence to recommendations using trustworthy guideline principles.

RESULTS

The panel agreed on 25 recommendations to gain and maintain control of AD for patients with mild, moderate, and severe AD. The eAppendix provides practical information and implementation considerations in 1-2 page patient-friendly handouts.

CONCLUSION

These evidence-based recommendations address optimal use of (1) topical treatments (barrier moisturization devices, corticosteroids, calcineurin inhibitors, PDE4 inhibitors [crisaborole], topical JAK inhibitors, occlusive [wet wrap] therapy, adjunctive antimicrobials, application frequency, maintenance therapy), (2) dilute bleach baths, (3) dietary avoidance/elimination, (4) allergen immunotherapy, and (5) systemic treatments (biologics/monoclonal antibodies, small molecule immunosuppressants [cyclosporine, methotrexate, azathioprine, mycophenolate, JAK inhibitors], and systemic corticosteroids) and UV phototherapy (light therapy).

Quality control of allergen products with mass spectrometry part I: Positioning within the EU regulatory framework

Mass spectrometry (MS) has advanced greatly and many of its applications are ready for utilization within regulatory procedures and could significantly contribute to overcome challenges in standardization of allergen products. It seems sensible to discuss MS within the regulatory framework, before addressing technical questions. While the application to purified proteins is well established from product development to manufacturer's release analytics, its application to complex products such as allergen products is still under development. It needs to be determined where it can complement or replace established methods or where MS offers limited improvement. Despite its technical appeal and versatility, currently MS is mentioned in regulatory guidelines only as one possible measurement method. For example, no specific MS method is given in the European Pharmacopoeia. We discuss applications of MS within the EU regulatory framework. This includes their advantages and disadvantages and their positioning between research, characterization, manufacturer's release analytics and official batch testing. We discuss the qualitative detection of single and multiple allergens as proof of identity, qualitative to semi-quantitative protein profiles for batch to batch consistency testing, and quantification of allergens to state mass units of allergens. MS may also facilitate standardization of allergen products, reference products and reference standards.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRY

Clinical trial registration number: ChiCTR1800017130.

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.

Antiallergic Activity of 3-O-Dodecyl-l-ascorbic Acid

2-O-Alkyl-l-ascorbic acids and 3-O-alkyl-l-ascorbic acids were synthesized, and their degranulation inhibitory activities were evaluated. Among ascorbic acid derivatives with butyl, octyl, dodecyl, hexadecyl, and octadecyl groups introduced at the C-2 or C-3 positions, an AA derivative with a dodecyl group introduced at the C-3 position, 3-O-dodecyl-l-ascorbic acid (compound 8), showed the strongest inhibitory activity against antigen-stimulated degranulation. Compound 8 also inhibited calcium ionophore-stimulated degranulation. Compound 11, in which the hydroxyl group at the C-6 position of compound 8 was substituted with an amino group, and compound 12, in which the dodecyloxy group at the C-3 position of compound 8 was exchanged with a dodecylamino group, were synthesized, and these derivatives showed weaker inhibitory activity against antigen-stimulated degranulation than that of compound 8. In addition, orally administered compound 8 inhibited passive cutaneous anaphylaxis reactions in mice with a potency equal to that of oxatomide, an antiallergic agent. These results suggest that compound 8 may be a candidate for antiallergic treatment.

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.

T cells specific to multiple Bet v 1 peptides are highly cross-reactive toward the corresponding peptides from the homologous group of tree pollens

Background

Allergens from Fagales trees frequently cause spring allergy in Europe, North America, and some parts of Asia. The definition of the birch homologous group, which includes birch (Bet v), oak (Que a), alder (Aln g), hazel (Cor a), hornbeam (Car b), beech (Fag s), and chestnut (Cas s), is based on high allergen sequence identity and extensive IgE cross-reactivity. Clinical effect was seen during the alder/hazel, birch, and oak pollen seasons after treatment with tree SLIT-tablets containing only birch allergen extract. Here, we characterize T-cell reactivity with respect to epitope specificities and cross-reactivity toward various Bet v 1 family members, (PR-10/group 1 major allergens). This cross-reactivity may be part of the immunological basis of clinical effect or cross-protection when exposed to birch homologous tree species.

Method

T-cell lines were generated from 29 birch-allergic individuals through stimulation of peripheral blood mononuclear cells (PBMCs) with birch/Bet v or oak/Que a allergen extracts. T-cell responses to allergen extracts, purified group 1 allergens, and overlapping 20-mer peptides (Bet v 1, Aln g 1, Cor a 1, and Que a 1) were investigated by T-cell proliferation and cytokine production. Cross-reactivity was evaluated based on Pearson's correlations of response strength and further investigated by flow cytometry using tetramer staining for homologous peptide pairs.

Results

T-cell reactivity toward extracts and group 1 allergens from across the birch homologous group was observed for birch/Bet v as well as oak/Que a T-cell lines. T-cell lines responded to multiple Bet v 1 homologous peptides from Aln g 1 and Cor a 1 and a subset of Que a 1 peptides. Significant Pearson's correlations between frequently recognized peptides derived from Bet v 1 and the corresponding peptides derived from alder, hazel, and oak strongly supported the T-cell cross-reactivity toward these allergens. Cross-reactivity between birch and birch homologous peptides was confirmed by pMHCII tetramer staining.

Conclusion

T cells from birch tree pollen allergic individuals respond to multiple trees within the birch homologous group in accordance with the level of sequence homology between Bet v 1 family members, (PR-10 allergens) from these allergen sources, confirming the basis for clinical cross-protection.

Standardization of clinical outcomes used in allergen immunotherapy in allergic asthma: An EAACI position paper

INTRODUCTION

In allergic asthma patients, one of the more common phenotypes might benefit from allergen immunotherapy (AIT) as add-on intervention to pharmacological treatment. AIT is a treatment with disease-modifying modalities, the evidence for efficacy is based on controlled clinical trials following standardized endpoint measures. However, so far there is a lack of a consensus for asthma endpoints in AIT trials. The aim of a task force (TF) of the European Academy of Allergy and Clinical Immunology (EAACI) is evaluating several outcome measures for AIT in allergic asthma.

METHODS

The following domains of outcome measures in asthmatic patients have been evaluated for this position paper (PP): (i) exacerbation rate, (ii) lung function, (iii) ICS withdrawal, (iv) symptoms and rescue medication use, (v) questionnaires (PROMS), (vi) bronchial/nasal provocation, (vii) allergen exposure chambers (AEC) and (viii) biomarkers.

RESULTS

Exacerbation rate can be used as a reliable objective primary outcome; however, there is limited evidence due to different definitions of exacerbation. The time after ICS withdrawal to first exacerbation is considered a primary outcome measure. Besides, the advantages and disadvantages and clinical implications of further domains of asthma endpoints in AIT trials are elaborated in this PP.

CONCLUSION

This EAACI-PP aims to highlight important aspects of current asthma measures by critically evaluating their applicability for controlled trials of AIT.

Nasal and blood transcriptomic pathways underpinning the clinical response to grass pollen immunotherapy

BACKGROUND

Allergen immunotherapy (AIT) is a well-established disease-modifying therapy for allergic rhinitis, yet the fundamental mechanisms underlying its clinical effect remain inadequately understood. Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy was a randomized, double-blind, placebo-controlled trial of individuals allergic to timothy grass who received 2 years of placebo (n = 30), subcutaneous immunotherapy (SCIT) (n = 27), or sublingual immunotherapy (SLIT) (n = 27) and were then followed for 1 additional year.

OBJECTIVE

We used yearly biospecimens from the Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy study to identify molecular mechanisms of response.

METHODS

We used longitudinal transcriptomic profiling of nasal brush and PBMC samples after allergen provocation to uncover airway and systemic expression pathways mediating responsiveness to AIT.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01335139, EudraCT Number: 2010-023536-16.

RESULTS

SCIT and SLIT demonstrated similar changes in gene module expression over time. In nasal samples, alterations included downregulation of pathways of mucus hypersecretion, leukocyte migration/activation, and endoplasmic reticulum stress (log2 fold changes -0.133 to -0.640, false discovery rates [FDRs] <0.05). We observed upregulation of modules related to epithelial development, junction formation, and lipid metabolism (log2 fold changes 0.104 to 0.393, FDRs <0.05). In PBMCs, modules related to cellular stress response and type 2 cytokine signaling were reduced by immunotherapy (log2 fold changes -0.611 to -0.828, FDRs <0.05). Expression of these modules was also significantly associated with both Total Nasal Symptom Score and peak nasal inspiratory flow, indicating important links between treatment, module expression, and allergen response.

CONCLUSIONS

Our results identify specific molecular responses of the nasal airway impacting barrier function, leukocyte migration activation, and mucus secretion that are affected by both SCIT and SLIT, offering potential targets to guide novel strategies for AIT.

Safety and effectiveness of a 300 IR house dust mite sublingual tablet: descriptive 4-year final analysis of a post-marketing surveillance in Japan

Background: Data are limited for clinical outcomes with house dust mite (HDM) allergen immunotherapy beyond 2 years' observation. Materials & methods: A post-marketing drug-use survey assessed the safety and effectiveness of the 300 index of reactivity (IR) HDM tablet during use for up to 4 years in Japan. Results: 538 patients were evaluable for safety and 383 for effectiveness. Most adverse drug reactions (ADRs) occurred early and were local reactions; 5.6% of 249 total events were reported during years 2 to 4 as new ADRs after the interim analysis. The CAP-RAST score was identified as a potential risk factor for ADRs. The proportion of evaluable patients with severe allergic rhinitis symptoms decreased from 46.4% at baseline (n = 317) to 1.0% at 4 years (n = 104). Patients (n = 16) who discontinued 300 IR HDM tablet due to symptomatic improvement had sustained improvement relative to baseline 1 to 2 years later. Conclusion: Long-term use of the 300 IR HDM tablet is safe and effective.

KAAACI Guidelines for Allergen Immunotherapy

Allergen immunotherapy (AIT) is a causative treatment for various allergic diseases such as allergic rhinitis, allergic asthma, and bee venom allergy that induces tolerance to offending allergens. The need for uniform practice guidelines in AIT is continuously growing because of the increasing discovery of potential candidates for AIT and evolving interest in new therapeutic approaches. This guideline is an updated version of the Korean Academy of Asthma Allergy and Clinical Immunology recommendations for AIT published in 2010. This updated guideline proposes an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. The guideline deals with basic knowledge and methodological aspects of AIT, including mechanisms, clinical efficacy, patient selection, allergens extract selection, schedule and doses, management of adverse reactions, efficacy measurements, and special consideration in pediatrics. The guidelines for sublingual immunotherapy will be covered in detail in a separate article.

Extract-Shaped Immune Repertoires as Source for Nanobody-Based Human IgE in Grass Pollen Allergy

The presence of allergen-specific IgE in serum is a biomarker for allergic disease. Specific IgE antibodies for research and diagnostics, however, remain scarce. In contrast to prototypic antibodies, camelid species have evolved single domains as moiety for antigen recognition. These so-called nanobodies represent a versatile platform for the development of diagnostic and therapeutic approaches. In this study, we aimed for generating nanobodies and derived IgE formats from an extract-shaped immune repertoire. Timothy grass pollen represents a complex, but well-defined mixture of individual allergens. Therefore, a repertoire library from a timothy grass pollen extract immunised llama was established. The selection by phage display yielded 3 nanobodies with immunoreactivity to the extract. IgE-like nanobody-based human IgE (nb-hIgE) antibodies were produced in mammalian cells and assessed in different immunoassays and commercial platforms. Immunoblotting and diagnostic ImmunoCap analysis of single timothy grass pollen allergens identified the major allergens Phl p 6 and Phl p 4 as targets. Assessment of immunoreactivity further documented significant molecular cross-reactivity with pollen extract of different grass species and variant presence of allergens within extracts of Pooideae grasses. In summary, our study shows that extract-based immunisation enables the generation of allergen-specific nanobodies and derived nb-hIgE formats linking nanobody technologies with allergological applications.

An update on recent developments and highlights in food allergy

While both the incidence and general awareness of food allergies is increasing, the variety and clinical availability of therapeutics remain limited. Therefore, investigations into the potential factors contributing to the development of food allergy (FA) and the mechanisms of natural tolerance or induced desensitization are required. In addition, a detailed understanding of the pathophysiology of food allergies is needed to generate compelling, enduring, and safe treatment options. New findings regarding the contribution of barrier function, the effect of emollient interventions, mechanisms of allergen recognition, and the contributions of specific immune cell subsets through rodent models and human clinical studies provide novel insights. With the first approved treatment for peanut allergy, the clinical management of FA is evolving toward less intensive, alternative approaches involving fixed doses, lower maintenance dose targets, coadministration of biologicals, adjuvants, and tolerance-inducing formulations. The ultimate goal is to improve immunotherapy and develop precision-based medicine via risk phenotyping allowing optimal treatment for each food-allergic patient.

Effectiveness of sublingual immunotherapy with house dust mite drops in asthmatic children at different ages

Background

Respiratory allergies in children, such as asthma and rhinitis, are becoming progressively common every year. Recent studies found that pediatric patients with asthma receiving regular medication and specific immunotherapy (SIT) had improved therapeutic outcomes in a wide age range. However, there are few studies that have examined the effectiveness of SIT treatment in children with allergic asthma at different ages in terms of the degree of asthma control, improvements in lung function, and changes in exhaled nitric oxide (FeNO).

Method

A total of 200 asthmatic pediatric patients who had been receiving regular treatment for at least a year were split into the observation and the control groups, which depended on whether sublingual immunotherapy was added based on conventional treatment medicines. The children who were divided by an age cut-off of 6 years old in these two groups were compared before and after therapy based on the exhaled levels of FeNO, pulmonary function, visual analog scale, medication scores, daytime and nighttime ratings of asthma symptom, and rhinitis symptom scores.

Results

Before treatment, there was no significant difference between the observation group and the control group in various indicators of the patients under 6 years old; and in the older children (6-16 years old) group, the scores of FVC, FEV1, and FEF25 in the observation group were significantly lower than those in the control group (P < 0.05). The FEF75, FEF50, FEF25, and MMEF75/MMEF25 indexes in the observation group were significantly higher than those in the control group after treatment (P < 0.05), but there was no statistical significance in other indexes (P > 0.05). The scores of ACT, FEF75, FEF50, MMEF72/MMEF25, and FeNO in the observation group were all higher than those in the control group after treatment (P < 0.05), and the differences in other indexes were not statistically significant (P > 0.05). Between the young-age group and the elder group, there was no significant difference in all indexes in the observation group before and after treatment (P > 0.05).

Conclusion

Children with asthma of all ages can considerably benefit from sublingual immunotherapy. Specifically, younger patients showed greater tendency on the improvement of small airway resistance, whereas school-age children with asthma significantly improved their small airway resistance as well as their asthma control and inflammation alleviation.

Mechanistic and Therapeutic Approaches to Occupational Exposure-Associated Allergic and Non-Allergic Asthmatic Disease

PURPOSE OF REVIEW

Occupational lung disease, including asthma, is a significant cause of disability worldwide. The dose, exposure frequency, and nature of the causal agent influence the inflammatory pathomechanisms that inform asthma disease phenotype and progression. While surveillance, systems engineering, and exposure mitigation strategies are essential preventative considerations, no targeted medical therapies are currently available to ameliorate lung injury post-exposure and prevent chronic airway disease development.

RECENT FINDINGS

This article reviews contemporary understanding of allergic and non-allergic occupational asthma mechanisms. In addition, we discuss the available therapeutic options, patient-specific susceptibility and prevention measures, and recent scientific advances in post-exposure treatment conception. The course of occupational lung disease that follows exposure is informed by individual predisposition, immunobiologic response, agent identity, overall environmental risk, and preventative workplace practices. When protective strategies fail, knowledge of underlying disease mechanisms is necessary to inform targeted therapy development to lessen occupational asthma disease severity and occurrence.

Equine allergic skin diseases: Clinical consensus guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Allergic skin diseases are common in horses worldwide. The most common causes are insect bites and environmental allergens.

OBJECTIVES

To review the current literature and provide consensus on pathogenesis, diagnosis, treatment and prevention.

MATERIALS AND METHODS

The authors reviewed the literature up to November 2022. Results were presented at North America Veterinary Dermatology Forum (2021) and European Veterinary Dermatology Congress (2021). The report was available to member organisations of the World Association for Veterinary Dermatology for feedback.

CONCLUSIONS AND CLINICAL RELEVANCE

Insect bite hypersensitivity (IBH) is the best characterised allergic skin disease. An immunoglobulin (Ig)E response against Culicoides salivary antigens is widely documented. Genetics and environmental factors play important roles. Tests with high sensitivity and specificity are lacking, and diagnosis of IBH is based on clinical signs, seasonality and response to insect control. Eosinophils, interleukin (IL)-5 and IL-31 are explored as therapeutic targets. Presently, the most effective treatment is insect avoidance. Existing evidence does not support allergen-specific immunotherapy (ASIT) using commercially available extracts of Culicoides. Hypersensitivity to environmental allergens (atopic dermatitis) is the next most common allergy. A role for IgE is supported by serological investigation, skin test studies and positive response to ASIT. Prospective, controlled, randomised studies are limited, and treatment relies largely on glucocorticoids, antihistamines and ASIT based on retrospective studies. Foods are known triggers for urticaria, yet their role in pruritic dermatitis is unknown. Recurrent urticaria is common in horses, yet our understanding is limited and focussed on IgE and T-helper 2 cell response. Prospective, controlled studies on treatments for urticaria are lacking. Glucocorticoids and antihistamines are primary reported treatments.

Potential Effects of AIT on Nonspecific Allergic Immune Responses or Symptoms

Allergen immunotherapy (AIT) is a treatment in which clinically corresponding allergens are administered to patients with allergic diseases, either by subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT), or by oral immunotherapy (OIT) in the case of food allergy. Since etiological allergens are administered to patients, AIT is presumed to modify mainly allergen-specific immune responses. In bronchial asthma, AIT with house dust mites (HDM) alleviates clinical symptoms, suppresses airway hyperresponsiveness, and reduces medication doses of HDM-sensitive asthmatics. Moreover, AIT can suppress the symptoms of other allergic diseases associated with asthma including allergic rhinitis. However, AIT sometimes reduces allergic symptoms not induced by the responsible allergens, such as non-targeted allergens, in clinical settings. Furthermore, AIT can suppress the spread of sensitization to new allergens that are not targeted allergens by AIT, suggesting the suppression of allergic immune responses in an allergen-nonspecific manner. In this review, the nonspecific suppression of allergic immune responses by AIT is discussed. AIT has been reported to increase regulatory T cells that produce IL-10, transforming growth factor-β, and IL-35, IL-10-producing regulatory B cells, and IL-10-producing innate lymphoid cells. These cells can suppress type-2 mediated immune responses mainly through the production of anti-inflammatory cytokines or a cell-cell contact mechanism, which may be involved in the nonspecific suppression of allergic immune responses by AIT.

Mechanisms of Allergen Immunotherapy and Potential Biomarkers for Clinical Evaluation

Allergen-immunotherapy (AIT) is an efficacious and disease-modifying treatment option for IgE-mediated diseases. Among these allergic rhinitis, insect venom allergy, food allergy, and allergic asthma are the most common candidates for AIT. AIT gives rise to clinical immunotolerance which may last for years after the treatment cessation. Mechanisms of AIT include suppression of allergic inflammation in target tissues and stimulation of the production of blocking antibodies, especially IgG4 and IgA. These mechanisms are followed by a reduction of underlying allergen-specific Th2 cell-driven responses to the allergens. Tolerance induction takes place through the desensitization of effector cells and stimulation of regulatory T cells that show their effects by mechanisms involving cell-cell cross-talk, but also other mechanisms, e.g., by the production of immunomodulatory cytokines such as, e.g., IL-10 and TGF-beta. From a personalized medical perspective, there is a need for clinical biomarkers of value in selecting responders and optimizing patient care during AIT. Also, a deeper understanding of underlying mechanistic processes will improve AIT's future outcomes. In this paper, the current knowledge of mechanisms in AIT is reviewed with a special focus on biomarkers of this therapy.

Randomized, Double-Blind, Placebo-Controlled Trial of Vitamin D Supplementation in the Build-up Phase of House Dust Mite-Specific Immunotherapy

PURPOSE

Vitamin D (VitD) is an immunomodulatory molecule capable of alleviating allergic symptoms. However, the effectiveness of allergen-specific immunotherapy (AIT) is not commonly evidenced in the early build-up phase. The aim of the study was to determine the potential of VitD supplementation in this treatment phase.

METHODS

Thirty-four house dust mite (HDM)-allergic adult patients treated with subcutaneous AIT were randomized to receive VitD2 60,000 IU/week or placebo for 10 weeks and followed up for 10 weeks. The primary endpoints were the symptom-medication score (SMS) and the treatment response rate. The secondary endpoints were eosinophil count and levels of plasma IL-10, Der p 2-specific IgG4, and dysfunctional regulatory T (CRTH2⁺ Treg) cells.

RESULTS

Of 34 patients, 15 in each group completed the study. Patients with VitD deficiency receiving a VitD supplement showed significantly lower mean change SMS than the placebo group in weeks 10 (mean difference -54.54%, P = 0.007) and 20 (mean difference -42.69%, P = 0.04). The percentage of treatment responders reached 78% and 50% in the VitD and placebo groups, respectively, and the effect remained in week 20 (89% and 60%). No significant difference was observed for the tested immunological read-outs, with the exception of the frequency of CRTH2⁺ Treg cells, which was remarkably reduced in the VitD-treated patients. Moreover, improvement in SMS was correlated to the number of CRTH2⁺ Treg cells. Our in vitro experiment indicated that VitD downregulated activation markers, whereas it improved the function of CRTH2⁺ Treg cells.

CONCLUSIONS

VitD supplementation in the build-up phase of AIT could relieve symptoms and decrease Treg cell dysfunction, especially in patients with VitD deficiency.

Clinical and experimental treatment of allergic asthma with an emphasis on allergen immunotherapy and its mechanisms

Allergen immunotherapy (AIT) is currently the only form of treatment that modifies allergic asthma. Pharmacotherapy alone seeks to control the symptoms of allergic asthma, allergic rhinitis, and other atopic conditions. In contrast, AIT can induce long-term physiological modifications through the immune system. AIT enables individuals to live improved lives many years after treatment ends, where they are desensitized to the allergen(s) used or no longer have significant allergic reactions upon allergen provocation. The leading forms of treatment with AIT involve injections of allergen extracts with increasing doses via the subcutaneous route or drops/tablets via the sublingual route for several years. Since the initial attempts at this treatment as early as 1911 by Leonard Noon, the mechanisms by which AIT operates remain unclear. This literature-based review provides the primary care practitioner with a current understanding of the mechanisms of AIT, including its treatment safety, protocols, and long-term efficacy. The primary mechanisms underlying AIT include changes in immunoglobulin classes (IgA, IgE, and IgG), immunosuppressive regulatory T-cell induction, helper T cell type 2 to helper T cell type 1 cell/cytokine profile shifts, decreased early-phase reaction activity and mediators, and increased production of IL-10, IL-35, TGF-β, and IFN-γ. Using the databases PubMed and Embase, a selective literature search was conducted searching for English, full-text, reviews published between 2015 and 2022 using the keywords (with wildcards) "allerg*," "immunotherap*," "mechanis*," and "asthma." Among the cited references, additional references were identified using a manual search.

Allergic rhinitis behavioral changes after Indonesian house dust mites allergenic extract administration as immunotherapy

Background: Allergy is a hypersensitivity reaction that is generally mediated by Immunoglobulin E (IgE). More than 25% of the world’s population is suspected of having these various diseases, and the prevalence and progression of these diseases have continued to increase significantly in recent years. Among these allergy-related diseases, allergic rhinitis and food allergy are the types of allergies with the highest prevalence. Clinical manifestations of allergic rhinitis include sneezing, rhinorrhea, nasal itching, and nasal congestion. Objective: This study aimed to determine the behavioral changes of allergic rhinitis after Indonesian House Dust Mites (IHDM) allergenic extract administration as an immunotherapy. Methods: Eight male BALB/c mice aged 6-8 weeks in each group were treated for seven groups. The sensitization phase is given intraperitoneal, the desensitization phase is given by subcutaneous, and the challenge phase is given intranasal. The allergic parameters were observed, such as nose rubbing and sneezing. The parameters were observed for 15 minutes after the challenge administration. Results: The results showed that the administration of Indonesian House Dust Mites as immunotherapy decreased the frequency of nose rubbing and sneezing after the administration of immunotherapy compared to the allergic rhinitis model. Conclusions: The administration of the Indonesia House Dust Mites as immunotherapy decreased the allergic rhinitis immune response by altering the behavioral parameter.

Molecular Mechanisms of Neurogenic Inflammation of the Skin

The skin, including the hypodermis, is the largest body organ and is in constant contact with the environment. Neurogenic inflammation is the result of the activity of nerve endings and mediators (neuropeptides secreted by nerve endings in the development of the inflammatory reaction in the skin), as well as interactions with other cells such as keratinocytes, Langerhans cells, endothelial cells and mast cells. The activation of TRPV-ion channels results in an increase in calcitonin gene-related peptide (CGRP) and substance P, induces the release of other pro-inflammatory mediators and contributes to the maintenance of cutaneous neurogenic inflammation (CNI) in diseases such as psoriasis, atopic dermatitis, prurigo and rosacea. Immune cells present in the skin (mononuclear cells, dendritic cells and mast cells) also express TRPV1, and their activation directly affects their function. The activation of TRPV1 channels mediates communication between sensory nerve endings and skin immune cells, increasing the release of inflammatory mediators (cytokines and neuropeptides). Understanding the molecular mechanisms underlying the generation, activation and modulation of neuropeptide and neurotransmitter receptors in cutaneous cells can aid in the development of effective treatments for inflammatory skin disorders.

LMAN1 is a receptor for house dust mite allergens

Development of therapies with the potential to change the allergic asthmatic disease course will require the discovery of targets that play a central role during the initiation of an allergic response, such as those involved in the process of allergen recognition. We use a receptor glycocapture technique to screen for house dust mite (HDM) receptors and identify LMAN1 as a candidate. We verify the ability of LMAN1 to directly bind HDM allergens and demonstrate that LMAN1 is expressed on the surface of dendritic cells (DCs) and airway epithelial cells (AECs) in vivo. Overexpression of LMAN1 downregulates NF-κB signaling in response to inflammatory cytokines or HDM. HDM promotes binding of LMAN1 to the FcRγ and recruitment of SHP1. Last, peripheral DCs of asthmatic individuals show a significant reduction in the expression of LMAN1 compared with healthy controls. These findings have potential implications for the development of therapeutic interventions for atopic disease.

Current advances in house dust mite allergen immunotherapy (AIT): Routes of administration, biomarkers and molecular allergen profiling

Allergy to house dust mites (HDM) is a perennial respiratory disease that affect more than half a billion people worldwide. Dermatophagoides pteronyssinus and D. farinae, two HDM species, are major sources of indoor allergens triggering allergic inflammation. Although symptomatic drugs are widely used to block the allergic reaction, allergen immunotherapy is the only curative treatment of IgE-mediated type I respiratory allergies. In this article, we review recent advances in various routes of allergen immunotherapy. We particularly focus on subcutaneous (SCIT) and sublingual (SLIT) immunotherapy, used as a reference therapy since they have transformed allergic treatments by improving symptoms (asthma and rhinitis) as well as the quality of life of patients. We also highlight recent data in more exploratory routes (i.e., oral, intralymphatic, epicutaneous and intradermal) and discuss respective advantages of various route, as well as their foreseen modes of action. Finally, we provide an update on biomarkers as well as on the relevance of the molecular profiling of allergic individuals related to treatment efficacy or asthma prediction.

RNA sequencing of single allergen-specific memory B cells after grass pollen immunotherapy: Two unique cell fates and CD29 as a biomarker for treatment effect

BACKGROUND

Sublingual immunotherapy (SLIT) for grass pollen allergy can modify the natural history of allergic rhinitis and is associated with increased allergen-specific IgG4 . IgG4 competitively inhibits functional IgE on the surface of effector cells, such as mast cells and basophils, from binding to allergens. To further understand the important role memory B-cell (Bmem) responses play in mediating the beneficial effects of SLIT, we assessed changes in allergen-specific Bmem subsets induced by SLIT for grass pollen allergy.

METHODS

Blood samples were collected twice outside the pollen season from twenty-seven patients with sensitization to ryegrass pollen (RGP; Lolium perenne) and seasonal rhinoconjunctivitis. Thirteen received 4-month pre-seasonal SLIT for grass pollen allergy, and 14 received standard pharmacotherapy only. Single-cell RNA sequencing was performed on FACS-purified Lol p 1-specific Bmem before and after SLIT from four patients, and significant genes were validated by flow cytometry on the total cohort.

RESULTS

Four months of SLIT increased RGP-specific IgE and IgG4 in serum and induced two Lol p 1-specific Bmem subsets with unique transcriptional profiles. Both subsets had upregulated expression of beta 1 integrin ITGB1 (CD29), whereas IGHE (IgE), IGHG4 (IgG4 ), FCER2 (CD23), and IL13RA1 were upregulated in one subset. There was an increase in the proportion of Lol p 1+ Bmem expressing surface IgG4 , CD23, and CD29 after SLIT.

CONCLUSIONS

A clinically successful 4 months course of SLIT for grass pollen allergy induces two transcriptionally unique Bmem fates. Associated changes in surface-expressed proteins on these Bmem subsets can be used as early biomarkers for treatment effects.

Real-world study: drug reduction in children with allergic rhinitis and asthma receiving immunotherapy

Background: The reduction of pharmacological treatment after allergen immunotherapy (AIT) for house dust mites (HDMs) has been little studied in children. Objective: To evaluate the reduction of pharmacological treatment comparing children that receive HDM immunotherapy (AIT group) versus only pharmacotherapy. Methods: A historic cohort of children with rhinitis or asthma was assessed. The main outcome was the frequency of complete drug discontinuation. Results: 100% drug reduction was higher for rhinitis (4-year cumulative incidence: 30 vs 10.7%) and asthma (24.1 vs 10.5%) in the AIT group (n = 987) than in the pharmacotherapy group (n = 2012). Conclusion: Immunotherapy is associated with a significant reduction of pharmacotherapy in children. This is a marker of clinical control and could be associated with positive economic impact.

Seafood allergy: Allergen, epitope mapping and immunotherapy strategy

Seafoods are fashionable delicacies with high nutritional values and culinary properties, while seafood belongs to worldwide common food allergens. In recent years, many seafood allergens have been identified, while the diversity of various seafood species give a great challenge in identifying and characterizing seafood allergens, mapping IgE-binding epitopes and allergen immunotherapy development, which are critical for allergy diagnostics and immunotherapy treatments. This paper reviewed the recent progress on seafood (fish, crustacean, and mollusk) allergens, IgE-binding epitopes and allergen immunotherapy for seafood allergy. In recent years, many newly identified seafood allergens were reported, this work concluded the current situation of seafood allergen identification and designation by the World Health Organization (WHO)/International Union of Immunological Societies (IUIS) Allergen Nomenclature Sub-Committee. Moreover, this review represented the recent advances in identifying the IgE-binding epitopes of seafood allergens, which were helpful to the diagnosis, prevention and treatment for seafood allergy. Furthermore, the allergen immunotherapy could alleviate seafood allergy and provide promising approaches for seafood allergy treatment. This review represents the recent advances and future outlook on seafood allergen identification, IgE-binding epitope mapping and allergen immunotherapy strategies for seafood allergy prevention and treatment.

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.

Deciphering Differential Behavior of Immune Responses as the Foundation for Precision Dosing in Allergen Immunotherapy

Like in many fields of medicine, the concept of precision dosing has re-emerged in routine practice in allergology. Only one retrospective study on French physicians' practice has addressed this topic so far and generated preliminary data supporting dose adaptation, mainly based on experience, patient profile understanding and response to treatment. Both intrinsic and extrinsic factors shape the individual immune system response to allergen immunotherapy (AIT). Herein, we focus on key immune cells (i.e., dendritic cells, innate lymphoid cells, B and T cells, basophils and mast cells) involved in allergic disease and its resolution to further understand the effect of AIT on the phenotype, frequency or polarization of these cells. We strive to discriminate differences in immune responses between responders and non-responders to AIT, and discuss the eligibility of a non/low-responder subset for dose adaptation. A differential behavior in immune cells is clearly observed in responders, highlighting the importance of conducting clinical trials with large cohorts of well-characterized subjects to decipher the immune mechanism of AIT. We conclude that there is a need for designing new clinical and mechanistic studies to support the scientific rationale of dose adaptation in the interest of patients who do not properly respond to AIT.

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.

Malaysian Society of Allergy and Immunology Consensus Statement on Sublingual Immunotherapy in Allergic Rhinitis

Allergic rhinitis (AR) is an IgE-mediated inflammatory disease of the upper airway. AR affects the patients' quality of life, is a known risk factor for asthma and a socio-economic burden. Allergen-specific immunotherapy (AIT), comprising sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT), involves administering increasing doses of the causative allergen to induce clinical and immunologic tolerance to the allergens. It is the only currently available treatment for AR that has been proven to induce disease-modifying effects (i.e., long-term remission of allergic symptoms or potential prevention of asthma and new sensitizations). Although AIT is conventionally recommended for patients who are non-responsive to symptom-relieving pharmacotherapy, it is presently recommended as a first-line treatment for patients with moderate to severe AR who prefer a treatment with the potential for long-term remission. In light of the relatively recent implementation of AIT in Malaysia, guidelines on its appropriate indication and application are important to attain optimal outcomes. This consensus statement was developed by an expert group formed by the Malaysian Society of Allergy and Immunology to provide evidence-based recommendations for the practice of AIT in Malaysia. Patient and product selection, choice of AIT, and strategy towards an effective treatment outcome in AIT are presented.

Specific immunoglobulin G4 correlates with Th2 cytokine reduction in patients with allergic asthma treated by Dermatophagoides pteronyssinus subcutaneous immunotherapy

Background

The modulations of lymphocyte subsets and cytokine production due to subcutaneous allergen immunotherapy (SCIT) are not fully clarified.

Objective

We investigated the changes in T-lymphocyte subsets and serum Dermatophagoides pteronyssinus-specific immunoglobulin G4 (Der-p sIgG4), as well as cytokine production during Der-p SCIT, in patients with allergic asthma.

Methods

This study involved 20 patients with allergic asthma who were receiving 156-week Der-p SCIT and 20 patients without SCIT (non-SCIT). We measured symptom and medication scores (SMS), serum Der-p sIgG4 levels, CD4⁺CD25⁺Foxp3⁺ T regulatory (Treg), CD4⁺IL-4^-IFN-γ⁺ T-helper (Th) 1, and CD4⁺IL-4⁺IFN-γ^- Th2 lymphocyte percentages in peripheral blood mononuclear cells (PBMCs) with/without Der-p extract stimulation at weeks 0, 4, 12, 16, 52, 104, and 156. Cytokine release inhibition assays were performed by incubation with serum from SCIT and non-SCIT patients, Der-p allergen, and PBMCs. Levels of interleukin (IL)-4, IL-5, IL-10, IL-13, IL-17, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β1 were evaluated in supernatant.

Results

We found that SCIT patients had significantly lower SMS after week 52. Der-p sIgG4 levels in SCIT patients significantly increased at week 16 compared with non-SCIT subjects. CD4⁺IL-4⁺IFN-γ^- Th2% in SCIT patients showed a significant decrease from weeks 104-156 compared with week 0, while no change was observed in CD4⁺CD25⁺Foxp3⁺ Treg and CD4⁺IL-4^-IFN-γ⁺ Th1 percentages. IL-5, IL-13, IL-4, IL-17, and TNF-α levels in supernatant of PBMCs cultured with serum of SCIT patients after 16 weeks showed significant lower levels compared with non-SCIT patients, and showed significant reverse associations with Der-p sIgG4 levels.

Conclusion

SCIT induced Dep-p sIgG4 may be involved in downregulating Th2 cytokine production in Der-p allergic asthma patients.

Single-cell RNA sequencing identifies precise tolerogenic cellular and molecular pathways induced by depigmented-polymerized grass pollen allergen extract

BACKGROUND

Immunologic mechanism of action of allergoids remains poorly understood. Previous models of allergenicity and immunogenicity have yielded suboptimal knowledge of these immunotherapeutic vaccine products. Novel single-cell RNA sequencing technology offers a bridge to this gap in knowledge.

OBJECTIVE

We sought to identify the underpinning tolerogenic molecular and cellular mechanisms of depigmented-polymerized Phleum pratense (Phl p) extract.

METHODS

The molecular mechanisms underlying native Phl p, depigmented Phl p (DPG-Phl p), and depigmented-polymerized (DPG-POL-Phl p) allergoid were investigated by single-cell RNA sequencing. Allergen-specific T_H2A, T follicular helper (Tfh), and IL-10⁺ regulatory B cells were quantified by flow cytometry in peripheral blood mononuclear cells from 16 grass pollen-allergic and 8 nonatopic control subjects. The ability of Phl p, DPG-Phl p, and DPG-POL-Phl p to elicit FcεRI- and FcεRII-mediated IgE responses was measured by basophil activation test and IgE-facilitated allergen binding assay.

RESULTS

Analysis revealed that DPG-POL-Phl p downregulated genes associated with T_H2 signaling, induced functional regulatory T cells exhibiting immunosuppressive roles through CD52 and Siglec-10, modulated genes encoding immunoproteasome that dysregulate the processing and presentation of antigens to T cells and promoted a shift from IgE toward an IgA₁ and IgG responses. In grass pollen-allergic subjects, DPG-POL-Phl p exhibited reduced capacity to elicit proliferation of T_H2A, IL-4⁺ Tfh and IL-21⁺ Tfh cells while being the most prominent at inducing IL-10⁺CD19⁺CD5^hi and IL-10⁺CD19⁺CD5^hiCD38^intCD24^int regulatory B-cell subsets compared to Phl p (all P < .05). Furthermore, DPG-POL-Phl p demonstrated a hypoallergenic profile through basophil activation and histamine release compared to Phl p (31.54-fold, P < .001).

CONCLUSIONS

Single-cell RNA sequencing provides an in-depth resolution of the mechanisms underlying the tolerogenic profile of DPG-POL-Phl p.

DNA methylation regulatory patterns and underlying pathways behind the co-pathogenesis of allergic rhinitis and chronic spontaneous urticaria

Background

Allergic rhinitis (AR) and chronic spontaneous urticaria (CSU) are often concurrent in patients. Changes in DNA methylation affect T cell biological processes, which may explain the occurrence and progression of comorbidity. However, downstream regulatory pathways of DNA methylation in two diseases and the underlying mechanisms have not been fully elucidated.

Methods

The GSE50101, GSE72541, GSE50222 and OEP002482 were mined for the identification of differentially expressed genes (DEGs) or co-expressed genes and differentially methylated genes (DMGs) in AR and CSU patients. We applied GO analysis and consensus clustering to study the potential functions and signal pathways of selected genes in two diseases. GSVA and logistic regression analysis were used to find the regulatory pathway between DNA methylation and activation patterns of CD4+ T cells. Besides, we used the Illumina 850k chip to detect DNA methylation expression profiles and recognize the differentially methylated CpG positions (DMPs) on corresponding genes. Finally, we annotated the biological process of these genes using GO and KEGG pathway analysis.

Result

The AR-related DEGs were found closely related to the differentiation and activation of CD4+ T cells. The DEGs or co-expressed genes of CD4+ T cells in AR and CSU patients were also clustered using GO and KEGG analysis and we got 57 co-regulatory pathways. Furthermore, logistic regression analysis showed that the regulation of cellular component size was closely related to the activation of CD4+ T cells regulated by DNA methylation. We got self-tested data using the Illumina 850k chip and identified 98 CpGs that were differentially methylated in patients. Finally, we mapped the DMPs to 15 genes and found that they were mainly enriched in the same CD4+T cell regulating pathway.

Conclusion

Our study indicated that DNA methylation affected by pollen participated in the activation patterns of CD4 + T cells, providing a novel direction for the symptomatic treatment of the co-occurrence of AR and CSU.

Cationic liposomes bearing Bet v 1 by coiled coil-formation are hypo-allergenic and induce strong immunogenicity in mice

Although aluminum hydroxide (alum) is widely accepted and used as safe vaccine adjuvant, there is some concern about possible toxicity upon long-lasting repeated exposure during subcutaneous allergen immunotherapy (SCIT). Our objective was to evaluate allergen-bearing liposomes as possible alternative for alum-adsorption in SCIT. A self-assembling, coiled-coil forming peptide pair was used to anchor the major birch pollen allergen Bet v 1 to the surface of cationic liposomes. The resulting nanoparticulate liposomes were characterized with respect to their physicochemical, allergenic and immunological properties. Allergenicity was studied by ImmunoCAP inhibition and rat basophil leukemia (RBL) cell assays. Immunogenicity (immunoglobulin responses) and immune skewing (cytokine responses) were evaluated upon immunization of naïve mice, and compared to alum-adsorbed Bet v 1. Bet v 1-bearing cationic liposomes with a diameter of ∼200 nm showed a positive zeta potential. The coiled-coil conjugation of Bet v 1 to the surface of liposomes resulted in about a 15-fold lower allergenicity than soluble Bet v 1 as judged by RBL assays. Moreover, the nanoparticles induced Bet v 1-specific IgG1/IgG2a responses in mice that were several orders of magnitude higher than those induced by alum-adsorbed Bet v 1. This strong humoral response was accompanied by a relatively strong IL-10 induction upon PBMC stimulation with Bet v 1. In conclusion, their hypo-allergenic properties, combined with their capacity to induce a strong humoral immune response and a relatively strong IL-10 production, makes these allergen-covered cationic liposomes a promising alternative for aluminum salt-adsorption of allergen currently used in SCIT.

Effects of combination treatment with tezepelumab and allergen immunotherapy on nasal responses to allergen: A randomized controlled trial

BACKGROUND

Thymic stromal lymphopoietin (TSLP) has been shown to play a central role in the initiation and persistence of allergic responses.

OBJECTIVE

We evaluated whether tezepelumab, a human monoclonal anti-TSLP antibody, improved the efficacy of subcutaneous allergen immunotherapy (SCIT) and promoted the development of tolerance in patients with allergic rhinitis.

METHODS

We conducted a double-blind parallel design trial in patients with cat allergy. A total of 121 patients were randomized to receive either intravenous tezepelumab plus subcutaneous cat SCIT, cat SCIT alone, tezepelumab alone, or placebo for 52 weeks, followed by 52 weeks of observation. Nasal allergen challenge (NAC), skin testing, and blood and nasal samples were obtained throughout the study.

RESULTS

At week 52, the NAC-induced total nasal symptom scores (TNSS) (calculated as area under the curve [AUC0-1h] and as peak score [Peak0-1h] during the first hour after NAC) were significantly reduced in patients receiving tezepelumab/SCIT compared to SCIT alone. At week 104, one year after stopping treatment, the primary end point TNSS AUC0-1h was not significantly different in the tezepelumab/SCIT group compared to SCIT alone, while TNSS Peak0-1h was significantly lower in those receiving combination treatment versus SCIT. Transcriptomic analysis of nasal epithelial samples demonstrated that treatment with the combination of SCIT/tezepelumab, but neither monotherapy, caused persistent downregulation of a gene network related to type 2 inflammation that was associated with improvement in NAC responses.

CONCLUSIONS

Inhibition of TSLP augments the efficacy of SCIT during therapy and may promote tolerance after a 1-year course of treatment. (ClinicalTrials.gov NCT02237196).

Allergen immunotherapy for atopic dermatitis: Systematic review and meta-analysis of benefits and harms

BACKGROUND

Atopic dermatitis (AD, eczema) is driven by a combination of skin barrier defects, immune dysregulation, and extrinsic stimuli such as allergens, irritants, and microbes. The role of environmental allergens (aeroallergens) in triggering AD remains unclear.

OBJECTIVE

We systematically synthesized evidence regarding the benefits and harms of allergen immunotherapy (AIT) for AD.

METHODS

As part of the 2022 American Academy of Allergy, Asthma & Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters AD Guideline update, we searched the MEDLINE, EMBASE, CENTRAL, CINAHL, LILACS, Global Resource for Eczema Trials, and Web of Science databases from inception to December 2021 for randomized controlled trials comparing subcutaneous immunotherapy (SCIT), sublingual immunotherapy (SLIT), and/or no AIT (placebo or standard care) for guideline panel-defined patient-important outcomes: AD severity, itch, AD-related quality of life (QoL), flares, and adverse events. Raters independently screened, extracted data, and assessed risk of bias in duplicate. We synthesized intervention effects using frequentist and Bayesian random-effects models. The GRADE approach determined the quality of evidence.

RESULTS

Twenty-three randomized controlled trials including 1957 adult and pediatric patients sensitized primarily to house dust mite showed that add-on SCIT and SLIT have similar relative and absolute effects and likely result in important improvements in AD severity, defined as a 50% reduction in SCORing Atopic Dermatitis (risk ratio [95% confidence interval] 1.53 [1.31-1.78]; 26% vs 40%, absolute difference 14%) and QoL, defined as an improvement in Dermatology Life Quality Index by 4 points or more (risk ratio [95% confidence interval] 1.44 [1.03-2.01]; 39% vs 56%, absolute difference 17%; both outcomes moderate certainty). Both routes of AIT increased adverse events (risk ratio [95% confidence interval] 1.61 [1.44-1.79]; 66% with SCIT vs 41% with placebo; 13% with SLIT vs 8% with placebo; high certainty). AIT's effect on sleep disturbance and eczema flares was very uncertain. Subgroup and sensitivity analyses were consistent with the main findings.

CONCLUSIONS

SCIT and SLIT to aeroallergens, particularly house dust mite, can similarly and importantly improve AD severity and QoL. SCIT increases adverse effects more than SLIT. These findings support a multidisciplinary and shared decision-making approach to optimally managing AD.

Effects of subcutaneous immunotherapy in allergic rhinitis children sensitive to dust mites

BACKGROUND

Subcutaneous immunotherapy (SCIT) is now the only treatment that can modify the natural course of allergic rhinitis (AR). However, not all children with AR benefit from SCIT.

OBJECTIVE

To evaluate the efficacy of SCIT in dust-mites-induced AR children and explore correlative factors predicting treatment response to SCIT.

METHODS

225 children aged 4-17 years old with AR were recruited from January 2016 to September 2019, and monitored at baseline, 4, 12, and 24 months after the start of SCIT treatment. The visual-analogue-score (VAS) was used to assess the clinical symptoms. Multivariate binary logistic regression analyses and receiver operating characteristic curves were used to explore correlative factors in predicting the efficacy of SCIT.

RESULTS

The significant declines in VAS started after 4 months of SCIT and continued to improve throughout the study compared with baseline. An increase in children's age (OR=0.688, 95%CI: 0.479-0.988) and those with allergic history (OR=0.097, 95%CI: 0.009-1.095) were negatively associated with the risk of poor efficacy. Polysensitized children were more likely to suffer poor efficacy (OR=15.511 95%CI: 1.319-182.355). The clinical response at month 4 (r=0.707) and month 12 (r=0.925) was related to that at month 24. The area under the curve (AUC) for improvement at month 4 and month 12 was 0.746 and 0.860, respectively.

CONCLUSION

Our study confirmed the clinical efficacy of SCIT in AR children. Children with younger age, negative allergic history, and multiple allergens may predict a worse efficacy. The onset of action and the clinical response to SCIT in the second year can be predicted as early as by month 4.

Regulation and directed inhibition of ECP production by human neutrophils

Background

Neutrophils are involved in the pathophysiology of allergic asthma, where the Eosinophil Cationic Protein (ECP) is a critical inflammatory mediator. Although ECP production is attributed to eosinophils, we reported that ECP is also present in neutrophils from allergic patients where, in contrast to eosinophils, it is produced in an IgE-dependent manner. Given the key role of ECP in asthma, we investigated the molecular mechanisms involved in ECP production as well as the effects induced by agonists and widely used clinical approaches. We also analyzed the correlation between ECP production and lung function.

Methods

Neutrophils from allergic asthmatic patients were challenged with allergens, alone or in combination with cytokines, in the presence of cell-signaling inhibitors and clinical drugs. We analyzed ECP levels by ELISA and confocal microscopy. Lung function was assessed by spirometry.

Results

IgE-mediated ECP release is dependent on phosphoinositide 3-kinase, the extracellular signal-regulated kinase (ERK1/2) and the production of reactive oxygen species by NADPH-oxidase. Calcineurin phosphatase and the transcription factor NFAT are also involved. ECP release is enhanced by the cytokines interleukin (IL)-5 and granulocyte macrophage-colony stimulating factor, and inhibited by interferon-γ, IL-10, clinical drugs (formoterol, tiotropium and budesonide) and allergen-specific IT. We also found an inverse correlation between asthma severity and ECP levels.

Conclusions

Our results suggest the molecular pathways involved in ECP production and potential therapeutic targets. We also provide a new method to evaluate disease severity in asthmatic patients based on the quantification of in vitro ECP production by peripheral neutrophils.

Immunogenicity of a novel anti-allergic vaccine based on house dust mite purified allergens and a combination adjuvant in a murine prophylactic model

The outer-membrane-derived proteoliposome (PL) of Neisseria meningitidis has been reported as a potent vaccine adjuvant, inducing a Th1-skewed response. This work aimed to assess the immunogenicity of a novel anti-allergic vaccine candidate based on allergens from Dermatophagoides siboney house dust mite and a combination adjuvant containing PL and Alum. In a preventative experimental setting, BALB/c mice were administered with three doses containing 2 µg of Der s1 and 0.4 µg Der s2 allergen, PL and Alum, at 7 days intervals, by subcutaneous route. Furthermore, mice were subjected to an allergen aerosol challenge for 6 consecutive days. Serum IgE, IgG1, and IgG2a allergen-specific antibodies were assessed by ELISA. Cytokine levels in supernatants of D. siboney stimulated lymphocyte cultures and in bronchoalveolar lavage (BAL) were measured by ELISA. Lung tissues were subjected to histological examination. The vaccine prevented the development of both, systemic (IgE) and local allergic responses (featuring lower IL-4, and IL-5 levels in BAL) upon allergen exposure by the inhalant route. Histological examination showed also a diminished allergic inflammatory response in the lungs. After the allergen challenge, cytokine levels in stimulated lymphocyte cultures showed lower values of IL-13 and augmented IFN-γ and IL-10. The vaccine induced a mixed IgG2a/IgG1 antibody response; although only IgG2a was PL-dependent. Both, IgG1/IgE and IgG2a/IgE ratios, showed significantly greater values in vaccinated mice. The findings support a preventative anti-allergic effect associated with the induction of a Th1-like IFN-γ/IL-10 response. IgG1/IgE and IgG2a/IgE ratios could be useful biomarkers for translation into clinical trials.