In contrast to sublingual immunotherapy (SLIT) with recombinant Mal d 1 (rMal d 1-SLIT), SLIT with rBet v 1 (rBet v 1-SLIT) induced Mal d 1-cross-reactive antibodies without IgE blocking activity. To elucidate whether the development of cross-protective IgG responses depends on the degree of molecular identity of allergens we compared the cross-reactivity, cross-blocking activity, and affinity of SLIT-induced antibodies with allergens of varying amino acid sequence identities to Bet v 1 and Mal d 1, namely Cor a 1.04 (hazelnut), Pru av 1 (cherry), and Dau c 1 (carrot).

Allergen-specific antibodies were quantified by ELISA. IgE blocking was analyzed by inhibition of allergen induced basophil activation and IgE-facilitated allergen-presentation to T cells. The affinity of SLIT-induced antibodies was studied by acidic dissociation ELISA and competition ELISA. Identical surface areas on allergens were predicted using an in-house designed script based on structural alignments.

rBet v 1-SLIT-induced IgG antibodies cross reacted with all allergens except Dau c 1. rMal d 1-SLIT induced antibodies predominantly cross-reacted with Pru av 1 and displayed significantly higher IgE blocking to Pru av 1 than rBet v 1-SLIT-induced antibodies. rMal d 1-SLITinduced IgG1 showed higher affinity to Mal d 1 and Pru av 1. Surface analysis revealed 84% identical area on Mal d 1 and Pru av 1. Furthermore, we identified two surface areas potentially containing epitopes present on these allergens and absent on Bet v 1.

In summary, our findings suggest that a relatively high threshold of similarity is required to establish effective cross blocking antibodies to related allergens. Apparently, the structural identity between Bet v 1 and Mal d 1 is below this threshold. Therefore, this study may explain why immunotherapy with birch pollen allergen often fails to reduce birch pollen-related apple allergy.

Omalizumab (XOLAIR®)-assisted multi-food oral immunotherapy (mOIT) has been shown to safely, effectively, and rapidly desensitize patients with multiple food allergies. In our clinical trial (NCT02626611) on omalizumab-assisted mOIT, different desensitization outcomes (success or failure of desensitization) were observed following a period of either continued or discontinued mOIT. However, the association between the immunological changes induced by omalizumab-assisted mOIT and desensitization outcomes has not yet been fully elucidated. In this study, due to the key roles of regulatory T (Treg) cells and the type 2 helper T cell (Th2) pathway in immune tolerance to food allergens, we aimed to characterize their association with the desensitization outcomes of omalizumab assisted mOIT.

Mass cytometry and multiplex cytokine assays were performed on blood samples obtained from participants with allergies to peanut, cashew, or milk in our phase 2 clinical study (NCT02626611). Comprehensive statistical and bioinformatic analyses were conducted on high-dimensional cytometry-based single-cell data and high-throughput multiplex cytokine data.

Our results demonstrated that the frequency of HLA-DR+ Treg cells, and the production of Th2 cytokines (IL-4, IL-5, IL-13, and IL-9) as well as the immunoregulatory cytokine IL-10 by peripheral blood mononuclear cells (PBMCs) was significantly increased in cultures with allergen compared to cultures with media alone at baseline (Week 0). We also observed increased frequency of allergen responsive HLA-DR+ Treg cells and enhanced production of IL-10 by PBMCs in participants who achieved successful desensitization compared to those with failure of desensitization. However, the production of Th2 cytokines by PBMCs did not show significant differences between participants with different desensitization outcomes (success vs. failure of desensitization), despite omalizumab-assisted mOIT inducing a significant reduction in the production of Th2 cytokines.

We demonstrated that the frequency of HLA DR+ Treg cells and IL-10 cytokine production by PBMCs are associated with desensitization outcomes of omalizumab-assisted mOIT. These findings suggest potential immunological parameters that could be targeted to enhance desensitization success rates.

Severe atopic dermatitis (AD) is a complex disease requiring systemic treatment. This study aimed to assess the effectiveness of combined therapy consisting of dupilumab and sublingual dust mite allergen immunotherapy (SLIT-HDM) in patients with severe AD and HDM allergies.

Patients diagnosed with severe AD were included in this randomised, placebo-controlled, double blind 12-month trial; they received SLIT for HDMs and/or dupilumab for 12 months and were compared with patients on cyclosporine. The primary outcomes for the treatment arms were changes in the Eczema Area and Severity Index (EASI), body surface area (%BSA), and Investigator Global Assessment (IsGA) over 12 months. The secondary outcomes were the proportion of patients who achieved IsGA success and reduced medication scores.

Significant improvements were observed in all analysed groups after 12 months of therapy based on the EASI, %BSA, and IsGA. However, the most substantial changes were observed in the groups treated with dupilumab or a combination of SLIT-HDM and dupilumab. Additionally, the proportion of patients who achieved an IsGA reduction was significantly greater in the group receiving combination therapy than in the other groups (9/14 [64% of the group receiving SLIT-HDM] vs. 11/14 [73% of the group receiving dupilumab] vs. 15/17 [88% of the group receiving dupilumab and SLIT-HDM] vs. 7/13 [53% of the group receiving cyclosporine]) (p < 0.05).

In patients with severe AD and HDM allergies, combination treatment with dupilumab and allergen immunotherapy for HDMs may increase the therapeutic benefit over treatment with these methods separately.

Peanut allergy treatment options remain limited, but novel approaches are being studied, including epicutaneous immunotherapy (EPIT). EPIT uses the cutaneous immune system to promote tolerance to food allergens. Viaskin Peanut, an approach to EPIT in late-stage clinical development uses an occlusive patch with a condensation chamber that enables natural epidermal water loss to solubilize dry antigen on the patch, which is then absorbed and captured by skin Langerhans cells. This form of EPIT does not require disruption of the skin barrier, thus avoiding a proinflammatory cytokine response by targeting the nonvascularized epidermis and limiting systemic allergen exposure. Extensive preclinical research suggests that Viaskin Peanut has a distinct mechanism of desensitization, including the potential for disease modification, driven by a unique population of regulatory T cells. Numerous clinical studies of Viaskin Peanut have demonstrated desensitization and reductions in reaction severity, particularly in children aged 1 through 11 years, as well as a favorable safety profile with mostly mild-to-moderate skin reactions that were observed to decrease over time. EPIT with Viaskin Peanut may be a potential therapeutic option for peanut allergy that is clinically practical with long-term efficacy and tolerability.

Up to now, there is no generally accepted biomarker to indicate the clinical response of immunotherapy. This study mainly analyzed the correlation between eosinophil cationic protein myeloperoxidase (ECP-MPO) test papers and other immunotherapy indices in subcutaneous immunotherapy of dust mites and to explore whether the test paper can be used as an auxiliary index to quickly evaluate the efficacy of immunotherapy.

This study included 53 participants who received subcutaneous immunotherapy at the allergy clinic of Renmin Hospital of Wuhan University and 28 control participants. Six visits were conducted during a prospective study over one year. The results of the ECP-MPO test paper, nasal secretion eosinophil smear and count, nasal secretion ECP concentration, and clinical symptom scores were collected during five follow-up visits after the start of subcutaneous immunotherapy. Th1/Th2/Th17 cytokines, chemokines, IgE, IgG4 against dust mite components, and ECP concentrations were detected in the serum of participants at baseline, six months, and one year after subcutaneous immunotherapy.

The ECP test paper is not only easy to operate, but also can effectively and quickly detect the concentrations of ECP in the nasal secretion and diagnose allergic rhinitis. Symptom score is an important index for evaluating clinical immune efficacy, during subcutaneous immunotherapy, the ECP test paper showed a positive correlation with the symptom score. Simultaneously, during immunotherapy, the changes in the chromogenic grading of the test paper were synchronized with the changes in inflammatory cytokines and eosinophilic chemokines in Th2 cells of serum dust mite IgE. The sIgG4 against dust mites weakly negatively correlated with the concentration of ECP in nasal secretions and the color classification of the ECP test paper.

The ECP-MPO test paper has a certain correlation with subcutaneous immunotherapy markers of allergic rhinitis, indicating that the ECP test paper may become an auxiliary biomarker to replace other complex laboratory tests.

Allergen immunotherapy (AIT) is the only disease-modifying treatment in allergy. Its efficacy has been demonstrated in the treatment of Local Allergic Rhinitis (LAR) in adults. This study intends to evaluate the effectiveness of AIT in specific nasal reactivity of paediatric patients with LAR.

Patients diagnosed with LAR to Dermatophagoides pteronyssinus (Dp) were submitted to subcutaneous AIT (SCIT) (depigmented-polymerized Dp allergen extracts) for 3 years. Nasal allergen challenge (NACs) with Dp extract were performed before and 3 years after AIT. NAC response was assessed with peak nasal inspiratory flow (PNIF) and symptom score of Lebel. NACs were considered positive when there was a flow decrease of ≥ 20% in PNIF and a score of symptoms ≥ 3 points. Demographic data and NAC results were analysed.

We included 32 paediatric patients (mean age 9.9±3.08 years, 18 female) and 10 adult patients, (mean age 30.4±12.2 years, 7 female). The symptom score obtained at the 1st minute, 5th minute, 15th minute and 30th minute in response to NAC, were reduced after AIT. The nasal inspiratory flow decrease induced by NAC was also reduced after AIT. This reduction in nasal reactivity was observed in paediatric and in adult patients, both with statistical significance.

AIT induced a decrease in Dp-nasal specific reactivity in children with LAR. This decline of nasal response to allergen exposure, after AIT treatment, emphasis the interest of this therapeutic approach in LAR, even in paediatric patients.

House dust mite subcutaneous immunotherapy (HDM SCIT) is a therapeutic option for allergic rhinitis (AR) patients who are unable to properly manage symptoms with standard medications.

This study aimed to determine long-term efficacy and identify predictive factors in the clinical remission of AR patients who completed and discontinued HDM SCIT.

This study included 240 AR patients, who completed a three-year course of HDM SCIT at two tertiary hospitals and were currently being discontinued. We followed-up the patients to ask about their current symptoms and allergy medication. Clinical remission was defined by patients who no longer required daily intranasal steroid or oral antihistamine. We compared patients in clinical remission to those still taking medication.

The enrolled patients had a median age of 21.0 (11.0-36.0) years at the time they began HDM SCIT. The clinical remission of AR was achieved in 174 (72.5%) patients. Starting HDM SCIT before the age of 15 and not having asthma were identified as significant and independent predictors of remission (aOR 4.44; 95%CI, 1.72-11.50; p-value 0.002, and 2.67, 95%CI 1.00-7.12; p value 0.049), respectively, as determined by multivariate logistic regression analysis. There were no significant differences in HDM SCIT duration or sensitization patterns between patients in remission and those on medication after discontinuing HDM SCIT for at least one year.

HDM SCIT exhibited persistent long-term efficacy after treatment discontinuation. Starting HDM SCIT before the age of 15 and without asthma comorbidity might be predictors of AR remission with HDM SCIT.

The basophil activation test (BAT) has been limited to research settings due to technical issues. Novel approaches using dry, ready-to-use reagents and streamlined protocols offer greater flexibility and may open opportunities for easier implementation in clinical research.

Using a streamlined BAT (sBAT) strategy and the settings of the baseline study of the EPITOPE trial of EPicutaneous ImmunoTherapy (EPIT ) for peanut allergy, we aimed to assess the feasibility of implementing BAT in a multicenter trial and to evaluate its utility in predicting the outcomes of peanut double-blind placebo-controlled food challenge (DBPCFC).

Whole blood samples were collected from subjects aged 1-3 years (n=241) undergoing baseline eligibility DBPCFC in the EPITOPE study across 15 clinical sites in North America. After preparation with sBAT reagents, processed samples were analyzed in a single central laboratory within 5 days of collection and preparation. The eliciting dose (ED) at DBPCFC was determined using PRACTALL criteria. Using a machine learning (ML) approach which incorporated BAT derived features, clinical characteristics, and peanut specific IgE, the ability to predict outcomes of interest (ED [300 mg] and use of epinephrine) was assessed using data randomly split into training (n=182) and validation (n=59) subsets.

The expression of basophil activation markers CD203c and CD63 correlated with ED and severity outcomes of DBPCFC. Most informative concentrations of peanut extract in the sBAT assay for these associations were 1 and 10 ng/ml. Using ML to assess the ability to predict the outcomes of DBPCFC, the best models using only the BAT-derived features provided relatively high sensitivities of 0.86 and 0.85 for predicting eliciting dose and epinephrine use, respectively, while specificities were lower, ranging from 0.60 to 0.80. While including specific IgE and SPT data in addition to those from sBAT did not improve the ability to identify individuals most at risk for severe reactions, it did improve the ability to identify patients with an eliciting dose above 300 mg.

In addition to facilitating implementation in multicenter trials, sBAT retains the potential of BAT to characterize allergic patients and confirms its potential to contribute to predicting the outcome of oral food challenges.

Allergen-specific immunotherapy, a unique inducer of tolerance, may result in T cell exhaution.

To investigate how the duration of house dust mite (HDM) subcutaneous immunotherapy (SCIT) affects the expression of major immune checkpoint (ICP) molecules on the surface of CD4+ T-helper and regulatory T (Treg) cells.

Cross-sectional study.

We enrolled 28 children with HDM-induced allergic rhinitis (AR) and six controls. The study participants were divided into six groups: one group each of patients in their first, second, and third years of HDM-SCIT; one group each comprising those in the first year following HDM-SCIT and those on pharmacotherapy; and the control group. The expression of ICPs on CD4+ T and Treg cells was determined using flow cytometry, and plasma levels of soluble ICPs were estimated by ELISA.

Our results revealed a significant increase in the expression of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and lymphocyte activation gene 3 (LAG-3) on CD4+ T cells during the second and third years of SCIT, respectively. Additionally, a strong correlation was observed between the expression of CTLA-4 and T cell immunoglobulin and mucin domain containing molecule 3 in CD4+ T cells. Furthermore, we observed a significant correlation between the expressions of programmed cell death protein-1, CTLA-4, T cell Immunoreceptor with Immunoglobulin and Immunoreceptor Tyrosine-Based Inhbitory Motif domain, and LAG-3 on both CD4+ T and Treg cells. A robust correlation was observed between the plasma levels of soluble ICPs.

HDM-SCIT induces CD4+ T cell exhaution, which may contribute to tolerance induction in children with AR.

While there are compelling arguments for developing subcutaneous allergen-specific immunotherapy for alleviation of food allergies, there is a limited number of studies in the public domain. The review seeks to present the approaches taken, to explain the paucity of studies, and to identify new roads for development.

A literature search revealed clinical trials of immunotherapy of food allergies to fish and peanut, but studies had limited patient numbers, short treatment courses and follow-up periods. Indications, but no clearcut effects, were seen with both classical allergen extracts and hypo-allergenic preparations. A special case is the influence on cross-reactive food allergies, when subcutaneously administered birch-pollen extracts are used for treatment of birch pollen hayfever and/or asthma. Again indications, but no convincing efficacy has been registered. Newer developments include recombinant hypoallergens and DNA-technologies. Subcutaneous immunotherapy for food allergies has not matured to provide clinically relevant treatment opportunities.