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Abstract: Background: Accurate allergen quantification is needed to document the consistency of allergen extracts used for immunotherapy. Herein, we characterize the epitope specificities of two monoclonal antibodies used in an ELISA for the quantification of the major birch pollen allergen Bet v 1, established as a reference by the BSP090 European project. Methods: The ability of mAbs 5B4 and 6H4 to recognize Bet v 1 isoforms was addressed by immunochromatography. The capacity of each mAb to compete with patients’ IgE for binding to Bet v 1 was measured by ELISA inhibition. Epitope mapping was performed by pepscan analysis, site‐directed mutagenesis, and hydrogen/deuterium exchange‐mass spectrometry. Results: The 5B4 epitope corresponds to a peptide sequence (I56‐K68) overlapping with the binding sites of patients’ serum IgEs. Mutation of residues P59, E60, and K65 abolishes 5B4 binding to Bet v 1 and reduces the level of IgE recognition. In contrast, 6H4 recognizes a conformational epitope lying opposite to the 5B4 binding site, involving residues located in segments I44‐K55 and R70‐F79. Substitution of E45 reduces the binding capacity of 6H4, confirming that it is critical for the interaction. Both mAbs interact with >90% of Bet v 1 content present in the birch pollen extract, while displaying a weak cross‐reactivity with other allergens of the PR‐10 family. Conclusions: MAbs 5B4 and 6H4 recognize structurally distinct epitopes present in the vast majority of Bet v 1 isoforms. These results support the relevance as a reference method of the Bet v 1‐specific quantitative ELISA adopted by the European Pharmacopoeia. [ABSTRACT FROM AUTHOR]

Background Sublingual immunotherapy (SLIT) is safe and reduces both symptoms and medication requirements in patients with type I respiratory allergies. Nonetheless, immune mechanisms underlying SLIT need to be further documented. Objective A detailed characterization of the lingual immune system was undertaken in mice, to investigate the presence of tolerogenic and pro-inflammatory mechanisms. Methods Immune cells were characterized in lingual tissues from BALB/c mice using immunohistology and flow cytometry. Resident CD4+ T cells were sorted and toll-like receptor (TLR) expression profiles as well as functional characterization were assessed by RT-PCR, T cell suppressive assays and cytokine gene expression, respectively. Results Eosinophils and mast cells were only detected in submucosal tissues. No NK, NK-T, γ/δ, CD8+ T cells, nor B-lymphocytes were detected. Potential antigen presenting cells include various subsets of dendritic cells (CD207+ Langerhans cells, CD11b+CD11c+ myeloid cells and 120G8+ plasmacytoid DCs) together with F4/80+ macrophages. Noteworthy, both CD103− and CD103+ CD4+ T cells expressing TLR2 and TLR4 receptors are present along the lamina propria, in vicinity of myeloid CD11b+CD11c± dendritic cells. Such resident lingual CD4+ T lymphocytes comprise both suppressive T cells as well as cells with memory/effector functions (i.e. expressing IFNγ, IL4, IL10 and IL17 genes following stimulation), irrespective of the presence of the mucosal addressing marker CD103. Conclusion The sublingual route is pertinent to induce antigen-specific tolerance, due to (i) limited numbers of pro-inflammatory cells, rather located in submucosal tissues, (ii) co-localization of APCs and resident CD4+ T cells with regulatory functions. Since the oral immune system can also elicit pro-inflammatory effector responses, the cytokine milieu in which allergens are presented by sublingual APCs needs to be controlled during immunotherapy (e.g. with adjuvants) in order to favour tolerance over inflammation. [ABSTRACT FROM AUTHOR]

The MODERN project addresses coherence issues in sentence-by-sentence statistical MT, by propagating across sentences discourse-level information regarding discourse connectives, verb tenses, noun phrases and pronouns. [ABSTRACT FROM AUTHOR]

Allergic asthma is the predominant phenotype among asthmatics. Although conventional pharmacotherapy is a central component in the management of asthma, it does not enable control of asthma symptoms in all patients. In recent decades, some uncontrolled asthmatic patients, especially those with allergic asthma, have benefited from biological therapies. However, biologics do not address all the unmet needs left by conventional pharmacotherapy. Furthermore, it is noteworthy that neither conventional pharmacotherapy nor biological therapies have disease-modifying properties. In this context, allergen immunotherapy (AIT) represents an indispensable component of the therapeutic arsenal against allergic asthma, due to its disease-modifying immunological effects. In this review article, funded by an AIT manufacturer, we find clinical trials support AIT as the only treatment option able both to improve allergic asthma symptoms and to prevent the onset and worsening of the condition. For patients with severe asthma or other safety concerns, the combination of AIT and biologics offers very promising new treatment modalities for the management of allergic asthma. Trial Registration: clinicaltrials.gov identifier: NCT06027073., (© 2024 Stallergenes SAS and The Author(s). Clinical & Experimental Allergy published by John Wiley & Sons Ltd.)

Background: House dust mite (HDM) is the most common allergen trigger globally for allergic rhinitis and atopic asthma., Objectives: To expedite accurate confirmation of allergen sensitization, we designed fluorescent allergen tetramers to directly stain specific IgE on basophils to detect specific allergen sensitization using the flow cytometric CytoBas assay., Methods: Recombinant proteins of major HDM allergens (component), Der f 1, Der p 1, and Der p 2 were biotinylated and conjugated with fluorochrome streptavidins as tetramers. Blood samples from 64 patients who are HDM-allergic and 26 controls that are non-HDM-sensitized were incubated with allergen tetramers for evaluation of basophil binding (CytoBas) and activation (BAT) with flow cytometry., Results: The tetramers effectively bound and activated basophils from patients who are allergic but not from controls who are nonsensitized. CytoBas with Der p 1 as a single allergen had comparable sensitivity and specificity (92% and 100%) to BAT (91% and 100%) in detecting allergen sensitization, as did CytoBas with Der p 2 (95% and 96%) to BAT (95% and 87%). A positive staining for Der p 1 and/or Der p 2 in CytoBas was 100% sensitive and 96% specific for HDM allergy., Conclusions: CytoBas has diagnostic accuracy for group 1 and group 2 HDM allergens that is comparable to BAT, but with additional advantages of multiple allergen components in a single tube and no requirement for in vitro basophil activation. These findings endorse a single, multiplex CytoBas assay for accurate and component-resolved diagnosis of aeroallergen sensitization in patients with allergic asthma and/or rhinitis., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2023. Published by Elsevier Ltd.)

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.

Background: Molecular antibody reactivity profiles have not yet been studied in depth in patients treated by sublingual house dust mite (HDM) tablet immunotherapy. Humoral immune responses to a large panel of HDM mite allergens were studied using allergen microarray technology in a subset of clinically defined high and low responder patients from a double-blind placebo-controlled allergen-specific immunotherapy (AIT) trial using sublingual 300 IR HDM tablets., Methods: Serum levels of IgE, IgG and IgG 4 to 13 Dermatophagoides pteronyssinus molecules were measured at baseline and after 1-year AIT, using allergen microarrays in 100 subjects exhibiting high or low clinical benefit., Results: Der p 1, Der p 2 and Der p 23 were the most frequently recognized allergens in the study population. Patients with HDM-related asthma had significantly higher allergen-specific IgE levels to Der p 1 and Der p 23. No significant difference in the distribution of allergen sensitization pattern was observed between high and low responders. An increase in serum allergen-specific IgG and IgG 4 occurred upon AIT, in particular to allergens Der p 1, Der p 2 and Der p 23 (p < 0.0001)., Conclusions: We confirm for our study population that Der p 1- and Der p 23-specific IgE levels are associated with asthma. IgE reactivity profiles were not predicitive of sublingual AIT outcomes, with 300 IR tablets as efficacious in pauci- and multi-sensitized subjects. Our study is the first to demonstrate the induction of IgG and IgG 4  specific for the HDM allergens Der p 1, Der p 2 and Der p 23 by sublingual AIT., (© 2022 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: IgG2 responses are associated with repeated antigen exposure and display highly mutated variable domains. A recent study highlighted a role of IgG2+ memory B cells and allergen-specific IgG2 levels after a 3rd consecutive pre-seasonal sublingual allergen immunotherapy (AIT) with grass pollen tablet. Herein, we aim to explore changes in allergen-specific IgG2 in individuals undergoing house dust mite immunotherapy (HDM-AIT) and explore whether the interrelationship with other humoral responses (i.e., IgG4 and IgE) may discriminate between high and low responders., Methods: Levels of serum Dermatophagoides pteronyssinus and Dermatophagoides farinae-specific IgG2, IgG4, and IgE antibodies were measured by ELISA or ImmunoCap in a sub-group of individuals enrolled in a randomized, double-blind, placebo-controlled, sublingual AIT study evaluating the safety and efficacy of a 300 IR HDM tablet., Results: After 1-year sublingual AIT, HDM-specific serum IgG2 responses increase mostly in high versus low responders and are distinctive according to the clinical benefit. Higher correlation between HDM-specific IgG2, IgE, and/or IgG4 responses is seen in subjects benefiting the most from HDM-AIT as indicated by changes in Average Total Combined Scores. More strikingly, statistically significant correlation between HDM-specific IgG2 and IgE responses is only observed in individuals stratified as high responders., Conclusions: We provide evidence for coordinated serum immune responses upon AIT in HDM-allergic subjects exhibiting high clinical benefit when compared with low responders. Assessing HDM-specific IgE, IgG2, and IgG4 in serum could be used as follow-up combined markers to support decision as to AIT continuation and/or adaptation., (© 2021 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: In line with evidence for a role of pathogenic TH2A in seasonal allergies, we previously showed that individuals suffering from food allergy exhibited a decrease in circulating TH2A cells following multi-food immunotherapy. Herein, we aim to confirm the decline of TH2A cells in individuals undergoing house dust mite immunotherapy (HDM-AIT) and extend our observation to a new subset of CD38 expressing activated TH2A cells., Methods: The frequencies of TH2A and CD38 + TH2A cells were analysed by flow cytometry in blood cells from 182 Japanese HDM-allergic individuals included in a 1-year clinical trial assessing the efficacy of HDM tablets. Interrelationship between these cellular responses and humoral mite-specific IgE and IgG4 levels was further explored., Results: A decrease in TH2A cells was observed in both active and placebo groups. Interestingly, CD38 + TH2A cell frequencies significantly decreased only in active groups. In younger individuals (16-30 years), both TH2A and CD38 + TH2A cells were significantly reduced in active groups but not in the placebo group. Significant inverse correlations were observed in the course of HDM-AIT between changes in TH2A or CD38 + TH2A frequencies and IgG4 antibody levels., Conclusions: We confirm the value of monitoring TH2A cell frequencies in allergic individuals and extend this observation to perennial allergy to HDM. We highlight the interest of CD38 to better identify the subset of TH2A cell down-regulated by AIT. Finally, correlated cellular and humoral responses observed in immunoreactive individuals stress that coordinated pathways occur in the adaptive responses during AIT., (© 2021 John Wiley & Sons Ltd.)

Background: Whereas sublingual allergen immunotherapy (AIT) is routinely performed without any adjuvant or delivery system, there is a strong scientific rationale to better target the allergen(s) to oral dendritic cells known to support regulatory immune responses by using appropriate presentation platforms., Objective: To identify a safe presentation platform able to enhance allergen-specific tolerance induction., Methods: Virosomes with membrane-integrated contiguous overlapping peptides (COPs) of Bet v 1 and TLR4 or TLR2/TLR7 agonists were assessed for induction of Bet v 1-specific IgG1, IgG2a and IgE antibodies, hypersensitivity reactions and body temperature drop following subcutaneous injection in naive CD-1 mice. The most promising candidate, Bet v 1 COPs anchored to virosomes with membrane-incorporated TLR4 agonist (Vir.A-Bet v 1 COPs), was further evaluated by the sublingual route in a therapeutic setting in BALB/c mice with birch pollen-induced allergic asthma. Airway hyperresponsiveness, pro-inflammatory cells in bronchoalveolar lavages and polarization of Th cells in the lungs and spleen were then assessed., Results: Both types of adjuvanted virosomes coupled to Bet v 1 COPs triggered a boosted Th1 immunity. Given a more favourable safety profile, Vir.A-Bet v 1 COPs were further evaluated and shown to able to fully reverse asthma symptoms and lung inflammation in a sublingual therapeutic model of birch pollen allergy., Conclusions and Clinical Relevance: We report herein for the first time on the capacity of a novel and safe presentation platform, that is virosomes with membrane-integrated TLR4 agonist, to improve dramatically sublingual AIT efficacy in a murine model due to its intrinsic dual properties of targeting and stimulating to further promote anti-allergic immune responses. As such, our study paves the ground for further clinical development of this allergen presentation platform for patients suffering from respiratory allergies., (© 2020 John Wiley & Sons Ltd.)

Introduction : Allergen bioavailability underpins the efficacy and safety of SLIT tablets. Three product-related factors are likely to influence this: tablet potency, formulation and sublingual holding time. Areas covered : Tablet formulation determines the rate and extent of solubilized allergen release. Using validated in vitro dissolution assays, the two licensed grass pollen SLIT tablets are shown to release ≥85% of their total allergenic activity within several minutes. Sublingual holding time affects the contact duration between solubilized allergens and sublingual tissue. Maximal uptake of allergens by sublingual tissue requires ~5 minutes, with little uptake occurring within the first minute. A higher potency tablet with longer sublingual holding time would provide higher bioavailability, while faster rates of allergen release in vitro are unlikely to translate to a greater increase in bioavailability. Differences in dissolution times cannot serve as a surrogate of in vivo bioavailability, and are not related to differences in efficacy at the marketed tablet dosages. Rapid in vitro dissolution is likely not a key requirement for inducing a potent immune response. Expert opinion : In vitro dissolution cannot predict the clinical efficacy of SLIT tablets but could be important in immune tolerance and safety. In addition, a discontinuous administration regimen may have benefits for adherence and cost without compromising efficacy.