Transcriptome analysis and safety profile of the early-phase clinical response to an adjuvanted grass allergoid immunotherapy

Peripheral blood mononuclear cell transcriptome profile in a clinical trial with subcutaneous, grass pollen allergoid immunotherapy

INTRODUCTION

Allergen-specific immunotherapy (AIT) is the only disease-modifying treatment in allergic airway diseases. Underlying immunological mechanisms and candidate biomarkers, which may be translated into predictive/surrogate measures of clinical efficacy, remain an active area of research. The aim of this study was to evaluate Pollinex Quattro (PQ) Grass AIT induced immunomodulatory mechanisms, based on transcriptome profiling of peripheral blood mononuclear cells.

METHODS

119 subjects with grass pollen induced seasonal allergic rhinitis (SAR) were randomized in a 2:2:1:1 ratio to receive a cumulative dose of PQ Grass as a conventional or extended pre-seasonal regimen, placebo, or placebo with MicroCrystalline Tyrosine. Gene expression analysis was an exploratory endpoint evaluated in a subgroup of 30 subjects randomly selected from the four treatment arms. Samples were collected at three time points: screening (baseline), before the start of the grass pollen season and at the end of the season. This study was funded by the manufacturer of PQ.

RESULTS

Transcriptome analysis demonstrated that the most significant changes in gene expression, for both treatment regimens, were at the end of the grass pollen season, with the main Th1 candidate molecules (IL-12A, IFNγ) upregulated and Th2 signature cytokines downregulated (IL-4, IL-13, IL-9) (p < .05). Canonical pathways analysis demonstrated Th1, Th2, Th17 and IL-17 as the most significantly enriched pathways based on absolute value of activation z-score (IzI score ≥ 2, p < .05). Upstream regulator analysis showed pronounced inhibition of pro-inflammatory allergic molecules IgE, IL-17A, IL-17F, IL-25 (IL-17E) (IzI score ≥ 2, FDR < 0.05) and activation of pro-tolerogenic molecules IL-12A, IL-27, IL-35 (EBI3) at the end of the grass pollen season.

CONCLUSION

Peripheral blood mononuclear cells transcriptome profile showed an inhibition of Th2, Th17 pro-inflammatory allergic responses and immune deviation towards Th1 responses. PQ Grass extended regimen exhibited a superior mechanistic efficacy profile in comparison with PQ conventional regimen.

The Present and Future of Allergen Immunotherapy in Personalized Medicine

Allergic diseases are particularly suitable for personalized medicine, because they meet the needs for therapeutic success, which include a known molecular mechanism of the disease, a diagnostic tool for that disease and a treatment that blocks this mechanism. A range of tools is available for personalized allergy diagnosis, including molecular diagnostics, treatable traits and omics (i.e., proteomics, epigenomics, metabolomics, transcriptomics and breathomics), to predict patient response to therapies, detect biomarkers and mediators and assess disease control status. Such tools enhance allergen immunotherapy. Higher diagnostic accuracy results in a significant increase (based on a greater performance achieved with personalized treatment) in efficacy, further increasing the known and unique characteristics of a treatment designed to work on allergy causes.

Integrative Transcriptomics Reveals Activation of Innate Immune Responses and Inhibition of Inflammation During Oral Immunotherapy for Egg Allergy in Children

We previously reported the results of a randomized, open-label trial of egg oral immunotherapy (OIT) in 50 children where 44% were desensitized and 46% were partially desensitized after 8 months of treatment. Here we focus on cell-mediated molecular mechanisms driving desensitization during egg OIT. We sought to determine whether changes in genome-wide gene expression in blood cells during egg OIT correlate with humoral responses and the clinical outcome. The blood cell transcriptome of 50 children receiving egg OIT was profiled using peripheral blood mononuclear cell (PBMC) samples obtained at baseline and after 3 and 8 months of OIT. We identified 467 differentially expressed genes (DEGs) after 3 or 8 months of egg OIT. At 8 months, 86% of the DEGs were downregulated and played a role in the signaling of TREM1, IL-6, and IL-17. In correlation analyses, Gal d 1–4-specific IgG4 antibodies associated positively with DEGs playing a role in pathogen recognition and antigen presentation and negatively with DEGs playing a role in the signaling of IL-10, IL-6, and IL-17. Desensitized and partially desensitized patients had differences in their antibody responses, and although most of the transcriptomic changes were shared, both groups had also specific patterns, which suggest slower changes in partially desensitized and activation of NK cells in the desensitized group. OIT for egg allergy in children inhibits inflammation and activates innate immune responses regardless of the clinical outcome at 8 months. Changes in gene expression patterns first appear as posttranslational protein modifications, followed by more sustained epigenetic gene regulatory functions related to successful desensitization.

Allergens and Adjuvants in Allergen Immunotherapy for Immune Activation, Tolerance, and Resilience

Allergen immunotherapy (AIT) is the only setting in which a vaccine is applied in patients allergic exactly to the active principle in the vaccine. Therefore, AIT products need to be not only effective but also safe. In Europe, for subcutaneous AIT, this has been achieved by the allergoid strategy in which IgE epitopes are destroyed or masked. In addition, adjuvants physically precipitate the allergen at the injection site to prevent too rapid systemic distribution. The choice of adjuvant critically shapes the efficacy and type of immune response to the injected allergen. In contrast to T_H2-promoting adjuvants, others clearly counteract allergy. Marketed products in Europe are formulated with aluminum hydroxide (alum) (66.7%), microcrystalline tyrosine (16.7%), calcium phosphate (11.1%), or the T_H1 adjuvant monophosphoryl lipid A (5.6%). In contrast to the European practice, in the United States mostly nonadjuvanted extracts and no allergoids are used for subcutaneous AIT, highlighting not only a regulatory but maybe a "historic preference." Sublingual AIT in the form of drops or tablets is currently applied worldwide without adjuvants, usually with higher safety but lower patient adherence than subcutaneous AIT. This article will discuss how AIT and adjuvants modulate the immune response in the treated patient toward immune activation, modulation, or-with new developments in the pipeline-immune resilience.

Changes in Immunologic Indicators During Allergen-Specific Immunotherapy for Allergic Rhinitis and Determinants of Variability: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

To date, there are no generally recognized biomarkers for allergen immunotherapy (AIT) and even the changes in immunological indicators during AIT are inconsistent in different publications.

OBJECTIVE

This study was conducted to quantify the immunological changes that occur during AIT and identify the determinants of heterogeneity.

METHODS

Randomized controlled trials of AIT published in the past 10 years were searched in Medline, Embase and Cochrane CENTRAL. Data on immunological indicators were extracted, and the characteristics of the included studies were collected. Meta-analysis and meta-regression were conducted for each indicator. The study was registered on the PROSPERO website (CRD42020176127).

RESULTS

We reviewed 1898 studies. Forty-six studies met the inclusion criteria, and 31 studies were included in the quantitative analyses. Subset analyses by time demonstrated that serum allergen-specific IgE (sIgE) of AIT patients increased in the first 12 months, then decreased and became slightly lower than that of control patients. Allergen-specific IgG4 (sIgG4) was elevated in the AIT group during and after treatment. IgE-blocking factor (IgE-BF) was increased and IgE-facilitated allergen binding (IgE-FAB) was reduced in AIT patients. Both of them of the 2 factors were associated with clinical efficacy in the multivariate regression analysis. sIgE/sIgG4 decreased in AIT patients, while there was no change in total IgE.

CONCLUSION

The levels of serum sIgE and sIgG4 during AIT showed a time-dependent pattern. IgE-BF and IgE-FAB should be further investigated as biomarkers for predicting and monitoring AIT efficacy.

Shaping Modern Vaccines: Adjuvant Systems Using MicroCrystalline Tyrosine (MCT®)

The concept of adjuvants or adjuvant systems, used in vaccines, exploit evolutionary relationships associated with how the immune system may initially respond to a foreign antigen or pathogen, thus mimicking natural exposure. This is particularly relevant during the non-specific innate stage of the immune response; as such, the quality of this response may dictate specific adaptive responses and conferred memory/protection to that specific antigen or pathogen. Therefore, adjuvants may optimise this response in the most appropriate way for a specific disease. The most commonly used traditional adjuvants are aluminium salts; however, a biodegradable adjuvant, MCT®, was developed for application in the niche area of allergy immunotherapy (AIT), also in combination with a TLR-4 adjuvant-Monophosphoryl Lipid A (MPL®)-producing the first adjuvant system approach for AIT in the clinic. In the last decade, the use and effectiveness of MCT® across a variety of disease models in the preclinical setting highlight it as a promising platform for adjuvant systems, to help overcome the challenges of modern vaccines. A consequence of bringing together, for the first time, a unified view of MCT® mode-of-action from multiple experiments and adjuvant systems will help facilitate future rational design of vaccines while shaping their success.