Allergen-specific immunotherapy enhances CD8+ CD25+ CD137+ regulatory T cells and decreases nasal nitric oxide

Allergen-Encapsulating Nanoparticles Reprogram Pathogenic Allergen-Specific Th2 Cells to Suppress Food Allergy

Food allergy is a prevalent, potentially deadly disease caused by inadvertent sensitization to benign food antigens. Pathogenic Th2 cells are a major driver for disease, and allergen-specific immunotherapies (AIT) aim to increase the allergen threshold required to elicit severe allergic symptoms. However, the majority of AIT approaches require lengthy treatments and convey transient disease suppression, likely due to insufficient targeting of pathogenic Th2 responses. Here, the ability of allergen-encapsulating nanoparticles to directly suppress pathogenic Th2 responses and reactivity is investigated in a mouse model of food allergy. NPs associate with pro-tolerogenic antigen presenting cells, provoking accumulation of antigen-specific, functionally suppressive regulatory T cells in the small intestine lamina propria. Two intravenous doses of allergen encapsulated in poly(lactide-co-glycolide) nanoparticles (NPs) significantly reduces oral food challenge (OFC)-induced anaphylaxis. Importantly, NP treatment alters the fates of pathogenic allergen-specific Th2 cells, reprogramming these cells toward CD25+FoxP3+ regulatory and CD73+FR4+ anergic phenotypes. NP-mediated reductions in the frequency of effector cells in the gut and mast cell degranulation following OFC are also demonstrated. These studies reveal mechanisms by which an allergen-encapsulating NP therapy and, more broadly, allergen-specific immunotherapies, can rapidly attenuate allergic responses by targeting pathogenic Th2 cells.

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

BACKGROUND

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

SUMMARY

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

KEY MESSAGE

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

Predicting the therapeutic efficacy of AIT for asthma using clinical characteristics, serum allergen detection metrics, and machine learning techniques

Bronchial asthma is a prevalent non-communicable disease among children. The study collected clinical data from 390 children aged 4-17 years with asthma, with or without rhinitis, who received allergen immunotherapy (AIT). Combining these data, this paper proposed a predictive framework for the efficacy of mite subcutaneous immunotherapy in asthma based on machine learning techniques. Introducing the dispersed foraging strategy into the Salp Swarm Algorithm (SSA), a new improved algorithm named DFSSA is proposed. This algorithm effectively alleviates the imbalance between search speed and traversal caused by the fixed partitioning pattern in traditional SSA. Utilizing the fusion of boosting algorithm and kernel extreme learning machine, an AIT performance prediction model was established. To further investigate the effectiveness of the DFSSA-KELM model, this study conducted an auxiliary diagnostic experiment using the immunotherapy predictive medical data collected by the hospital. The findings indicate that selected indicators, such as blood basophil count, sIgE/tIgE (Der p) and sIgE/tIgE (Der f), play a crucial role in predicting treatment outcome. The classification results showed an accuracy of 87.18% and a sensitivity of 93.55%, indicating that the prediction model is an effective and accurate intelligent tool for evaluating the efficacy of AIT.

Pathogenesis and novel therapeutics of regulatory T cell subsets and interleukin-2 therapy in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous multisystem inflammatory disease with wide variability in clinical manifestations. Natural arising CD4+ regulatory T cells (Tregs) play a critical role in maintaining peripheral tolerance by suppressing inflammation and preventing autoimmune responses in SLE. Additionally, CD8+ regulatory T cells, type 1 regulatory T cells (Tr1), and B regulatory cells also have a less well-defined role in the pathogenesis of SLE. Elucidation of the roles of various Treg subsets dedicated to immune homeostasis will provide a novel therapeutic approach that governs immune tolerance for the remission of active lupus. Diminished interleukin (IL)-2 production is associated with a depleted Treg cell population, and its reversibility by IL-2 therapy provides important reasons for the treatment of lupus. This review focuses on the pathogenesis and new therapeutics of human Treg subsets and low-dose IL-2 therapy in clinical benefits with SLE.

CD8+ Tregs ameliorate inflammatory reactions in a murine model of allergic rhinitis

BACKGROUND

CD8⁺CD25⁺fork-head box transcription factor (Foxp3)⁺ regulatory T cells (CD8⁺ Tregs) play a role in immune tolerance. However, the role of these cells in allergic rhinitis (AR) has not been elucidated. The study aimed to evaluate influences of CD8⁺ Tregs on inflammatory conditions in a murine model of AR.

METHODS

A murine model of AR was established. CD8⁺ Tregs were isolated from mice nasal mucosa and cultured in vitro. We examined interleukin (IL)-10 and transforming growth factor (TGF)-β in cell cultures. Then, we administered CD8⁺ Tregs into mice nasal mucosal cultures, and examined eosinophil cation protein (ECP), IL-4, IL-5 and IL-13 in these cultures. Finally, we adoptively transferred CD8⁺ Tregs into mice models, and evaluated percentages of CD8⁺ Tregs, numbers of sneezing and nasal rubbing, and counts of eosinophils and contents of ECP, IL-4, IL-5, IL-13, IL-10 and TGF-β in nasal lavage fluid (NLF) in mice.

RESULTS

The percentage of CD8⁺ Tregs from AR mice was reduced. IL-10 and TGF-β were increased in cell cultures from AR mice. ECP, IL-4, IL-5 and IL-13 were decreased after the AR mice CD8⁺ Tregs administration in mucosal cultures. However, their contents were not changed after normal CD8⁺ Tregs treatment. Additionally, the adoptive transfer of AR CD8⁺ Tregs enhanced the percentage of CD8⁺ Tregs and levels of IL-10 and TGF-β in NLF, reduced numbers of sneezing and nasal rubbing, and counts of eosinophils and concentrations of ECP, IL-4, IL-5 and IL-13 in NLF. However, normal CD8⁺ Tregs could not change above parameters.

CONCLUSION

These findings show that CD8⁺ Tregs may inhibit inflammatory responses in the AR condition.

Sublingual Immunotherapy: How Sublingual Allergen Administration Heals Allergic Diseases; Current Perspective about the Mode of Action

Owing to the successful application of sublingual immunotherapy (SLIT), allergen immunotherapy (AIT) has become one of the leading treatments for allergic diseases. Similar to the case with other AITs, such as subcutaneous and oral immunotherapies, not only the alleviation of allergic symptoms, but also the curing of the diseases can be expected in patients undergoing SLIT. However, how and why such strong efficacy is obtained by SLIT, in which allergens are simply administered under the tongue, is not clearly known. Various potential mechanisms, including the induction of blocking antibodies, T cell tolerance, regulatory B and T cells, CD103^-CD11b⁺ classical dendritic cells, and CD206⁺ macrophages, and the reduction of innate lymphoid cells, mast cells, and basophils, have been suggested. Recently, through a comparative analysis between high- and non-responder patients of SLIT, we have successfully proposed several novel mechanisms. Here, we introduce our recent findings and summarize the current understanding of the mechanisms underlying the strong efficacy of SLIT.

CD8+ T Lymphocytes: Crucial Players in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease associated with damage to multiple organs and glands. The most common clinical manifestations are dry eyes, dry mouth, and enlarged salivary glands. Currently, CD4+ T lymphocytes are considered to be key factors in the immunopathogenesis of pSS, but various studies have shown that CD8+ T lymphocytes contribute to acinar injury in the exocrine glands. Therefore, in this review, we discussed the classification and features of CD8+ T lymphocytes, specifically describing the role of CD8+ T lymphocytes in disease pathophysiology. Furthermore, we presented treatment strategies targeting CD8+ T cells to capitalize on the pathogenic and regulatory potential of CD8+ T lymphocytes in SS to provide promising new strategies for this inflammatory disease.

Predicting Success of Allergen-Specific Immunotherapy

The immune response to antigens is a key aspect of immunology, as it provides opportunities for therapeutic intervention. However, the induction of immunological tolerance is an evolving area that is still not sufficiently understood. Allergen immunotherapy (AIT) is a disease-modulating therapy available for immunoglobulin E (IgE)-mediated airway diseases such as allergic rhinitis or allergic asthma. This disease-modifying effect is not only antigen driven but also antigen specific. The specificity and also the long-lasting, often life-long symptom reduction make the therapy attractive for patients. Additionally, the chance to prevent the onset of asthma by treating allergic rhinitis with AIT is important. The mechanism and, in consequence, therapy guiding biomarker are still in its infancy. Recent studies demonstrated that the interaction of T, B, dendritic, and epithelial cells and macrophages are individually contributing to clinical tolerance and therefore underline the need for a system to monitor the progress and success of AIT. As clinical improvement is often accompanied by decreases in numbers of effector cells in the tissue, analyses of cellular responses and cytokine pattern provide a good insight into the mechanisms of AIT. The suppression of type-2 immunity is accompanied by decreased levels of type-2 mediators such as epithelial CCL-26 and interleukin (IL)-4, IL-13 produced by T cells that are constituting the immune memory and are increasingly controlled by regulatory T and B cells following AIT. Immune tolerance is also associated with increased production of type-1 mediators like interferon-gamma, tissue-homeostating factors like indoleamine 2,3-dioxygenase (IDO) expressed by macrophages and dendritic cells. Although these individual genes were convincingly demonstrated to play a role immune tolerance, they do not predict therapy outcomes of AIT on an individual level. Therefore, combinations or ratios of gene expression levels are a promising way to achieve predictive value and definition of helpful biomarker.

The role of trogocytosis in immune surveillance of Hodgkin lymphoma

Hodgkin lymphoma (HL) is a unique type of hematopoietic cancer that has few tumor cells but a massive infiltration of immune cells. Findings on how the cancerous Hodgkin and Reed-Sternberg (HRS) cells survive and evade immune surveillance have facilitated the development of novel immunotherapies for HL. Trogocytosis is a fast process of intercellular transfer of membrane patches, which can significantly affect immune responses. In this review, we summarize the current knowledge of how trogocytosis contributes to the suppression of immune responses in HL. We focus on the ectopic expression of CD137 on HRS cells, the cause of its expression, and its implication on developing novel therapies for HL. Further, we review data demonstrating that similar mechanisms apply to CD30, PD-L1 and CTLA-4.

Recent developments and highlights in immune monitoring of allergen immunotherapy

Allergic diseases are the most common chronic immune-mediated disorders and can manifest with an enormous diversity in clinical severity and symptoms. Underlying mechanisms for the adverse immune response to allergens and its downregulation by treatment are still being revealed. As a result, there have been, and still are, major challenges in diagnosis, prediction of disease progression/evolution and treatment. Currently, the only corrective treatment available is allergen immunotherapy (AIT). AIT modifies the immune response through long-term repeated exposure to defined doses of allergen. However, as the treatment usually needs to be continued for several years to be effective, and can be accompanied by adverse reactions, many patients face difficulties completing their schedule. Long-term therapy also potentially incurs high costs. Therefore, there is a great need for objective markers to predict or to monitor individual patient's beneficial changes in immune response during therapy so that efficacy can be identified as early as possible. In this review, we specifically address recent technical developments that have generated new insights into allergic disease pathogenesis, and how these could potentially be translated into routine laboratory assays for disease monitoring during AIT that are relatively inexpensive, robust and scalable.

Future prospects for CD8+ regulatory T cells in immune tolerance

CD8⁺ Tregs have been long described and significant progresses have been made about their phenotype, their functional mechanisms, and their suppressive ability compared to conventional CD4⁺ Tregs. They are now at the dawn of their clinical use. In this review, we will summarize their phenotypic characteristics, their mechanisms of action, the similarities, differences and synergies between CD8⁺ and CD4⁺ Tregs, and we will discuss the biology, development and induction of CD8⁺ Tregs, their manufacturing for clinical use, considering open questions/uncertainties and future technically accessible improvements notably through genetic modifications.