Mechanisms of Dupilumab Harb, Hani; Chatila, Talal A.
Clinical & experimental allergy/Clinical and experimental allergy,
January 2020, Volume:
50, Issue:
1
Journal Article
Peer reviewed
Open access
The Th2 cytokines interleukin 4 (IL‐4) and IL‐13 and the heterodimeric IL‐4 receptor (IL‐4R) complexes that they interact with play a key role in the pathogenesis of allergic disorders. Dupilumab is ...a humanized IgG4 monoclonal antibody that targets the IL‐4 receptor alpha chain (IL‐4Rα), common to both IL‐4R complexes: type 1 (IL‐4Rα/γc; IL‐4 specific) and type 2 (IL‐4Rα/IL‐13Rα1; IL‐4 and IL‐13 specific). In this review, we detail the current state of knowledge of the different signalling pathways coupled to the IL‐4R complexes and examine the possible mechanisms of Dupilumab action and survey its clinical efficacy in different allergic disorders. The development of Dupilumab and the widening spectrum of its clinical applications is relevant to the current emphasis on precision medicine approaches to the blockade of pathways involved in allergic diseases.
Regulatory T cells in allergic diseases Noval Rivas, Magali, PhD; Chatila, Talal A., MD, MSc
Journal of allergy and clinical immunology,
09/2016, Volume:
138, Issue:
3
Journal Article
Peer reviewed
Open access
The pathogenesis of allergic diseases entails an ineffective tolerogenic immune response to allergens. Regulatory T (Treg) cells play a key role in sustaining immune tolerance to allergens, yet ...mechanisms by which Treg cells fail to maintain tolerance in patients with allergic diseases are not well understood. We review current concepts and established mechanisms regarding how Treg cells regulate different components of allergen-triggered immune responses to promote and maintain tolerance. We will also discuss more recent advances that emphasize the “dual” functionality of Treg cells in patients with allergic diseases: how Treg cells are essential in promoting tolerance to allergens but also how a proallergic inflammatory environment can skew Treg cells toward a pathogenic phenotype that aggravates and perpetuates disease. These advances highlight opportunities for novel therapeutic strategies that aim to re-establish tolerance in patients with chronic allergic diseases by promoting Treg cell stability and function.
Oral immunotherapy has had limited success in establishing tolerance in food allergy, reflecting failure to elicit an effective regulatory T (Treg) cell response. We show that disease-susceptible ...(Il4raF709) mice with enhanced interleukin-4 receptor (IL-4R) signaling exhibited STAT6-dependent impaired generation and function of mucosal allergen-specific Treg cells. This failure was associated with the acquisition by Treg cells of a T helper 2 (Th2)-cell-like phenotype, also found in peripheral-blood allergen-specific Treg cells of food-allergic children. Selective augmentation of IL-4R signaling in Treg cells induced their reprogramming into Th2-like cells and disease susceptibility, whereas Treg-cell-lineage-specific deletion of Il4 and Il13 was protective. IL-4R signaling impaired the capacity of Treg cells to suppress mast cell activation and expansion, which in turn drove Th2 cell reprogramming of Treg cells. Interruption of Th2 cell reprogramming of Treg cells might thus provide candidate therapeutic strategies in food allergy.
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•Treg cells manifest a Th2-cell-like phenotype in food allergy•Th2-cell-like reprogramming of Treg cells promotes food allergy•Inactivation of Th2 cell pathways in Treg cells protects against food allergy
Food allergy is characterized by failure of oral-tolerance mechanisms. Chatila and colleagues demonstrate that in food allergy, regulatory T (Treg) cells acquire a T helper 2 (Th2)-cell-like phenotype that plays a pathogenic role in disease.
•Food allergy (FA) is characterized by pathogenic dysbiosis.•The dysbiosis in FA disrupts oral tolerance to dietary antigens by impairing the generation of ROR-γt+ induced regulatory T cells.•Therapy ...with Clostridiales and Bacteroidales commensal bacteria activates a MyD88- ROR-γt axis in nascent iTreg cells to restore immune tolerance in FA.
The steep rise in the incidence and prevalence of food allergy (FA) in the last few decades have focused attention of environmental mechanisms which act to promote disease, chief among which is the microbiome. Recent studies have now established the presence of pathogenic dysbiosis in FA that could be precipitated by a variety of environmental insults, including among others antibiotic usage and mode of delivery, that act to subvert the immune regulatory response that enforce tolerance to dietary antigens. A key attribute of this dysbiosis is the loss of Clostridial bacterial species that act to promote the formation of food allergen-specific nascent regulatory T cells in the gut. Significantly, different immunoprotective commensal bacteria, including members of the Clostridiales and Bacteroidales orders act to induce the transcription factor RORγt in nascent Treg cells via an upstream MyD88-dependent mechanism to promote tolerance to dietary antigens. Activation of this axis is disrupted by the dysbiosis, and can be restored by treatment with therapeutic microbiota. These findings highlight the potential for novel microbiota-based approaches to the prevention and treatment of the FA epidemic.
We report the updated classification of Inborn Errors of Immunity/Primary Immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee. This report documents ...the key clinical and laboratory features of 430 inborn errors of immunity, including 64 gene defects that have either been discovered in the past 2 years since the previous update (published January 2018) or were characterized earlier but have since been confirmed or expanded upon in subsequent studies. The application of next-generation sequencing continues to expedite the rapid identification of novel gene defects, rare or common; broaden the immunological and clinical phenotypes of conditions arising from known gene defects and even known variants; and implement gene-specific therapies. These advances are contributing to greater understanding of the molecular, cellular, and immunological mechanisms of disease, thereby enhancing immunological knowledge while improving the management of patients and their families. This report serves as a valuable resource for the molecular diagnosis of individuals with heritable immunological disorders and also for the scientific dissection of cellular and molecular mechanisms underlying inborn errors of immunity and related human diseases.
Abstract Dedicator of Cytokinesis 8 (DOCK8) deficiency is a combined immunodeficiency that exemplifies the broad clinical features of primary immunodeficiencies (PIDs), extending beyond recurrent ...infections to include atopy, autoimmunity and cancer. It is caused by loss of function mutations in DOCK8 , encoding a guanine nucleotide exchange factor highly expressed in lymphocytes that regulates the actin cytoskeleton. Additional roles of DOCK8 have also emerged, including regulating MyD88-dependent Toll-like receptor signaling and the activation of the transcription factor STAT3. DOCK8 deficiency impairs immune cell migration, function and survival, and it impacts both innate and adaptive immune responses. Clinically, DOCK8 deficiency is characterized by allergic inflammation as well as susceptibility towards infections, autoimmunity and malignancy. This review details the pathophysiology, clinical features and management of DOCK8 deficiency. It also surveys the recently discovered combined immunodeficiency due to DOCK2 deficiency, highlighting in the process the emerging spectrum of PIDs resulting from DOCK protein family abnormalities.
Regulatory T Cells: the Many Faces of Foxp3 Georgiev, Peter; Charbonnier, Louis-Marie; Chatila, Talal A.
Journal of clinical immunology,
10/2019, Volume:
39, Issue:
7
Journal Article
Peer reviewed
Open access
Regulatory T (Treg) cells expressing the transcription factor forkhead box P3 (Foxp3) play a requisite role in the maintenance of immunological homeostasis and prevention of peripheral self-tolerance ...breakdown. Although Foxp3 by itself is neither necessary nor sufficient to specify many aspects of the Treg cell phenotype, its sustained expression in Treg cells is indispensable for their phenotypic stability, metabolic fitness, and regulatory function. In this review, we summarize recent advances in Treg cell biology, with a particular emphasis on the role of Foxp3 as a transcriptional modulator and metabolic gatekeeper essential to an effective immune regulatory response. We discuss these findings in the context of human inborn errors of immune dysregulation, with a focus on
FOXP3
mutations, leading to Treg cell deficiency. We also highlight emerging concepts of therapeutic Treg cell reprogramming to restore tolerance in the settings of immune dysregulatory disorders.
RORγt+ regulatory T (Treg) cells are critical toward maintaining gut immune tolerance. In recent studies published in Nature, Kedmi et al., Lyu et al., and Akagbosu et al. describe MHCII+RORγt+ ...antigen-presenting cells that mediate RORγt+ Treg cell differentiation but propose disparate identities for these cells.
RORγt+ regulatory T (Treg) cells are critical toward maintaining gut immune tolerance. In recent studies published in Nature, Kedmi et al., Lyu et al., and Akagbosu et al. describe MHCII+RORγt+ antigen-presenting cells that mediate RORγt+ Treg cell differentiation but propose disparate identities for these cells.
Since 2013, the International Union of Immunological Societies (IUIS) expert committee (EC) on Inborn Errors of Immunity (IEI) has published an updated phenotypic classification of IEI, which ...accompanies and complements their genotypic classification into ten tables. This phenotypic classification is user-friendly and serves as a resource for clinicians at the bedside. There are now 430 single-gene IEI underlying phenotypes as diverse as infection, malignancy, allergy, autoimmunity, and autoinflammation. We herein report the 2019 phenotypic classification, including the 65 new conditions. The diagnostic algorithms are based on clinical and laboratory phenotypes for each of the ten broad categories of IEI.
The steep rise in food allergy (FA) has evoked environmental factors involved in disease pathogenesis, including the gut microbiota, diet, and their metabolites. Early introduction of solid foods ...synchronizes with the “weaning reaction,” a time during which the microbiota imprints durable oral tolerance. Recent work has shown that children with FA manifest an early onset dysbiosis with the loss of Clostridiales species, which promotes the differentiation of ROR-γt+ regulatory T cells to suppress FA. This process can be reversed in pre-clinical mouse models by targeted bacteriotherapy. Here, we review the dominant tolerance mechanisms enforced by the microbiota to suppress FA and discuss therapeutic intervention strategies that act to recapitulate the early life window of opportunity in stemming the FA epidemic.
The steep rise in food allergy (FA) has evoked environmental factors involved in disease pathogenesis, including the gut microbiota, diet, and their metabolites. Early introduction of solid foods synchronizes with the “weaning reaction,” a time during which the microbiota imprints durable oral tolerance. Recent work has shown that children with FA manifest an early onset dysbiosis with the loss of Clostridiales species, which promotes the differentiation of ROR-γt+ regulatory T cells to suppress FA. This process can be reversed in pre-clinical mouse models by targeted bacteriotherapy. Here, we review the dominant tolerance mechanisms enforced by the microbiota to suppress FA and discuss therapeutic intervention strategies that act to recapitulate the early life window of opportunity in stemming the FA epidemic.
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