Cited by 2IL-33, ST2, and ILC PathwaysAsthma and respiratory diseasesMast cells and histamine

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Understanding the Type 2 Immunity: An Evolving View Beyond Allergic Diseases

Open access

Abstract

Type 2 (T2) immunity is classically associated with defense against helminths and environmental threats, from a physiological perspective, and with allergies and eosinophilic inflammatory diseases, in a pathological sense. However, growing evidence reveals that T2 pathways also support other essential homeostatic functions, including tissue protection and repair. There are major clues from the early evolution of T2 responses for protection against massive tissue damage and positive selection for survival against parasites starting over 500 million years ago. These responses likely co‐evolved stepwise with immune‐regulatory circuits, culminating in the emergence of the fully functional human‐type IgG4 in the great apes (Hominidae) within the last ~10 million years. The involvement of body barriers along with the strong influence of local epithelial cells and their interaction with the microbiome and the immune system is a common characteristic of T2 inflammation. An expanding list of new T2 diseases is being reported, characterized by epithelial cell and immune system activation, epithelial barrier damage, and microbial dysbiosis, including opportunistic pathogen colonization and loss of commensals. This evolving understanding coincides with the clinical success of biologics targeting key T2 mediators such as IL‐4, IL‐5, IL‐13, IL‐31, TSLP, and IgE, which have transformed the management of severe allergic diseases and other T2‐driven pathologies. However, the contribution of T2 immunity to homeostatic programs raises questions about the long‐term consequences of sustained T2 suppression. In this review, we examine the dual role of T2 immunity in health and disease, revisit its evolutionary origins, highlight its protective functions beyond allergy, and discuss the potential implications of prolonged T2 pathway blockade.

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Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This review argues that type 2 (T2) immunity is not only a driver of allergic disease but an evolutionarily ancient surface-surveilling system with homeostatic roles in barrier repair, parasite defense, toxin neutralization, food aversion, cancer surveillance, cardiovascular health, aging/thymic regeneration, metabolism, and neuroimmune function. It reviews biologics targeting IL-4/IL-13, IL-5, IL-31, TSLP, and IgE, and cautions that long-term, broad T2 suppression may have understudied consequences.

Key findings

  • T2 immunity evolved as a survival system at body surfaces: mast-cell-like cells date back >500 million years, ILCs arose ~500 Mya, IgE arose in early mammals 220–300 Mya, and fully functional human-type IgG4 emerged in great apes within the last ~10 million years; allergic diseases affect nearly 1 billion people.
  • Beyond allergy, T2 pathways contribute to anti-helminth defense, toxin neutralization, food aversion, tissue repair, cancer immune surveillance, cardiovascular homeostasis, thymic regeneration, adipose/metabolic regulation, and neuronal function.
  • New T2 diseases are characterized by epithelial cell and immune activation, epithelial barrier damage, and microbial dysbiosis; biologics targeting IL-4, IL-5, IL-13, IL-31, TSLP, and IgE have transformed management of severe allergic and other T2-driven pathologies.
  • Safety signals include helminth infections with eosinophil-depleting therapies (reporting OR typically >3–4), increased lymphoma/CTCL risk with anti-IL-4Rα in real-world data, and cardiovascular event signals with omalizumab, dupilumab, and tezepelumab, though absolute risks are low and evidence remains inconclusive.

Methods

  • Narrative review; no datasets were generated or analyzed (Data availability statement).
  • Synthesizes evolutionary, preclinical, epidemiological, clinical trial, and pharmacovigilance literature, with figures and tables summarizing mechanisms and biologic therapies.
  • No systematic search strategy, inclusion criteria, or meta-analysis is reported.

Limitations

  • Stated: long-term consequences of sustained T2 suppression remain unclear, particularly for barrier integrity and repair, host defense against infections, and cancer immune surveillance; evidence linking T2-targeted therapies to infections, malignancy, and cardiovascular events remains inconclusive and requires prospective validation.
  • Stated: real-world and pharmacovigilance data have inherent limitations, including potential misclassification of early CTCL as atopic dermatitis and confounding by indication.
  • Evident: as a narrative review, it lacks systematic methods and primary data, and many conclusions rely on preclinical models and observational associations.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1111/all.70512

Cites

283 of 284 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

FIGURE 1 Evolution of T2 immunity and immune regulatory pathways. Development from invertebrate ancestors (Chordates) to Hominidae. The period when the 'immune Big Bang' occurred (Gnathostomes), establishing the modern immune system of jawed vertebrates, is highlighted in orange in the background. Blue indicates cells and molecules involved in T2 inflammation and orange those implicated in regulation. The IgG4 shown in the timeline refers specifically to the fully functional human IgG4 subclass. Breg, regulatory B cells; Ig, immunoglobulin; IL, interleukin; ILC2, group 2 innate lymphoid cell; Mya, million years ago; TGF-­ β, transforming growth factor β; Treg, regulatory T cells; TSLP, thymic stromal lymphopoietin.
FIGURE 1 Evolution of T2 immunity and immune regulatory pathways. Development from invertebrate ancestors (Chordates) to Hominidae. The period when the 'immune Big Bang' occurred (Gnathostomes), establishing the modern immune system of jawed vertebrates, is highlighted in orange in the background. Blue indicates cells and molecules involved in T2 inflammation and orange those implicated in regulation. The IgG4 shown in the timeline refers specifically to the fully functional human IgG4 subclass. Breg, regulatory B cells; Ig, immunoglobulin; IL, interleukin; ILC2, group 2 innate lymphoid cell; Mya, million years ago; TGF-­ β, transforming growth factor β; Treg, regulatory T cells; TSLP, thymic stromal lymphopoietin.CC-BY-NC · From the PDF
FIGURE 2 Tissue responses to damage on the body surfaces. Various environmental factors introduced by human activity can induce damage to epithelial barriers. This damage leads to structural and functional alterations, characterized by disruption of TJ and increased epithelial permeability, which facilitates the translocation of microorganisms and microbial products. This triggers the release of alarmins, inflammasome activation, and the production of pro-­ inflammatory cytokines and chemokines, which collectively promote inflammation and tissue damage. Over time, these processes can lead to the development of chronic inflammatory diseases. In this context, the T2 response contributes transiently to the opening of the epithelial barrier, facilitating the expulsion of toxins, pollutants, and microorganisms through dynamic regulation of TJ and increased mucus secretion. On the other hand, the T2 response also participates in the resolution of inflammation and the restoration of tissue homeostasis by different mechanisms contributing to the restoration of the integrity of body surfaces and limiting progression toward chronic pathological inflammation. TJ, tight junctions.
FIGURE 2 Tissue responses to damage on the body surfaces. Various environmental factors introduced by human activity can induce damage to epithelial barriers. This damage leads to structural and functional alterations, characterized by disruption of TJ and increased epithelial permeability, which facilitates the translocation of microorganisms and microbial products. This triggers the release of alarmins, inflammasome activation, and the production of pro-­ inflammatory cytokines and chemokines, which collectively promote inflammation and tissue damage. Over time, these processes can lead to the development of chronic inflammatory diseases. In this context, the T2 response contributes transiently to the opening of the epithelial barrier, facilitating the expulsion of toxins, pollutants, and microorganisms through dynamic regulation of TJ and increased mucus secretion. On the other hand, the T2 response also participates in the resolution of inflammation and the restoration of tissue homeostasis by different mechanisms contributing to the restoration of the integrity of body surfaces and limiting progression toward chronic pathological inflammation. TJ, tight junctions.CC-BY-NC · From the PDF
FIGURE 3 T2 response against extracellular parasites. Extracellular parasites can infect different tissues, causing epithelial disruption. This damage triggers the release of alarmins, which induce the activation of ILC2s, thereby amplifying the early T2 response through the production of cytokines, the expansion of granulocytes, and M2 polarization. These cell populations cooperate in the containment, elimination, and expulsion of the parasite by several mechanisms including mucus hypersecretion and muscular hypercontractility, which facilitate the flushing out of the parasite; vasodilation and increased vascular permeability, promoting the recruitment of immune cells; and pruritus, causing scratching and mechanically contributing to parasite elimination. Moreover, M2 are also involved in defending against larvae within the tissue lumen through encapsulation processes and granuloma formation; as well as by metabolic modulation via Arg1 expression, which reduces the bioavailability of arginine, thereby limiting the parasite's survival. Eosinophils contribute to the direct elimination of the parasite via EETs, which immobilize the parasite; and by the release of cytotoxic proteins (MBP, ECP, and EPO), which damage its structural integrity. Arg1, arginase 1; BAS, basophils; ECP, eosinophil cationic protein; EETs, eosinophil extracellular traps; EOS, eosinophil; EPO, eosinophil peroxidase; ILC2, group 2 innate lymphoid cells; M2, M2 macrophage; MBP, major basic protein; MC, mast cell; TSLP, thymic stromal lymphopoietin.
FIGURE 3 T2 response against extracellular parasites. Extracellular parasites can infect different tissues, causing epithelial disruption. This damage triggers the release of alarmins, which induce the activation of ILC2s, thereby amplifying the early T2 response through the production of cytokines, the expansion of granulocytes, and M2 polarization. These cell populations cooperate in the containment, elimination, and expulsion of the parasite by several mechanisms including mucus hypersecretion and muscular hypercontractility, which facilitate the flushing out of the parasite; vasodilation and increased vascular permeability, promoting the recruitment of immune cells; and pruritus, causing scratching and mechanically contributing to parasite elimination. Moreover, M2 are also involved in defending against larvae within the tissue lumen through encapsulation processes and granuloma formation; as well as by metabolic modulation via Arg1 expression, which reduces the bioavailability of arginine, thereby limiting the parasite's survival. Eosinophils contribute to the direct elimination of the parasite via EETs, which immobilize the parasite; and by the release of cytotoxic proteins (MBP, ECP, and EPO), which damage its structural integrity. Arg1, arginase 1; BAS, basophils; ECP, eosinophil cationic protein; EETs, eosinophil extracellular traps; EOS, eosinophil; EPO, eosinophil peroxidase; ILC2, group 2 innate lymphoid cells; M2, M2 macrophage; MBP, major basic protein; MC, mast cell; TSLP, thymic stromal lymphopoietin.CC-BY-NC · From the PDF
FIGURE 4 T2 response in life cycle and migration of Ascaris lumbricoides in human infection. The infection begins with the ingestion of fertilized eggs (1), which reach the intestine and hatch (2). Then, the larvae migrate through the bloodstream to the lungs (3), where they mature (4) before being coughed up and swallowed with an eosinophilic type 2 response (5). The expulsion response developed here is essential for the survival of the host organism, as the adults can grow to over 20 cm in length; both the parasite and host cannot survive if the growth from larva to adult takes place in the lungs. Subsequently, they return to the intestine where they develop into adult worms and complete their life cycle (6).
FIGURE 4 T2 response in life cycle and migration of Ascaris lumbricoides in human infection. The infection begins with the ingestion of fertilized eggs (1), which reach the intestine and hatch (2). Then, the larvae migrate through the bloodstream to the lungs (3), where they mature (4) before being coughed up and swallowed with an eosinophilic type 2 response (5). The expulsion response developed here is essential for the survival of the host organism, as the adults can grow to over 20 cm in length; both the parasite and host cannot survive if the growth from larva to adult takes place in the lungs. Subsequently, they return to the intestine where they develop into adult worms and complete their life cycle (6).CC-BY-NC · From the PDF
FIGURE 5 T2 mechanisms in toxin neutralization. Toxins (e.g., snake venom, Hymenoptera venom, and bacterial proteins) that enter the body through the epithelium can be contained (left) and neutralized (right) through a process mediated by MCs and IgE. Containment occurs through the release of mediators (histamine, prostaglandins, and leukotrienes) that induce smooth muscle contraction, limiting the tissue progression of toxins, as well as vasodilation and increased endothelial permeability for leukocyte recruitment, thereby reducing the passage of these toxins into the systemic circulation. Neutralization happens through the release of proteases (CPA3, chymase, and tryptase) that degrade the toxins and through the release of heparin, which can block charged toxins. CPA3, carboxypeptidase 3; MC, mast cell.
FIGURE 5 T2 mechanisms in toxin neutralization. Toxins (e.g., snake venom, Hymenoptera venom, and bacterial proteins) that enter the body through the epithelium can be contained (left) and neutralized (right) through a process mediated by MCs and IgE. Containment occurs through the release of mediators (histamine, prostaglandins, and leukotrienes) that induce smooth muscle contraction, limiting the tissue progression of toxins, as well as vasodilation and increased endothelial permeability for leukocyte recruitment, thereby reducing the passage of these toxins into the systemic circulation. Neutralization happens through the release of proteases (CPA3, chymase, and tryptase) that degrade the toxins and through the release of heparin, which can block charged toxins. CPA3, carboxypeptidase 3; MC, mast cell.CC-BY-NC · From the PDF
FIGURE 6 Food aversion in allergic mice. (1) Exposure to the allergen induces a T2 immune response that culminates in the production of specific IgE, which binds to FcεRI on the surface of MCs, sensitizing them. (2) Upon re-­ ingestion of the allergen, it is recognized by these IgEs bound to MCs, triggering their activation and degranulation. The mediators released by MCs, and particularly cysteinyl leukotrienes, act on the colonic epithelial cells inducing the expression and release of GDF15. (3) GDF15 affects the central nervous system, activating neural circuits in the nucleus tractus solitarius, the parabranchial nucleus, and the central amygdala, resulting in specific avoidance of the food responsible for the allergic response. GDF15, growth differentiation factor 15; MC, mast cells; NTS, nucleus tractus solitarius; PBN, parabranchial nucleus.
FIGURE 6 Food aversion in allergic mice. (1) Exposure to the allergen induces a T2 immune response that culminates in the production of specific IgE, which binds to FcεRI on the surface of MCs, sensitizing them. (2) Upon re-­ ingestion of the allergen, it is recognized by these IgEs bound to MCs, triggering their activation and degranulation. The mediators released by MCs, and particularly cysteinyl leukotrienes, act on the colonic epithelial cells inducing the expression and release of GDF15. (3) GDF15 affects the central nervous system, activating neural circuits in the nucleus tractus solitarius, the parabranchial nucleus, and the central amygdala, resulting in specific avoidance of the food responsible for the allergic response. GDF15, growth differentiation factor 15; MC, mast cells; NTS, nucleus tractus solitarius; PBN, parabranchial nucleus.CC-BY-NC · From the PDF
FIGURE 7 T2 response in tumors. (A) ILC2s exert an antitumoral effect mediated by increasing DC recruitment and antigen presentation. (B) TSLP-­ derived Th2 cells block the EMT via IL-­ 3, IL-­ 5, and GM-­ CSF signaling. (C) Eosinophils can exert direct tumoricidal activity. (D) The IL-­ 33-­ ST2 axis induces the release of IL-­ 4 by ILC2s, leading to metabolic reprogramming in immune cells. In addition, it enhances the activation of tumor-­ specific CD8 + T cells through cDC1s. (E) apMCs generate immune activation with antitumoral effect. (F) Tumor-­ antigen-­ specific IgE antibodies can engage Fcε receptor-­ bearing effector cells and mediate antitumour activity. apMCs, antigen-­ presenting mast cells; CD8, CD8 + T cells; cDC1, conventional type 1 dendritic cell; DC, dendritic cell; EMT, epithelial-mesenchymal transition; EOS, eosinophils; GM-­ CSF, granulocyte macrophage colony-­ stimulating factor; IgE, immunoglobulin E; IL, interleukin; ILC2, type 2 innate lymphoid cells; Th2, T helper 2 cells; TSLP, thymic stromal lymphopoietin.
FIGURE 7 T2 response in tumors. (A) ILC2s exert an antitumoral effect mediated by increasing DC recruitment and antigen presentation. (B) TSLP-­ derived Th2 cells block the EMT via IL-­ 3, IL-­ 5, and GM-­ CSF signaling. (C) Eosinophils can exert direct tumoricidal activity. (D) The IL-­ 33-­ ST2 axis induces the release of IL-­ 4 by ILC2s, leading to metabolic reprogramming in immune cells. In addition, it enhances the activation of tumor-­ specific CD8 + T cells through cDC1s. (E) apMCs generate immune activation with antitumoral effect. (F) Tumor-­ antigen-­ specific IgE antibodies can engage Fcε receptor-­ bearing effector cells and mediate antitumour activity. apMCs, antigen-­ presenting mast cells; CD8, CD8 + T cells; cDC1, conventional type 1 dendritic cell; DC, dendritic cell; EMT, epithelial-mesenchymal transition; EOS, eosinophils; GM-­ CSF, granulocyte macrophage colony-­ stimulating factor; IgE, immunoglobulin E; IL, interleukin; ILC2, type 2 innate lymphoid cells; Th2, T helper 2 cells; TSLP, thymic stromal lymphopoietin.CC-BY-NC · From the PDF
FIGURE 8 T2 response in atherosclerosis and cardiovascular disease. (A) ILC2 deletion aggravates atherosclerosis, while the adoptive transfer of ILC2s or IL-­ 25-­ mediated ILC2 expansion decreases plaque lipid content. (B) Administration of IL-­ 33 prevents the formation of pathogenic foam cells by inhibiting the uptake of oxidized LDL and promoting cholesterol efflux from macrophages. In addition, IL-­ 33 exerts vascular protection through IL-­ 5 production by ILC2s, which increases the number of B1 B-­ cells that induce oxidized LDL-­ specific antibodies and reduces carotid intima-­ media thickness. (C) IL-­ 13 exhibits an atheroprotective role mediated by a more stable plaque phenotype with increased collagen deposition, enhanced M2 polarization, and reduced macrophage accumulation. Moreover, IL-­ 13-­ derived Treg promotes IL-­ 10 production and macrophage efferocytosis. (D) Increased Th2 reduces carotid intima-­ media thickness and the risk of myocardial infarction. IL, interleukin; ILC2, type 2 innate lymphoid cells; LDL, low-­ density lipoprotein; M2, macrophage type 2; MΦ, macrophage; oxLDL, oxidized low-­ density lipoprotein; Th2, T helper 2 cells; Treg, T regulatory cells.
FIGURE 8 T2 response in atherosclerosis and cardiovascular disease. (A) ILC2 deletion aggravates atherosclerosis, while the adoptive transfer of ILC2s or IL-­ 25-­ mediated ILC2 expansion decreases plaque lipid content. (B) Administration of IL-­ 33 prevents the formation of pathogenic foam cells by inhibiting the uptake of oxidized LDL and promoting cholesterol efflux from macrophages. In addition, IL-­ 33 exerts vascular protection through IL-­ 5 production by ILC2s, which increases the number of B1 B-­ cells that induce oxidized LDL-­ specific antibodies and reduces carotid intima-­ media thickness. (C) IL-­ 13 exhibits an atheroprotective role mediated by a more stable plaque phenotype with increased collagen deposition, enhanced M2 polarization, and reduced macrophage accumulation. Moreover, IL-­ 13-­ derived Treg promotes IL-­ 10 production and macrophage efferocytosis. (D) Increased Th2 reduces carotid intima-­ media thickness and the risk of myocardial infarction. IL, interleukin; ILC2, type 2 innate lymphoid cells; LDL, low-­ density lipoprotein; M2, macrophage type 2; MΦ, macrophage; oxLDL, oxidized low-­ density lipoprotein; Th2, T helper 2 cells; Treg, T regulatory cells.CC-BY-NC · From the PDF
FIGURE 9 T2 immunity in aging and thymic tolerance. (A, B) T2 molecular mechanisms related to aging. (A) IL-­ 4 blocks macrophage senescence and induces tissue repair through M2 polarization. (B) The absence of IL-­ 4, IL-­ 13, IL-­ 4Rα, and STAT6 leads to reduced lifespan and cognitive function, and increased inflammation and DNA damage. (C-E) T2 molecular mechanisms related to thymus repair and central tolerance development. (C) Tissue damage activates tuft cells and fibroblasts, which release IL-­ 25 and IL-­ 33, promoting thymus regeneration via IL-­ 13 and AREG released by ILC2s. (D) IL-­ 5, produced by ILC2s, and CCL11, produced by epithelial cells in response to IL-­ 4, enhance the ability of eosinophils to promote thymus recovery and apoptotic cell clearance. (E) IL-­ 4 and IL-­ 13 stimulate DC2s, inducing the deletion of autoreactive CD4 + T cells. AREG, amphiregulin; CCL11, C-­ C motif chemokine 11; CD4 + , CD4 + T cells; DC2, Type 2 dendritic cell; EOS, eosinophils; EpC, epithelial cells; IL, interleukin; IL-­ 4Rα, IL-­ 4 receptor α; ILC2, Type 2 innate lymphoid cells; M2, macrophage Type 2; MΦ, macrophage; SIRPα, signal-­ regulatory protein α; STAT6, signal transducer and activator of transcription 6.
FIGURE 9 T2 immunity in aging and thymic tolerance. (A, B) T2 molecular mechanisms related to aging. (A) IL-­ 4 blocks macrophage senescence and induces tissue repair through M2 polarization. (B) The absence of IL-­ 4, IL-­ 13, IL-­ 4Rα, and STAT6 leads to reduced lifespan and cognitive function, and increased inflammation and DNA damage. (C-E) T2 molecular mechanisms related to thymus repair and central tolerance development. (C) Tissue damage activates tuft cells and fibroblasts, which release IL-­ 25 and IL-­ 33, promoting thymus regeneration via IL-­ 13 and AREG released by ILC2s. (D) IL-­ 5, produced by ILC2s, and CCL11, produced by epithelial cells in response to IL-­ 4, enhance the ability of eosinophils to promote thymus recovery and apoptotic cell clearance. (E) IL-­ 4 and IL-­ 13 stimulate DC2s, inducing the deletion of autoreactive CD4 + T cells. AREG, amphiregulin; CCL11, C-­ C motif chemokine 11; CD4 + , CD4 + T cells; DC2, Type 2 dendritic cell; EOS, eosinophils; EpC, epithelial cells; IL, interleukin; IL-­ 4Rα, IL-­ 4 receptor α; ILC2, Type 2 innate lymphoid cells; M2, macrophage Type 2; MΦ, macrophage; SIRPα, signal-­ regulatory protein α; STAT6, signal transducer and activator of transcription 6.CC-BY-NC · From the PDF
FIGURE 10 Role of T2 cells and molecules in obesity and nervous system. (A-F) Mechanisms related to obesity and adipose tissue homeostasis. (A) Sympathetic neurons release GDNF and RET, regulating adipose tissue homeostasis in a process mediated by ILC2s, eosinophils, and M2. (B) IL-­ 33-­ activated ILC2s increase energy expenditure and thermogenesis by modulating PDGFRα + precursors. (C) IL-­ 4 and IL-­ 13 induce insulin sensitivity and white fat browning, while blocking hepatic gluconeogenesis. (D) The IL-­ 4 released by IL-­ 5-­ activated eosinophils, suppresses leptin production by adipocytes. (E) Adipocytes release IL-­ 4 and IL-­ 13, causing M2 polarization. (F) Obesity alters ILC2 FA metabolism, exacerbating insulin resistance. (G-I) Mechanisms related to the nervous system. (G) IL-­ 4 regulates vesicle cycling, the balance of excitatory and inhibitory transmission, and excitotoxicity in cortical and hippocampal neurons; (H) cognition and plasticity in inhibitory neurons; (I) and synaptic plasticity and learning in an astrocyte-­ dependent manner. BDNF, brain-­ derived neurotrophic factor; EOS, eosinophils; FA, fatty acids; GDNF, glial cell line-derived neurotrophic factor; IL, interleukin; M2, macrophage type 2; PDGFRα, platelet-­ derived growth factor receptor α; PPARδ, peroxisome proliferator-­ activated receptor δ; RET, rearranged during transfection.
FIGURE 10 Role of T2 cells and molecules in obesity and nervous system. (A-F) Mechanisms related to obesity and adipose tissue homeostasis. (A) Sympathetic neurons release GDNF and RET, regulating adipose tissue homeostasis in a process mediated by ILC2s, eosinophils, and M2. (B) IL-­ 33-­ activated ILC2s increase energy expenditure and thermogenesis by modulating PDGFRα + precursors. (C) IL-­ 4 and IL-­ 13 induce insulin sensitivity and white fat browning, while blocking hepatic gluconeogenesis. (D) The IL-­ 4 released by IL-­ 5-­ activated eosinophils, suppresses leptin production by adipocytes. (E) Adipocytes release IL-­ 4 and IL-­ 13, causing M2 polarization. (F) Obesity alters ILC2 FA metabolism, exacerbating insulin resistance. (G-I) Mechanisms related to the nervous system. (G) IL-­ 4 regulates vesicle cycling, the balance of excitatory and inhibitory transmission, and excitotoxicity in cortical and hippocampal neurons; (H) cognition and plasticity in inhibitory neurons; (I) and synaptic plasticity and learning in an astrocyte-­ dependent manner. BDNF, brain-­ derived neurotrophic factor; EOS, eosinophils; FA, fatty acids; GDNF, glial cell line-derived neurotrophic factor; IL, interleukin; M2, macrophage type 2; PDGFRα, platelet-­ derived growth factor receptor α; PPARδ, peroxisome proliferator-­ activated receptor δ; RET, rearranged during transfection.CC-BY-NC · From the PDF
FIGURE 11 Interplay between allergens and subversive factors in the induction of allergy. (A) Exposure to allergens alone is unlikely to cause allergic sensitization. (B) The external exposome (e.g., detergents, certain food additives, pollutants, pathogens, etc.) and internal subversive factors (e.g., genes involved in the deterioration of tissue barriers or damage) act together to amplify tissue damage, resulting in a microenvironment conducive to the development of allergies. (C) External (e.g., commensal microbiota) and internal factors (genes involved in inflammatory and regulatory responses) that lower the Th2 polarization threshold can facilitate allergic sensitization. Figure adapted from Ellenbogen & Jiménez-­ Saiz et al. [6].
FIGURE 11 Interplay between allergens and subversive factors in the induction of allergy. (A) Exposure to allergens alone is unlikely to cause allergic sensitization. (B) The external exposome (e.g., detergents, certain food additives, pollutants, pathogens, etc.) and internal subversive factors (e.g., genes involved in the deterioration of tissue barriers or damage) act together to amplify tissue damage, resulting in a microenvironment conducive to the development of allergies. (C) External (e.g., commensal microbiota) and internal factors (genes involved in inflammatory and regulatory responses) that lower the Th2 polarization threshold can facilitate allergic sensitization. Figure adapted from Ellenbogen & Jiménez-­ Saiz et al. [6].CC-BY-NC · From the PDF

Verification

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  • Probably not a substantial claim. 19
  • It may state two separate claims as one. 67
81 of 81
  • The paper relies on this without support.

    Findings from murine and preclinical models can be extrapolated to human T2 immunity and disease.

    “Most mechanistic insights into the ontogeny of allergic disease come from murine models [163], which consistently revealed environmental cues (alarmins), usually but not exclusively of epithelial origin, that precondition the tissue and, ultimately, the immune system to sense exogenous antigens as threats, thereby promoting T2 responses [4, 164-167] (Figure 11).”
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Citations

Cites

Research works printed but not linked: 11

  1. Galli S. J., 2017, Mast Cells and IgE Can Enhance Survival During Innate and Acquired Host Responses to Venoms, Transactions of the American Clinical and Climatological Association, 128, 193
  2. Atagozli T., 2023, Helminth Lessons in Inflammatory Bowel Diseases (IBD), Biomedicine, 11
  3. Suarez‐Lopez L., 2018, MK2 Contributes to Tumor Progression by Promoting M2 Macrophage Polarization and Tumor Angiogenesis, Proceedings of the National Academy of Sciences of the United States of America, 115, E4236
  4. Mendez‐Garcia L. A., 2025, Role of the Th2‐Like Immune Response in Obesity: IL‐4 as a Metabolic Regulator and IL‐13 as an Effector of Muscle Energy Metabolism, Biomedicine, 13
  5. Mikhail E. S., 2026, StatPearls
  6. Chen X., 2001, Elevated Interleukin‐13 in Patients With Active Lupus Nephritis, Chinese Medical Journal (English Edition), 114, 1022
  7. Mavalia C., 1997, Type 2 Helper T‐Cell Predominance and High CD30 Expression in Systemic Sclerosis, American Journal of Pathology, 151, 1751
  8. 10.1016/j.jacig.2025.100592 · DOI
  9. Gallagher A., 2021, Anti‐Interleukin‐13 and Anti‐Interleukin‐4 Agents Versus Placebo, Anti‐Interleukin‐5 or Anti‐Immunoglobulin‐E Agents, for People With Asthma, Cochrane Database of Systematic Reviews, 10
  10. Food US, Drug A, 2025, Approved Drug Products With Therapeutic Equivalence Evaluations (Orange Book)
  11. 10.1016/j.jaip.2020.12.031 · DOI

Metadata

Authors
Jiménez‐Saiz, R., Iborra, S., Blanco, C., González‐Pérez, R., Nuñez‐Borque, E., Zeyneloglu, C., Babayev, H., Göksel, O., Göksel, T., Khaitov, M., Kudlay, D., Gao, Y., Sevim, M., Brüggen, M., Alpan, O., Wang, M., Zhang, L., Torres, M. J., Shamji, M., Akdis, M., Nadeau, K. C., Ogulur, I., & Akdis, C. A.
Affiliations
  • Universidad Francisco de Vitoria (ES)
  • Fundación Inmunotek Alcalá de Henares Spain
  • Hospital Universitario de La Princesa (ES)
  • Hospital Universitario de Canarias (ES)
  • University of Zurich (CH)
  • Department of Pulmonary Medicine, Division of Immunology and Allergy, Laboratory of Occupational & Environmental Respiratory Diseases and Asthma, Faculty of Medicine, Translational Pulmonary Research Center (EgeSAM) Ege University Izmir Turkey
  • Ege University (TR)
  • Pirogov Russian National Research Medical University (RU)
  • Sechenov University (RU)
  • First Affiliated Hospital Zhejiang University (CN)
  • Istinye Universitesi Istanbul Turkey
  • University Hospital Zurich (CH)
  • Amerimmune McLean Virginia USA
  • Beijing Tongren Hospital (CN)
  • Hospital Regional Universitario de Málaga (ES)
  • Imperial College London (GB)
  • Swiss Institute of Allergy and Asthma Research (SIAF) University of Zurich Davos Switzerland
  • Harvard University (US)
Corresponding author
Jiménez‐Saiz, Rodrigo
Venue
Allergy
Publisher
Wiley
Published
2026-09-09
Volume
81
Issue
11
Pages
3825-3852
ISSN
  • 0105-4538 (ISSN-L)
  • 1398-9995
OpenAlex
W7212017201
Cited by
2
References
283
Citations by year
2026: 2
FWCI
1.18
Type
journal article
Language
en
Open access
Locations
  • Allergy (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
Funders
  • Instituto de Salud Carlos III (RD24/0007/0037, PI22/00236, PI25/00477, CD23/00125, MV25/00085)
  • Fundación Domingo Martínez (FDM2025)
  • Weston Family Foundation (POP24‐11435)
  • Comunidad de Madrid (IND2024/BMD‐33910)
  • Fundación BBVA (LEO26‐1‐21202)
Topics
  • Life Sciences › Immunology and Microbiology › Immunology › IL-33, ST2, and ILC Pathways
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Asthma and respiratory diseases
  • Life Sciences › Immunology and Microbiology › Immunology › Mast cells and histamine
Keywords
Th2 immune response, helminthiasis, allergic diseases, eosinophilic inflammation, tissue repair, tissue protection, immune system evolution, IgG4, great apes, epithelial barrier function, microbiome, dysbiosis, opportunistic pathogens, IL-4, IL-5, IL-13, IL-31, thymic stromal lymphopoietin, IgE, biologic therapy, immune homeostasis

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-11-12, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-11-12 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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