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ILC2 Roles In Pulmonary Disease

Scope

This topic page describes how ILC2s are represented in the current ILC_in_lung wiki as disease-relevant cells in lung and airway contexts. It focuses on asthma/allergic airway inflammation, respiratory viral infection, post-viral repair, airway hyperreactivity, macrophage niche effects, and plastic or non-type-2 ILC2-like states.

This page expands the disease branch of ILC2. Use the entity page for the canonical cell-level model, then use this topic when the question is specifically about disease context and pathology.

Evidence tags

#cell/ILC2 #tissue/lung #outcome/airway_hyperresponsiveness #outcome/infection #outcome/repair #outcome/inflammation #axis/ILC_lung_infection #axis/ILC_airway_inflammation #axis/ILC_plasticity

Confidence snapshot

  • High confidence: the local source set supports ILC2s as major contributors to type 2 airway inflammation, allergic asthma-like responses, and airway hyperresponsiveness.
  • High confidence: the source set also supports reparative or tissue-protective ILC2 roles after respiratory viral injury.
  • Medium confidence: ILC2 disease function is shaped by memory-like behavior, metabolic state, neuroimmune inputs, epithelial alarmins, and macrophage/niche interactions.
  • Medium confidence: ILC2s can deviate from canonical type 2 output toward IL-17-producing or ILC3-like states in selected inflammatory contexts.
  • Low confidence: the exact equivalence between mouse lung ILC2 states and human asthma or nasal-polyp ILC2 states remains unresolved in this wiki.

Established observations

Asthma and allergic airway inflammation

Respiratory viral infection and repair

Non-type-2 and plastic disease states

Niche-positioned and interferon-regulated disease roles

Tumor and innate checkpoint context

Therapy and Extrapulmonary Mechanism Context

  • Immunotherapy for asthma supports endotype-aware therapy framing for asthma, but it should not be treated as primary evidence for a specific ILC2 mechanism.
  • Gut ILC2 sources now add AHR, RXRgamma, ADM2, and tuft-cell IL-17RB/IL-25 regulatory branches. These are useful comparators for type 2 restraint, repair, and alarmin bioavailability, but direct pulmonary disease claims require lung, airway, sputum, BAL, or bronchial evidence.

Interpretation

The safest disease-level model is that ILC2s are lung tissue-response amplifiers whose role depends on the type of epithelial injury, inflammatory context, and timing. In allergic asthma, ILC2s are usually disease-amplifying through IL-5/IL-13, mucus, eosinophilia, and airway hyperresponsiveness. In respiratory viral infection, ILC2s are context-dependent: they can contribute to airway hyperreactivity, but they can also promote tissue repair and protective resolution programs.

The disease interpretation should separate three layers:

  • cell abundance: whether ILC2s expand or accumulate in lung, airway, sputum, blood, or tissue.
  • effector output: whether ILC2s produce IL-5, IL-13, amphiregulin, IL-17, GM-CSF, or other mediators.
  • disease outcome: whether the measured result is airway hyperresponsiveness, mucus metaplasia, eosinophilia, neutrophilia, lung injury, repair, or tumor control.

Treating these layers as interchangeable would overstate the evidence.

flowchart TD
    accTitle: ILC2 Disease Outcomes
    accDescr: Working map of ILC2 roles across lung disease states in the current wiki source set.

    cues["Tissue cues"]
    ilc2["Lung ILC2"]
    type2["Type 2 output<br/>IL-5, IL-13"]
    repair["Repair output<br/>AREG"]
    plastic["Plastic output<br/>IL-17, GM-CSF"]
    asthma["Allergic disease<br/>AHR, mucus"]
    virus["Viral outcomes<br/>AHR or repair"]
    niche["Niche effects<br/>AM or NK"]

    cues --> ilc2
    ilc2 --> type2 --> asthma
    ilc2 --> repair --> virus
    ilc2 --> plastic --> asthma
    plastic --> niche

    classDef cue fill:#e8f3ff,stroke:#3b6ea8,stroke-width:2px,color:#17324d
    classDef cell fill:#fff4de,stroke:#b47a1f,stroke-width:2px,color:#4a3108
    classDef output_class fill:#f6eefc,stroke:#7a55a3,stroke-width:2px,color:#2d1645
    classDef disease fill:#eef7ed,stroke:#4d8a50,stroke-width:2px,color:#173d1d

    class cues cue
    class ilc2 cell
    class type2,repair,plastic output_class
    class asthma,virus,niche disease

Contradiction and supersession

  • Contradiction: ILC2s can worsen airway inflammation in asthma models but support repair after viral injury. These are context-specific roles, not mutually exclusive claims.
  • Contradiction: ILC2s are commonly type 2 cytokine producers, but multiple sources point to plastic IL-17-producing or ILC3-like disease states.
  • Contradiction: viral infection can either trigger ILC-associated airway hyperreactivity or dampen type 2 ILC2 properties depending on viral model and timing.
  • Supersession: no current source supersedes the full ILC2 disease model. The working strategy is to partition by disease, species, model, and timepoint.

Open questions

  • Which ILC2 disease branch is most relevant to the user's current project: allergic asthma, respiratory virus infection, repair, or macrophage/niche reprogramming?
  • In the project data, are ILC2s measured by flow phenotype, scRNA-seq cluster, cytokine protein, or inferred marker score?
  • Are the project-relevant ILC2s canonical type 2 cells, memory-like cells, repair-like cells, or IL-17/ILC3-like plastic cells?
  • Does the local dataset distinguish resident lung ILC2s from recruited or tissue-conditioned ILC2s?
  • Which disease endpoint matters most: AHR, mucus, eosinophilia, neutrophilia, epithelial repair, macrophage state, or tissue damage?

Future Expansion Directions

This short appendix highlights future literature directions rather than current disease conclusions. The most useful additions for later versions of this page would be:

  • Primary asthma sources that cleanly separate mouse perturbation evidence from human association evidence.
  • Respiratory-virus ILC2 studies resolved by timepoint, especially acute AHR, tissue repair, and post-infection macrophage or niche imprinting.
  • Additional lung-compartment studies that sharpen human airway subsets, steroid-resistant asthma, and plastic IL-17 boundary states within ILC2.