In vitro Culture with Cytokines Provides a Tool to Assess the Effector Functions of ILC2s in Peripheral Blood in Asthma

Interleukin (IL)-33 immunobiology in asthma and airway inflammatory diseases

OBJECTIVE

Identify key features of IL-33 immunobiology important in allergic and nonallergic airway inflammatory diseases and potential therapeutic strategies to reduce disease burden.

DATA SOURCES

PubMed, clinicaltrials.gov.

STUDY SELECTIONS

A systematic and focused literature search was conducted of PubMed from March 2021 to December 2021 using keywords to either PubMed or BioMed Explorer including IL-33/ST2, genetic polymorphisms, transcription, translation, post-translation modification, nuclear protein, allergy, asthma, and lung disease. Clinical trial information on IL-33 was extracted from clinicaltrials.gov in August 2021.

RESULTS

In total, 72 publications with relevance to IL-33 immunobiology and/or clinical lung disease were identified (allergic airway inflammation/allergic asthma n = 26, non-allergic airway inflammation n = 9, COPD n = 8, lung fibrosis n = 10). IL-33 levels were higher in serum, BALF and/or lungs across inflammatory lung diseases. Eight studies described viral infections and IL-33 and 4 studies related to COVID-19. Mechanistic studies (n = 39) including transcript variants and post-translational modifications related to the immunobiology of IL-33. Single nucleotide polymorphism in IL-33 or ST2 were described in 9 studies (asthma n = 5, inflammatory bowel disease n = 1, mycosis fungoides n = 1, ankylosing spondylitis n = 1, coronary artery disease n = 1). Clinicaltrials.gov search yielded 84 studies of which 17 were related to therapeutic or biomarker relevance in lung disease.

CONCLUSION

An integral role of IL-33 in the pathogenesis of allergic and nonallergic airway inflammatory disease is evident with several emerging clinical trials investigating therapeutic approaches. Current data support a critical role of IL-33 in damage signaling, repair and regeneration of lungs.

Upregulation of IL-4 receptor signaling pathway in circulating ILC2s from asthma patients

Background

Group 2 innate lymphoid cells (ILC2s) produce type 2 cytokines by stimulation with epithelial cell-derived cytokines and are implicated in the pathogenesis of various allergic diseases, including asthma. However, differences in the molecular characteristics of ILC2s between patients with asthma and healthy subjects remain unclear.

Objective

We sought to evaluate differences in cytokine production capacity and gene expression profile of ILC2s in the peripheral blood of patients with asthma and healthy subjects.

Methods

We evaluated ILC2s derived from 15 patients with asthma and 7 healthy subjects using flow cytometry, live-cell imaging of secretion activity analysis, and RNA-sequencing.

Results

ILC2s were sorted as CD45+Lineage-CRTH2+CD127+CD161+ cells from the peripheral blood of patients with asthma and healthy subjects, and the number of ILC2s was decreased in patients with asthma (851 ± 1134 vs 2679 ± 3009 cells/20 mL blood; P = .0066). However, patient-derived ILC2s were activated to produce more IL-5 and IL-13 in response to stimulation with IL-2, IL-33, and thymic stromal lymphopoietin compared with healthy subject-derived ILC2s (P = .0032 and P = .0085, respectively). Furthermore, RNA-sequencing analysis revealed that patient-derived ILC2s had different gene expression profiles, such as increased expression in cell growth-related genes (CDKN1b, CCNG2, CCND2, CCN1), prostaglandin E receptor (PTGER2), and IL-4 receptor. In addition, a gene set of the IL-4 receptor signaling pathway was significantly upregulated in ILC2s in patients with asthma (P = .042).

Conclusions

Our results suggest that circulating ILC2s in patients with asthma are preactivated via the IL-4 receptor signaling pathway and produce IL-5 and IL-13 vigorously by stimulation.