Fceri

The serum samples were achieved through 15 minutes centrifugation of 10 ml venous blood at 1000 × g. Ficoll density gradient was used for the purification of peripheral blood mononuclear cells (PBMC) from the blood of AR and controls.
Purified PBMCs (10⁶/mL) from AR patients were activated by phorbol myristate acetate (PMA, Sigma-Aldrich), ionomycin (Sigma-Aldrich), and Brefeldin A (Sigma-Aldrich) for 3 hours. Then, the ILC2s were sorted through staining by FITC lineage-negative cocktail kit, CD45, CRTH2, and CD127 (BD Bioscience). In detail, the lineage negative (Lin⁻) cells were obtained using the FITC lineage cocktail (CD2, CD3, CD14, CD16, CD19, CD56, and CD235a; BD Bioscience) and FceRI (eBioscience). Then, the Lin⁻ cells were stained with CD45, CRTH2, and CD127 (BD Bioscience) for isolation of ILC2s. Finally, the ILC2 was sorted using a FACS ARIA flow cytometer (BD Biosciences) with a purity of greater than 93%. Then, the data were analyzed by FlowJo software (TreeStar).
Sorted ILC2s (Lin⁻ CD45⁺CRTH2⁺CD127⁺) were incubated in 96-well plates with a density of 2.5 × 10⁵ cells/mL. The culture medium contained recombinant IL-25, IL-33, TSLP (all 10 ng/mL), IL-2 (50 ng/mL), or rhIL-37b (1–100 ng/mL) (all from the R&D Systems) for 72 hours. The ILC2s' proliferation was detected using the incorporation of tritiated thymidine.

Lineage negative cells were enriched from PBMCs using FITC lineage cocktail (eBioscience, San Diego, CA) and FceRI (eBioscience). Cells were further stained with PE-conjugated CRTH2 (BD Bioscience, NJ) and PE-Cy7 conjugated CD127 (BD Bioscience, NJ). Human and mice ILC2s were identified as Lin⁻CRTH2⁺CD127⁺ and Lin⁻ST2⁺CD45⁺CD90.2⁺CD25⁺Sca1⁺ lymphocytes, respectively. Flow cytometry was performed by the Beckman flow cytometer machine (Beckman Coulter, Hercules, CA, USA).