Journal of Asthma and Allergy (Jan 2021)
In vitro Culture with Cytokines Provides a Tool to Assess the Effector Functions of ILC2s in Peripheral Blood in Asthma
Abstract
Li Y Drake,1,2 Kathleen R Bartemes,1,3 Kay A Bachman,1 John B Hagan,1 Hirohito Kita1,4 1Division of Allergic Diseases and Department of Medicine, Mayo Clinic, Rochester, MN, USA; 2Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; 3Department of Otorhinolaryngology, Mayo Clinic, Rochester, MN, USA; 4Division of Allergy, Asthma, and Clinical Immunology and Department of Medicine, Mayo Clinic Arizona, Scottsdale, AZ, USACorrespondence: Hirohito KitaDivision of Allergy, Asthma, and Clinical Immunology and Department of Medicine, Mayo Clinic Arizona, Scottsdale, AZ 85259, USATel +1 480 301 9616Fax +1 480 301 7017Email [email protected]: Group 2 innate lymphoid cells (ILC2s) play crucial roles in type 2 immunity and asthma development. While ILC2s are resident in mucosal tissues, they also circulate in peripheral blood. It remains controversial whether ILC2s are increased in the peripheral blood of patients with asthma.Purpose: The goal of this project was to study the effector functions of ILC2s in peripheral blood samples by in vitro culture with cytokines.Patients and Methods: Peripheral blood mononuclear cells (PBMCs) were collected from 11 adult patients with mild asthma and 12 healthy control subjects. The number of peripheral blood ILC2s in PBMCs was analyzed by flow cytometry. PBMCs were cultured with IL-33 and IL-25 without any antigens, and the amounts of type 2 cytokines in cell-free supernatants were analyzed by ELISA. In selected experiments, production of cytokines by ILC2s was analyzed by intracellular cytokine staining and flow cytometry.Results: In response to either IL-33 or IL-25 stimulation, PBMCs from patients with mild asthma produced larger amounts of IL-5 and IL-13 than PBMCs from healthy control subjects. However, ILC2 numbers or proportions were not significantly different between these two groups. Flow cytometric analysis confirmed production of IL-5 by ILCs when stimulated with IL-33.Conclusion: In vitro culture of PBMCs with a cocktail of cytokines, such as either IL-33 or IL-25 plus IL-2, may provide a valuable tool to assess the effector functions of ILC2s and may serve as a biomarker for human asthma.Keywords: IL-33, IL-25, IL-5, IL-13
