Allergen-induced increases in sputum levels of group 2 innate lymphoid cells in asthmatic subjects

Ruchong Chen, Steven G Smith, B Salter, Amani I El-Gammal, John-Paul Oliveria, Caitlin Obminski, Rick Watson, Paul O'Byrne, Gail Gauvreau, Roma Sehmi

Research output: Contribution to journalArticlepeer-review


Group 2 innate lymphoid cells (ILC2), a major source of type 2 cytokines, initiate eosinophilic inflammatory responses in murine models of asthma.

To investigate the role of ILC2 in allergen-induced airway eosinophilic responses in subjects with atopy and asthma.

Using a diluent-controlled allergen challenge crossover study, where all subjects (n = 10) developed allergen-induced early and late responses, airway eosinophilia, and increased methacholine airway responsiveness, bone marrow, blood, and sputum samples were collected before and after inhalation challenge.

ILC2 (lin-FcεRI-CD45+CD127+ST2+) and CD4+T lymphocytes were enumerated by flow cytometry, as well as intracellular IL-5 and IL-13 expression. Steroid sensitivity of ILC2 and CD4+ T cells was investigated in vitro. A significant increase in total, IL-5+, IL-13+, and CRTH2+ ILC2 was found in sputum, 24 hours after allergen, coincident with a significant decrease in blood ILC2. Total, IL-5+, and IL-13+, but not CRTH2+, CD4+ T cells significantly increased at 24 and 48 hours after allergen in sputum. In blood and bone marrow, only CD4+ cells demonstrated increased activation after allergen. Airway eosinophilia correlated with IL-5+ ILC2 at all time points and allergen-induced changes in IL-5+ CD4+ cells at 48 hours after allergen. Dexamethasone significantly attenuated IL-2- and IL-33-stimulated IL-5 and IL-13 production by both cell types.

Innate and adaptive immune cells are increased in the airways associated with allergic asthmatic responses. Total and type 2 cytokine-positive ILC2 are increased only within the airways, whereas CD4+ T lymphocytes demonstrated local and systemic increases. Steroid sensitivity of both cells may explain effectiveness of this therapy in those with mild asthma.
Original languageEnglish
Pages (from-to)700-712
JournalAmerican Journal of Respiratory and Critical Care Medicine
Issue number6
Publication statusPublished - 2017


Dive into the research topics of 'Allergen-induced increases in sputum levels of group 2 innate lymphoid cells in asthmatic subjects'. Together they form a unique fingerprint.

Cite this