Type 2 innate lymphoid cells: A novel biomarker of eosinophilic airway inflammation in patients with mild to moderate asthma.

Abstract Background Eosinophilic airway inflammation can predict the exacerbation of asthma, and we can improve the management of asthma by monitoring the eosinophilic airway inflammation. Although induced sputum and sputum eosinophil count is the gold standard test for diagnosing eosinophilic asthma, a more accessible and receptive method is needed for clinical practice. Type 2 innate lymphoid cells (ILC2) have recently been proposed to play a crucial role in eosinophilic inflammation and have been identified in peripheral blood from patients with asthma. Objectives We sought to identify simple and feasible biomarkers which can predict eosinophilic airway inflammation in asthmatic patients. Methods Sputum was induced for the assessment of eosinophils in 150 asthmatic patients. In parallel, the proportion of ILC2s of peripheral blood lymphocytes (%ILC2), blood eosinophil counts, total immunoglobulin E (IgE), fractional exhaled nitric oxide (FeNO) and lung function tests were measured. 42 healthy donors served as controls. Results 126 patients finished sputum induction and produced adequate sputum. The ILC2 level was significantly increased in eosinophilic asthmatic patients compared with non-eosinophilic asthmatic patients (0.117 ± 0.090versus0.035 ± 0.021, p  Conclusion ILC2 is a surrogate marker of airway eosinophilic inflammation in patients with mild to moderate asthma and has great potential advantages for selecting the asthmatic patients most likely to benefit from therapeutics targeting Th2 inflammation.