Airway Interleukin-33 and type 2 cytokines in adult patients with acute asthma

Background Several animal studies, and one inoculation study in adult asthmatics have shown that interleukin-33 (IL-33) is a major contributor to type-2 inflammation in acute asthma. However, the link between IL-33 and type-2 inflammation has not been shown in naturally occurring asthma exacerbations. Objectives To determine if airway IL-33 is associated with type-2 inflammation measured by type-2 cytokines, FeNO and sputum eosinophils in patients presenting to the Emergency Department with an asthma exacerbations. Methods Adult patients hospitalized due to acute asthma were enrolled. Upper airways were sampled with nasal swabs and lower airways with induced sputum. Cytokines were measured at protein level using a Luminex® assay and mRNA expression level using droplet-digital-PCR. Airway sampling was repeated four weeks after exacerbation. Results At the time of exacerbation, upper airway IL-33 correlated with upper airway IL-5 and IL-13 (R = 0.84, p
Highlights • IL-33 correlates to type 2 cytokines in hospitalized patients with acute asthma. • Airway IL-13 and IL-33 positively correlate with fractional exhaled nitric oxide. • Airway IL-5 correlates to blood eosinophils in naturally occurring acute asthma.