Factors associated with plasma IL-33 levels in patients with chronic obstructive pulmonary disease.

Abstract

BackgroundInterleukin (IL)-33 promotes T helper (Th)2 immunity and systemic inflammation. The role of IL-33 in asthma has been widely investigated. IL-33 has also been suggested to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study investigated the clinical significance and usefulness of plasma IL-33 level in patients with COPD.MethodsA total of 307 patients with stable COPD from 15 centers, who were in the Korean Obstructive Lung Disease cohort, were enrolled in this study. Plasma IL-33 levels were measured by enzyme-linked immunosorbent assay. We analyzed the association between IL-33 level and other clinical characteristics related to COPD. We also examined the features of patients with COPD who exhibited high IL-33 levels.ResultsIL-33 levels varied, but were very low in most patients. Eosinophil count was significantly correlated with a plasma IL-33 level. In addition, old age and current smoking were related to a low IL-33 level. Significantly more patients with a higher IL-33 level had chronic bronchitis compared with those with a low IL-33 level.ConclusionPlasma IL-33 level in patients with stable COPD was related to eosinophil count and chronic bronchitis phenotype. Further studies are needed to identify the precise mechanisms of IL-33/ST2 pathway in patients with COPD.