The Role of the Serum IL-33/sST2 Axis and Inflammatory Cytokines in Chronic Obstructive Pulmonary Disease

The IL-33/sST2 axis is associated with inflammation and cardiac stress. This study examined the roles of serum IL-33/sST2 and other inflammatory cytokines in chronic obstructive pulmonary disease (COPD) patients, with or without chronic cor pulmonale (CCP). The levels of serum IL-33 and sST2 in 36 COPD patients without CCP, 42 cases with CCP, and 37 healthy controls (HCs) were analyzed by enzyme-linked immunosorbent assay. The concentrations of serum TNF-α, IL-1β, IL-6, IL-8, IL-10, and IL-12 were analyzed by cytometric bead array. The pulmonary function was also determined. The levels of IL-33 in COPD patients were lower than in patients with CCP during the acute episode stage and HCs, and increased as patients transitioned into the stable phase, especially in patients whose modified medical research council scale values decreased. IL-33 levels were correlated positively with FEV1%pre, FVC%pre, FEF50%pre, and MMEF75/25%pre, while they correlated negatively with center airway resistance. There were no differences in the levels of sST2 among these groups. The concentrations of IL-6 and IL-10 in COPD patients during acute episodes were significantly higher, and decreased during stable phases. IL-33 may be considered an important factor in the pathogenesis of COPD, and decreased IL-33 levels may be an indicator of the pulmonary function decline of COPD patients.