Elevated levels of interleukin‐33 are associated with allergic and eosinophilic asthma

IL‐33 is a recently discovered cytokine which plays an important role in asthma pathogenesis. Aim To evaluate serum IL‐33 in patients with asthma and healthy controls, and to evaluate the association of IL‐33 with different asthma phenotypes. Methods Patients with asthma (n = 115) and healthy subjects (n = 85) were included in the study. Subjects with asthma were divided into groups according to their phenotype: allergic/non‐allergic, eosinophilic/non‐eosinophilic, obese/non‐obese and severity according to GINA (mild, moderate and severe). The concentration of IL‐33 in serum was measured by standardized enzyme‐linked immunosorbent assay. Results The level of IL‐33 was significantly higher in patients with asthma when compared to healthy subjects (672.73 ± 104.47 pg/mL vs 268.52 ± 27.56 pg/mL, P