Comparison of Interleukin‐33 Serum Levels in Asthmatic Patients with a Control Group and Relation with the Severity of the Disease

The relation between interleukin‑33 (IL‑33) and asthma is not precisely known yet. The present study set to compare the serum level of IL‑33 in patients with asthma and controls and study the relation with the severity of disease.
The serum level of IL‑33 and total IgE in 89 asthmatic patients and 57 controls were analyzed. The association of levels of IL‑33 with the severity of disease, levels of total IgE, measures of spirometry (forced expiratory volume in 1 s [FEV1]), age, sex, presence or absence of other allergic diseases, and the disease duration was evaluated.
Higher levels of IL‑33 and total IgE were detected in asthmatic patients compared with controls (P = 0.0001 and P = 0.008, respectively). In the asthmatic group, a signifcant direct association of IL‑33 with age (P = 0.02, R = 0.23) and with total IgE level (P = 0.003, R = 0.31) were observed, but there was no relationship between other variables. Comparison of mean level of IL‑33 in different asthma groups concerning the disease severity showed the statistically signifcant difference between them and a signifcant increased serum level of total IgE was observed in more severe disease. The results showed a signifcant negative correlation between FEV1 and total IgE (P = 0.028, R = -0.23) and IL‑33 level (P = 0.0001, R = -0.83).
IL‑33 is suggested as a new inflammatory marker of severe and refractory asthma. Therefore, it may be a unique therapeutic target in these patients.