Introduction/Objective. Interleukin 33 (IL-33) has a very significant function in inflammatory and autoimmune mechanisms, but its significance in immunopathogenic mechanisms of different allergic diseases, including allergic asthma (AA), is becoming increasingly emphasized. The objective of the study was to investigate serum levels of IL-33 in children with AA before applying inhalation corticosteroid therapy (ICS Th) and six months after it, correlating the gathered values of IL-33 with some clinical traits of the patient. Methods. The serum value of IL-33 has been determined in 61 children with AA before starting treatment and six months after treatment with ICS Th, and this was repeated in 30 healthy children. Results. Values of IL-33 in serum are significantly higher in children with AA that have not been treated with ICS Th during six months (p = 0.00; p < 0.05), which is also the case when comparing with healthy children (p = 0.00; p < 0.05). Serum values of IL-33 in children with AA after six months of ICS Th and in healthy children do not show significant difference (p = 0.88; p > 0.05). The correlation between serum values of IL-33 before applying ICS Th and the severity, degree of AA control, and the applied dose of ICS Th is statistically significant and positive. Conclusion. IL-33 values in the serum are significantly higher in children with untreated AA in those with poorly controlled AA. Six-month treatment with ICS Th leads to significant reduction of IL-33 serum levels, whose values are in positive correlation with the severity and control of AA.
