The relationship of serum IL-18 levels with body mass index, the presence of obstructive disorders in children and adolescents with bronchial asthma

Introduction . Bronchial asthma (BA) in combination with obesity is a complex phenotype, an important pathogenetic factor in the formation of which is low-intensity systemic inflammation accompanied by the secretion of a spectrum of proinflammatory cytokines, including interleukin-18 (IL-18). However, the effect of IL-18 on the formation of bronchial obstruction syndrome in children and adolescents with BA obesity cannot be considered established. Objective : to study the content of IL-18 in blood serum in children and adolescents with asthma and its relationship with the body mass index of patients, taking into account obstructive disorders. Materials and methods. A single-center observational cross-sectional pilot study was conducted. 85 patients with asthma aged from 8 to 17 years were examined. Anthropometric and spirometric parameters were measured, and serum IL-18 levels were assessed. The study participants were divided into 2 groups: 1 — patients with low and normal body weight, 2 — overweight and obese. Results. A direct statistically significant correlation was established between the level of IL-18 in blood serum and zBMI, R = 0.30, p = 0.008. In the general group and in patients with obstructive disorders, the level of IL-18 was statistically significantly higher in group 2 compared with group 1, 247.0 [207.0; 334.5] against 208.0 [134.0; 293.0] pg/ml, p = 0.012 and 349.0 [176.0; 452.0] versus 212.0 [148.0; 250.0] pg/ml, p = 0.02, respectively. In the absence of obstructive disorders, the level of IL-18 was comparable in children of these groups, 242.0 [194.5; 313.0] and 204.0 [134.0; 304.0] pg/ml, p = 0.282. In patients of the second group and in the general group, the level of IL-18 was statistically significantly higher in the presence of obstructive disorders, 227.5 [171.0; 352.5] versus 223.0 [163.0; 307.0] pg/ml, p = 0.048 and 349.0 [176.0; 452.0] versus 242.0 [194.5; 313.0] pg/ml, p = 0.046. Conclusion. In patients with asthma and overweight or obesity, the presence of bronchial obstruction is characterized by a statistically significantly higher level of IL-18 in blood serum compared with patients without bronchial patency disorders. This may indicate the inclusion of this interleukin in the genesis of bronchial obstruction in overweight and obese patients.