Relationship between vitamin D sufficiency and interferon-γ levels in children with chronic lung diseases

Abstract

Introduction. The role and mechanism of the effect of vitamin D on the course of chronic lung diseases in children are not yet fully understood. In particular, there are not enough studies on the effect of vitamin D status on the production of interferon-γ (IFN-γ) in children with cystic fibrosis and bronchial asthma.Aim. To analyse the changes in IFN-γ levels in children with cystic fibrosis and bronchial asthma according to the serum 25(OH)D level before and during cholecalciferol supplementation.Materials and methods. A total of 114 children (aged from 3 months to 18 years old) were examined, including 51 (44.7%) children with bronchial asthma, 34 (29.8%) children with cystic fibrosis, and 29 (25.5%) children of the control group. If hypovitaminosis D was diagnosed, the children received a three-month cholecalciferol course at doses in accordance with the recommendations of the national consensus - Cystic Fibrosis: Definition, Diagnostic Criteria, Therapy and the national program - Vitamin D Deficiency in Children and Adolescents of the Russian Federation: Current Approaches to Management. The 25(OH)D and IFN-γ levels were twice determined in all children.Results. Median 25(OH)D levels in patients with cystic fibrosis and bronchial asthma did not reach the level of healthy children either before or after supplementation with cholecalciferol drugs at the recommended doses. Vitamin D intake resulted in a decrease in IFN-γ levels in healthy children from 3.07 [2.29; 4.81] pg/ml to 2.18 [1.74; 3.45] pg/ml (p < 0.05), whereas such changes were not detected in the paediatric patients with cystic fibrosis and bronchial asthma in the general population. However, after supplementation with cholecalciferol, the IFN-γ level was significantly higher in patients with cystic fibrosis and bronchial asthma - 2.86 [2.13; 3.86] pg/ml and 3.11 [0.89; 5.0] pg/ml, respectively, than in healthy children - 2.18 [1.74; 3.45] pg/ml (p < 0.05). A statistically significant decrease in IFN-γ level was observed in girls with cystic fibrosis and in healthy girls after supplementation with cholecalciferol, whereas no significant changes in IFN-γ levels were detected in the groups of boys.Conclusion. Modulation of IFN-γ levels appears to be one of the mechanisms of immunotropic effect of vitamin D on the course of chronic inflammation of infectious (cystic fibrosis) and allergic (bronchial asthma) etiology in children.