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Abstract

Background. The purpose was to study the pathophysiological relationship of vitamin D and interleukin-6 (IL-6) and its role in the development of anemia of inflammation in young children with acute inflammatory bacterial diseases of the respiratory tract. Materials and methods. The content of 25(OH)D3, IL-6, and ferritin was analyzed in 40 young children (average age 1.6 ± 0.4 years) by enzyme immunoassay. The basic group consisted of 20 children with acute inflammatory bacterial diseases of the respiratory tract: 14 patients were diagnosed with acute bacterial bronchitis, and 6 children were diagnosed with pneumonia. Patients of the basic group were divided into two subgroups: the first group consisted of 10 children with anemia of inflammation, the second — 10 children with acute bacterial diseases of the respiratory tract without manifestations of anemia. The comparison group consisted of 10 children with iron deficiency anemia without manifestations of inflammatory respiratory diseases. Ten apparently healthy children represented the control group. Results. In the first subgroup of children, the level of 25(OH)D3 was borderline (29.99 (28.1; 36.5) ng/ml), in the second subgroup, its insufficiency was observed (27.4 (26.1; 31.2) ng/ml). The level of 25(OH)D3 was 1.3–1.6 times lower than the indicators of patients in the control group (43.0 (38.2; 47.0) ng/ml) (p < 0.05). The level of 25(OH)D3 in the blood serum of children from the comparison group (38.0 (34.0; 41.0) ng/ml) did not differ from the data in the control group (p > 0.05), but compared to the basic group, it was significantly higher (p < 0.05). The analysis of the IL-6 content in the blood serum of children showed that in the first subgroup its level exceeded the values of the control group (5.63 (4.52; 5.74) pg/ml) (p < 0.05) but was statistically lower than the indices obtained in the second subgroup (6.63 (4.82; 8.93) pg/ml) (p < 0.05). At the same time, we did not find a statistically significant difference between the indices of the comparison and control groups (p > 0.05). When the level of vitamin D supply is below 30 ng/ml, the established relationships are violated and the deposition of iron worsens, which in turn creates conditions for the further vital activity of the pathogen. Conclusions. The course of acute inflammatory bacterial diseases of the respiratory system in young children is characterized by a decrease in the level of vitamin D3 in the blood serum whereby the content of pro-inflammatory cytokines negatively correlates with the level of vitamin D. The development of anemia of inflammation indicates a certain balance of pro- and anti-inflammatory factors in the pathogenesis of acute inflammatory bacterial diseases of the respiratory tract in young children.