Ability of neutrophils to form extracellular traps in children with primary tuberculosis complex and intrathoracic lymph node tuberculosis

The process of neutrophil extracellular trap (NET) formation is one of the functions of neutrophils that could be a potentially useful marker to assess innate immunity in tuberculosis patients. Patients and methods. The study included 28 children aged 4 to 14 years who contracted tuberculosis in the Omsk and Omsk regions between 2023 and 2024. Comparative analysis was conducted between children with the primary tuberculosis complex (PTC), tuberculosis of intra-breast lymph nodes (IBLN) and uninfected children. The method of luminescent microscopy calculated the percentage of NET and leukocytes in the drug isolated fraction of neutrophils after stimulation. The level of citrullinated histon H3 (citH3) was determined in the blood serum by immunoenzyme analysis. Results. The total proportion of cloud-shaped and filamentous NETs in the groups of children with tuberculosis was higher (p = 0.0384) than in controls. In the IBLN group, neutrophils were more likely to form cloud-shaped NETs, while in the PTC group, neutrophils were more likely to form filamentous NETs. In the IBLN group, the proportion of early nethotic cells was lower than in the PTC group (p = 0.0428). Extracellular traps formed by neutrophils of the IBLN group were worse (p = 0.0100) at capturing lactobacilli. Blood citH3 levels were higher in the PTC group than in the IBLN group. In both groups of TB patients, the level of citH3 was higher than in the сontrol group. Conclusion. Neutrophils of children with tuberculosis were characterized by a greater ability to form NETs compared to the Control group. In children from the PTC group, filiform NETs were more often detected, and in the IBLN group, cloud-like NETs. Key words: children, neutrophil extracellular traps, neutrophil non-trapping ability, primary forms of tuberculosis, neutrophil extracellular trap formation ability, citrullinated histone H3