Hormones and cytokines as biomarkers of severe infections in children

This review summarizes the available information on the condition of two systems that regulate immune responses, namely the hypothalamic–pituitary–adrenal axis and hypothalamic–pituitary–thyroid axis, in children with neuroinfections or sepsis. We used the Pubmed and eLibrary databases to prepare this review. Serum cortisol is a well-studied biomarker of neuroinfections. Its elevated level is known to be associated with disease severity and outcome in both adults and children. A critical condition in patients with sepsis and septic shock is usually accompanied by critical illness-related corticosteroid insufficiency (CIRCI) and non-thyroidal illness syndrome (NTIS), whose pathogenetic role is unclear and is being actively studied. There is a close correlation between cortisol and cytokine levels in adult patients with neuroinfections or sepsis; however few studies demonstrated this correlation in children. Further investigation of the interaction between neuroendocrine and immune mechanisms will clarify the real need for corticosteroid therapy which is widely used in children with severe infections now. The causal therapy for severe neuroinfections with sepsis and septic shock should include drugs with metabolic and endothelium-protective action (such as cytoflavin), since it can alleviate the disease. Key words: infection, neuroendocrine system, sepsis, hormones, glucocorticoid receptor, cytokines, children, cytoflavin