Cytokine profile in community-acquired pneumonia in children

Abstract

Community-acquired pneumonia (CAP) is one of the most common acute infectious diseases. To date, the incidence of CAP among children was decreased significantly worldwide, mainly due to increasing use of effective preventive measures. Nevertheless, CAP remains a common cause of childhood morbidity and mortality. Pneumonia may develop at any age, but most often it occurs in young children, who are more likely to have a more severe course of pneumonia. Currently, early diagnosis and prognosis of the disease severity in children is an urgent issue. It was found that, in most cases, a panel of conventional biomarkers, including the number of leukocytes, procalcitonin, CRP is not sufficient for the diagnosis of pediatric CAP. There is a demand for new biological markers which, along with clinical evaluation, may significantly improve diagnostics and management of CAP in children, thus reducing the risk of adverse outcomes associated with this disease. Such markers could be found among the cytokines, which are active participants in the CAP pathogenesis. The aim of this study was to determine the level of several cytokines in blood serum of children with CAP and to assess changes in the cytokine profile depending on the patient’s age and severity of the disease. The study included 117 children aged 1 to 18 years with a diagnosis of CAP confirmed by X-ray examination. The comparison group included 28 healthy children who did not have CAP or other signs of acute respiratory viral infection at the time of examination, being free of any chronic pathology requiring outpatient observation. A number of cytokines were determined quantitatively in blood serum, i.e., IL-1β, IFNγ, IL-2, IL-4, IL-6, IL-10, TNFα, IFNλ2 (IL-28A), IFNλ3 (IL-28B), IL-8, MCP-1, IL-17AF, GM-CSF using test systems based on the “sandwich” method of solid-phase ELISA using peroxidase labeling. As a result, it was found that the content of IL-6, IL-17AF, IL-1β, IFNγ, MCP-1, IFNλ2 (IL-28A), IFNλ3 (IL-28B), GM-CSF was significantly higher in the group of children with severe community-acquired pneumonia. The levels of certain cytokines, e.g., IL-6, IFNλ2 (IL-28A), IFNλ3 (IL-28B), GM-CSF varied depending on the age of patients, thus, probably, reflecting the degree of immune system activation in the children of different age groups.