Background Early diagnostic indicators and the identification of possible progression to severe or critical COVID-19 in children are unknown. To investigate the immune characteristics of early SARS-CoV-2 infection in children and possible key prognostic factors for early identification of critical COVID-19, a retrospective study including 121 children with COVID-19 was conducted. Peripheral blood lymphocyte subset counts, T cell-derived cytokine concentrations, inflammatory factor concentrations, and routine blood counts were analyzed statistically at the initial presentation. Results The T lymphocyte subset and natural killer cell counts decreased with increasing disease severity. Group III (critical cases) had a higher Th/Tc ratio than groups I and II (common and severe cases); group I had a higher B cell count than groups II and III. IL-6, IL-10, IFN-γ, SAA, and procalcitonin levels increased with increasing disease severity. Hemoglobin concentration, and RBC and eosinophil counts decreased with increasing disease severity. Groups II and III had significantly lower lymphocyte counts than group I. T, Th, Tc, IL-6, IL-10, RBC, and hemoglobin had relatively high contribution and area under the curve values. Conclusions Decreased T, Th, Tc, RBC, hemoglobin and increased IL-6 and IL-10 in early SARS-CoV-2 infection in children are valuable indices for early diagnosis of severe disease. The significantly reduced Th and Tc cells and significantly increased IL-6, IL-10, ferritin, procalcitonin, and SAA at this stage in children with critical COVID-19 may be closely associated with the systemic cytokine storm caused by immune dysregulation.
【저자키워드】 SARS-CoV-2, children, Lymphocyte subset, Severe case, Inflammatory factor, 【초록키워드】 COVID-19, IL-6, SARS-COV-2 infection, disease severity, diagnostic, ferritin, procalcitonin, cytokine, progression, eosinophil, B cell, Lymphocyte count, Retrospective study, early diagnosis, hemoglobin, IL-10, group, Critical, Blood, IFN-γ, Inflammatory, severe disease, critical cases, immune dysregulation, Prognostic factor, natural killer, procalcitonin level, T lymphocyte, cell count, significantly lower, immune characteristics, peripheral, Cell, concentrations, RBC, initial, significantly increased, SAA, Result, analyzed, caused, significantly, conducted, reduced, subset, statistically, Decreased, blood lymphocyte, children with COVID-19, Hemoglobin concentration, systemic cytokine, 【제목키워드】 immune response, Retrospective analysis, Prognostic factor, single-center,