Abstract
BACKGROUND: Cytokine levels in the peripheral blood of children infected with the influenza A virus are significantly associated with disease diagnosis and severity. This study aimed to investigate the correlation between the expression levels of six cytokines in the peripheral blood of pediatric patients with influenza and the diagnosis and severity of their condition. METHODS: The levels of six cytokines were measured using a flow cytometric microsphere array. Statistical analysis was performed using IBM SPSS Statistics 26.0 to compare differences between the groups, with a P value of less than 0.05 considered statistically significant. RESULTS: Univariate analysis showed that the levels of interferon alpha-2 (IFN-α2), monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), and interleukin-18 (IL-18) were significantly elevated in the influenza group (P≤0.001). IL-18 levels were higher in the H3N2 group than in the H1N1 group (P=0.03), and IFN-α2 levels were higher in the Mycoplasma coinfection group compared to the influenza-only group (P=0.04). Notably, significant differences in IFN-α2 and MCP-1 levels were observed between the mild-moderate and severe influenza A subgroups (P=0.008, P=0.01, respectively). Negative correlations were found between the severity of influenza A and the levels of IFN-α2 and MCP-1 (r=-0.357, P=0.006 and r=-0.329, P=0.01, respectively). Multifactorial logistic regression and receiver operating characteristic (ROC) curve analysis identified IFN-α2 and MCP-1 as independent risk factors for severe influenza A. CONCLUSIONS: Inflammatory cytokine levels are critical in modulating the immune and inflammatory responses of the body. IFN-α2 and MCP-1 could serve as early indicators of severe influenza A. IL-18 levels were significantly higher in the H3N2 group compared to the H1N1 group, this finding may aid in differentiating between influenza subtypes, providing insights for tailored interventions.