Abstract
OBJECTIVES: To investigate the expression of serum Interleukin-17 (IL-17) and its receptor IL-17R in patients with bacterial pneumonia and their diagnostic value for severe bacterial pneumonia. METHODS: In this retrospective analysis, 172 patients diagnosed with bacterial pneumonia were included and categorized into the severe (n = 61) and non-severe (n = 111) groups. Serum concentrations of IL-17, IL-17R, procalcitonin (PCT), and high-sensitivity C-reactive protein (hs-CRP) were measured using ELISA upon admission and after antibiotic treatment. ROC curves were drawn to assess the diagnostic performance of influencing factors, correlation analyses were performed to explore relationships among biomarkers, and logistic regression to identify independent risk factors. RESULTS: Before treatment, patients with severe bacterial pneumonia demonstrated significantly higher levels of IL-17, IL-17R, PCT, and hs-CRP compared to non-severe patients (all P < 0.001). All biomarkers decreased significantly after treatment in severe group (all P < 0.05). IL-17 and IL-17R showed good accuracy in identifying severe disease (AUC = 0.808 and 0.777, respectively) and were positively correlated with PCT and hs-CRP (all P < 0.05). Multivariate analysis identified IL-17, IL-17R, PCT, and hs-CRP as independent risk factors for severe bacterial pneumonia. CONCLUSIONS: IL-17 and IL-17R are elevated in bacterial pneumonia, demonstrating close association with disease severity and conventional markers. Their decline after treatment indicates therapeutic effectiveness. These cytokines show diagnostic potential and could help monitor disease progression and treatment response. Future research should confirm these findings in larger cohorts and investigate their interactions with other inflammatory pathways.