Prognostic value of IL-6, HMGB1, and TLR4 in bronchoalveolar lavage fluid of patients with community-acquired pneumonia

OBJECTIVES: To evaluate the prognostic value of inflammatory biomarkers in bronchoalveolar lavage fluid (BALF) in patients with community-acquired pneumonia (CAP). METHODS: A retrospective case-control study was conducted on 109 patients with CAP who were admitted between June 2022 and May 2024. Based on clinical outcome on day 10 after treatment initiation, patients were classified into an improved group (n = 58) and a deteriorated group (n = 51). Levels of white blood cells (WBC), C-reactive protein (CRP), interleukin-6 (IL-6), high-mobility group box 1 (HMGB1), and Toll-like receptor 4 (TLR4) in BALF were measured and compared between the two groups. Risk factors associated with poor prognosis were identified using logistic regression analyses, and a predictive model for disease deterioration was developed incorporating the identified independent risk factors. The clinical use of the predictive model was evaluated using receiver operating characteristic (ROC) analysis and decision curve analysis (DCA). RESULTS: = 0.002) as independent predictors of adverse outcome. A combined predictive model incorporating IL-6, HMGB1, and TLR4 demonstrated excellent discriminative ability, with an AUC of 0.940, outperforming each single marker. CONCLUSIONS: IL-6, HMGB1, and TLR4 in BALF are critical prognostic biomarkers in CAP, reflecting their roles in inflammatory response and disease progression.