Peripheral blood E2F1 expression and clinical significance in asthma with persistent airflow obstruction

OBJECTIVE: This study aimed to examine the clinical characteristics of patients with fixed airflow obstruction (FAO) during acute asthma exacerbations, with a focus on quantifying E2F1 expression in peripheral blood and induced sputum. Our objective was to assess its potential role as a biomarker for airway remodeling in asthma. METHODS: A total of 59 adult patients presenting with acute asthma exacerbations were prospectively enrolled between September 2022 and March 2024 and stratified into two groups: FAO (n = 33) and reversible airflow obstruction (RAO, n = 26). Additionally, 20 healthy controls were included for comparative analysis. Clinical data, induced sputum, and peripheral blood samples were collected to measure E2F1, retinoblastoma (Rb), miR107, and cyclin-dependent kinase 6 (CDK6) expression. Pulmonary function testing, complete blood counts, and sputum cytology were performed. The diagnostic efficacy of candidate biomarkers was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: Patients in the FAO group exhibited significantly elevated E2F1 mRNA and protein expression compared to the RAO group, along with prolonged disease duration and impaired pulmonary function. ROC analysis demonstrated that E2F1 mRNA yielded an area under the curve (AUC) of 0.853, with 88.2% sensitivity and 71.4% specificity. Multivariate regression identified peripheral blood E2F1 mRNA as an independent predictor of airway remodeling (OR = 3.052, P = 0.049). E2F1 expression showed significant negative correlations with FEV1/FVC and MEF50%, while E2F1 protein levels inversely correlated with MMEF75/25%. CONCLUSION: Peripheral blood E2F1 mRNA serves as an independent risk factor for FAO in asthma and may represent a promising biomarker for evaluating airway remodeling severity in affected patients. Further validation is warranted to confirm its clinical utility.