Elevated plasma Ang2/Tie2 ratio as a diagnostic and prognostic biomarker for sepsis in leukemia patients

Dysregulation of the Ang-Tie pathway drives vascular leakage in sepsis. This study investigates plasma Ang-Tie axis components as sepsis biomarkers in leukemia through a retrospective cohort of 77 patients (36 with sepsis, 41 without sepsis). Septic patients exhibited significantly lower Ang1 (log₁₀: 2.685 vs 3.143 pg/mL) and Tie2 (log₁₀: 2.300 vs 2.800 pg/mL), but higher Ang2 (3.258 vs 2.841 pg/mL) than controls (P < 0.01). Critically, elevated Ang2/Ang1 (1.185 vs 0.917) and Ang2/Tie2 ratios (1.381 vs 0.995) strongly correlated with sepsis susceptibility. The Ang2/Tie2 ratio demonstrated superior diagnostic accuracy (AUC = 0.860, sensitivity = 86.1%, specificity = 80.5%) compared to routine biomarkers (D-dimer, procalcitonin). Strikingly, an Ang2/Tie2 ratio > 1.121 (Youden index) predicted a 3.5-fold increased mortality risk (95% CI: 1.51-8.25), independent of the leukemia subtype or treatment phase. These findings position the Ang2/Tie2 ratio as a dual diagnostic and pro gnostic biomarker for sepsis in leukemia patients, offering a mechanistic link between endothelial injury and poor outcomes. Our work bridges vascular biology and hematologic oncology, providing actionable insights for early intervention and targeted therapies to mitigate vascular leakage in high-risk populations.