Cytokine and chemokine profiles linked to early severity of scrub typhus: multicenter validation of soluble PD-L1

= 0.082). sPD-L1 demonstrated a significant trend with increasing severity and showed superior performance to conventional markers in distinguishing patients with organ dysfunction. Receiver operating characteristic analysis of sPD-L1 levels at hospital admission confirmed high discriminatory power, with AUCs of 0.997 and 0.981 in the two validation cohorts. This multicenter study identified sPD-L1 as a potential early biomarker for early risk stratification of patients with scrub typhus. IMPORTANCE: , affects over one million people annually in the Asia-Pacific region, with an in-hospital mortality rate of more than 30% among patients with severe disease. Early identification of patients at high risk of progression to multi-organ failure remains a major clinical challenge. Timely risk stratification to identify high-risk patients is essential to prevent poor clinical outcomes. This study identifies soluble programmed death-ligand 1 as a potential early biomarker that distinguishes patients at risk of developing severe disease within the first week of hospitalization.