Identification of Monocyte CD11c as a Potential Biomarker for Distinguishing Sepsis From Non-Infectious Inflammation and Predicting the Outcome of Sepsis

Objective: To investigate whether monocyte CD11c (mCD11c) can serve as a promising biomarker for the diagnosis and prognosis of sepsis, distinguishing it from non-infectious inflammatory conditions. Methods: A prospective, observational cohort study was conducted using a discovery cohort (sepsis, mild infection, patients after cardiovascular surgery, recovered sepsis patients, and healthy controls) and a validation cohort (sepsis, mild infection, and patients after cardiovascular surgery). Peripheral blood samples were analyzed using Cytometry by Time-of-Flight (CyTOF), single-cell RNA sequencing, and flow cytometry to assess the immune cell composition and mCD11c expression. Clinical data and outcomes were collected for analysis. Results: The discovery cohort showed a significant downregulation of mCD11c in patients with sepsis. The validation cohort confirmed a lower mCD11c% in sepsis than in the other groups. Receiver operating characteristic (ROC) curve analysis showed that mCD11c had a higher AUC (0.939, P < 0.001) than traditional markers in distinguishing sepsis from non-infectious inflammation. mCD11c% was an independent prognostic factor for 7-day mortality ( P < 0.05), with significant differences in survival rates between patients with mCD11c% above and below 96.445%. Conclusion: mCD11c is a promising biomarker for early sepsis diagnosis and short-term survival prediction, outperforming the traditional markers. Larger multicenter studies are needed to validate these findings and to explore their potential as intervention targets.