Identification of novel sepsis-related neutrophil subsets and surface markers for clinical diagnosis and outcome.

Sepsis, a life-threatening immune dysregulation caused by infection, lacks specific laboratory indicators for differential diagnosis and outcome assessment. This study aimed to identify immune cell heterogeneity and surface characteristic molecules for sepsis diagnosis and outcome evaluation. Transcriptomic and proteomic profiling were designed to identify immune cell-related molecules and form a detection panel for cytometry by time-of-flight (CyTOF) analysis. CyTOF revealed three neutrophil subsets: TGF-βhiCD62Llow (immunosuppressive phenotype), CD54+CD62L+ (proinflammatory phenotype), and CD54lowCD62L+ (compensatory immunosuppressive phenotype), correlating with sepsis severity, progression and prognosis. In the acute stage of sepsis, the number of CD54+ and CD62L+ neutrophils increased, and their expression gradually decreased as the course of the disease progresses; however, their expression in the mild group decreased rapidly and then stabilized, whereas that in the severe group decreased slowly. At 24 h, the severe group retained higher CD54+ (p = 0.0051) and CD62L+ (p = 0.0003) expression. Serum sCD54 in sepsis patients (PXD027485 dataset) was elevated vs controls (p < 0.0001, AUC = 0.9627). Parallel reaction monitoring (PRM) analysis confirmed higher sCD54 in sepsis cohorts (p = 0.0242, AUC = 0.9433). Plasma exosomal CD54 in septic rats also increased (p = 0.0013). In conclusion, three identified neutrophil subsets and CD54 serve as sepsis-specific indicators for outcome assessment and differential diagnosis, guiding personalized therapies.