NINJ1: A Novel Sepsis Severity and Mortality Biomarker.

Background: Multiple cell death modalities are implicated in sepsis pathobiology. However, the clinical relevance of NINJ1, a key mediator of plasma membrane rupture during lytic cell death, in sepsis progression and outcomes has remained poorly explored.

Methods: Circulating NINJ1 levels were measured in 116 septic ICU patients, 16 non-septic ICU controls, and 16 healthy controls. Comparative analysis of serum NINJ1 across these groups was performed. Correlations between NINJ1 and clinical disease severity scores (SOFA, APACHE II) as well as laboratory parameters were examined in the sepsis cohort. Furthermore, we assessed the prognostic performance of NINJ1 for predicting 28-day mortality in septic patients using receiver operating characteristic (ROC) analyses.

Results: Circulating NINJ1 levels were elevated in septic patients and positively correlated with sepsis severity scores. NINJ1 also showed positive correlations with liver injury markers (AST/ALT) and coagulation parameters (D-dimer, APTT, PT, TT) in sepsis. Further analysis using the ISTH overt DIC scoring system revealed an association between NINJ1 and sepsis-induced coagulopathy.ROC analysis demonstrated NINJ1 outperformed traditional inflammatory biomarkers PCT and CRP in predicting 28-day sepsis mortality, although its prognostic accuracy was lower than SOFA and APACHE II scores. Combining NINJ1 with SOFA improved mortality prediction from an AUC of 0.6843 to 0.773.

Conclusions: Circulating NINJ1 serves as a novel sepsis biomarker indicative of disease severity, coagulopathy and mortality risk, and its integration with SOFA and APACHE II scores substantially enhances prognostic risk stratification. These findings highlight the prospective clinical utility of NINJ1 for sepsis prognostication and monitoring, warranting further validation studies to facilitate implementation.