Necroptotic and Apoptotic Pathways in Sepsis: A Comparative Analysis of Pediatric and Adult ICU Patients

Background: Necroptosis, a regulated form of inflammatory cell death, is increasingly recognized as a key driver of sepsis and critical illness. The balance between necroptosis and apoptosis may influence immune responses and outcomes in ICU patients. Objective: To evaluate necroptosis- and apoptosis-related protein expression in critically ill pediatric and adult patients with sepsis/septic shock, trauma/SIRS, or cardiac conditions, and assess their association with clinical outcomes. Methods: In this prospective, observational study, 88 patients admitted to a tertiary ICU were categorized into four groups: sepsis/septic shock, trauma/SIRS, cardiac disease, and healthy controls. Serum levels of RIPK1, RIPK3, MLKL, A20, caspase-8, IL-1β, and IL-18 were measured within 24 h of admission using ELISA. Biomarkers were analyzed by disease group, age, and severity indices. Results: Patients with sepsis-both adults and children-exhibited significantly elevated levels of RIPK1, IL-1β, and IL-18 (p < 0.001) and reduced levels of caspase-8 (p = 0.015), indicating activation of the necroptosis pathway. A20 was significantly upregulated (p < 0.001) and independently associated with lactate levels. RIPK1, IL-1β, and IL-18 were positively correlated with ICU length of stay and illness severity, whereas caspase-8 showed an inverse correlation. ROC analysis demonstrated strong predictive performance for sepsis/septic shock using RIPK1 (AUC = 0.81), IL-18 (AUC = 0.71), and A20 (AUC = 0.71); conversely, caspase-8 was inversely associated with sepsis (AUC = 0.32). Conclusions: Necroptosis appears to play a central role in the pathophysiology of sepsis across age groups. Elevated levels of RIPK1, IL-1β, IL-18, and A20 may serve as biomarkers of disease severity, while reduced caspase-8 supports a shift away from apoptosis toward necroptotic cell death. These findings highlight the potential of necroptosis-related pathways as targets for risk stratification and therapeutic intervention in critically ill patients of all ages.