Supplementary Material for: Soluble interleukin-1 receptor type 2 (sIL-1R2) as a marker of inflammation and disease severity in patients with cirrhosis

Introdution: Cirrhosis involves immune dysfunction and systemic inflammation, especially during acute decompensation (AD) and acute-on-chronic liver failure (ACLF). Soluble interleukin-1 receptor type 2 (sIL-1R2) acts as a decoy receptor for IL-1β with anti-inflammatory effects, but its role in cirrhosis is unclear. Our aim was to assess serum sIL-1R2 levels in patients with cirrhosis, compare them across disease stages and healthy controls, and examine associations with inflammation, bacterial infection, organ failure, and short-term mortality. Methods: We studied 240 individuals: 200 hospitalized with AD, 20 with stable cirrhosis, and 20 healthy controls. Serum sIL-1R2 was measured by ELISA. Clinical data, infection, organ failure, and 30-day outcomes were analyzed using Cox regression and Kaplan-Meier methods. Results: sIL-1R2 levels were significantly higher in AD patients than in stable cirrhotics or controls (p < 0.05). Levels correlated with leukocyte and neutrophil counts, liver function scores (Child-Pugh, MELD, CLIF-SOFA), and were elevated in cases of liver and coagulation failure. Among infected patients, the Kaplan-Meier survival probability was 81.6% in sIL-1R2 < 8300 pg/mL and 57.1% in values ≥ 8300 pg/mL (p = 0.009). Conclusions: Serum sIL-1R2 increases with cirrhosis severity and may reflect inflammation and organ failure. It may serve as a short-term prognostic biomarker in infected patients.