Increase Level of Interleukin-6 in Patients of Sepsis Admitted in Tertiary Care Center

Abstract

Background: Sepsis is a life-threatening condition characterized by a dysregulated host response to infection, contributing significantly to global morbidity and mortality. Interleukin-6 (IL-6), a multifunctional cytokine, is increasingly recognized as a potential biomarker for early diagnosis, severity assessment, and treatment monitoring in sepsis.

Aim: To estimate serum Interleukin-6 levels in patients with sepsis admitted to a tertiary care center.

Objectives: To measure serum IL-6 levels in patients diagnosed with sepsis. To compare serum IL-6 levels with C-reactive protein (CRP). To assess the role of IL-6 as a diagnostic and monitoring biomarker in sepsis.

Methods: This observational follow-up study was conducted in the Department of Biochemistry in collaboration with the ICU of MGM Medical College and Hospital, Chhatrapati Sambhajinagar, over 12 months (January–December 2024). A total of 52 sepsis patients (aged 35–70 years) were enrolled as per Sepsis-3 criteria. Serum IL-6 was measured using the Beckman Coulter Access 2 immunoassay analyzer, and CRP was estimated by the Vitros 5600 Ortho Clinical Diagnostics system. Statistical analysis included t-tests, chi-square, correlation analysis, and ROC curve evaluation.

Results: The mean serum IL-6 levels showed a stepwise rise with severity: mild sepsis 428.5 ± 180.2 pg/mL, severe sepsis 643.9 ± 240.7 pg/mL, and septic shock 881.7 ± 310.4 pg/mL (overall mean 612.7 pg/mL; p<0.001). IL-6 was ≥35 pg/mL in 90.4% of patients. A moderate positive correlation was observed between IL-6 and CRP (r=0.58, p<0.001). Patients with IL-6 ≥683 pg/mL had significantly higher CRP (129.3 ± 52.7 mg/L vs. 90.6 ± 44.9 mg/L, p=0.0062). Diagnostic accuracy of IL-6 was good (overall AUC=0.82; sensitivity 77.8%, specificity 76.5%). IL-6 levels declined significantly post-treatment across all severity groups (overall mean reduction -252.4 pg/mL, p=3.0×10⁻¹⁰).

Conclusion: Serum IL-6 levels rise significantly with increasing sepsis severity and show strong correlation with CRP, making it a promising biomarker for early diagnosis, severity stratification, and treatment monitoring in sepsis patients.