Prediction of Hyperinflammatory Phenotypes in Critically Ill Patients via Routine Clinical Data and IL-6: Towards...

Area of Science:

• Critical care medicine
• Immunology
• Translational research

Background:

• Interleukin-6 (IL-6) is a key mediator of systemic inflammation, frequently elevated in critical illnesses such as sepsis and ARDS.
• Varied patient responses to immunomodulatory treatments necessitate a deeper understanding of IL-6 regulation and clinical significance.

Purpose of the Study:

• To investigate the determinants of IL-6 regulation in critically ill patients.
• To identify clinical and inflammatory phenotypes associated with IL-6 levels and mortality.
• To explore the prognostic value of IL-6 in intensive care unit (ICU) settings.

Main Methods:

• Retrospective analysis of ICU patients with comprehensive clinical and laboratory data, including plasma IL-6.
• IL-6 quantification via electrochemiluminescence immunoassay.
• Statistical analyses including survival analysis, Lasso regression, Bayesian logistic regression, and latent class analysis.

Main Results:

• IL-6 levels were significantly elevated in sepsis and neutropenia, with extreme concentrations when both conditions coexisted.
• While IL-6 was not a universal predictor of ICU mortality, thresholds (≥200 pg/mL) correlated with reduced survival.
• A hyperinflammatory phenotype (IL-6 ≥ 100 pg/mL) was identified, associated with >40% predicted mortality and 58% observed mortality, alongside distinct patient subgroups.

Conclusions:

• Sepsis and neutropenia are major drivers of elevated IL-6 in critical illness.
• Distinct inflammatory phenotypes characterized by IL-6 levels can aid in risk stratification.
• These findings support the potential for targeted anti-cytokine therapies in critical care.