Circulating complement proteins in patients with sepsis or systemic inflammatory response syndrome

Area of Science:

• Immunology
• Critical Care Medicine
• Biochemistry

Background:

• Sepsis triggers a significant activation of the complement system, a key early event in the syndrome.
• Early diagnosis of sepsis is crucial for effective treatment and improved patient outcomes.

Purpose of the Study:

• To investigate the utility of plasma complement components C3a, C5a, and C3, and the C3a/C3 ratio for early sepsis diagnosis.
• To assess the potential of these markers in differentiating sepsis from systemic inflammatory response syndrome (SIRS) and predicting prognosis.

Main Methods:

• Plasma levels of C3a, C5a, and C3 were measured in 33 intensive care unit patients and healthy donors over 10 days.
• Patients were monitored for clinical and microbiological criteria of sepsis and SIRS.
• Statistical analyses were performed to compare marker levels between groups and correlate them with clinical outcomes.

Main Results:

• Intensive care unit patients exhibited significantly elevated C3a levels and C3a/C3 ratios upon admission compared to healthy donors (P < 0.0001).
• C3 levels were significantly reduced on admission but increased during the study (P < 0.0001). C5a levels showed no significant difference.
• C3a levels and C3a/C3 ratios differentiated sepsis patients from those with SIRS within 24 hours of sepsis onset (P < 0.05).
• Higher C3a levels were observed in non-survivors compared to survivors (P = 0.0185).

Conclusions:

• Plasma C3a concentration and the C3a/C3 ratio are valuable biomarkers for early sepsis diagnosis.
• These markers can aid in distinguishing sepsis from SIRS and serve as a prognostic indicator.
• C3a measurement offers a promising tool for improving sepsis management in critical care settings.