Circulating immune complexes in patients with gram negative septic shock

Area of Science:

• Immunology
• Critical Care Medicine
• Pathophysiology

Background:

• Septic shock involves complex immune dysregulation.
• Complement component abnormalities are frequently observed in septic shock patients.
• The role of circulating immune complexes (C.I.C.) in septic shock pathogenesis remains unclear.

Purpose of the Study:

• To investigate the presence and significance of C.I.C. in patients with gram-negative sepsis.
• To correlate C.I.C. levels with complement component abnormalities and clinical severity in septic shock.
• To elucidate the potential role of C.I.C. in the pathogenesis of human septic shock.

Main Methods:

• Sera from 34 gram-negative sepsis patients were analyzed for C.I.C. using polyethylene glycol precipitation and C1q deviation tests.
• Simultaneous determination of serum immunoglobulin (IgG, IgA, IgM) and complement component (C1q, C3, C4) levels.
• Patients were stratified based on the severity of haemodynamic abnormalities.

Main Results:

• Patients with minimal haemodynamic abnormalities showed normal or increased immunoglobulin and complement levels, with positive C.I.C. tests in 11 cases.
• Patients with severe septic shock exhibited decreased levels of IgG, IgM, C1q, C3, and C4.
• In severe septic shock, C.I.C. tests were consistently negative (P < 10(-4)), despite evidence of complement activation.

Conclusions:

• The disappearance of C.I.C. in severe septic shock patients, alongside complement activation, suggests their involvement in disease pathogenesis.
• C.I.C. may play a protective role or indicate a different disease mechanism in less severe sepsis.
• Further research is warranted to fully understand the complex interplay of C.I.C. and complement in septic shock.