Adaptive immune function in critical illness

Area of Science:

• Immunology
• Critical Care Medicine
• Pathophysiology

Background:

• Adaptive immune system function is crucial in critical illnesses like sepsis and acute lung injury.
• Dysregulation of the immune response significantly contributes to morbidity and mortality in these conditions.

Purpose of the Study:

• To review and update the literature on adaptive immune system function in critical illness.
• To specifically focus on the role of T cells in sepsis and acute lung injury.

Main Methods:

• Literature review focusing on T-cell function in sepsis and acute lung injury.
• Analysis of mechanisms contributing to immune dysfunction, including lymphocyte apoptosis and regulatory T-cell expansion.

Main Results:

• Adaptive immune responses are similarly dysfunctional in sepsis and acute lung injury, characterized by 'immunoparalysis'.
• Key mechanisms include T-cell suppression, lymphocyte apoptosis, altered cytokine expression, and increased regulatory T cells.
• Experimental reversal of these abnormalities improves outcomes.

Conclusions:

• Immunoparalysis is a critical factor in sepsis and acute lung injury outcomes.
• Therapeutic strategies targeting inhibited pathways and using immunostimulant cytokines show promise.
• Development of immunomonitoring diagnostics is essential for timely and effective treatment.