Central nervous system injury-induced immune suppression

Area of Science:

• Neuroscience
• Immunology
• Trauma Care

Background:

• Central nervous system (CNS) trauma, encompassing traumatic brain injury (TBI) and spinal cord injury (SCI), is a significant cause of death and disability, particularly in younger populations.
• Despite advances, pharmacological treatments for TBI and SCI have yielded disappointing results, with improvements primarily attributed to supportive care.
• Posttraumatic nosocomial infections represent a major, potentially reversible risk factor following neurotrauma, exacerbated by systemic immune suppression.

Purpose of the Study:

• To review the evidence of post-injury systemic immune suppression following TBI, TBI polytrauma, and SCI in both animal models and clinical research.
• To highlight the challenges and opportunities associated with understanding and reversing neurotrauma-induced immune suppression.
• To underscore the link between neurotrauma, immune suppression, and increased risk of infection, poorer recovery, and mortality.

Main Methods:

• Review of existing animal model studies investigating posttraumatic immune suppression.
• Analysis of clinical research examining systemic immune changes after TBI, TBI polytrauma, and SCI.
• Synthesis of evidence regarding potential etiologies of posttraumatic immune suppression.

Main Results:

• Multiple studies confirm posttraumatic systemic immune suppression following CNS injuries.
• Neurotrauma patients exhibit a higher susceptibility to in-hospital infections due to immune suppression.
• Infected neurotrauma patients demonstrate poorer recovery and increased mortality compared to non-infected patients.

Conclusions:

• Post-injury systemic immune suppression, particularly after neurotrauma, is a significant clinical challenge.
• Potential causes include damage-associated molecular patterns, myeloid-derived suppressor cells, and sympathetic nervous system activation.
• Reversing post-neurotrauma immune suppression presents a critical opportunity to improve patient outcomes and reduce morbidity and mortality.