Early nutrition support modifies immune function in patients sustaining severe head injury

Area of Science:

• Immunology
• Neuroscience
• Critical Care Medicine

Background:

• Severe head injury often leads to immunosuppression, characterized by a decreased CD4/CD8 T-lymphocyte ratio and blunted T-cell responsiveness.
• This immune dysfunction may stem from a hypermetabolic response and insufficient nutrient delivery post-injury.
• Previous findings suggested early parenteral nutrition (PN) might preserve the CD4-CD8 ratio in closed-head injury (CHI) patients.

Purpose of the Study:

• To investigate the impact of early parenteral nutrition (PN) on the immune function of patients with severe closed-head injury (CHI).
• To determine if early nutritional support can mitigate the characteristic depression in cellular immunity following CHI.

Main Methods:

• Prospective randomized trial involving nine severe CHI patients.
• Patients were assigned to either early PN (day 1) or delayed PN (day 5).
• Nutrient delivery: 2 g protein/kg/day and 40 non-protein kcal/kg/day for 14 days.
• Immune markers (CD4, CD8, IL-6) and T-lymphocyte activation (Con A, PHA, PWM) were assessed on days 1, 3, 7, and 14.

Main Results:

• Early PN group showed significant increases in total CD4 cell counts and CD4 percentage by day 14 compared to the delayed PN group.
• Lymphocyte response to concanavalin A (Con A) stimulation significantly improved from baseline to day 14 in the early PN group.
• A significant rise in the CD4-CD8 ratio was observed in the early PN group by day 14.

Conclusions:

• Early, aggressive nutritional support in CHI patients positively modulates immune function.
• This support is associated with increased CD4 cell counts, improved CD4-CD8 ratios, and enhanced T-lymphocyte responsiveness.
• Early PN appears to be a viable strategy to support immune recovery after severe head injury.