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Alterations in immune function following head injury in children
1Department of Pediatrics, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit 48201, USA.
Insights
Severe head injury in children impairs cell-mediated immunity, with many experiencing anergy. Plasma factors may also suppress T-cell function during recovery.
Area of Science:
- Pediatric critical care medicine
- Immunology
- Neurotrauma research
Background:
- Severe head injury (SHI) can significantly impact a child's immune system.
- Understanding immune responses post-SHI is crucial for predicting outcomes and developing interventions.
Purpose of the Study:
- To investigate cellular and humoral immune responses in children following severe head injury.
- To assess immune function during the acute phase and early recovery period after SHI.
Main Methods:
- Prospective observational study involving 15 children with SHI (Glasgow Coma Score ≤ 7).
- Assessed cellular immunity via skin antigen testing, lymphocyte counts, and mitogen proliferation tests (PHA, ConA, PWM).
- Measured humoral immunity through immunoglobulin concentrations and evaluated plasma effects on T-cell responses.
Main Results:
- Anergy was prevalent, affecting 71% on day 1 and decreasing to 18% by 3 months post-injury.
- Decreased T-cell counts and phytohemagglutinin responses were observed acutely, with elevated B-cell counts and later immunoglobulin increases.
- Patient plasma from day 7 post-injury suppressed normal lymphocyte proliferation, suggesting immunosuppressive factors.
Conclusions:
- Severe head injury in children is linked to significant depression of cell-mediated immunity.
- Immunosuppressive factors in plasma may play a role in the observed T-cell dysfunction after SHI.
Objective:
To investigate cellular and humoral immunity in children immediately after severe head injury and during the early recovery period.
Design:
Prospective, observational study with factorial design.
Setting:
Pediatric ICU of a university teaching hospital.
Patients:
Fifteen children (median age 9.6 yrs, range 1.7 to 18) with head injury and Glasgow Coma Score of < or = 7.
Interventions:
None.
Measurements And Main Results:
Skin testing with seven standard antigens was performed and blood samples were obtained for the following measurements: total lymphocyte count and subsets; proliferative response to phytohemagglutinin, concanavalin A, and pokeweed mitogen; and immunoglobulin concentrations on days 1, 7, and 14 and 3 months after injury. The effect of patient plasma on phytohemagglutinin-induced proliferative responses of normal donor lymphocytes was also assessed at these times. Anergy was present in 71% of patients on day 1, 54% of patients on day 7, 31% of patients on day 14, and 18% of patients at 3 months. Total, helper, and suppressor T-cell counts were decreased on day 1, and the T-cell response to phytohemagglutinin was decreased on days 1, 7, and 14 compared with values at 3 months. B-cell counts were increased on day 1, followed by an increase in serum immunoglobulin concentrations 1 to 2 wks later. The B-cell response to pokeweed mitogen was unchanged over the 3-month study period. The phytohemagglutinin responses of normal donor lymphocytes were decreased when incubated with patient plasma obtained on day 7 after injury.
Conclusions:
Severe head injury in children is associated with depressed cell-mediated immunity. Plasma immunosuppressive factors may contribute to T-cell dysfunction.