Alterations in immune function following head injury in children.

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.