Isolated head injury in children affects the neutrophil function and lymphocyte count

Outcomes of treatment of postinjury complications remain unsatisfactory and research continues into the impact of trauma on innate and acquired immunity. The aim of our study was to describe how head injury affects a child's immunity by measuring the neutrophil function and lymphocytes subsets.

The peripheral blood of 16 children with head trauma (Glasgow Coma Score < or =9) was examined. The blood samples were collected on the first and on the seventh day after trauma. The production of reactive oxygen species (ROS), spontaneous and stimulated, the expression of CD11b, and the lymphocyte subpopulations were measured. The blood of healthy children was studied as control. The impact of endotracheal intubation on the examined parameters was analyzed as well.

Head trauma leads to the increase of leukocytosis; the total production of ROS by peripheral blood neutrophils does not change after head injury. Correction of the results according to the number of neutrophils revealed a significant decrease in ROS production by a single neutrophil. The expression of adhesion molecule CD11b did not change. Head injury in children causes the decrease of the total lymphocyte count, CD3, CD4, CD8, and natural killer cells count on both the first and the seventh postinjury day. On the seventh day the significant decrease of natural killer cells subset was observed. The CD4/CD8 ratio increased from 1.5 (the first day) to 2.5 (the seventh day). The intubation did not affect the examined parameters.

After head injury, total ROS production and adhesion molecule CD11b expression remained unchanged when compared with control. The study did not demonstrate evidence for neutrophil activation in patients with head injuries. The total lymphocyte count was found to be decreased and the composition of lymphocytes' subsets was deeply impaired.