Early immunological defects in comatose patients after acute brain injury

The aim of this prospective study was to evaluate the phagocytic, humoral, and cellular arms of the immune system in comatose patients shortly after severe brain injury and to compare the findings with those reported earlier in patients in a persistent vegetative state. The study was conducted in intensive care units and immunology laboratories of university-affiliated hospitals in central Israel.

The study group consisted of 14 men aged 16 to 65 years who were comatose as a result of acute brain injury due to mechanical trauma. All were studied within 72 hours of injury. Brain damage was severe in all cases (Glasgow Coma Scale score < 8). Healthy age- and sex-matched volunteers served as simultaneous controls. Infections arose in nine (75%) of the 12 patients in whom data were available; the cumulative mortality rate was 38% (five of 13 patients in whom outcome data were available). Every patient exhibited one or more defects in at least one arm of the immune system. Significant deficiencies were noted in neutrophil superoxide release, immunoglobulin (Ig)G, IgG1, IgM, C1q, C2, properdin, alternate C pathway, T cells, T helper cells, T suppressor cells, and natural killer cells. In an earlier series of patients examined by the authors months after the primary insult, these impairments were absent in most of the patients in the vegetative state.

Significant deficiencies of the immune system, particularly the cellular arm, are precipitated by severe brain injury within 72 hours of the event. These impairments probably play a role in the high rate of complicating infections and multiple organ failure. Together with earlier findings, the results of this study indicate that if brain-injured patients survive these hazards, their immune system will eventually recover.