[Immunological function in head-injured patients. Relationship with severity of injury and age].

The immunological function of 29 head-injured patients was investigated, with special reference to the relationships between changes in immunity and both severity of head injury and age. The patients were classified according to Glasgow Coma Scale scores (15, 9 to 14, and 3 to 8) and age (under 35, 35 to 65, and over 65 years). T cell subsets (OKT4 and OKT8) and Leu-11 a cells were studied by flow cytometry with the use of monoclonal antibody. Lymphocyte stimulation indices were also evaluated. The percentage of OKT4 cells was significantly decreased in the young patients with severe head injury, whereas the percentage of OKT8 cells remained almost within the normal range. Thus, the ratio of OKT4 to OKT8 cells was decreased. The percentage of Leu-1 la cells showed no correlation with severity of injury or age. Lymphocyte stimulation indices were reduced in cases of severe head injury. In this study, patients with severe head injury were immunosuppressed, particularly those under age 35.