Clinical Analysis of Lymphocyte Population Changes in Severe Head Injured Patients Using Flow Cytometry

ABSTRACT

Despite advancement in diagnosis and progress in the management of intracranial pressure, infection remains a common complication following severe head injury. This following study attempts to better define the cell mediated immunity that decreased immediately following severe head injury. Twenty-five patients admitted with severe head injury(mean Glasgow Coma Scale, 5.32) were studied at the emergency rooms. The control group consisted of 25 mildly head-injured patients requiring hospital observation. Phenotyping of peripheral blood lymphocytes(PBL), determined by flow cytometry using monoclonal antibodies to lymphocytes subpopulation and HLA-DR receptors, was performed immediately following head injury. When severely head-injured patients were compared with controls, it was observed that the total T-cell counts(p<0.01) were markedly decreased, whereas the NK cell counts(p<0.01) were found to be increased. Infection rate of the study group was 44% and the majority of infections occur within the first 10 days after sever head injury. The results of this study suggests that severely head-injured patients had a decreased T-cell population and subpopulation in lines with higher infection rate.