engleski

Neuroimmunomodulation in severe traumatic brain injured patients

Purpose: Traumatic brain injury is a leading cause of death and permanent neurological damage in those below the age of 45 in industrialized countries and it is a silently growing epidemic. Much of the mortality is related to severity of primary neurological impairment and secondary brain injury caused by hypoxia and hypotension. Despite significant improvement in the intensive treatment of severe traumatic brain injured patients (STBI), these patients show high susceptibility to infections. The mechanism underlying the susceptibility to the infections is still unexplained. The purpose of the study was to investigate changes in frequency of leukocytes subpopulations in peripheral blood of patients with STBI during the course of intensive care treatment. Methods: Forty STBI patients between age of 18 and 75 years we included in the study. Healthy volunteers served as controls. Peripheral blood mononuclear cells (PBMC) were isolated from peripheral blood samples that were taken from these patients at day 1, 4 and 7 after the brain injury. The frequency of T, B lymphocyte, NK cells NKT cells and monocytes from peripheral blood of all the subjects include in the study were analysed by simultaneous detection of surface antigens using fluorochrome conjugated monoclonal antibodies. The two major subsets of T lymphocytes (CD3+CD56-CD4+ and CD3+CD56-CD8+) and NK cells (CD3-CD56+dim and CD3-CD56+bright) were also analysed by flow cytometry. Results: Infection (pneumonia, sepsis, uroinfection) occurred in 55% of STBI patients with the highest incidence on day 4 after the injury. At day 4, the percentage of T lymphocytes with cytotoxic phenotype significantly diminished and their numbers restored at day 7. The frequency of NKT cells showed the identical time dependent pattern, whereas the percentage of NK cells diminished on day 4 but did not restore after 7 days. The frequency of B lymphocytes did not change significantly during the time investigated, whereas the percentage of monocytes increased immediately after the injury and gradually diminished. Conclusion: The decrease of cells with cytotoxic phenotype might explain high incidence of susceptibility to infection of patients with STBI.

severe traumatic brain injured patients; T lymphocytes; NK cells; NKT cells

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