Features of altered immune status in acute brain concussion

Abstract

Traumatic brain injury (TBI) is one of the most common type of injuries, so that its mild form prevails in overall injury pattern. Currently, it is known that brain injury triggers immune system response, but its role in translating into clinical manifestations, potential complications and sequelae remains poorly understood. It necessitates assessment of cellular immunity in patients with acute TBI of varying severity followed by investigating relationship between identified changes. It is now believed that immune system plays a lead role in brain functioning. It may be accounted for by interplay between peripheral immune cells and the brain, which may become augmented during developing immune response. Here we quantitatively assessed composition of major peripheral blood helper T cell subsets in TBI patients by flow cytometry measuring percentage of central (CM, CD45RA-CD62L+) and effector (EM, CD45RA-CD62L-) memory Th cells. It was found that percentage of Th17 (CXCR5-CXCR3-CCR6+CCR4-), DP Th17 (CXCR5-CXCR3+CCR6+CCR4+) within CD3+CD4+T cell population were significantly increased (p 0.05) compared to control group. Moreover, percentage of Th1/Th17 subset (CXCR5-CXCR3+CCR6+CCR4-) was significantly increased (p 0.05) within EM and CM T cell subsets compared to control group. In addition, percentage of Th1 (CXCR5-CXCR3+CCR6-CCR4) was also significantly elevated in CD3+CD4+, EM and CM T cells compared to apparently healthy subjects. Hence, the data obtained allow to consider immune reactions among crucial arms in TBI pathogenesis related to concussion and its consequences. Thus, brain concussion affects cellular immune response triggering distortion in CD3+CD4+T cell composition as well as percentage of helper central and effector memory T cells. Hence, the changes revealed in patients with acute brain concussion may predetermine disease course and developing long-term complications, which requires advancing therapeutic and rehabilitation protocols in such patients.