The injured brain: TBI, mTBI, the immune system, and infection: connecting the dots.

Traumatic brain injury or stroke causes profound suppression of the cellular immune system and short- and long-term psychological sequelae. Infection is also a common result and is likely caused by bacterial translocation from the gut. Both the bacterial translocation from the gut and the ensuing pneumonia and sepsis are ameliorated by adoptive immune therapy. Huge health care costs are incurred by brain trauma and its sequelae in our soldiers, athletes, and general population. Diffusion tensor imaging and adoptive immune therapy should become standards of care to follow the injured brain serially as it heals and as the immune suppression and infections are overcome. Brain infrastructure healing is retarded by a suppressed immune system, and the blood-brain barrier's response to trauma offers opportunity for adoptive immune therapy to enhance microglial-directed neuronal repair and maintenance.