Flow Cytometric Characterization of T Cell Subsets and Microglia After Repetitive Mild Traumatic Brain Injury in Rats
Multiple communicative pathways among nervous, endocrine, and immune systems facilitate physiological immunoregulation. Spinal cord injury (SCI) patients had strikingly decreased natural and adaptive immune responses by 2 weeks post injury. While NK-cell function was decreased, plasma ACTH and urine-free cortisol levels were increased. T cell function and activation were both diminished. With rehabilitation therapy, NK and T function increased; without rehabilitation, NK levels remained depressed. When rehabilitation ceased, NK function decreased. Cervical SCI patients had less NK and T function than thoracic injury patients. SCI patients also had reduced levels of cellular adhesion molecules (CAMs) that participate in immune function and wound healing. SCI patients with pressure ulcers were compared to those without pressure ulcers. LFA-1, VLA-4, and other surface markers were decreased on the lymphocytes of all SCI patients. SCI patients with pressure ulcers had lower CAM levels than did patients without pressure ulcers. Nutritional status was determined by zinc, albumin, and prealbumin levels. SCI patients had decreased albumin levels. Those with pressure ulcers had decreased prealbumin levels and zinc levels.