Decreased immune reactivity and neuroendocrine alterations related to chronic stress in spinal cord injury and stroke patients.

Both natural and adaptive immune responses were found to be strikingly decreased 2 weeks after injury in 54 spinal cord injury and stroke patients, i.e., 28 quadriplegics, 21 paraplegics and 5 stroke patients, compared with those of age-matched controls. All values are expressed as means. Natural-killer (NK)-cell function decreased to 21.0% 2 weeks after spinal cord injury compared with 48.6% in controls. At 2 weeks, plasma ACTH values increased to 17.0 pg/ml in patients compared with 11.2 pg/ml in controls, and urine free cortisol levels were elevated to 162.4 micrograms/24 h in patients compared with 53.6 micrograms/24 h in controls. T-cell function decreased to 40.2% of normal (lymphocyte transformation) by 3 months after injury. T-cell activation (IL-2R) was diminished, i.e., 183.4 micrograms/ml compared with 328.2 micrograms/ml in controls. With rehabilitation therapy, NK-cell function increased to 41.6% by 7 months after injury. NK-cell-mediated lysis diminished sharply between 7 and 9 months, decreasing to 22.8% at 10 months and ultimately returning to the level seen 2 weeks after injury. Rehabilitation therapy contributed to the restoration of T-cell function to 92.0% of normal by 6 months after injury where it remained for 6+ months. IL-2R values improved in parallel with lymphocyte transformation. Whereas NK-cell-induced lysis remained depressed, i.e., 11.8% at 6 months and 11.4% at 12+ months in patients not receiving therapy, the restoration of NK-cell function at 6 months to 40.6% in rehabilitated patients decreased to 23.0% with cessation of treatment. NK-cell-mediated lysis values in cervical injury patients were significantly less than those in the thoracic injury group. Functional independence measurement (FIM) scores of the two paralleled their NK-cell function. With rehabilitation therapy, NK-cell-mediated lysis in the cervical group increased from 15.2 to 28.4%, whereas it improved in the thoracic group with therapy from 26.8 to 43.7%. With rehabilitation therapy, lymphocyte transformation in the cervical group increased from 37.3 to 85.6% and improved in the thoracic group from 48.4 to 88.9%. With rehabilitation therapy, FIM scores improved from 49.7 to 74.0 in the cervical group and from 79.8 to 97.3 in thoracic patients compared with 126 in controls. NK-cell-mediated lysis was depressed to 28.9% in 5 stroke patients and improved to 38.0% following rehabilitation therapy.