Restoration of depressed immune function in spinal cord injury patients receiving rehabilitation therapy
Both natural and adaptive immune responses were strikingly decreased 2 weeks after injury in 49 spinal cord injuries, 28 tetraplegie and 21 paraplegic patients compared to agematched controls. All values are expressed as means. NK cell function decreased to 21.0% 2 weeks after spinal cord injury compared to 48.6% in controls. At 2 weeks, plasma ACTH values increased to 17.0 pg/ml in patients compared to 11.2 pg/ml in controls and urine free Cortisol levels were elevated to 162.4 μg/24 h in patients compared to 53.6 ug/24 h in controls. T cell function decreased to 40.2% of normal (lymphocyte transformation) by 3 months post injury. T cell activation (IL-2R) was diminished, i.e., 183.4 ug/ml compared to 328.2 ug/ml in controls. With rehabilitation therapy, NK cell function increased to 41.6% by 7 months post injury. NK cell-mediated lysis diminished sharply between 7 and 9 months decreasing to 22.8% at 10 months and ultimately returning to the 2 week post injury level. Rehabilitation therapy contributed to the restoration of T cell function to 92.0% of normal by 6 months post 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. 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 to 126 in controls of healthy age matched controls.