Alteration of immune system function in tetraplegics. A pilot study

Over the past 20 yr, evidence has accumulated that implicates the autonomic nervous system as a central modulator of immune function. We hypothesized that injury to the cervical spinal cord would affect immune function by dysregulation of the sympathetic outflow tract. To test this hypothesis, peripheral blood lymphocytes were obtained from five individuals with complete cervical spinal cord injury (SCI) and from five age- and sex-matched neurologically intact controls. Immunologic parameters studied included cell counts by flow cytometry, lymphocyte proliferation response to three mitogens and a natural killer cell cytotoxicity assay. In addition the Ilfeld Psychiatric Symptom Index was completed by all subjects and controls. Repeated measures analysis of variance revealed an impaired lymphocyte proliferation response in the SCI group. Our results suggest that individuals who have sustained complete cervical SCI have alteration in immune function as compared with neurologically intact controls. This may contribute to infections after spinal cord injury. The mechanism may involve dysregulation of the sympathetic arm of the autonomic nervous system.