Altered innate immunity following spinal cord injury

Abstract

Study Design: Cross-sectional, paired cohort study. Objectives: To replicate the finding of impaired immunocyte function following spinal cord injury (SCI). To determine whether cellular immune function in SCI subjects with decentralized sympathetic nervous system (SNS) (T6 and above) varies from SCI subjects with intact SNS (below T6). Setting: University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ, USA. Method: In vitro immune assays: (1) natural killer (NK) cell cytotoxicity using a K562 target cell line in a 4-h chromium 51 release assay. The mean of three samples for each effector-to-target (E:F) ratio (25:1, 50:1, 100:1) was used in the analyses. (2) Cell enumeration was performed using commercially available antibodies and standard flow cytometry techniques. Results: Participation of 36 SCI subjects and 36 individually age-and sex-matched healthy controls. SCI subjects were stratified into two groups, that is, neurologic level of injury (NLI) at T6 or above (26 subjects) and NLI below T6 (10 subjects). No statistically significant differences were identified between NLI T6 and above and NLI below T6 groups for the NK cytotoxicity assay. There was a statistically significant reduction in NK cell numbers in all subjects with SCI as compared to their paired controls. There was a statistically significant reduction in NK cell cytotoxicity in SCI subjects, relative to the controls for E:F ratio of 100:1 (F ¼ 6.18, d.f. ¼ 34, P ¼ 0.02). Conclusion: We replicated the finding of decreased NK cell number and cytotoxicity in SCI subjects. The mechanism behind these findings needs to be further investigated, with the long-term goal of developing therapeutic strategies to improve immune function.

Immune dysfunction and chronic inflammation following spinal cord injury

“…21,22 Alternatively, certain aspects of post SCI immune alterations appear to be independent of injury level. Similar alterations in natural killer cell and T-cell cytotoxic activity have been demonstrated in humans with both high-and low-level injuries, 11,23 as have elevations in viral load following infection in mouse models of high and low thoracic SCI. 7 It may be possible that the level of injury has a greater impact on certain aspects of immunity than others.…”

“…[6][7][8][9] Suppressed function of natural killer cells, neutrophils, macrophages and lymphocytes have each been documented following SCI. 6,10,11 The loss of motor and sensory function also contribute to this population's greater susceptibility to a number of acute infections, including urinary tract infection (UTI) and pressure ulcers, as well as metabolic disorders associated with a more sedentary lifestyle such as obesity, atherosclerosis and type 2 diabetes. [12][13][14] A number of related disorders found to be significantly more prevalent following SCI such as depression and neuropathic pain may also contribute to a heightened systemic inflammatory state.…”

Immunoendocrine responses of male spinal cord injured athletes to 1-hour self-paced exercise: Pilot study

“…It is widely recognized that individuals with a spinal cord injury (SCI) experience recurrent infections, specifically of the respiratory system, urinary tract, and skin [4][5], and some evidence suggests that this susceptibility to infection is partly associated with immune dysfunction [6][7][8][9]. Alterations in natural killer (NK) cell number and cytotoxicity, T cell function and activation, macrophage phagocytosis, levels of interleukin (IL)-2 and -6, the soluble IL-2R receptor, and intracellular adhesion molecules have been reported [4].…”

Incidence of acute hepatitis B in patients with spinal cord injury

“…7 Furthermore, degree of reduced phagocytosis and impaired B-cell functions may be correlated with level of SCI injury. 8,9 The hepatitis B virus infection is a global public health problem. It is estimated that there are more than 350 million HBV carriers in the world, of whom roughly 1 million die annually from HBV-related liver disease.…”