CIRCULATING LEVELS OF IL-2R, ICAM-1, AND IL-6 IN SPINAL-CORD INJURIES

Objective: To measure circulating levels of well-studied, easily quant ifiable surrogate markers or mediators of inflammation and tissue remo deling in patients with spinal cord injury (SCI) suffering from pressu re ulcers. Cytokines or their receptors, eg, interleukins IL-6 and IL- 2, IL-2R (the soluble interleukin-2 receptor), and the intercellular a dhesion molecule ICAM-1, are mediators of immune response, inflammator y processes, and tissue remodeling involving the skin and other organs . Activation of these immune effecters and their accumulation in tissu e can be associated with pathological changes or healing, and elevated plasma concentrations can indirectly reflect the magnitude of immune activation. Design: Participants were consecutively enrolled in a cont rolled, gender-specific study of the relationship between circulating IL-1 beta, IL-2, IL-2R, and ICAM-1 and pressure ulcers in patients wit h chronic SCI. Setting: The department of medicine of a university-aff iliate medical center and the spinal cord injury service at a Departme nt of Veterans Affairs medical center. Patients or Other Participants: Seventy men with longstanding SCI (19 with pressure ulcers). The mean age was 49 +/- 14 (range 25 to 74 years). Duration of SCI ranged betw een 1 and 46 years, and the level of injury varied from C2 to L5. The control group consisted of 20 healthy, able-bodied volunteers (10 men and 10 women aged 25 to 50 years). Main Outcome Measures: Circulating plasma levels of IL-6, IL-2, IL-2R, and ICAM-1 and their relation to t he rate of wound healing in subjects with SCI. Results: Plasma concent rations of bioactive molecules IL-6, IL-2R, and ICAM-1 were numericall y or significantly elevated in all patients with SCI as compared to ab le-bodied individuals. The greatest increase in concentration was seen in those patients with pressure ulcers who demonstrated slow healing of their wounds. Conclusions: SCI and trauma to insensitive tissue res ult in immunoactivation. In patients with SCI and pressure ulcers, ele vated levels of circulating ICAM-1 and IL-2R may have diagnostic, prog nostic, and therapeutic value in predicting or differentiating subgrou ps of patients who will vary in the severity or the rate of healing of their wounds. (C) 1997 by the American Congress of Rehabilitation Med icine and the American Academy of Physical Medicine and Rehabilitation