Circulating levels of IL-2R, ICAM-1, and IL-6 in spinal cord injuries.

OBJECTIVE

To measure circulating levels of well-studied, easily quantifiable surrogate markers or mediators of inflammation and tissue remodeling in patients with spinal cord injury (SCI) suffering from pressure ulcers. Cytokines or their receptors, eg, interleukins IL-6 and IL-2, IL-2R (the soluble interleukin-2 receptor), and the intercellular adhesion molecule ICAM-1, are mediators of immune response, inflammatory processes, and tissue remodeling involving the skin and other organs. Activation of these immune effectors and their accumulation in tissue 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 controlled, gender-specific study of the relationship between circulating IL-1 beta, IL-2, IL-2R, and ICAM-1 and pressure ulcers in patients with chronic SCI.

SETTING

The department of medicine of a university-affiliated medical center and the spinal cord injury service at a Department 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 between 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 the rate of wound healing in subjects with SCI.

RESULTS

Plasma concentrations of bioactive molecules IL-6, IL-2R, and ICAM-1 were numerically or significantly elevated in all patients with SCI as compared to able-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 result in immunoactivation. In patients with SCI and pressure ulcers, elevated levels of circulating ICAM-1 and IL-2R may have diagnostic, prognostic, and therapeutic value in predicting or differentiating subgroups of patients who will vary in the severity or the rate of healing of their wounds.