Early elevation of soluble CD14 may help identify trauma patients at high risk for infection

Background: Elevated levels of soluble CD14 (sCD14) have been implicated in both gram-positive and gram-negative sepsis, and it has been associated with high mortality in trauma patients who become infected, Methods: Eleven healthy volunteers and 25 adult trauma patients with multiple:injuries and a mean Injury Severity Score of 32 participated, Whole blood was obtained at intervals. Immunohistochemistry,was used to quantify membrane CD14 (mCD14), by flow cytometry and plasma levels of sCD14 by enzyme-linked immunosorbent assay. Analysis of variance and Student's t test with Mann-Whitney posttest were used to determine significance at p < 0.05. Results: On posttrauma day 1, sCD14 was significantly different in the plasma of infected patients compared with normal controls (7.16 <plus/minus> 1.87 mug/mL vs. 4.4 +/- 0.92 mug/mL, p < 0.01), but not significantly different from noninfected patients. The percentage of monocytes expressing mCD14 in trauma patients did not differentiate them from normal controls; however, mCD14 receptor density did demonstrate significance in septic trauma patients (n = 15) versus normal controls on posttrauma day 3 (p = 0.0065). Conclusion: On the basis of our data, mCD14 did not differentiate infected and noninfected trauma patients, although trauma in general reduced mCD14 and elevated sCD14. Interestingly, 100% of patients who exceeded plasma levels of 8 mug/mL of sCD14 on day 1 after injury developed infections. Therefore, early high expressers of sCD14 mag. be at higher risk for infectious complications after trauma.