Nonsurviving Patients with Severe Traumatic Brain Injury Have Maintained High Serum sCD40L Levels

Soluble cluster of differentiation 40 ligand (sCD40L) is a member of the tumor necrosis factor family with proinflamatory and procoagulant effects. A previous study found higher serum sCD40L levels at day 1 of traumatic brain injury (TBI) in nonsurviving than surviving patients. Thus the objective of this study was to compare serum sCD40L levels during the first week of a severe TBI between surviving and nonsurviving patients and to determine whether it could be used as a mortality predictor biomarker.

In this multicenter study severe TBI patients (with Glasgow Coma Scale score <9) with an Injury Severity Score in noncranial item <9 were included. Serum sCD40L concentrations at days 1, 4, and 8 of TBI were determined. We performed receiver operating characteristic analyses to determine the capacity of 30-day TBI mortality prediction by serum sCD40L levels at days 1, 4, and 8 of TBI.

We found that nonsurviving (n = 34) patients in comparison with surviving (n = 90) patients had higher sCD40L levels on days 1 (P < 0.001), 4 (P = 0.004), and 8 (P < 0.001) of TBI. We also found that the areas under curve of serum sCD40L concentrations at days 1, 4, and 8 of TBI to 30-day mortality prediction were 82% (P < 0.001), 72% (P = 0.01) and 83% (P < 0.001), respectively.

The existence of higher serum sCD40L levels in nonsurviving than surviving patients during the first week of TBI and fact that serum sCD40L levels during the first week of TBI can be used as a mortality predictor biomarker are the new findings of our study.