Plasma levels of procalcitonin and neopterin in multiple trauma patients with or without brain injury

Clinical and experimental evidence suggests that traumatic brain injury (TBI) leads to a systemic immune response. To examine whether TBI causes a release of procalcitonin (PCT) or neopterin (NT) into the circulation, we compared plasmatic mediator levels among multiple injured patients with or without TBI. In total, 98 trauma patients (24 with TBI only, 39 with extracranial injuries excluding TBI, and 35 with combined injuries) and 35 healthy volunteers were studied. Blood was sampled at 15 predefined time points within 132 h after injury and analysed for NT and PCT. Multivariate statistical comparisons were adjusted for different severity of head, thorax, abdomen and extremity injuries, as quantified by the Abbreviated Injury Scale (AIS). PCT was normal 3 h after trauma, but 24 h after extracranial injuries a massive release (median 3 ng/mL) was observed. Significant positive associations between injury severity and posttraumatic PCT levels were found for abdominal and extremity, but not for cranial or thoracic injuries. Only modest changes of marginal statistical significance were detected for NT. The maximum increase per AIS point was 9% (95% confidence intervals [CI]: 3-16%). The effect of TBI on NT release was significant only at 108 h posttrauma with a 5% (95% CI: 1-10%) increase per AIS point. TBI induces a release of PCT and NT into the plasma, but this effect seems to be smaller for intra- than for extracranial injuries, probably due to more extensive surgery for abdominal and extremity injuries.