Traumatic brain injury is a common event where 70%-90% will be classified as mild TBI (mTBI). Among these, only 10% will have a brain lesion visible via CT scan. A triage
biomarker would help clinicians to identify patients with mTBI who are at risk of developing a brain lesion and require a CT scan. The brain cells damaged by the shearing, tearing and stretching of a TBI event set off
inflammation cascades. These cause altered concentrations of a high number of both pro-inflammatory and anti-inflammatory
proteins. This study aimed to discover a novel diagnostic
biomarker of mTBI by investigating a broad panel of
inflammation biomarkers and their capacity to correctly identify CT-positive and CT-negative patients. Patients enrolled in this study had been diagnosed with mTBI, had a GCS score of 15 and suffered from at least one clinical symptom. There were nine patients in the discovery group, 45 for verification, and 133 mTBI patients from two different European sites in the validation cohort. All patients gave blood samples, underwent a CT scan and were dichotomised into CT-positive and CT-negative groups for statistical analyses. The ability of each
protein to classify patients was evaluated with sensitivity set at 100%. Three of the 92
inflammation proteins screened-MCP-1,
MIP-1alpha and
IL-10 -were further investigated in the verification group, and at 100% sensitivity their specificities reached 7%, 0% and 31%, respectively.
IL-10 was validated on a larger cohort in comparison to the most studied mTBI diagnostic triage
protein to date, S100B. Levels of both
proteins were significantly higher in CT-positive than in CT-negative patients (p < 0.001). S100B's specificity at 100% sensitivity was 18% (95% CI 10.8-25.2), whereas
IL-10 reached a specificity of 27% (95% CI 18.9-35.1). These results showed that
IL-10 might be an interesting and clinically useful diagnostic tool, capable of differentiating between CT-positive and CT-negative mTBI patients.