The systematic review found elevated levels of IL-6 (time points: <24 h, 1–7 days and ≥ 30 days), TNF-α (≥30 days), IL-1β (1–7 days), IL-8 (time points: <24 h and ≥ 30 days), IFN-γ (<24 h), IL-1RA (<24 h), and MCP-1/CCL2 (time points: 1–7 days and ≥ 30 days) in patients with mTBI, compared with healthy controls, where any significant findings were replicated in at least two studies. This evidence concerns the gene IFNG and concussion.