Among the 34 pair-matched cases and controls, IL-6 was significantly higher in both PTSD positive cases [2.43 (0.00–14.54) pg/ml; p = 0.004] and PTSD negative cases [3.00 (0.92–3.86) pg/ml; p = 0.005], than in controls [0.39 (0.00–11.38) pg/ml]. This evidence concerns the gene IL6 and post-traumatic stress disorder.