Prognostic value of the relationship between serum levels of interleukin-6 and clinical outcome in patients with severe head injury

Damage caused by traumatic brain injury (TBI) depends on the extent of primary and secondary damages. The latter can cause induced neurological inflammation by releasing pro- and anti-inflammatory cytokines and chemokines. Measurement of serum interleukin-6 (IL-6), as a pro-inflammatory cytokine, can be useful in predicting outcome in patients with TBI. In a cross-sectional study, 44 patients with GCS≤8 (Glasgow Coma Scale) and age ≥ 14 years, hospitalized in Poursina teaching hospital, were included in the study. Blood samples were collected from patients in the first 6 hours after the accident; and serum was tested by ELISA method for the determination of IL-6 levels. Patient's outcomes were recorded 6 months after head injury according to Glasgow Outcome Scale (GOS), and were divided in two good (GOS ≥4) and bad (GOS<3) outcome groups. Data were analyzed in SPSS software version18 using the Spearman's rho, independent-t test, Fisher Exact test and Mann-Whitney test. Comparison of IL-6 serum levels, in the two groups after 6 months of head injury, showed that mean serum levels of IL-6 in good outcome group was lower than bad outcome group (85.2 ±51.6 vs. 162.3±141.1, respectively) (P <0.03). Elevated serum levels of IL-6 in patients with severe TBI, is associated with poor clinical outcome.