Association between interleukin-1 beta (IL-1β) gene polymorphism and outcome after head injury: an early report

Summary

Background. Recent studies focusing on the genetic influences on outcome after head injury (HI) have suggested that different alleles of certain genes are associated with different outcomes. Interleukin-1 beta (IL-1β) gene, especially β2 polymorphism, is frequently observed in Alzheimer’s disease, a remarkable degenerative state in which HI is among the known risk factors. Therefore, the aim of this paper was to search for the possible association between the outcome and IL-1β gene polymorphism in human HI.

Methods. The study group was composed of the 69 patients admitted to the neurosurgery department after HI. The severity of the initial injury was evaluated by means of the Glasgow Coma Scale and outcome six months later was assessed by means of the Glasgow Outcome Scale. IL-1β genotypes were determined from blood samples by standard methods.

Findings. Fourteen of 25 (56%) patients with IL-1β +3953 allele 2 had an unfavourable outcome (dead, vegetative state or severe disability) compared with eight of 44 (18.1%) patients without IL-1β +3953 (p = 0.0004). Similarly, 20 of 28 (71.4%) patients with IL-1β −511 allele 2 had an unfavourable outcome compared with two of 41 (4.8%) patients without IL-1β −511 (p = 0.005). Patients who had a composite of IL-1β 2/2 or 1/2 genotype from both −511 and +3953 region of the chromosome 2 were more prone to have bad prognosis.

Conclusion. Results of our study demonstrated that there might be a significant association between IL-1β gene polymorphism and outcome after HI, supporting the hypothesis of a genetically determined influence.