IL1RN intron 2 polymorphism caused by variable number tandem repeats is associated with 1-year outcome in patients with ischaemic stroke

Background: Results of experimental and clinical studies suggest that recombinant human interleukin 1 receptor antagonist (rhIL1ra) may be a good new therapeutic agent for acute stroke. In humans, IL1ra is encoded by the IL1RN gene located on chromosome 2. Objectives: To report on the association between different genotypes of the variable number tandem repeat (VNTR) polymorphism within IL1RN, and disease severity and 1-year outcome in patients with ischaemic stroke. Methods: IL1RN genotypes were evaluated using polymerase chain reaction in 391 patients with ischaemic stroke diagnosed according to the World Health Organization definition. The effects of IL1RN genotypes on severity of stroke at maximum impairment, and on the survival status and neurological and functional condition of patients at 7 days, 1 month, 3 months and 1 year after the onset, were evaluated. Results: No relationship was found between IL1RN genotypes and severity of symptoms at the time of maximum impairment. Homozygotes for the IL1RN*2 allele showed less severe neurological and functional impairments when assessed after the time period between 7 days and 1 year after stroke compared with carriers of the other two IL1RN genotypes. Patients with at least one copy of the IL1RN*2 allele had increased risk of death during the first week, and patients homozygotic for this allele had increased risk of death within the first month after stroke. Conclusion: IL1RN intron 2 variable number tandem repeats polymorphism influences the clinical outcome in patients with ischaemic stroke. It may possibly modify effects of treatment with rhIL1ra in patients with acute stroke.