LAUSR

Abstract Aims Previous studies have suggested that many inflammatory cytokines, including interleukin (IL)-1α, may be associated with lumbar radicular pain after disc herniation. In the present study, we examined how variability of the IL-1α gene affects pain intensity and the pressure pain threshold (PPT) in patients with symptomatic disc herniation. Methods A total of 121 patients with lumbar radicular pain due to disc herniation were recruited from Oslo University Hospital, Norway, and followed up at 6 weeks and 12 months. The primary outcome measures were pain intensity scores for the lower back and legs using a visual analog pain scale (VAS) and PPT for the gluteal muscles. Genotyping was carried out using a predesigned TaqMan assay for IL-1α rs1800587. The effect of the IL-1α genotype on the VAS and PPT was analyzed by repeated measure analyses of variance. Results The IL-1α gene C>T polymorphism rs1800587 affected VAS and PPT scores in patients with symptomatic disc herniation. Patients with the CT/TT genotype reported a higher VAS leg pain intensity (p = 0.002) and also a lower PPT in the gluteal muscles (left p = 0.016; right p = 0.016) compared to patients with the CC genotype during 1 year of follow-up. Conclusions The present data show that the IL-1α CT/TT genotype rs1800587 may be associated with increased pain intensity, and corresponding reduced PPT during the first year after disc herniation.