The interleukin-1α gene C>T polymorphism rs1800587 is associated with increased pain intensity and decreased pressure pain thresholds in patients with lumbar radicular pain.

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.