The role of IL-8 in patients with fibromyalgia: a prospective longitudinal study of 6 months.

OBJECTIVE: In this prospective longitudinal clinical study, we evaluated the role of proinflammatory cytokine IL-8 and its clinical relevance in patients with fibromyalgia (FM) who fulfilled clearly defined inclusion and exclusion criteria and underwent a 3-week inpatients multidisciplinary pain therapy.

METHODS: IL-8 in sera was measured in 20 patients with FM and 80 healthy participants at 4 fixed time points: at the beginning of the study, at 10 days, 21 days, and 6 months, respectively. Pain intensity, back function, depression, nicotine/alcohol consumption, and medication were assessed in the patient group and correlated with IL-8 levels.

RESULTS: Before and during the inpatient therapy, the serum level of IL-8 was significantly higher in patients with FM compared with controls (P<0.001), but did not correlated with pain intensity and medication. Already at T1 there was a significant reduction of IL-8 serum level (P=0.023) in patient group. Six months after multidisciplinary pain therapy, IL-8 serum level in FM patients was still significantly higher than controls (P=0.044) but reduced approximately to normal range and correlated significantly negatively with pain intensity (r=-0.782, P=0.001). Patients with FM had significantly less pain (P<0.001) and better back function (P<0.001) at day 2 than at day 0. In addition, in patients with FM, IL-8 serum level correlated with nicotine consumption (r=0.471, P=0.042).

CONCLUSIONS: Our results suggest that IL-8 level contributes in patients with FM whose pain intensity and back function can be improved under influence of multidisciplinary pain therapy without need of an anti-IL-8 therapy.