Cytokines play an aetiopathogenetic role in fibromyalgia: a hypothesis andpilot study

Objective. To measure soluble factors having a possible role in fibromyalgi a (FM) and compare the profiles of patients with recent onset of the syndro me with patients with chronic FM. Methods. The production of cytokines, cytokine-related molecules, and a CXC chemokine, interleukin (IL)-8, was examined. Fifty-six patients with FM (2 3 with < 2 yr and 33 with > 2 yr of symptoms) were compared with age- and s ex-matched healthy controls. Cytokines and cytokine-related molecules were measured in sera and in supernatants of peripheral blood mononuclear cells (PBMC) that were incubated with and without lectins and phorbol myristate a cetate (PMA). Results. No differences between FMS and controls were found by measuring IL -1 beta, IL-2, IL-10, serum IL-2 receptor (sIL-2R), interferon gamma (IFN-g amma), and tumour necrosis factor alpha (TNF-alpha). Levels of IL-IR antibo dy (IL-1Ra) and IL-8 were significantly higher in sera, and IL-1Ra and IL-6 were significantly higher in stimulated and unstimulated FM PBMC compared with controls. Serum IL-6 levels were comparable to those in controls, but were elevated in supernatants of in vitro-activated PBMC derived from patie nts with > 2 yr of symptoms. In the presence of PMA, there were additional increases in IL-1 Ra, IL-8 and IL-6 over control values. Conclusions. In patients with FM we found increases over time in serum leve ls and or PBMC-stimulated activity of soluble factors whose release is stim ulated by substance P. Because IL-8 promotes sympathetic pain and IL-6 indu ces hyperalgesia, fatigue kind depression, it is hypothesized that they may play a role in modulating FM symptoms.