Chronic widespread pain, a common medical condition, can be difficult to treat and is often associated with fatigue, poor sleep and depression.
A connection between fibromayalgia (FM) and cytokines (proteins that act as messengers between cells) was suspected after cancer patients treated with the cytokine interleukin -2 developed FM-like symptoms. Since then, other studies have shown contradictory results.
A new study published in the August 2006 issue of Arthritis & Rheumatism examined cytokine profiles in patients with chronic widespread pain and found that they had significantly lower levels of the anti-inflammatory cytokines IL-4 and IL-10.
Led by Nurcan Uceyler of Julius-Maximilians University in Wurzburg, Germany, researchers analyzed cytokines in 40 patients with chronic widespread pain (26 of whom had FM), 40 controls and an additional group of 15 patients. The 40 pain patients had received intravenous immunoglobulin (IVIG) as a novel treatment for pain that was not responsive to standard therapy, while the additional 15 patients did not receive this treatment. Blood samples were analyzed for both pro-inflammatory and anti-inflammatory cytokines. In addition, patients were asked to rate their pain, fatigue, mood, cognitive function and sleep quality on a scale of 1 to 10.
Patients in the pain group did not differ in the expression of the pro-inflammatory cytokines IL-2, IL-8 and TNFá, but did have significantly lower levels of the anti-inflammatory cytokines IL-4 and IL-10 compared with the healthy control group. The 15 patients in the additional group showed similar findings, although the difference in IL-10 between this group and the controls was not statistically significant.