Cytokines across the Night in Chronic Fatigue Syndrome

The symptoms of chronic fatigue syndrome (CFS) are consistent with cytokine dysregulation. This has led to the hypothesis of immune dysregulation as the cause of this illness. To further test this hypothesis, we did repeated blood sampling for cytokines while patients and matched healthy controls slept in the sleep lab. Because no one method for assaying cytokines is acknowledged to be better than another, we assayed for protein in serum, message in peripheral blood lymphocytes (PBLs), and function in resting and stimulated PBLs. We found no evidence of proinflammatory cytokine upregulation. Instead, in line with some of our earlier studies, we did find some evidence to support a role for an increase in interleukin-10, an anti-inflammatory cytokine. Although the changes were small, they may contribute to the common complaint in CFS patients of disrupted sleep. Chronic fatigue syndrome (CFS) is a medically unexplained illness lasting at least 6 months and characterized by severe fatigue that produces a substantial reduction in activity accom-panied by at least four of the following symptoms: sore throat, tender lymph nodes, headache, myalgia, arthralgia, unrefresh-ing sleep, difficulty concentrating, and the report of syndromi