Severity of symptom flare after moderate exercise is linked to cytokine activity in chronic fatigue syndrome


  • The project described was supported by NIH Grant R21 NS057821 from NINDS and NIAMS, with additional support provided by a Catalyst Grant from the University of Utah, by NIH Grant R21 AT002209 from NCAM and by the CFIDS Association.

  • [Correction added after online publication March 4, 2010: in Figure 1 and Table 2, several asterisks were missing.]

Address reprint requests to: Kathleen C. Light, Department of Anesthesiology, 3C444 SOM, 30 North 1900 East, Salt Lake City, UT 84132-2304, USA. E-mail:


Chronic fatigue syndrome (CFS) patients often report symptom flare (SF) for >24 h after moderate exercise (post-ex). We hypothesized that SF is linked to increases in circulating cytokines and CD40 Ligand (CD40L). In 19 CFS patients and 17 controls, mental and physical fatigue and pain symptom ratings were obtained together with serum for 11 cytokines and CD40L before and at 0.5, 8, 24, and 48 h post-ex. Before exercise, CFS had lower CD40L (p<.05) but similar cytokines versus controls. In subgroups based on SF at 48 h, high SF patients (n=11) increased in IL-1β, IL-12, IL-6, IL-8, IL-10, and IL-13 (p<.05) 8 h post-ex. Low SF patients (n=8) showed post-ex decreases in IL-10, IL-13, and CD40L, and controls decreased in IL-10, CD40L, and TNFα (p<.05). Thus, in CFS, cytokine activity may vary directly with SF, which may explain prior inconsistent findings.