CYTOKINE PRODUCTION AND FATIGUE IN PATIENTS WITH CHRONIC FATIGUE SYNDROME AND HEALTHY CONTROL SUBJECTS IN RESPONSE TO EXERCISE

We have studied the relationship between the cytokine production induc ed in vivo by prolonged isometric exercise and the symptom complex mar ked by fatigue in patients with chronic fatigue syndrome (CFS). Twelve male patients and 13 matched male control subjects undertook an isome tric hand-grip exercise protocol utilizing dynamometers. Subjects unde rtook 30 minutes of exercise, for which the target force was set at 40 % of the maximal voluntary contraction and the duty cycle was 50%. Pri or to, during, and for 24 hours following the exercise, blood samples were collected and assayed for the presence of cytokines, including in terferon-gamma and interferon-alpha, interleukin-1 beta, and tumor nec rosis factor-alpha. At those times subjects also completed the Profile of Mood States (POMS) questionnaire, which served as a measure of cha nges in subjective fatigue. No significant alteration in the level of any of the cytokines in the plasma of patients or control subjects was detected before, during, or after exercise. Surprisingly, the patient s' levels of fatigue, depression, and confusion, as measured by the PO MS, decreased in response to the exercise. These data do not confirm t he presence of an immunologic process correlating with the exacerbatio n of fatigue after exercise experienced by patients with CFS. Limitati ons in the study design and in the sensitivity of the cytokine assays may have affected our results.