CFS is characterized by profound levels of persistent/recurrent fatigue. It is proposed that chronic, low level inflammation may play a role in this fatigue.

We recruited 100 untreated patients with CFS (average age 33±12) and 100 age and sex matched healthy controls (HCs). Serum levels of TNF-α were assessed using ELISA. Subjective fatigue was determined by questionnaire and muscle function tests were undertaken in subgroups in which maximal voluntary contraction (MVC), electrically stimulated muscle force generation and rate of fatigue were assessed in the quadriceps muscle.

Subjective fatigue was higher in patients with CFS compared with HCs. Preliminary analyses showed that serum TNF-α was undetectable in 97% of HCs, whereas 15% of patients with CFS had detectable (4.4+/-0.18pg/ml) serum TNF-α. MVC was significantly reduced in subjects with CFS compared with HCs. No difference was seen in stimulated muscle fatigue between groups.

This preliminary data suggests that a sub-group of patients with CFS may have low level inflammation and analyses are underway to further characterise other inflammatory markers in serum and muscle of these patients and to determine whether such changes could affect indices of muscle function or central fatigue. Funded by MRC, BBSRC and the ME Association.

The role of cytokines in muscle fatigue in patients with Chronic Fatigue Syndrome (CFS), by Kate Earl, Giorgos Sakellariou, Daniel Owens, Melanie Sinclair, Manuel Fenech, Graeme Close, Clare Lawton, Louise Dye, Micheal Beadsworth and Anne McArdle in The FASEB journal vol. 29 no. 1 Supplement 1055.34

Comment by Dr Charles Shepherd: Mitochondrial dysfunction and the role of cytokines in ME/CFS