Abstract
Background: The chronic fatigue syndrome (CFS) is characterized by post-exertional malaise and fatigue. We designed this pilot study to explore whether the illness was associated with alterations in immunological markers following exercise.
Methods: We measured immunological markers before and up to three days after either a sub-maximal or maximal bicycle exercise test. We studied nine patients with CFS and nine age-and sex-matched healthy but sedentary controls. We also studied the same patients with CFS at home after a night's sleep and then after traveling to the study center.
Results: There were no significant differences in any of the cell markers after a sub-maximal exercise test compared to a maximal test. However, we found elevated concentrations of plasma transforming growth factor beta (TGF-ß), even before exercise, in subjects with CFS (median (IQR) of 904 (182-1072) pg/ml) versus controls (median (IQR) of 50 (45-68) pg/ml) (P < .001). Traveling from home to the hospital significantly elevated TGF-ß concentrations from a resting median (IQR) concentration of 1161 (130-1246) pg/ml to a median (IQR) concentration of 1364 (1155-1768) pg/ml (P < .02). There was also a sustained increase in plasma tumor necrosis factor alpha (TNF-cc) after exercise in CFS patients, but not in controls (P = .004 for the area under the curve), although traveling had no such effect. CD3, CD4 and HLA DR-expressing lymphocyte counts were lower in CFS patients, but exercise had the same effect in both groups, causing an immediate increase in circulating cell numbers that lasted less than three hours.
Conclusions: These results suggest that the relationship between physical activity and both pro-inflammatory and anti-inflammatory cytokines merits further investigation in patients with CFS. The results also emphasize the importance of defining a truly resting baseline condition in such studies.