Post-exertion malaise in chronic fatigue syndrome: symptoms and gene expression

Background: A primary complaint of chronic fatigue syndrome (CFS) patients is post-exertion malaise, which is a worsening of symptoms following activities such as exercise. Purpose: To examine the link between gene expression for metabolite, adrenergic, immune, and glucocorticoid receptors on leukocytes and symptoms (pain, fatigue, and mood) following a maximal exercise test. Methods: Thirteen CFS patients and 11 healthy participants matched on age and fitness underwent blood draws and completed questionnaires immediately before, and 15 minutes, 48 hours, and 72 hours following, maximal exercise. Symptom and genetic measures collected before and after exercise were compared using a doubly multivariate repeated-measures analysis of variance. Results: This comparison of CFS and healthy participants resulted in a significant multivariate main effect for Group (p < 0.05). Univariate analyses indicated group differences for adrenergic alpha-2A and glucocorticoid (NR3C1) receptor messenger ribonucleic acid and symptoms of fatigue and confusion. Changes in gene expression were significantly correlated with symptoms. Conclusions: Results suggest that increased glucocorticoid sensitivity may contribute to the symptoms of postexertion malaise in CFS. As NR3C1 interacts with other transcription factors, investigating the resulting cascades may lead to greater understanding of the biological mechanism of post-exertion malaise. This finding, if confirmed, could lead to novel approaches to prevent symptom exacerbation in CFS.