Clark, L V, Buckland, M, Murphy, G et al. · Clinical and experimental immunology · 2017 · DOI
This study examined whether people with ME/CFS have abnormal immune protein levels (cytokines) in their blood, especially after physical activity. Researchers compared 24 ME/CFS patients with 21 healthy controls and measured multiple immune markers at rest and after exercise. The study found no significant differences in immune protein levels between the two groups, and no link between post-exertional symptoms and increased cytokine levels.
This study addresses a long-standing hypothesis that immune dysregulation (specifically elevated cytokines) drives ME/CFS symptoms. If circulating cytokines are not significantly altered in ME/CFS, it redirects research attention toward other potential pathophysiological mechanisms, such as cellular immune dysfunction, neurological factors, or metabolic abnormalities.
This study does not prove that immune dysfunction is absent in ME/CFS—only that circulating cytokine protein and RNA levels measured in this manner are not prominently altered. It cannot exclude local tissue-based inflammation, intracellular cytokine production, or post-translational modifications. The small sample size and reliance on blood-based measurements limit generalizability to tissue-specific or compartmentalized immune responses.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Clark, L V, Buckland, M, Murphy, G, Taylor, N, Vleck, V, Mein, C, et al. (2017). Cytokine responses to exercise and activity in patients with chronic fatigue syndrome: case-control study.. Clinical and experimental immunology. https://doi.org/10.1111/cei.13023
BibTeX
@article{mecfsatlas-clark-2017-cytokine-responses,
author = {Clark, L V and Buckland, M and Murphy, G and Taylor, N and Vleck, V and Mein, C and Wozniak, E and Smuk, M and White, P D},
title = {Cytokine responses to exercise and activity in patients with chronic fatigue syndrome: case-control study.},
journal = {Clinical and experimental immunology},
year = {2017},
doi = {10.1111/cei.13023},
note = {PubMed: 28779554},
url = {https://www.mecfsatlas.com/evidence/clark-2017-cytokine-responses},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/clark-2017-cytokine-responses
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