E3 PreliminaryPreliminaryPEM requiredObservationalPeer-reviewedReviewed
Sex-Dependent Transcriptional Changes in Response to Stress in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Pilot Project.
Gamer, Jackson, Van Booven, Derek J, Zarnowski, Oskar et al. · International journal of molecular sciences · 2023 · DOI
Quick Summary
This study looked at how genes behave differently in men and women with ME/CFS when their bodies are stressed by exercise. Researchers tested blood samples from 33 ME/CFS patients and 34 healthy people before, during, and after exercise. They found that men and women with ME/CFS showed different patterns of gene activity in response to exercise—men's immune systems showed more dramatic changes, while women's genes related to stress response and virus handling showed bigger changes.
Why It Matters
Understanding that men and women with ME/CFS may have fundamentally different biological responses to exertion could explain why symptoms and disease progression differ by sex. These findings may guide the development of sex-specific diagnostic approaches and personalized treatments, improving care for both men and women with ME/CFS.
Observed Findings
- Male ME/CFS patients showed activation of immune-cell signaling pathways (including IL-12) and natural killer cell cytotoxicity genes during exercise challenge.
- Female ME/CFS patients showed minimal differential gene expression during acute exertion but significant changes during recovery.
- During recovery, males showed altered cytokine regulation (IL-1β), while females showed changes in stress response, herpesvirus response, and NF-κB signaling pathways.
- Healthy controls did not show the same sex-dependent response patterns to exercise.
Inferred Conclusions
- ME/CFS has distinct sex-dependent molecular pathophysiology, with males showing primarily immune-driven responses and females showing stress and viral reactivation responses.
- The different timing and nature of gene expression changes between sexes may explain clinical sex differences in ME/CFS presentation and severity.
- Sex-specific biomarkers and potentially sex-specific therapeutic approaches may be warranted for ME/CFS.
Remaining Questions
- Do these transcriptional differences persist across multiple exercise challenges or are they specific to a single event?
- How do these gene expression patterns relate to clinical symptoms and post-exertional malaise severity in men versus women?
What This Study Does Not Prove
This pilot study does not establish causation—it shows associations between gene expression patterns and exercise stress. The small sample size and single exercise challenge timepoint limit generalizability. Results cannot yet confirm whether these sex-dependent gene expression patterns are the cause of sex differences in ME/CFS symptoms or a consequence of the disease process.
Tags
Symptom:Post-Exertional MalaiseFatigue
Biomarker:CytokinesGene ExpressionBlood Biomarker
Method Flag:Small SampleExploratory OnlyStrong PhenotypingSex-StratifiedPEM Not Defined
Metadata
- DOI
- 10.3390/ijms241210255
- PMID
- 37373402
- Review status
- Editor reviewed
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- Last updated
- 12 April 2026
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 →
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