Giménez-Orenga, Karen, Martín-Martínez, Eva, Nathanson, Lubov et al. · eLife · 2025 · DOI
This study looked at special genetic materials called human endogenous retroviruses (HERVs) in the blood cells of women with ME/CFS, fibromyalgia, both conditions, or neither. The researchers found that the pattern of which HERVs were active could perfectly distinguish between these four groups—suggesting this could become a reliable blood test to diagnose these conditions. The study also found that ME/CFS patients had specific changes in immune cells that matched how severe their symptoms were.
ME/CFS lacks objective diagnostic tests, making diagnosis difficult and causing patients to wait years for recognition. This research provides evidence that HERV expression patterns could become a biomarker for diagnosis and may reveal important differences between ME/CFS alone versus co-occurring with fibromyalgia. Understanding the immune changes in ME/CFS could eventually lead to better treatments targeted to the actual biological causes of the disease.
This study does not prove that HERV activation causes ME/CFS—it only shows they occur together. The small sample size and cross-sectional design cannot establish whether HERV changes happen before symptoms develop or result from them. The findings need validation in larger, independent patient populations before HERV testing could be used clinically in medical practice.
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
Giménez-Orenga, Karen, Martín-Martínez, Eva, Nathanson, Lubov, & Oltra, Elisa (2025). HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity.. eLife. https://doi.org/10.7554/eLife.104441
BibTeX
@article{mecfsatlas-gimnez-orenga-2025-herv-activation,
author = {Giménez-Orenga, Karen and Martín-Martínez, Eva and Nathanson, Lubov and Oltra, Elisa},
title = {HERV activation segregates ME/CFS from fibromyalgia while defining a novel nosologic entity.},
journal = {eLife},
year = {2025},
doi = {10.7554/eLife.104441},
note = {PubMed: 40338225},
url = {https://www.mecfsatlas.com/evidence/gimnez-orenga-2025-herv-activation},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/gimnez-orenga-2025-herv-activation
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