Ryback, Audrey A, Hillier, Charles B, Loureiro, Camila M et al. · PloS one · 2026 · DOI
Researchers wanted to test whether something in the blood of people with ME/CFS could damage the energy-producing parts of cells (mitochondria) when added to healthy cells in the lab. They tested blood from 67 people with ME/CFS and 53 healthy people on cultured muscle cells and measured how well the cells could use oxygen. Unlike a previous smaller study, they found no difference between the ME/CFS blood and healthy blood samples.
If blood factors from ME/CFS patients could be identified as causing specific cell changes, this could lead to a diagnostic blood test for ME/CFS, which currently lacks objective biomarkers. This study clarifies whether mitochondrial dysfunction via serum factors is a viable mechanism to pursue in ME/CFS research, helping direct future investigative efforts and funding priorities.
This study does not rule out mitochondrial dysfunction in ME/CFS patients themselves—only whether their blood serum causes changes in healthy cells in a laboratory setting. It does not test whether other cell types or tissues might respond differently to ME serum factors, nor does it eliminate other potential blood-based biomarkers. The study also does not determine what biological mechanisms do underlie fatigue in ME/CFS.
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
Ryback, Audrey A, Hillier, Charles B, Loureiro, Camila M, Ponting, Chris P, & Dalton, Caroline F (2026). Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis/chronic fatigue syndrome or control serum.. PloS one. https://doi.org/10.1371/journal.pone.0341334
BibTeX
@article{mecfsatlas-ryback-2026-indistinguishable-mitochondrial,
author = {Ryback, Audrey A and Hillier, Charles B and Loureiro, Camila M and Ponting, Chris P and Dalton, Caroline F},
title = {Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis/chronic fatigue syndrome or control serum.},
journal = {PloS one},
year = {2026},
doi = {10.1371/journal.pone.0341334},
note = {PubMed: 41632778},
url = {https://www.mecfsatlas.com/evidence/ryback-2026-indistinguishable-mitochondrial},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/ryback-2026-indistinguishable-mitochondrial
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