Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis/chronic fatigue syndrome or control serum. — CFSMEATLAS
Indistinguishable mitochondrial phenotypes after exposure of healthy myoblasts to myalgic encephalomyelitis/chronic fatigue syndrome or control serum.
Ryback, Audrey A, Hillier, Charles B, Loureiro, Camila M et al. · PloS one · 2026 · DOI
Quick Summary
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.
Why It Matters
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.
Observed Findings
No significant difference in oxygen consumption rate at maximal respiratory capacity between healthy myoblasts treated with ME serum versus control serum.
Over 1,700 mitochondrial stress tests were performed across the study sample.
Results were consistent across sera from 67 ME/CFS patients and 53 healthy controls.
The failure to replicate the earlier findings occurred despite using a substantially larger sample size than the original 2016 study.
Inferred Conclusions
Blood serum from ME/CFS patients does not cause detectable changes in mitochondrial function of healthy cultured myoblasts in vitro.
Previous positive findings in this experimental model may not represent a reliable or reproducible phenomenon.
Mitochondrial dysfunction via serum factors is unlikely to be a primary biomarker mechanism suitable for developing diagnostic blood tests for ME/CFS.
Remaining Questions
What mechanisms do cause the reported energy metabolism abnormalities observed in some ME/CFS patient studies?
Do other cell types or tissue models respond differently to ME serum factors in ways that healthy myoblasts do not?
Are there other serum biomarkers or immune factors in ME/CFS blood that could be explored for diagnosis?
What This Study Does Not Prove
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.