E2 ModeratePreliminaryPEM unclearCross-SectionalPeer-reviewedReviewed
A new approach to find biomarkers in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) by single-cell Raman micro-spectroscopy.
Xu, Jiabao, Potter, Michelle, Tomas, Cara et al. · The Analyst · 2019 · DOI
Quick Summary
Researchers used a new scanning technology called Raman spectroscopy to look at individual cells from ME/CFS patients and healthy people. They found that cells from ME/CFS patients had higher levels of a protein building block called phenylalanine, similar to cells with broken energy-producing structures (mitochondria). Using computer learning, they could identify ME/CFS patient cells with 98% accuracy based on this signature.
Why It Matters
This research provides potential objective biomarker for ME/CFS diagnosis, addressing a critical clinical need since the disease currently lacks biological diagnostic tests. The connection between phenylalanine elevation and mitochondrial dysfunction offers new insight into disease mechanisms and could guide future therapeutic development.
Observed Findings
- Raman bands associated with phenylalanine were significantly elevated in CFS patient PBMCs compared to healthy controls
- Phenylalanine elevation in CFS patients mirrored the pattern observed in ρ0 cells lacking functional mitochondrial DNA
- A machine learning model correctly classified CFS versus control samples with 98% accuracy using Raman spectral data
- The biochemical signature detected by SCRM was consistent with mitochondrial/energetic dysfunction
Inferred Conclusions
- Elevated cellular phenylalanine may indicate mitochondrial or energetic dysfunction in ME/CFS patients
- Single-cell Raman micro-spectroscopy combined with machine learning shows promise as a potential diagnostic approach for ME/CFS
- The similarity between CFS patient cells and mitochondrial-deficient model cells suggests mitochondrial dysfunction may be relevant to CFS pathophysiology
Remaining Questions
- Does elevated phenylalanine reflect mitochondrial dysfunction specifically, or other metabolic changes in ME/CFS?
- Will SCRM-based diagnosis work reliably in larger, more diverse patient populations and different laboratories?
- What is the functional consequence of elevated phenylalanine—does it contribute to fatigue and other ME/CFS symptoms?
What This Study Does Not Prove
This study does not prove that elevated phenylalanine causes ME/CFS or that it is the primary driver of the disease. The finding is correlational and requires validation in larger independent populations before SCRM can be considered a clinical diagnostic tool. The mechanism linking elevated phenylalanine to ME/CFS symptoms remains unknown.
Tags
Symptom:Fatigue
Biomarker:MetabolomicsBlood Biomarker
Method Flag:PEM Not DefinedWeak Case DefinitionSmall SampleExploratory Only
Metadata
- DOI
- 10.1039/c8an01437j
- PMID
- 30207334
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- 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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