Circulating cell-free RNA signatures for the characterization and diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome.
Gardella, Anne E, Eweis-LaBolle, Daniel, Loy, Conor J et al. · Proceedings of the National Academy of Sciences of the United States of America · 2025 · DOI
Quick Summary
Researchers analyzed tiny pieces of RNA floating in the blood of people with ME/CFS and compared them to healthy people. They used a computer program to identify a pattern of these RNA pieces that could help diagnose ME/CFS with 77% accuracy. The study found that people with ME/CFS have different levels of immune cells releasing material into their blood, suggesting the immune system is behaving differently.
Why It Matters
This research offers hope for a non-invasive blood test to help diagnose ME/CFS, addressing a major gap in clinical practice where diagnosis currently relies on symptom reporting. The identification of specific immune abnormalities provides biological evidence that validates patient experiences and could guide future treatment development.
Observed Findings
Diagnostic model achieved test-set AUC of 0.81 and accuracy of 77% using condition-specific cfRNA signatures
Elevated platelet-derived cfRNA in ME/CFS cases compared to healthy controls
Increased plasmacytoid dendritic cell-derived cfRNA in ME/CFS patients
Elevated monocyte-derived cfRNA in ME/CFS
Elevated T cell-derived cfRNA in ME/CFS patients, with signatures consistent with T cell exhaustion
Inferred Conclusions
Cell-free RNA profiling reflects immune dysregulation in ME/CFS, particularly involving dendritic cells, monocytes, and T cells
Cytokine signaling and T cell exhaustion pathways are implicated in ME/CFS pathobiology
RNA liquid biopsy is a feasible minimally invasive approach for characterizing ME/CFS biology and developing diagnostic tools
The heterogeneity of immune cfRNA signatures suggests potential for future patient subtyping
Remaining Questions
Can these cfRNA biomarkers be validated in larger, geographically diverse, and independent patient cohorts?
Do cfRNA signatures change over time with disease progression or treatment, and do they correlate with symptom severity?
What This Study Does Not Prove
This study does not prove that cfRNA signatures cause ME/CFS or establish causative mechanisms—it demonstrates association. The 77% accuracy means this biomarker panel alone is not yet sufficiently reliable for clinical diagnostic use. Results require validation in larger, independent cohorts before implementation in routine clinical practice.
Which specific upstream mechanisms drive the observed changes in immune cell-derived cfRNA—persistent viral infection, immune activation, or other triggers?
Can cfRNA profiling distinguish ME/CFS from other conditions with similar symptoms, such as long COVID or Lyme disease?