Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective pilot cohort study. — CFSMEATLAS
Association of circulating biomarkers with illness severity measures differentiates myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 condition: a prospective pilot cohort study.
Domingo, Joan Carles, Battistini, Federica, Cordobilla, Begoña et al. · Journal of translational medicine · 2024 · DOI
Quick Summary
This study compared blood markers and body responses between people with ME/CFS, people with long COVID, and healthy controls. Researchers found that people with ME/CFS had distinct patterns of inflammation and blood vessel dysfunction compared to long COVID patients, suggesting these are different conditions with different underlying problems. By measuring specific proteins in the blood and testing how the body responds to positional changes, researchers could tell the two patient groups apart.
Why It Matters
This study provides objective biological evidence that ME/CFS and long COVID are distinct conditions with different biomarker signatures, which could help clinicians improve diagnosis and tailor treatments. Finding specific markers for ME/CFS—particularly inflammatory proteins—opens avenues for developing targeted therapies and better understanding disease mechanisms.
Observed Findings
ME/CFS patients showed significantly higher levels of PAI-1 (serpin E1) and E-selectin compared to both long COVID and healthy controls.
Both ME/CFS and long COVID groups had elevated TNF-α compared to healthy controls, but ME/CFS showed additional elevation in multiple interleukins (IL-1β, IL-4, IL-6, IL-10) and leptin.
Long COVID patients had significantly lower TSP-1 levels than both ME/CFS patients and healthy controls.
Both patient groups showed reduced nitrite (NOx) and elevated endothelin-1 (ET-1) and VCAM-1 compared to controls, indicating endothelial dysfunction.
Principal component analysis successfully differentiated the three groups using combined biomarker and self-reported outcome measures.
Inferred Conclusions
ME/CFS and long COVID have distinct biomarker profiles despite shared features, suggesting different underlying pathophysiological mechanisms.
Combining endothelial dysfunction markers with inflammatory cytokine measurements may provide a robust diagnostic approach to differentiate these conditions.
Biomarkers of inflammation and endothelial dysfunction represent potential therapeutic targets for both conditions.
Remaining Questions
Do these biomarker patterns change over time, and can they predict disease progression or treatment response?
What This Study Does Not Prove
This study cannot establish causation—elevated biomarkers may be consequences rather than causes of illness. The cross-sectional design captures only a single timepoint, so it cannot determine whether these markers change over time or predict disease progression. Results are limited to a small sample from one site and require validation in larger, multi-center cohorts before clinical application.