Seifert et al. (2026)
- Authors: Martina Seifert, Johannes Schäfers, Fiona F. Douglas, Carl Schwarzburg, Diana Boristowski, Anne Birke, Oliver Klein, Franziska Sotzny, Kerstin Rubarth, Lara Windzio, Christien M. Beez, Claudia Kedor Peters, Kirsten Wittke, Carmen Scheibenbogen, Anna Greco
- Institutes: Institute of Medical Immunology, Charité – Universitätsmedizin Berlin, Berlin, Germany, Berlin Institute of Health (BIH) at Charité – Universitätsmedizin Berlin, Berlin, Germany
- Publisher: International Journal of Molecular Sciences
- Link: DOI
Summary
This research provides a significant step toward developing a blood-based diagnostic test for ME/CFS by identifying specific molecular ‘fingerprints’ within extracellular vesicles. By distinguishing between post-COVID-19 and other infectious triggers, the study highlights how different viral origins may lead to unique biological signatures. These findings could eventually allow clinicians to more accurately diagnose patients and potentially tailor treatments based on their specific molecular profile.
What was researched?
The study aimed to identify unique protein and microRNA (miRNA) signatures within plasma extracellular vesicles (EVs) that could serve as biomarkers for post-infectious ME/CFS. Researchers specifically looked at differences between female patients who developed the condition after COVID-19 versus those with other infectious triggers.
Why was it researched?
ME/CFS currently lacks validated diagnostic biomarkers, leading to delayed diagnosis and limited understanding of its underlying biological mechanisms. Extracellular vesicles are promising targets because they carry cargo that reflects the physiological state of their cells of origin.
How was it researched?
Researchers isolated small EVs from the plasma of female ME/CFS patients and healthy controls using size-exclusion chromatography. The cargo was analyzed using proteomic profiling via mass spectrometry and small RNA sequencing followed by qPCR to validate specific miRNA levels. The team then correlated these molecular findings with clinical symptoms such as fatigue, pain, and physical functioning.
What has been found?
Two proteins, hemoglobin subunit alpha and insulin-like growth factor-binding protein acid labile subunit, were identified as altered in ME/CFS patients. Additionally, the miRNA hsa-let-7b-5p was significantly downregulated in patients with post-COVID-19 ME/CFS. Lower levels of this specific miRNA were directly associated with more severe fatigue, increased pain, and higher levels of immune activation.
Discussion
A notable finding was that while the internal cargo of the vesicles differed significantly, the surface markers on the outside of the vesicles remained largely the same between patients and healthy donors. This suggests that the disease’s impact is contained within the signaling molecules the vesicles carry. The study’s focus on a female-only cohort and relatively small sample sizes are limitations that require broader validation.
Conclusion & Future Work
The identified EV cargo signatures represent promising candidates for the objective diagnosis and stratification of ME/CFS patients. Future research should focus on validating these markers in larger, more diverse populations to confirm their clinical utility.