Exosome-Based Biomarkers

Recent progress in exosome biology, including the demonstration that engineered exosomes can deliver functional mRNA across the BBB to reverse neuroinflammation (Kang et al. 2026), has implications for biomarker development in ME/CFS, independent of therapeutic applications. Brain-derived exosomes (BDEs) — exosomes shed by neurons, astrocytes, microglia, and oligodendrocytes — cross the BBB into peripheral blood where they can be captured and analysed. Each subpopulation carries molecular cargo reflecting the state of its cell of origin.

1 Salivary Metabolomic Fingerprint of Sleep Deprivation as Candidate ME/CFS Biomarker

The absence of a biochemical test for sleep deprivation has been a long-standing gap in both forensic and clinical medicine. Acute sleep loss produces cognitive and motor impairment comparable to alcohol intoxication, yet no objective roadside or clinical assay exists to quantify it. Scholz et al. (2026) demonstrated the first direct salivary metabolomic biomarkers of acute sleep deprivation, achieving 94% classification accuracy with a 12-feature machine learning model (Scholz et al. 2026).

2 GPCR Autoantibody-Based Diagnostic and Prognostic Biomarkers

All below are research-stage; none validated in independent cohort. (Azcue et al. 2026).

References

Azcue, N., A. Prada, R. Del Pino, M. Acera, T. Fernández-Valle, N. Ayo-Mentxakatorre, T. Pérez-Concha, et al. 2026. “Involvement of Autoantibodies Against G Protein-Coupled Receptors in Post-COVID Condition and Chronic Fatigue Syndrome.” Scientific Reports 16. https://doi.org/10.1038/s41598-026-49131-9.
Kang, Zhenming, Guoshao Zhu, Changsheng Su, Xianmei Zhong, Jianchuan Lin, and Yiqin Lin. 2026. “Delivery of HSP70 mRNA via Exosomes Ameliorates Sleep Deprivation-Induced Cognitive Impairments in Mice.” Translational Psychiatry 16: 123. https://doi.org/10.1038/s41398-026-04044-z.
Scholz, Michael, Andrea E. Steuer, Akos Dobay, Hans-Peter Landolt, and Thomas Kraemer. 2026. “Leveraging the Metabolic Fingerprint of Sleep Deprivation and Sleep Restriction for Forensic Applications: A Machine Learning Study in Oral Fluid Metabolomics.” J Proteome Res, May. https://doi.org/10.1021/acs.jproteome.5c01064.