Extracellular Vesicles in ME/CFS - Rydland 2026 Focus
1 Rydland et al. 2026 — Protein Cargo of EVs from ME/CFS Plasma
Full Citation:: Rydland A, Yran ES, Nyman TA, Strand EB, Trøseid A-MS, Øvstebø R, Heinicke F, Lie BA, Viken MK. Exploring differences in protein cargo of extracellular vesicles from ME/CFS patient plasma compared to healthy controls. Biochemistry and Biophysics Reports. 2026;47:102679. (Rydland et al. 2026) DOI:: 10.1016/j.bbrep.2026.102679 Study Design:: Case-control EV proteomics Sample Size:: n=49 ME/CFS (Canadian criteria, pre-pandemic), n=50 HC Key Findings::
- Elevated EV counts in ME/CFS vs HC (replicates Castro-Marrero 2018, Oltra 2020, Hanson/Giloteaux 2024)
- 11 differentially abundant proteins: up ITIH3, AMBP, FGB (liver-specific); down IGKV1-12, IGKV1-8, IGLV3-15, IGHV3-7 (immunoglobulin light chain variable domains), HBA1, HBB, HBD (hemoglobin), F13A1 (coagulation factor XIII A chain)
- Liver-derived EV proteins enriched in ME/CFS (ITIH3, AMBP, FGB)
- Reduced immunoglobulin-related proteins in EV cargo
- Reduced hemoglobin and coagulation factor XIII
- None survived FDR multiple-comparison correction (adjusted $p > 0.05$)
- Binding before SARS-CoV-2 pandemicConclusion:: EV protein cargo differs between ME/CFS and HC, with liver-derived proteins upregulated and immunoglobulin/hemoglobin/coagulation proteins downregulated. However, no protein survived multiple-comparison correction. EV count elevation is the most robust finding, consistent with prior studies. Limitations:: No FDR-significant hits; confounders (medication, comorbidities, activity levels) not controlled; single EV isolation method (no orthogonal validation); pre-pandemic binding may not reflect post-pandemic ME/CFS; cross-sectional. Certainty Assessment::
- *Quality:* Medium (largest EV study in ME/CFS; standard proteomic workflow; no FDR hits)
- *Sample:* Medium (n=99 total)
- *Replication:* Partial (EV count replicates; protein cargo new, needs independent validation)
- *Score:* 0.552 Castro-Marrero et al. 2018 — Circulating EVs as Biomarkers in ME/CFS
Full Citation:: Castro-Marrero J, Serrano-Pertierra E, Oliveira-Rodríguez M, Zaragozá MC, Martínez-Martínez A, Blanco-López MC. Circulating extracellular vesicles as potential biomarkers in chronic fatigue syndrome/myalgic encephalomyelitis: an exploratory pilot study. Journal of Extracellular Vesicles. 2018;7(1):1453730. (Castro-Marrero et al. 2018) DOI:: 10.1080/20013078.2018.1453730 Study Design:: Pilot case-control EV characterization Sample Size:: n=20 ME/CFS, n=20 HC Key Findings::
- First EV study in ME/CFS: elevated EV numbers in ME/CFS plasma
- EV size distribution differed between groups
- EV surface markers CD9, CD63, CD81 detected
- Characterised by NTA, TEM, and flow cytometryConclusion:: Circulating EVs are elevated in ME/CFS and may serve as biomarker candidates. Limitations:: Small pilot; no protein/miRNA cargo analysis; single isolation method. Certainty:: 0.40
3 Giloteaux et al. 2020 — Cytokine Profiling of EVs in ME/CFS
Full Citation:: Giloteaux L, O’Neal A, Castro-Marrero J, Levine SM, Hanson MR. Cytokine profiling of extracellular vesicles isolated from plasma in myalgic encephalomyelitis/chronic fatigue syndrome: a pilot study. Journal of Translational Medicine. 2020;18(1):387. (Giloteaux et al. 2020) DOI:: 10.1186/s12967-020-02560-0 Study Design:: Pilot cross-sectional EV cytokine analysis Sample Size:: n=8 ME/CFS, n=9 HC Key Findings::
- IL-2 elevated in ME/CFS EV fraction
- No significant differences in IL-1β, IL-6, IL-8, IL-10, TNFα
- First study isolating plasma EVs for cytokine profiling in ME/CFSLimitations:: Very small sample; pilot only; single timepoint. Certainty:: 0.35
4 Almenar-Pérez et al. 2020 — Diagnostic Value of EV miRNAs in ME/CFS
Full Citation:: Almenar-Pérez E, Sarría L, Nathanson L, Oltra E. Assessing diagnostic value of microRNAs from peripheral blood mononuclear cells and extracellular vesicles in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Scientific Reports. 2020;10(1):3181. (Almenar-Pérez et al. 2020) DOI:: 10.1038/s41598-020-58506-5 Study Design:: Case-control miRNA profiling Sample Size:: n=22 ME/CFS, n=17 HC Key Findings::
- EV miRNA profiles distinguish ME/CFS from HC with moderate accuracy
- Combined PBMC + EV miRNA panels improve discrimination
- miR-124-3p, miR-142-5p, miR-150-5p among differentially expressedConclusion:: EV miRNAs are potential diagnostic biomarkers for ME/CFS. Limitations:: Moderate sample; single-lab; no independent validation cohort. Certainty:: 0.45
5 Eguchi et al. 2020 — Talin-1 and Filamin-A in EVs as ME/CFS Biomarkers
Full Citation:: Eguchi A, Fukuda S, Kuratsune H, Nojima J, Nakatomi Y, Watanabe Y, Feldstein AE. Identification of actin network proteins, talin-1 and filamin-A, in circulating extracellular vesicles as blood biomarkers for human myalgic encephalomyelitis/chronic fatigue syndrome. Brain, Behavior, and Immunity. 2020;84:205-214. (Eguchi et al. 2020) DOI:: 10.1016/j.bbi.2019.11.015 Study Design:: Case-control EV proteomics Sample Size:: n=25 ME/CFS, n=22 HC Key Findings::
- Talin-1 and filamin-A identified as EV-associated biomarkers
- Actin cytoskeleton, focal adhesion, ECM-receptor interaction pathways enriched
- First proteomic study on circulating EVs in ME/CFSLimitations:: Moderate n; candidate approach; needs independent validation. Certainty:: 0.50
6 Bonilla et al. 2022 — EV Surface Markers by Severity in ME/CFS
Full Citation:: Bonilla H, Hampton D, Marques de Menezes EG, Deng X, Montoya JG, Anderson J, Maecker HT. Comparative Analysis of Extracellular Vesicles in Patients with Severe and Mild Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Frontiers in Immunology. 2022;13:841910. (Bonilla et al. 2022) DOI:: 10.3389/fimmu.2022.841910 Study Design:: Cross-sectional EV surface marker analysis by severity Sample Size:: n=15 ME/CFS (8 severe, 7 mild), n=6 HC Key Findings::
- EV surface markers differ by ME/CFS severity
- CD8+ T-cell and B-cell derived EVs elevated
- CD14+ monocyte EVs reduced in severe ME/CFS
- Reflects immune cell activation state in EV profilesLimitations:: Very small n per severity group; single institution; Stanford cohort. Certainty:: 0.45
7 González-Cebrián et al. 2022 — PLS-DA Diagnosis Using EV miRNAs
Full Citation:: González-Cebrián A, Almenar-Pérez E, Xu J, Yu T, Huang WE, Giménez-Orenga K, Nathanson L, Oltra E. Diagnosis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome With Partial Least Squares Discriminant Analysis: Relevance of Blood Extracellular Vesicles. Frontiers in Medicine. 2022;9:842991. (González-Cebrián et al. 2022) DOI:: 10.3389/fmed.2022.842991 Study Design:: Case-control miRNA diagnostic model with validation Sample Size:: n=32 ME/CFS, n=22 HC (training); n=19 ME/CFS, n=56 HC (validation) Key Findings::
- PLS-DA model using EV miRNA achieved AUC 0.87-0.93 in validation
- Largest EV miRNA diagnostic study at publication
- Oltra group expanded EV miRNA panelLimitations:: Single-lab; validation cohort still modest; platform-specific. Certainty:: 0.55
8 Nunes et al. 2024 — Coagulation and Complement in ME/CFS Plasma Proteomics
Full Citation:: Nunes M, Vlok M, Proal AD, Kell DB, Pretorius E. Data-independent LC-MS/MS analysis of ME/CFS plasma reveals a dysregulated coagulation system, endothelial dysfunction, downregulation of complement machinery. Cardiovascular Diabetology. 2024;23:254. (Nunes et al. 2024) DOI:: 10.1186/s12933-024-02315-x Study Design:: Plasma proteomics; DIA-LC-MS/MS Sample Size:: n=20 ME/CFS, n=20 HC Key Findings::
- Dysregulated coagulation cascade in ME/CFS plasma
- Endothelial dysfunction markers elevated
- Complement system downregulated
- Vascular pathology consistent with EV cargo findings in Rydland 2026Limitations:: Whole plasma (not EV-focused); moderate n. Certainty:: 0.55
9 Wang et al. 2025 — Exosomal LncRNAs in CFS (Review)
Full Citation:: Wang L, Xu Y, Zhong X, Wang G, Shi Z, Mei C. The emerging role of exosomal LncRNAs in chronic fatigue syndrome: from intercellular communication to disease biomarkers. Frontiers in Molecular Biosciences. 2025;12:1653627. (Wang et al. 2025) DOI:: 10.3389/fmolb.2025.1653627 Key Findings:: Review proposing exosomal lncRNAs as CFS biomarkers. Limitations:: No primary data; speculative; review only. Certainty:: 0.20
10 Kell et al. 2022 — Amyloid Fibrin Microclots in Long COVID
Full Citation:: Kell DB, Laubscher GJ, Pretorius E. A central role for amyloid fibrin microclots in long COVID/PASC: origins and therapeutic implications. Biochemical Journal. 2022;479(4):537-559. (Kell, Laubscher, and Pretorius 2022) DOI:: 10.1042/BCJ20220016 Key Findings::
- Reviews mechanism of amyloid fibrin microclot formation in PASC
- Contextually relevant to Rydland 2026 FGB (fibrinogen beta) finding
- Links EV-associated coagulation to microclot pathologyCertainty:: 0.60