Charting the circulating proteome in ME/CFS using cross-system profiling to uncover mechanistic insights.
Hoel, August, Hoel, Fredrik, Dyrstad, Sissel Elisabeth et al. · Cell reports. Medicine · 2026 · DOI
Quick Summary
Researchers analyzed thousands of proteins in the blood of ME/CFS patients and compared them to healthy people. They found significant differences in protein patterns, including too much of certain immune-related proteins and too little of proteins normally made by muscles. These differences might help explain why ME/CFS causes such severe exhaustion and could eventually lead to new ways to diagnose or treat the condition.
Why It Matters
This is one of the first comprehensive proteomics studies to map the blood protein landscape in ME/CFS, offering potential biological markers that could transform diagnosis from symptom-based to biomarker-based. Understanding these protein changes may reveal which biological systems are malfunctioning and guide development of targeted therapies. For patients, validated biomarkers could improve disease recognition and legitimacy in medical settings.
Observed Findings
1,823 aptamers showed significant differences between ME/CFS patients and controls (845 after FDR correction)
Broad elevation of secreted proteins in ME/CFS patient serum
Selective reduction of intracellular proteins, particularly those derived from skeletal muscle
Distinct reduction in proteins secreted by activated neutrophils, indicating altered immune cell function
Antibody-based validation confirmed findings for a selected subset of proteins
Inferred Conclusions
ME/CFS involves complex immune reprogramming characterized by diminished neutrophil activation signatures and altered secretory patterns
Muscle-derived protein reductions may reflect reduced muscle function or mass, consistent with post-exertional symptom exacerbation
The proteomic signature reflects dysregulation across multiple tissue and biological systems (immune, vascular, metabolic) rather than isolated organ pathology
Serum proteome profiling could serve as a foundation for developing diagnostic biomarkers and understanding disease pathophysiology
Remaining Questions
Do these protein alterations precede symptom onset, or do they develop as a consequence of illness? Can longitudinal follow-up establish whether protein patterns correlate with disease severity or clinical improvement?
What This Study Does Not Prove
This study shows associations between ME/CFS and specific blood protein patterns, but does not prove these proteins cause the disease or whether they are primary drivers or secondary effects of illness. It is a snapshot in time and cannot establish whether these protein changes occur before symptom onset, persist chronically, or vary with disease activity. The cross-sectional design prevents determination of causality or whether protein normalization would improve clinical outcomes.
Which of these protein changes are primary drivers of ME/CFS pathology versus secondary responses, and can any be therapeutically targeted?
How do these proteome patterns relate to other proposed ME/CFS mechanisms, such as metabolic dysfunction, viral persistence, or autoimmune processes?
Do the identified protein signatures differ across ME/CFS symptom subtypes or disease duration, and could they help stratify patients for different treatments?