Immunoglobulin G complexes from post-infectious ME/CFS, including post-COVID ME/CFS disrupt cellular energetics and alter inflammatory marker secretion. — CFSMEATLAS
Immunoglobulin G complexes from post-infectious ME/CFS, including post-COVID ME/CFS disrupt cellular energetics and alter inflammatory marker secretion.
Liu, Zheng, Hollmann, Claudia, Kalanidhi, Sharada et al. · Brain, behavior, & immunity - health · 2026 · DOI
Quick Summary
This study found that antibodies (immune proteins) from ME/CFS patients can damage the mitochondria—the energy-producing parts of cells—and change how cells function. Researchers isolated antibodies from ME/CFS patients and added them to healthy cells in the lab, discovering that these antibodies caused changes in cell energy production and inflammation. This suggests that abnormal antibodies may be part of what makes ME/CFS patients feel exhausted and unwell.
Why It Matters
This research provides mechanistic evidence that autoimmune dysfunction—specifically abnormal antibodies—directly impairs cellular energy metabolism in ME/CFS, supporting the biological validity of post-infectious ME/CFS as an organic disease. Understanding how these antibodies damage cellular function opens avenues for targeted therapeutic interventions that could address a fundamental disease mechanism rather than merely symptom management.
Observed Findings
IgG from ME/CFS patients induced mitochondrial fragmentation in human endothelial cells compared to controls
The Fab fragment of IgG alone was sufficient to alter cellular energetics, independent of the Fc region
Post-infectious ME/CFS and post-COVID ME/CFS patients showed distinct proteomic signatures in their immune complexes
IgG-immune complexes from ME/CFS patients affected extracellular matrix organization proteins
IgG-immune complexes from post-COVID ME/CFS patients showed alterations related to hemostasis and blood clotting regulation
Inferred Conclusions
Abnormal IgG antibodies from ME/CFS patients carry pathogenic properties that directly disrupt cellular energy metabolism through mitochondrial fragmentation
The variable region (Fab) of the antibody, rather than the constant region (Fc), is responsible for the energetic effects observed
Post-infectious ME/CFS and post-COVID ME/CFS may involve distinct autoimmune mechanisms affecting different cellular pathways
Antibody-mediated metabolic dysregulation represents a novel therapeutic target in post-infectious ME/CFS
Remaining Questions
Do the in vitro mitochondrial changes correlate with disease severity or specific symptoms in ME/CFS patients?
What This Study Does Not Prove
This study does not prove that antibody-mediated mitochondrial changes are the sole or primary cause of ME/CFS symptoms in patients, as the experiments were conducted in isolated cell cultures, not living organisms. The correlation between in vitro cellular changes and clinical disease severity remains unclear. Additionally, the study cannot establish whether these antibody changes are a cause or consequence of underlying ME/CFS pathology.
What specific antigen(s) are these pathogenic IgG antibodies targeting in post-infectious ME/CFS?
Can blocking or removing these abnormal antibodies reverse the cellular dysfunction and improve patient symptoms?
How do the distinct proteomic signatures in post-COVID ME/CFS versus other post-infectious ME/CFS relate to differences in clinical presentation and recovery patterns?