E2 ModerateModerate confidencePEM unclearCross-SectionalPeer-reviewedReviewed
Evidence for the existence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) with and without abdominal discomfort (irritable bowel) syndrome.
Maes, Michael, Leunis, Jean-Claude, Geffard, Michel et al. · Neuro endocrinology letters · 2014
Quick Summary
This study found that many people with ME/CFS experience stomach and digestive problems, and this appears to be linked to bacteria from the gut leaking into the bloodstream. Researchers identified two groups of ME/CFS patients: those with significant abdominal discomfort and those without. The group with digestive symptoms showed higher levels of immune responses to gut bacteria, suggesting their intestinal barrier may be more permeable.
Why It Matters
This research provides evidence that digestive problems in ME/CFS may have a biological basis involving intestinal barrier dysfunction and bacterial translocation, rather than being purely functional. Identifying ME/CFS subgroups with distinct biological markers could eventually lead to more targeted treatments and better patient stratification in future research.
Observed Findings
- Abdominal discomfort syndrome (ADS) was significantly more prevalent in ME/CFS patients (59.6%) compared to chronic fatigue patients (17.7%)
- IgA and IgM antibody responses to commensal bacterial lipopolysaccharides were significantly elevated in ME/CFS patients with ADS compared to those without ADS
- Cluster analysis identified four independent symptom factors: inflammation-hyperalgesia, fatigue-malaise, gastro-intestinal symptoms/ADS, and neurocognitive symptoms
- ADS diagnosis showed strong association with irritable bowel syndrome (IBS) diagnosis
Inferred Conclusions
- ME/CFS comprises at least two distinct subgroups differentiated by presence or absence of abdominal discomfort syndrome
- Bacterial translocation ("leaky gut") appears to be a pathway phenotype associated with the ADS-positive ME/CFS subgroup
- Increased intestinal permeability in ME/CFS patients with ADS may contribute to systemic inflammatory processes
Remaining Questions
- Does bacterial translocation cause ME/CFS symptoms, or does ME/CFS pathology cause increased intestinal permeability? Does this ADS subgroup represent a distinct disease entity with different etiology or treatment response?
- What triggers the intestinal barrier dysfunction in the ADS-positive ME/CFS subgroup, and can this be reversed?
What This Study Does Not Prove
This study does not prove that bacterial translocation causes ME/CFS symptoms, only that they are associated. The cross-sectional design cannot establish whether gut barrier dysfunction precedes ME/CFS development or results from it. These findings apply specifically to the studied population and may not generalize to all ME/CFS patients.
Tags
Symptom:Cognitive DysfunctionPainFatigue
Biomarker:AutoantibodiesBlood Biomarker
Method Flag:PEM Not DefinedWeak Case DefinitionMixed CohortExploratory Only
Metadata
- PMID
- 25433843
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 12 April 2026
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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