Maes, Michael, Kubera, Marta, Leunis, Jean-Claude et al. · Journal of affective disorders · 2012 · DOI
This study looked at whether depression might be linked to bacteria leaking from the gut into the bloodstream. Researchers measured immune proteins (IgA and IgM antibodies) in the blood of depressed patients that target common gut bacteria, and found these antibodies were higher in depressed people than in healthy controls. The findings suggest that if gut bacteria do leak into the blood, the body's immune system reacts to them, which could contribute to depression—particularly long-lasting depression.
ME/CFS patients frequently experience both depression and gastrointestinal dysfunction, and some research suggests leaky gut may be involved in ME/CFS pathophysiology. This study provides mechanistic insight into how gut permeability and bacterial translocation could link gastrointestinal and psychiatric symptoms, potentially explaining overlapping symptoms seen in ME/CFS and comorbid depression.
This study does not prove that bacterial translocation causes depression—only that elevated antibodies against gut bacteria are associated with depression. The cross-sectional design cannot establish whether increased antibodies occur before depression onset, after it develops, or whether both are consequences of a third factor. The findings in depressed patients do not automatically apply to ME/CFS patients, even though symptom overlap exists.
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 →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Maes, Michael, Kubera, Marta, Leunis, Jean-Claude, & Berk, Michael (2012). Increased IgA and IgM responses against gut commensals in chronic depression: further evidence for increased bacterial translocation or leaky gut.. Journal of affective disorders. https://doi.org/10.1016/j.jad.2012.02.023
BibTeX
@article{mecfsatlas-maes-2012-increased-iga-2,
author = {Maes, Michael and Kubera, Marta and Leunis, Jean-Claude and Berk, Michael},
title = {Increased IgA and IgM responses against gut commensals in chronic depression: further evidence for increased bacterial translocation or leaky gut.},
journal = {Journal of affective disorders},
year = {2012},
doi = {10.1016/j.jad.2012.02.023},
note = {PubMed: 22410503},
url = {https://www.mecfsatlas.com/evidence/maes-2012-increased-iga-2},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/maes-2012-increased-iga-2
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