Eaton-Fitch, Natalie, du Preez, Stanley, Cabanas, Hélène et al. · Systematic reviews · 2019 · DOI
This review examined research on natural killer cells, which are immune cells that help fight infections and abnormal cells in the body. Scientists found that people with ME/CFS consistently have natural killer cells that don't work as well as they should. This discovery was the most reliable and consistent finding across all the studies reviewed, suggesting it could be an important marker for understanding ME/CFS.
Identifying a consistent immune abnormality in ME/CFS is crucial because it provides objective evidence of biological dysfunction and could help validate the disease as a real medical condition rather than a psychological disorder. If NK cell dysfunction proves reliable across patients, it might eventually be used as a diagnostic marker or therapeutic target for treatment development. This research offers hope that understanding immune mechanisms could lead to better management strategies for ME/CFS patients.
This review does not prove that NK cell dysfunction causes ME/CFS or that correcting it would cure the disease—only that an association exists. The heterogeneity in findings suggests NK cell abnormalities may characterize only a subset of ME/CFS patients rather than all affected individuals. The study design (reviewing observational studies) cannot establish causation, and the variability in how different studies measured NK function limits definitive conclusions about which specific NK cell features are most important.
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
Eaton-Fitch, Natalie, du Preez, Stanley, Cabanas, Hélène, Staines, Donald, & Marshall-Gradisnik, Sonya (2019). A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome.. Systematic reviews. https://doi.org/10.1186/s13643-019-1202-6
BibTeX
@article{mecfsatlas-eaton-fitch-2019-systematic-review,
author = {Eaton-Fitch, Natalie and du Preez, Stanley and Cabanas, Hélène and Staines, Donald and Marshall-Gradisnik, Sonya},
title = {A systematic review of natural killer cells profile and cytotoxic function in myalgic encephalomyelitis/chronic fatigue syndrome.},
journal = {Systematic reviews},
year = {2019},
doi = {10.1186/s13643-019-1202-6},
note = {PubMed: 31727160},
url = {https://www.mecfsatlas.com/evidence/eaton-fitch-2019-systematic-review},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/eaton-fitch-2019-systematic-review
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