Underhill, J A, Mahalingam, M, Peakman, M et al. · European journal of immunogenetics : official journal of the British Society for Histocompatibility and Immunogenetics · 2001 · DOI
Researchers tested whether certain immune system genes (HLA genes) were more common in ME/CFS patients compared to healthy people. They studied 58 ME/CFS patients and 134 healthy controls using modern genetic testing methods. They found no significant differences in HLA genes between the two groups, suggesting that these particular immune genes are not a major cause of ME/CFS.
Understanding whether immune genes predispose people to ME/CFS is important for identifying disease mechanisms and potential therapeutic targets. This study's finding that HLA genes are not strongly associated with ME/CFS redirects research attention toward other biological pathways and suggests the disease may develop through mechanisms independent of classical HLA-restricted immune responses.
This study does not prove that infections play no role in ME/CFS—only that HLA genes are not a major genetic risk factor. It does not exclude the possibility that other immune genes or non-genetic factors (like specific viral exposures) contribute to disease development. The relatively small sample size may have limited statistical power to detect modest associations.
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
Underhill, J A, Mahalingam, M, Peakman, M, & Wessely, S (2001). Lack of association between HLA genotype and chronic fatigue syndrome.. European journal of immunogenetics : official journal of the British Society for Histocompatibility and Immunogenetics. https://doi.org/10.1046/j.1365-2370.2001.00235.x
BibTeX
@article{mecfsatlas-underhill-2001-lack-association,
author = {Underhill, J A and Mahalingam, M and Peakman, M and Wessely, S},
title = {Lack of association between HLA genotype and chronic fatigue syndrome.},
journal = {European journal of immunogenetics : official journal of the British Society for Histocompatibility and Immunogenetics},
year = {2001},
doi = {10.1046/j.1365-2370.2001.00235.x},
note = {PubMed: 11422420},
url = {https://www.mecfsatlas.com/evidence/underhill-2001-lack-association},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/underhill-2001-lack-association
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