Nishikai, M, Tomomatsu, S, Hankins, R W et al. · Rheumatology (Oxford, England) · 2001 · DOI
Researchers tested blood samples from ME/CFS and fibromyalgia patients to look for specific antibodies (immune proteins) that might be unique to these conditions. They found that about 13% of ME/CFS patients and 16% of fibromyalgia patients had antibodies against a protein called 68/48 kDa. Importantly, patients with these antibodies were more likely to experience severe sleep problems, memory issues, and trouble concentrating.
This study suggests that certain ME/CFS patients may have a distinct immune signature involving specific autoantibodies, which could help identify a subgroup with particular symptom profiles. If validated, these antibodies could serve as a biological marker to improve diagnosis and enable more targeted research into the immune mechanisms underlying cognitive and sleep problems in ME/CFS.
This study does not prove that these autoantibodies *cause* ME/CFS or its cognitive symptoms—it only shows they are more common in affected patients. The cross-sectional design cannot establish causation or determine whether the antibodies arise before or after illness onset. It also does not explain the biological mechanism by which these antibodies might contribute to hypersomnia or cognitive dysfunction.
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
Nishikai, M, Tomomatsu, S, Hankins, R W, Takagi, S, Miyachi, K, Kosaka, S, et al. (2001). Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders.. Rheumatology (Oxford, England). https://doi.org/10.1093/rheumatology/40.7.806
BibTeX
@article{mecfsatlas-nishikai-2001-autoantibodies-kda,
author = {Nishikai, M and Tomomatsu, S and Hankins, R W and Takagi, S and Miyachi, K and Kosaka, S and Akiya, K},
title = {Autoantibodies to a 68/48 kDa protein in chronic fatigue syndrome and primary fibromyalgia: a possible marker for hypersomnia and cognitive disorders.},
journal = {Rheumatology (Oxford, England)},
year = {2001},
doi = {10.1093/rheumatology/40.7.806},
note = {PubMed: 11477286},
url = {https://www.mecfsatlas.com/evidence/nishikai-2001-autoantibodies-kda},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/nishikai-2001-autoantibodies-kda
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