Koelle, David M, Barcy, Serge, Huang, Meei-Li et al. · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2002 · DOI
Researchers compared 22 pairs of identical twins—where one twin had ME/CFS and one was healthy—to see if viral infections might cause the illness. They tested blood and saliva samples for antibodies and DNA from 10 different viruses known to hide in the body. Surprisingly, they found no differences in viral markers between the twins with ME/CFS and their healthy siblings.
This study addresses a longstanding hypothesis that persistent viral infections drive ME/CFS pathophysiology. By using identical twins as a natural control for genetic factors, the findings help clarify whether viral markers differentiate affected from unaffected individuals, potentially redirecting research focus toward other disease mechanisms.
This study does not prove that viruses are not involved in ME/CFS—it only shows no difference in detectable viral markers between affected and unaffected twins at one point in time. It cannot rule out temporal, tissue-specific, or intermittent viral reactivation patterns that might be missed by snapshot testing, nor does it address whether viral infection might trigger ME/CFS through mechanisms that resolve before antibody elevation.
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
Koelle, David M, Barcy, Serge, Huang, Meei-Li, Ashley, Rhoda L, Corey, Lawrence, Zeh, Judy, et al. (2002). Markers of viral infection in monozygotic twins discordant for chronic fatigue syndrome.. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. https://doi.org/10.1086/341774
BibTeX
@article{mecfsatlas-koelle-2002-markers-viral,
author = {Koelle, David M and Barcy, Serge and Huang, Meei-Li and Ashley, Rhoda L and Corey, Lawrence and Zeh, Judy and Ashton, Suzanne and Buchwald, Dedra},
title = {Markers of viral infection in monozygotic twins discordant for chronic fatigue syndrome.},
journal = {Clinical infectious diseases : an official publication of the Infectious Diseases Society of America},
year = {2002},
doi = {10.1086/341774},
note = {PubMed: 12173124},
url = {https://www.mecfsatlas.com/evidence/koelle-2002-markers-viral},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/koelle-2002-markers-viral
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