Paprotka, Tobias, Delviks-Frankenberry, Krista A, Cingöz, Oya et al. · Science (New York, N.Y.) · 2011 · DOI
Scientists studied a virus called XMRV that had been reported in some ME/CFS patients. They traced where this virus actually came from by examining cancer cell lines and tumors that had been grown in mice. They found that XMRV didn't exist in the original tumor but was created when two similar mouse viruses accidentally combined during laboratory handling. This suggests that when XMRV appeared in patient samples, it likely came from contamination during testing rather than being a real cause of ME/CFS.
This study is important because it provides a mechanistic explanation for why XMRV, once proposed as a potential ME/CFS biomarker, could not be reliably replicated in independent laboratories. Understanding that XMRV arose from laboratory contamination rather than being a genuine pathogen helps explain conflicting research findings and guides future biomarker discovery efforts in ME/CFS.
This study does not prove that XMRV has no role in any human disease, nor does it definitively rule out other retroviruses from playing a role in ME/CFS. It also does not address whether other infections or mechanisms might contribute to ME/CFS pathogenesis. The findings are specific to the origin of this particular virus strain and do not encompass all ME/CFS etiological hypotheses.
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
Paprotka, Tobias, Delviks-Frankenberry, Krista A, Cingöz, Oya, Martinez, Anthony, Kung, Hsing-Jien, Tepper, Clifford G, et al. (2011). Recombinant origin of the retrovirus XMRV.. Science (New York, N.Y.). https://doi.org/10.1126/science.1205292
BibTeX
@article{mecfsatlas-paprotka-2011-recombinant-origin,
author = {Paprotka, Tobias and Delviks-Frankenberry, Krista A and Cingöz, Oya and Martinez, Anthony and Kung, Hsing-Jien and Tepper, Clifford G and Hu, Wei-Shau and Fivash, Matthew J and Coffin, John M and Pathak, Vinay K},
title = {Recombinant origin of the retrovirus XMRV.},
journal = {Science (New York, N.Y.)},
year = {2011},
doi = {10.1126/science.1205292},
note = {PubMed: 21628392},
url = {https://www.mecfsatlas.com/evidence/paprotka-2011-recombinant-origin},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/paprotka-2011-recombinant-origin
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