Paolucci, Stefania, Piralla, Antonio, Zanello, Cinzia et al. · The new microbiologica · 2012
This study looked for two viruses (XMRV and MLV-related viruses) that had been suggested as possible causes of ME/CFS. Researchers tested 12 ME/CFS patients and 40 healthy control subjects. They found these viruses in only 2 of the 12 patients, while all controls tested negative. The results suggest these viruses are not common in ME/CFS patients, and previous reports of finding them may have been due to laboratory contamination with mouse DNA.
This study addresses a significant controversy in ME/CFS research regarding whether viral infections like XMRV might be involved in disease pathogenesis. By demonstrating that these viruses are not prevalent in ME/CFS patients and that contamination does not fully explain previous conflicting results, it helps clarify the actual role—if any—of these agents in ME/CFS and redirects research focus toward more promising etiological pathways.
This study does not prove that XMRV and MLV-related viruses play no role in ME/CFS pathogenesis, as the small sample size and the detection of these sequences in 2 patients leaves open the possibility of involvement in a subset of cases. It also does not establish whether other viral or infectious agents might be involved in ME/CFS. The study cannot determine causation or explain the mechanism behind the controversial earlier findings.
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
Paolucci, Stefania, Piralla, Antonio, Zanello, Cinzia, Minoli, Lorenzo, & Baldanti, Fausto (2012). Xenotropic and polytropic murine leukemia virus-related sequences are not detected in the majority of patients with chronic fatigue syndrome.. The new microbiologica. https://pubmed.ncbi.nlm.nih.gov/22842604/
BibTeX
@article{mecfsatlas-paolucci-2012-xenotropic-polytropic,
author = {Paolucci, Stefania and Piralla, Antonio and Zanello, Cinzia and Minoli, Lorenzo and Baldanti, Fausto},
title = {Xenotropic and polytropic murine leukemia virus-related sequences are not detected in the majority of patients with chronic fatigue syndrome.},
journal = {The new microbiologica},
year = {2012},
note = {PubMed: 22842604},
url = {https://www.mecfsatlas.com/evidence/paolucci-2012-xenotropic-polytropic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/paolucci-2012-xenotropic-polytropic
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