A virus considered as a possible causative factor for chronic fatigue syndrome, prostate cancer, and even Lyme disease, XMRV is now thought to be a result of laboratory contamination from mouse cells or DNA. XMRV (Xenotropic Murine Leukemia Virus-Related Virus) is a retrovirus that was found in a significant number of samples from patients with CFS and prostate cancer in studies published in 2009, and some scientists have suggested that it is also a possible factor in Lyme disease patients.
A near worldwide blood ban was placed on CFS patients, and some even began treatment with potentially harmful antiretrovial drugs such as those used for HIV/AIDS patients. The researchers, from University College London and University of Oxford Wellcome Trust Sanger Institute, may have cast doubt on the link between Lyme disease, XMRV, CFS, and prostate cancer but are careful to note that there may be a virus cause of CFS, just not XMRV.
CFS, Lyme Disease, and XMRV
The original studies showed a high number of patients with CFS (also known as myalgic encephalomyelitis, or ME) to have evidence of XMRV in their samples. The British researchers observed, however, that the patients’ samples showed an unusual heterogeneity in the virus that would not normally be expected. A virus that spreads through the human population would normally undergo some degree of evolutionary change, but the fact that the XMRV found in these patients was very similar suggests that the samples were contaminated rather than the patients infected. Dr Stéphane Hué, Post Doctoral Researcher at UCL said “When we compare viral genomes, we see signs of their history…Viral infection is a battle between the virus and the host, and XMRV does not have the scars of a virus that transmits between people.” That XMRV was found in the samples in the earlier studies is not under dispute, it is the relevance of the presence of the virus that the scientific community is now debating.
Avoiding XMRV Contamination in the Laboratory
The research at UCL and in Oxford also observed that existing methods of testing would find that one in fifty human cell lines were infected with XMRV-related viruses, which has profound ramifications for researchers investigating the causes of disease. More rigorous standards of containment are needed to ensure that cell and DNA samples are not contaminated and results confounded by such contamination. The researchers who made the connection between the retrovirus and CFS originally have disputed the recent findings however, and continue to make claims that XMRV is involved in the development of Lyme disease, CFS, prostate cancer, and even autism.
Lack of Transparency Thwarts XMRV Investigations
Looking back at the original research presented by Dr. Judy Mikovits (2009) making the connection between XMRV, CFS, and Lyme disease, the exact methodology used remains unavailable for scrutiny by the scientific community. The journal (Science) in which the paper was published has asked for a retraction of the study now that the results appear unsafe but Mikovits continues to refuse to give in to the requests. In a private request to Mikovits the editors at Science explained their reasoning for requesting the retraction, but Mikovits called the request ‘premature’ in her response to the letter. The Wall Street Journal published leaked details of the exchange, which was shortly followed by publication in Science of the two new papers casting doubt on the Whittemore Peterson Institute (WPI) study along with an Editorial Expression of Concern written by the Editor-in-Chief Bruce Alberts. Alberts and Monica Bradford, the Executive Editor, asked Mikovits in a letter of the 26th May, 2011, to retract the paper as “it would be in the best interest of the scientific community”.
XMRV Formed from A Prostate Tumor
One study details the creation of XMRV in the 1990s as it was accidentally formed during work with mice and a human prostate tumor. The study at Tufts University, led by Coffin and Pathak, aimed to create an immortalized cell line to enable researchers to study prostate cancer, but reports of XMRV from laboratories studying prostate cancer began to arise. The XMRV virus was created because of genetic recombination of two separate mouse viruses. The link between the retrovirus XMRV, Lyme disease, and CFS may simply be one of contamination rather than causation.
Continue Reading –> Lyme Disease – XMRV and its Origins