There have been several new articles published about xenotropic murine leukemia virus-related virus (XMRV) over the past month, bringing the total of peer-reviewed articles published this year to 60. A regularly updated listing of journal and media articles about the retrovirus can be found on our main website.
This week, two important publications were issued. First, a special issue of the open access peer-reviewed journal Advances in Virology is dedicated to research on XMRV. Most of the articles have been posted ahead of this special issue, so they will not be new to readers keeping up with the literature. The editors for the issue titled, “Xenotropic and Other Murine Leukemia Virus-Related Viruses in Humans,” are Arifa S. Khan (Food and Drug Administration, USA), Myra McClure (Imperial College, England), Yoshinao Kubo (Nagasaki University, Japan) and Paul Jolicoeur (McGill University, Canada). They have written an editorial introducting the publication, available at http://www.hindawi.com/journals/av/aip/787394.pdf.
“This Special Issue provides the current thinking and recent research results of studies on XMRV and other murine leukemia retrovirus-related sequences in humans. At this point, a consensus appears to be emerging that XMRV footprints or infectious XMRV detected in normal human individuals or in some diseased patients represent laboratory contaminations. Indeed, numerous studies have now failed to confirm the presence of XMRV in humans and XMRV has recently been found to be a laboratory-derived rare recombinant, which originated during serial passages of a patient’s prostate cancer cells in nude mice. The information provided in this issue should be of interest to a broad audience including scientists, clinicians, patient populations, and public health agencies.”
The listing of contents of the special issue (http://www.hindawi.com/journals/av/2011/si.xmlv/) does not yet include all 13 articles described in the editorial, but they can be accessed from hyperlinks in the text of the editorial.
A second publication made available this week is a technical report on XMRV from the European Centre for Disease Control and Prevention titled, “Risk Assessment of XMRV: Implications for Blood Donation.” The report was produced in response to a Sept. 23, 2010, request from the European Commission DG SANCO Directorate C. The ECDC was asked by the Commission to assess:
1) the epidemiological profile of XMRV;
2) the scientific evidence of
a. the link between chronic fatigue syndrome and the presence of XMRV in the blood and;
b. transmission [of XMRV] via blood donation; and
3) to advise the Commission on the possible value and need of introducing deferral criteria and/or testing requirements in the European Union.
The report is dated July 6, 2011, but it was just made available this week, posted to the website of the German national association of state and local blood transfusion services, StKB. The internal experts who conducted the review of the literature and prepared the 41-page report are: Tobias Bergroth, Mika Salminen and Ana-Belen Escriva.
Their conclusion reads as follows:
“Currently there is not enough evidence to reliably assess the potential role of XMRV and MLVs in human pathology. Only two studies have been published so far reporting positive findings in CFS patients, in contrast to 13 studies where no virus have been found. Many questions remain regarding the possible prevalence of XMRV in the human population, the incidence of XMRV in cases of CFS, the extent of genetic variation between XMRV isolates, and whether XMRV infection is a causal factor in the pathogenesis of a subset of CFS or prostate cancer cases (or of any other disorder) or is no more than a passenger virus identified in immunocompromised patients and some normal subjects. It can also turn out to simply be the results of laboratory contamination.
“Although it is theoretically presumed that XMRV could be transmitted through blood transfusion, no such transmission event has been identified, and there is no known evidence of XMRV or MLV infection or related illness or disease in transfusion recipients. XMRV may represent another emerging infectious agent that poses a risk to transfusion safety, and as with other agents, it is imperative that action taken on behalf of blood safety be expeditious, yet based on the best available science. Currently, the scientific data are incomplete and conflicting although the majority of the evidence favours a conclusion of contamination or at least non-causal relation to disease. With the development of validated assays, additional data will become available in the near future and these data will help inform decisions on blood donor eligibility and screening.”
The report can be read in its entirety at http://stkb.org/pdf/XMRV_Risk_assessment.pdf.
There are other publications in the pipeline. Phase III of the Blood XMRV Scientific Working Group study has been completed and results are being analyzed and prepared for publication. For links to other resources about XMRV, please visit http://www.cfids.org/xmrv/resource-listing.asp