The leader of the group that linked xenotropic murine leukemia virus-related virus (XMRV) with chronic fatigue syndrome (CFS) has left her research institute. The departure follows the partial retraction of a paper by co-authors and the publication of another study that failed to reproduce the results published in that paper.
Last week, two co-authors of the 2009 paper retracted their contributions (2). By reexamining the samples used in the study, Cleveland Clinic researchers Robert Silverman and Jaydip Das Gupta found that some of the CFS peripheral blood mononuclear cell DNA preparations were contaminated with XMRV plasmid DNA. As a result, the two co-authors retracted their contributions, which included two figures and a table from the paper and supplementary material.
“It certainly was called for. Parts of that paper were failing,” said John Coffin, special adviser to director for the Center for Cancer Research at the National Cancer Institute. “XMRV didn’t arise until the 1990s, and it makes it impossible people could have been infected before or after.”
Accompanying the partial retraction isthe publication of a new multi-lab study that failed to reproducibly detect XMRV in blinded samples (3). Led by the National Institutes of Health (NIH) Blood XMRV Scientific Working Group (SRWG), only two of nine labs detected XMRV in samples that were previously reported to be infected with XMRV and in samples that were previously determined to be XMRV-free. But the results from these labs were not in agreement. Furthermore, these labs detected XMRV in both CFS patients and the negative controls. Mikovits lab participated in this study. One of the two labs that detected XMRV was Mikowits.
In their final analysis, the SRWG has concluded that current nucleic acid amplification testing assays cannot reproducibly detect XMRV in blood samples. As a result, the group sees little benefit to screening blood donors for XMRV.
Since the publication of the 2009 XMRV-CFS paper, the American Association of Blood Banks (AABB) has discouraged CFS patients from donating blood to prevent possible transmission of the virus. As for now, the AABB will not end this policy as a precautionary measure until the scientific community comes to an agreement on the XMRV-CFS link.
But an agreement is not likely soon. While most CFS patient groups have embraced the findings, which promised future diagnostic and therapeutic possibilities, other researchers have suggested that the results were the result of contamination. At last month’s International Association for Chronic Fatigue Syndrome/ME biennial conference, experts argued for both sides of the findings during a dedicated session.
Currently, the NIH is conducting a larger study to further investigate the link between XMRV and CFS. Those results are expected in early 2012.
As for Mikowits, who declined to comment, it is unclear if she will continue her XMRV research elsewhere after her departure from the WPI.
- Lombardi VC, Ruscetti FW, Das Gupta J, Pfost MA, Hagen KS, Peterson DL, Ruscetti SK, Bagni RK, Petrow-Sadowski C, et al. 2009. Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome. Science 326:585-9.
- Silverman RH, Das Gupta J, Lombardi VC, Ruscetti FW, Pfost MA, Hagen KS, Peterson DL, Ruscetti SK, Bagni RK, Petrow-Sadowski C, Gold B, Dean M, Mikovits JA. 2011. Partial Retraction. Science. 2011 Sep 22. [Epub ahead of print]
- Simmons G, Glynn SA, Komaroff AL, Mikovits JA, Tobler LH, Hackett J Jr, Tang N, Switzer WM, Heneine W, et al. 2011. Failure to Confirm XMRV/MLVs in the Blood of Patients with Chronic Fatigue Syndrome: A Multi-Laboratory Study. Science. 2011 Sep 22. [Epub ahead of print]