Two years ago, researchers from the Whittemore Peterson Institute, the Cleveland Clinic and the National Cancer Institute published a study linking retrovirus to chronic fatigue syndrome. It was thought to be only the third retrovirus to ever infect humans. The study found that seven percent of healthy individuals might harbor the virus, suggesting that millions of Americans could be infected, concerns which caused the FDA and blood safety officials to enter the retrovirus hunt. Fearing that a new retrovirus could be infecting the nation's blood supply, the federal government launched a series of studies to determine its prevalence.
The finding promised hope to legions of patients who had received little attention or funding from federal officials in the past. The findings promised a new and exciting arena of study to retrovirologists after years of an almost-exclusive focus on HIV.
Almost two years and 30 studies later, however, XMRV had yet to turn up in another single research study in either chronic fatigue syndrome or other disorders. When a series of papers found that mouse contamination could mimic what appeared to be positive findings, concerns began to mount about the findings of the original paper.
Last December, studies found complementary bits of the XMRV genome in laboratory mice, but not in wild mice; this again raised concerns that XMRV was a lab contamination and not a virus found in humans. Another study examined the original samples of an XMRV prostrate cell line, which unexpectedly found to be producing large amounts of XMRV.
The study found that the XMRV in this prostate cancer cell line came from the mice, not from the prostrate cancer cell tissues. This suggested that, instead of being a human infection, XMRV may have inadvertently been produced in a Midwestern US laboratory in the early 1990s and was contaminating laboratory samples, not infecting humans.
From there the trail grew dim. The Whittemore Peterson Institute had no history of using the prostate cancer cell XMRV; this left the question of how XMRV could be a laboratory escape. At the Ottawa International Conference on ME/CFS in October, however, Dr. Robert Silverman from the Cleveland Clinic announced some crushing news: further testing had shown that contamination from a laboratory produced what appeared in the original study samples. With that, the authors of the Science study retracted the major finding of the paper and two others.
At the same conference, a federal working group on XMRV (the Blood Working Group) announced that a blinded study involving nine laboratories indicated that only the two labs in the original paper (Whittemore Peterson Institute/National Cancer Institute) were able to detect XMRV. However, they found XMRV in equal numbers of CFS patients and healthy controls, where neither lab agreed which patients had XMRV. A year and a half after the WPI had licensed the XMRV test to a commercial lab, the test was found to be worthless.