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Chronic Fatigue Syndrome Health Center

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Virus Theory for Chronic Fatigue Syndrome Discredited

XMRV Virus Probably Not a Cause of CFS; Original Study Partially Retracted
WebMD Health News
Reviewed by Laura J. Martin, MD

Sept. 22, 2011 -- Researchers are disputing a 2009 study that found a virus in the blood of people with chronic fatigue syndrome, which some hoped might have pointed to a cause of the disease.

The researchers, who were trying to confirm the 2009 study results, say they have failed to find evidence of XMRV infection in some of the same patients who were involved in the original study.

Additionally, some of the authors of the original study announced that they were retracting some of their results after finding evidence of contamination in some of their study samples.

Experts say the new study and partial retraction, which are published in the journal Science, should finally discredit the controversial theory that XMRV causes chronic fatigue syndrome.

“The original findings that led to the concern and the excitement that this is real aren’t reproducible,” says Michael P. Busch, MD, PhD, professor of laboratory medicine at the University of California at San Francisco and director of the Blood Systems Research Institute.

“I take that as an indication that those results are unreliable,” Busch says.

But the authors of the original paper, who were also involved in the new research, have a different interpretation.

They believe XMRV couldn’t be found in blood tests because it may hide in the body’s tissues, only rarely being picked up in the blood.

They point to recent studies in primates that were experimentally infected with XMRV. The infected monkeys were able to clear the virus from their blood within about a month, but it lingered in other tissues like the spleen and lymph nodes.

“All this study really says is that we can’t detect it in the blood reproducibly,” says Judy A. Mikovits, PhD, director of research at the Whittemore Peterson Institute in Reno, Nev.

“The interpretation says that it’s not there or that it’s not a human infection, and there’s no data in this study or any other to support that,” she says.

Mikovits says she just got a federal grant to continue her work on XMRV. “Clearly things aren’t over or they wouldn’t be awarding grants for people like us to study this virus and understand those questions,” she says.

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