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Chronic Fatigue Syndrome Health Center

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New Doubts on XMRV as Chronic Fatigue Syndrome Cause

Studies Suggest Contamination of Lab Samples May Have Influenced Earlier Research

Evidence of Contamination continued...

Citing the "far-reaching impact" of the 2009 paper, the editors of the journal Science, which published both the original paper and the two new studies that give weight to the contamination theory, have published a "Letter of Concern" and asked the authors of the 2009 paper to retract their research.

Some researchers applauded the journal's decision to question the validity of the paper.

"It's giving a false message to patients who have placed a lot of hope on the fact that they might be infected with XMRV and therefore XMRV might be the cause of their disease and they're going to be able to be treated with antiretrovirals," says Vinay K. Pathak, PhD, chief of the viral mutation section at the National Cancer Institute in Frederick, Md. "It would be nice if it's true, but it's just not reality."

Study Researchers Respond

In a written response, study researcher Judy A. Mikovits, PhD, director of Research at the Whittemore Peterson Institute in Reno, Nev., defended her 2009 paper. She called the journal's expression of concern "premature" and said its publication "would have a disastrous impact on the future of this field of science."

A government-sponsored trial is under way to see if the XMRV virus can be detected in patients with CFS, and researchers pledged that it would go on, even in light of the negative findings of the new studies.

Failure to Replicate Findings

Since the publication of the original paper in 2009, at least 11 groups have tried, and failed, to find XMRV in chronic fatigue patients, while one group found evidence of related viruses called murine leukemia viruses in about 87% CFS patients compared with only about 7% of healthy patients.

Study researcher Jay A. Levy, MD, head of the Laboratory for Tumor and AIDS Virus Research at the University of California at San Francisco, who was one of the first scientists to identify XMRV, says he became suspicious when he noticed how similar the virus appeared to be between samples.

"They were so identical that it did not make sense," Levy says. "When the virus replicates it always changes."

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