http://www.nytimes.com/2011/12/27/h...l=1&adxnnlx=1325143030-ebdh/9kBPbGRz628SSS4 w December 26, 2011 Scholars Retract Another Study Linking Virus to Fatigue SyndromeBy DAVID TULLER For the second time in a week, a key study suggesting a link between a retroviral infection and chronic fatigue syndrome has been retracted. A controversial study published in the journal Science in October 2009, which found an association between the illness and a mouse leukemia retrovirus known as XMRV, was retracted last week by the editors of the journal. On Monday, a study that linked the syndrome to retroviruses closely related to XMRV, published in August 2010 by The Proceedings of the National Academy of Sciences, was retracted by its authors. The second study had provided crucial support to the idea that these pathogens were connected to chronic fatigue syndrome, but other researchers were not able to confirm such an association. Some scientists reported that XMRV itself had been created accidentally during laboratory procedures and that contamination of laboratory materials was widespread. The authors of the study retracted on Monday included highly respected researchers from the Food and Drug Administration, the National Institutes of Health and Harvard Medical School. Randy Schekman, the former editor in chief of PNAS, said the journal had been encouraging the authors to reconsider their findings in light of subsequent research. In the retraction, the authors cited several concerns, including the failure of many labs to find similar associations and their own failure to find antibodies, isolate the virus by culture and identify integration sites for the retroviruses on the human genome. It is our current view that the association of murine gamma retroviruses with C.F.S. has not withstood the test of time or of independent verification and that this association is now tenuous, wrote the authors. Despite the recent retractions, the N.I.H. is continuing a large-scale study that is likely to be the final word on whether chronic fatigue syndrome is related to mouse (or murine) leukemia viruses. Results are expected by March.