Dr. John Coffin of the US NCI co-authored two of the papers and he says flat-out that his Brit co-authors have overstated their results. I'll go with Coffin.
http://home.ncifcrf.gov/hivdrp/Coffin.html
The UK studies published 12/20 were completed last summer and the contamination issues, though potentially serious, have been addressed and ruled out sufficiently for an FDA advisory panel last week to recommend that all CFS sufferers be excluded from blood/organ donations to to likelihood that CFS is caused by a retrovirus.
Is XMRV a laboratory contaminant?
21 December 2010
Since the first observations that the human retrovirus XMRV is associated with prostate cancer and chronic fatigue syndrome (CFS), new studies have been carried out to determine the role of the virus in these diseases.
http://www.virology.ws/2010/12/21/is-xmrv-a-laboratory-contaminant/
Xenotropic murine leukemia virus-related virus (XMRV retrovirus), first described in 2006, belongs to the virus family Retroviridae and the genus gammaretrovirus.
Livestock retroviruses have been found in humans. Google H-CAEV. CAE is an incurable retrovirus in goats, closely related to one in sheep, OPP. Both cause arthritis, lung damage and sometimes brain damage. Both are transmitted primarily thru milk to offspring. People drink goat’s milk and voila!
The finding of these retroviruses in humans - - mostly in Mexico - - were linked in some cases to disease in humans.
Doubtful that there could be lab contamination with goats!