Some researchers were concerned about contamination from the first reports of XMRV-disease associations , and these concerns spread as study after study failed to replicate WPI 's results . In December , 2010 , four independent articles published in the journal '' Retrovirology '' presented evidence that reported XMRV detection could be explained by contamination of laboratory reagents , tissue samples and blood . Samples that were positive for XMRV were also positive for mouse DNA contaminants . Furthermore , the striking identity of XMRV genomic sequences and their similarity to xenotropic MLVs in several human cell lines suggested that XMRV is not a transmissible human pathogen . The British Medical Journal responded with an article entitled , " Chronic fatigue syndrome is not caused by XMRV virus , study shows " . A fifth study supporting the contamination hypothesis was published in February , 2011 , just ahead of the 18th Conference on Retroviruses and Opportunistic Infections ( CROI ) . At CROI , WPI representatives were absent , and a large amount of negative data was presented . Two groups showed evidence that XMRV is a recombinant of two mouse retroviruses , which infected a prostate cancer cell line during passage through nude mice . Virologist John Coffin , who had previously expressed optimism about the initial WPI data , declared , " It 's all contamination . " Robert Silverman , who was a co-author of the original XMRV-CFS article but is no longer collaborating with Mikovits , told the Chicago Tribune that he was " concerned about lab contamination , despite our best efforts to avoid it "
Conference on Retroviruses and Opportunistic Infections
Conference on Retroviruses and Opportunistic Infections
Whittemore Peterson Institute