Published in InterAction 76 (Summer 2011)
In February, a further study published online in the journal Retrovirology failed to find XMRV in people with CFS/M.E.
Researchers tested blood specimens from 45 people with CFS and 42 healthy controls from more than 20 states in the USA for XMRV and signs of mouse leukemia virus. They found no evidence of either in all 45 CFS cases, nor in the 42 cases without CFS.
However, just days earlier, a study published online in the Journal of Virology found that XMRV causes chronic, persistent infection in monkeys. This study also found that the virus was difficult to detect in the monkeys’ blood, raising the possibility that someone could be infected with XMRV but show no symptoms until years later.
Giving an overview of XMRV research in the journal Reviews in Medical Virology in January, Dr Luis Menéndez-Arias, University of Madrid, said, “The relevance and significance of XMRV to human disease remain unclear, since the association has not been confirmed in other studies. XMRV is the first gammaretrovirus to be found in humans. XMRV and murine leukaemia viruses share similar structures and genomic organisation.
“Evidence supporting the involvement of XMRV in chronic fatigue syndrome is still very weak, and needs further confirmation and validation. Currently approved anti-retroviral drugs such as zidovudine, tenofovir and raltegravir are efficient inhibitors of XMRV replication in vitro. These drugs might be useful to treat XMRV infection in humans. The identification of XMRV has potentially serious health implications for the implementation of novel techniques including gene therapy or xenotransplantation, while raising concerns on the need for screening donated blood to prevent transmission through transfusion.”
Heated debate about XMRV dominated the M.E./CFS State of the Knowledge Workshop, a National Institutes of Health research event, 7-8 April.
Judy Mikovits of the Whittemore Peterson Institute, whose team originally found XMRV in patients with M.E. in 2009, presented published and unpublished data on how patients make antibodies to XMRV and the way the virus leaves ‘footprints in the blood.’
However, John Coffin of Tufts University said his unpublished work confirms that Mikovits’ findings are the result of laboratory contamination.
Look out for a full report on the State of the Knowledge Workshop and its findings in the next issue of InterAction.
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