Saturday, February 26, 2011

No negative study has cultured XMRV (for 45 days)

Andrew S. Wiecek, 02/23/2011:

As for her XMRV work, Mikovits says that researchers have focused on her PCR technique because it is the easiest element to replicate. “A lot of the negative studies assume that in this age of molecular technology, there’s not a detection limit for PCR,” she says. “We could detect one copy in one milliliter of blood. But there is a limit of detection to PCR.”

When she was studying HIV latency monocytes in the 1980s, biologists did not rely upon molecular-based detection methods in virology. They relied on culturing—which, for a retrovirus, is a complicated task even for expert biologists. “The first paper on the isolation of HIV was in 1982,” says Mikovits. “We didn’t have a single-copy assay of HIV by PCR until 1991.”

It’s only been about a year since XMRV arrived on the scene, and Mikovits argues that since opposing studies focused only on plasma and did not culture the virus, there could be discrepancies. “If you simply look for proviral DNA and look for very low–copy number virus, you have to make the cells divide.”

“Some of these newer technologies are just not cutting it. You have to go back to culturing the virus,” says Pfost. ““It’s hard to find the needle in the haystack if you’re not looking in a big enough haystack.” To this end, since the 2009 Science paper, Mikovits has traveled around the world to teach other labs how to culture and detect the virus with positive results.

“No one to my knowledge has cultured the virus,” she says. Read more>>

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