Evidence is mounting that a retrovirus called XMRV is not a new human pathogen infecting millions, as was feared, but a laboratory contaminant.
"I am concerned about lab contamination, despite our best efforts to avoid it," Silverman wrote in an e-mail, adding that similar cell lines "are in many, many labs around the world. Contamination could come from any one of a number of different sites."
A European research team this week reported being unable to find any evidence of XMRV in the blood of people diagnosed with chronic fatigue syndrome and their healthy peers, the latest in a stream of studies in which researchers looking for the retrovirus in the blood of both sick and healthy people have come up empty. Others have reported no evidence of the retrovirus in the blood of patients who were previously found to be XMRV-positive.
The Tribune reported last year that the original research on chronic fatigue syndrome and XMRV had led some patients to get tested for the retrovirus and take anti-retroviral drugs intended to treat HIV, which causes AIDS. The situation highlights the danger in putting too much stock in one scientific study, even one in a prestigious journal. Studies need to be replicated, and early research is often proved wrong.
The original study, published in Science in 2009, was led by retroviral immunologist Judy Mikovits of the private Whittemore Peterson Institute for Neuro-Immune Disease in Reno, Nev. The institute plans to open a clinic that in May would begin treating patients diagnosed with chronic fatigue syndrome and other neuro-immune diseases. Despite the newer research, its leaders strongly deny that contamination could account for their findings.
"It is clearly a human infection," Mikovits, the institute's director of research, told an audience at a January presentation hosted by a California alternative medical practice. "It is clearly circulating through the population as is our fear and your fear."
Scientists say there is no evidence to support her statement.
"Saying that is just inciting fear," said Columbia University virologist Vincent Racaniello.
Mikovits, who once worked at the National Cancer Institute in Frederick, Md., has made increasingly broad statements about XMRV. At the January talk, she showed a slide connecting XMRV to a list of frustrating medical conditions like ALS, Parkinson's disease, multiple sclerosis and dementia. She also linked it to autism. But no published data exist to support those links.
Mikovits also talked about potential treatments, including the powerful anti-retroviral drugs used to treat people who have HIV. These have not been proved safe or effective for people with chronic fatigue syndrome or any of the other conditions listed.
The WPI's director of clinical services, Dr. Jamie Deckoff-Jones, who has chronic fatigue syndrome and has taken anti-retroviral drugs for a year, is using a personal blog to allege a cover-up by researchers seeking to discredit the XMRV link.
"So is there motivation for the cover-up and baseless attacks against Dr. Mikovits?" she wrote in a posting that has been widely circulated on patient forums. "They cannot attack the data because it is impeccable."
WPI President Annette Whittemore, whose daughter has been diagnosed with chronic fatigue syndrome, said in an interview that she thinks politics are at play.
"I thought we were going to solve my daughter's illness or at least fund more significant treatments," said Whittemore, who founded the institute. "I didn't think we would have such political pushback. That was so naive of me."
Whittemore also defended patients trying anti-retrovirals, saying they are safe if used under an experienced doctor's care.
"Patients choose to try these drugs because they are so sick they have lost their entire lives to this illness," she wrote in an e-mail. "As far as I am concerned, they are the pioneers paving the way forward for other sufferers."
In her presentation, Mikovits also described the antiretroviral drugs as "very well tolerated" by patients trying them for chronic fatigue syndrome.