One year ago, researchers at the National Cancer Institute published a paper that linked Chronic Fatigue Syndrome with an obscure retrovirus known as XMRV. The article caused a stir because 4% of the supposedly healthy people in the study were infected with the virus. That could mean nearly 12 million Americans are infected with a poorly understood virus that potentially causes a poorly understood disease.
There has followed a mad dash to commercialize a blood test for XMRV, since arguably, the nation’s blood supply needs to be screened for the virus. Unfortunately, progress on this endeavor has been slow.
Like HIV-the virus that causes AIDS-XMRV is a retrovirus. XMRV has also been associated with prostate cancer, although no one really knows whether the virus causes diseases of any kind in humans.
Labs involved the effort to develop an XMRV blood test include those at the CDC and the National Cancer Institute, as well private sector programs at Roche, Abbott and Gen-Probe.
Scientists at Abbott are working with the Cleveland Clinic and Emory University. They have created unequivocally positive blood samples from monkeys that were deliberately infected with XMRV. The infected monkeys produced antibodies to 3 proteins on the surface of the virus, but blood levels of these antibodies became undetectabe within weeks after the infection. Tests based on these antibodies can therefore generate false negative results. False negative results can also be caused by the unusually long delay between the time the monkeys were infected with the virus and the time the antibodies appeared.
Even if these issues can be overcome and the antibody test subsequently proven to be useful on human blood, there would remain additional challenges in commercializing the test. For example, the elapsed time between when the blood is obtained and when it is tested could impact test results.
“When there is a new agent that we don’t know a lot about, it’s always a process,” Michael Busch lamented in an interview with the Wall Street Journal. Bush is the director of San Francisco’s Blood Systems Research Institute and a participant in the working group tasked by the Feds to study the potential impact of XMRV on the nation’s blood supply.
Final Thought: It’s hard to criticize a proactive effort to commercialize a blood test for a virus that could be contaminating our nation’s blood supply, but it sure would be nice to know that XMRV actually causes human disease, and that it actually can be transmitted through a blood transfusion. #CartBeforeTheHorse?