The trouble seems to start when the old retrovirus genes—broken down and disabled over time, and silent in healthy people—are hijacked, turned on again or put to a new use. "Retroviruses inserting themselves into our genome—or hijacking copies of other genes to insert in our genome—wreak havoc,'' says Stephen Tapscott of the Fred Hutchinson Cancer Research Center, part of a team that published a paper last year on the link between the ancient process and why some people get a common type of muscular dystrophy.
In healthy people, one particular ancient retrovirus is barely detectable, but in HIV patients who also have lymphoma, the virus is found in high levels. The researchers think in some patients, HIV stirs things up, "turning on DNA that in healthy people is usually dormant,'' says Mark Kaplan of the University of Michigan, who has been studying the old viruses in people with HIV and HIV lymphoma.
The researchers will see if the old retrovirus gene is activated in those who developed chronic fatigue syndrome compared with those who didn't. If a connection is demonstrated, therapies could be developed to turn off the old retrovirus gene. "The idea is that if you don't have chronic stimulation then the symptoms would go away,'' Dr. Huber says.