Two injections of the cancer drug Rituximab, which suppresses the immune system, relieved chronic fatigue symptoms in 10 of 15 patients several months later, according to a small Norwegian clinical trial. The drug works by depleting the body's B-cells, lymphocytes that release antibodies important for fighting infections. It has also been shown to relieve symptoms of rheumatoid arthritis, another autoimmune disease.
The study suggests antibodies might be misguidedly attacking patients' own tissues in chronic fatigue syndrome, and that the delayed relief from Rituximab is linked to the "gradual elimination of autoantibodies," Øystein Fluge of Haukeland University Hospital in Bergen, Norway, and colleagues wrote in the journal PLoS One.
The trial stemmed from a fluky finding: A patient taking Rituximab for non-Hodgkin's lymphoma experienced an unexpected decrease in chronic fatigue symptoms. The researchers have now launched a phase 2 clinical trial that will incorporate "maintenance" Rituximab injections three to 15 months after the initial treatment.
The autoimmune theory of chronic fatigue syndrome was bolstered by a 2009 study that linked the condition to a virus called XMRV. But the study was knocked down last month when nine independent labs failed to replicate the findings, leaving chronic fatigue patients -- many of whom battle skepticism about their condition -- still searching for answers.
For Becky Blanton, a freelance journalist in Richmond, Va., the virus link made sense. She fought what she thought was the flu two months before her diagnosis. And in the 19 years since, her symptoms have relapsed and remitted like those of multiple sclerosis, an autoimmune disease thought by some to be triggered by an infection.
"I'm still convinced it's a virus," Blanton told ABCNews.com at the time.
So are several researchers. Although the authors of the Norwegian study failed to find evidence of a XMRV infection in their study subjects, an unknown virus could be triggering an autoimmune reaction. Guillain-Barre syndrome, a paralytic autoimmune disease caused by antibodies attacking the nervous system, can be triggered by a virus.
Dr. Michael Busch, professor of laboratory medicine at University of California, San Francisco, and lead author of the XMRV knockdown study, said he hopes the research effort spurred by the wayward finding will continue.
"A lot of new groups are searching and a lot of patients have stepped forward to try to identify a new virus," Busch told ABCNews.com at the time.
Kim McCleary, president and CEO of the Chronic Fatigue and Immune Dysfunction Syndrome Association of America, echoed Busch's optimism.
"We're determined to translate the heightened attention and deeper engagement XMRV has attracted into sustainable progress," McCleary said. "There are many other solid leads that merit the same rigorous follow-up as XMRV has received over the past two years."