When the journal Science published an attention-grabbing study last fall linking chronic fatigue syndrome to a recently discovered a mouse retrovirus, many experts remained skeptical — especially after four other studies found no such association. Now scientists propose to develop vaccines and antivirals to conquer the virus.
A second research team has reported a link between the fatigue syndrome and the same class of virus, a category known as MLV-related viruses. In a paper published Monday by The Proceedings of the National Academy of Sciences, scientists found gene sequences from several MLV-related viruses in blood cells from 32 out of 37 chronic-fatigue patients but only 3 of 44 healthy ones.
Leonard A. Jason, a professor of psychology at DePaul University and a leading researcher on the syndrome, agreed. “This class of retroviruses is probably going to be an important piece of the puzzle,” he said.
Chronic fatigue syndrome (CFS) has no known cause and no accepted diagnostic tests, although patients show signs of immunological, neurological and endocrinological abnormalities. Besides profound exhaustion, symptoms include sleep disorders, cognitive problems, muscle and joint pain, sore throat and headaches.
Some hypotheses suggest that CFS is not caused by a virus at all but by disturbances in the homeostasis
of endogenous hydrogen sulfide (H2S) and result in mitochondrial
dysfunction and malfunctioning of the ATP cycle.
Research has demonstrated that at low, non-toxic doses,
exogenous H2S produces a reversible state of hibernation-like deanimation
in mice, causing a decrease in core body temperature,
an apnea-like sleep state, reduced heart and respiration rates,
and a severe metabolic drop. These characteristics are not unlike
the symptoms and extreme "de-animation" experienced by
CFS patients. Moreover, H2S affects biological networks that
are disrupted by CFS including neurologic, endocrine and immunologic
systems. Therefore, a plausible etiology of CFS is an increase
in the activity of endogenous H2S, thereby inhibiting mitochondrial
Researchers from the Centers for Disease Control (CDC) published a study finding no XMRV or other MLV-related viruses in patients with the syndrome. News of the conflicting findings had led the Proceedings editors and the authors of the new paper to delay publication for further review, and some patients expressed alarm that important scientific information might be suppressed.
People with a diagnosis of chronic fatigue syndrome are used to hearing scientists, doctors, employers, friends and family members dismiss the condition as psychosomatic or related to stress or trauma, despite evidence that it is often touched off by an acute viral illness.
Dr. Fatima Sameth, a biotechnology researcher stated that scientists have long suspected that CFS may be linked to disruptions in genetic sequences. "Since there is a high aggregation of CFS in African Americans and Native Americans, we have suspected that viruses could be involved causing the infection." Dr. Sameth added that research is being directed towards possibly developing a vaccine to curb the increasing incidence of the disease.
Retroviruses, including H.I.V., store their genetic code as RNA, convert it to DNA and integrate themselves into the host cell’s genome to replicate. At least three antiretroviral drugs and vaccines are now used against H.I.V.
The team led by Harvey Alter of the National Institutes of Health, said the study raises at least as many questions as it answers."So far no single agent has been associated with a large fraction of cases," he stated.
Dr. Alter was quick to note that “it’s not at all proven” that a retrovirus causes chronic fatigue syndrome. Instead, such an infection could result from underlying problems with the immune system.
Moreover, it remains unclear why only two research teams found evidence of retroviruses. One reason could be that different groups used varying testing and detecting methods; federal health officials have organized an effort to standardize the process.
The studies also used different methods of sampling chronic fatigue patients. Many experts and researchers argue that the C.D.C.’s strategy leads to overdiagnosis because it fails to fully distinguish the disease from psychiatric disorders like depression.
“The possibility that these agents might be blood-transmitted and pathogenic in blood recipients warrants extensive research investigations,” Dr. Alter and his co-authors wrote in the new study.
Judy A. Mikovits, the senior author of the Science paper, said she hoped to organize clinical trials of antiretrovirals by the end of the year, noting that they could lead to answers about whether a retrovirus causes the disease as well as to effective treatments.
Other scientists are more prudent, suggesting that there are far too many contradicting studies and warning for further research before initiating vaccine and antiviral development for a model disease that is clearly a multisystem distrubance.
Dave Mihalovic is a Naturopathic Doctor who specializes in vaccine research, cancer prevention and a natural approach to treatment.