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Het verhaal van

twee virussen







Alhoewel de afloop (?) van de XMRV/MLV-theorie tot grote teleurstelling heeft geleid,

heeft die theorie in ieder geresulteerd in vakmatige belangstelling van "buitenstaanders",

zoals viroloog Racaniello, die het immunologische karakter van ME/CFS onderschrijven.






A Tale of Two Viruses:

Why AIDS Was Pinned to HIV, but Chronic Fatigue Remains a Mystery



Vincent Racaniello



The detection of a new virus called XMRV in the blood of patients with chronic fatigue syndrome (CFS) in 2009 raised hope that a long-sought cause of the disease, whose central characteristic is extreme tiredness that lasts for at least six months, had been finally found. But that hypothesis has dramatically fallen apart in recent months. Its public demise brings to mind an instance when a virus *was* successfully determined to be behind a mysterious scourge: the case of HIV and AIDS. How are these two diseases different - how was it that stringent lab tests and epidemiology ruled one of these viruses out, and one of them in?




Why have investigators failed to identify a virus behind CFS? (It is not due to the lack of appropriate technology; this has improved substantially since the 1980s with the development of polymerase chain reaction and rapid DNA sequencing.) One explanation for this dilemma is that an infectious agent does not cause CFS. However, there is plausible evidence for an infectious etiology, including observations that the disease is known to occur in outbreaks. Furthermore, in many cases the onset of symptoms appears to begin with a flu-like illness. Additionally, CFS is a heterogeneous disease, and may be caused by several different agents or a combination of viruses and non-infectious conditions. Another possibility is that an infection initiates an immune response that spirals out of control, leading to CFS symptoms. This scenario implies that at least some CFS patients have underlying deficits in immune regulation. If thatís true, it will be very difficult to identify the virus involved because it will likely have been eliminated from patients' systems by the time CFS symptoms become apparent.


In retrospect, it is clear that the properties of AIDS made it an easy disease to understand. While the path to understanding CFS has been clouded by non-scientific issues, in the end the main reason why we do not understand this disease is because it is extraordinarily complex. But that never stopped a good scientist.