Q. Dr. Klimas, Do you have any thoughts as to how many C.F.S. patients are under the radar because they were not eager to sign up for a wastebasket diagnosis, or otherwise frustrated out of the medical system early on?
A. Currently only 16 percent to 17 percent of the people with chronic fatigue syndrome whose symptoms are severe enough to meet the case definition for the illness have been diagnosed. Whether this is coming from the patient, as you suggest, or a medical community that does not know how or is reluctant to make the diagnosis is less clear.
Q.Have there been clusters or outbreaks of chronic fatigue syndrome, as some have described? And if there were outbreaks, doesnt that make it more likely to be contagious and less likely that the exposure came from exposures between great-great-grandparents and maintained for generations as latent infections, or as infections from early experiences of any sexual partner in a chain of partners?
A. Dr. Klimas responds: These clusters of post-infectious chronic fatigue syndrome are very interesting. Studies by Andrew Lloyd and colleagues showed the one and only predictor of persistent illness after an acute infection was the severity of that initial infection. No psychiatric factors were shown to predict who remains ill.
Some very common infections seem to set off C.F.S. and lead to several theories about the disease. My favorite theory is that any infection that can activate the immune system in a profound way could allow a hidden latent virus or viruses to reactivate and perpetuate a chronic illness. Anything that suppresses the immune system, like some treatments for cancer, might do the same thing, causing profound fatigue in some recovered cancer patients years after chemotherapy.
But why can one person do well and another stay ill after the same infection? Genetics may play a role, but this concept of a vulnerable population with latent XMRV infection is intriguing.
Q. Are There Two Viruses Linked With Chronic Fatigue Syndrome?
A. Dr. Klimas responds: Elaine DeFreitass work and that of Dr. Michael Holmes of New Zealand both involved scanning electron micrographs of viruses. Their findings look a great deal like those that were published in the recent Science article by Dr. Lombardi and colleagues, which Ms. Grady wrote about in The Times,) that found a possible link between chronic fatigue syndrome and the XMRV retrovirus. Could they be looking at the same virus? I dont really know, because I am not a laboratory virologist. But it makes good sense to me.
I remember in the early 1990s a member of our laboratory, Dr. Roberto Patarca, found evidence of production of an enzyme called reverse transcriptase in our cell cultures, more evidence of an active retroviral infection. So the key thing now is for another reputable lab to find the same thing in chronic fatigue syndrome. Then we will see what happens next.
