On Jan. 15th i attended a lecture by Dr. David Bell discussing XMRV and CFS. I thought i had read all of the latest XMRV news, but i really got alot out of the lecture.
He started out discussing the basics like the definition and criteria of chronic fatigue syndrome.
The current definition says that a person has to have 4 of the following 8 symptoms to meet the criteria for CFS. Those symptoms are:
1 – post exertional malaise
2 – cognitive disturbance
3 – non-refreshing sleep
4 – recurring sore throat
5 – lymph node pain
6 – recurring muscle pain
7 – multi-joint pain
8 – headache
& the absence of any alternative explanation.
( i personally only have 3 out of 8, i have no pain issues)
Then, he discussed the basics of what retroviruses are and how they infect cells.
XMRV stands for xenotropic murine retrovirus. It is an RNA virus that is able to “change the DNA within a cell and insert itself within the human genome. The xmrv virus then replicates as part of the host cell’s DNA. Once the virus’ genetic material is incorporated into the host cell, further generations of the cell will also contain this viral DNA.
Then he talked about the Whittermore-Peterson XMRV study.
The results of that study were:
68/101 people that fit the criteria of CFS were DNA positive for the presence of XMRV.
19 were antibody positive for XMRV
10 had protein expression (meaning that the virus was replicating)
So, in all 97 out of 101 had some type of positive result for XMRV.
Dr. Bell believed that the WPI study was a very strong paper and very good evidence in spite of the recent study out of the London Imperial college study (which failed to detect XMRV using a nested PCR technique). Also, there are around 10 more XMRV studies currently in progess.
He stated that there are currently tests for XMRV, but he believed that it wasnt really worth it to get tested now because: A) the test is very expensive B) there may be more accurate tests in the near future. He thought it might be a good idea to wait 6 mo. to a year, until the results of the replication studies are out.
He talked about some findings in CFS patients:
1) 70% of Lymphocytes activated
2) Abnormal RNAse L
3) Decreased Natural Killer Cell function and number
4) Immune Activation: Activated T-Cell, Cytokines, and Chemokines
How is XMRV Infectious?: it is unknown at this time. (he talked more about this when questions opened up and was open to the idea that it might be infectious the way mono is infectious. As he and other people noticed that couples did not tend to get sick, so he didn’t think that it was passed as an STD. He did note that it tended to run in families, but he thought that might be due to inhertited mitochondrial dysfunction.)
The WPI studies also showed that XMRV infected live cells in culture, showing that it was infecting B,T, and natural killer cells. So there proof of the infection passing from cell to cell.
The cytokine profiles of CFS patients support the theory of retroviral infection. RNase-L is very active in CFS patients and this may be seen in people that are fighting an RNA based virus (whch is what XMRV and other retroviruses are). RNAse L is an effector in the interferon induced antiviral response. This fits the RNase-L abnormalities noted in CFS patients.
In CFS patients NK cells become impaired and there is a “subtle immunodeficiency”. This may allow other viruses and infectious agents to persist. He believed that many of CFS symptoms may be caused by secondary infections and noted that some patients had improvement by treating secondary infections like: mycoplasma, HHV6, Epstein Barr, etc.
He also talked about a case a case in Belgium where 8 people contracted CFS after a blood transfusion. Fear of the contamination of the blood supply might be what creates alot of attention on CFS and XMRV. He stated that virologists seem to be very interested in XMRV.
He also thought CFS may just be the beginning of what diseases XMRV may have a hand in. He stated that fibromyalgia and multiple sclerosis might be XMRV related.
He discussed treatments for XMRV
He thought that the 25 years of HIV research would be very helpful when looking for treatments for XMRV. But that anti-retroviral drugs are very dangerous and he didnt think doctors would prescribe these drugs based on an unproven theory.
- One thing that i really found interesting was when he started about low blood volume in CFS (in response to a question from the audience). Dr. Bell was involved in studies that looked at the blood volume of CFS patients and he found that “eighty percent of [the] patients with CFS had either a low red blood cell mass, plasma volume, or both”. (This was also supported in an NIH study)
The audience member had his blood volume tested and he had 30% less blood volume than normal.
Dr. Bell’s theory for the low blood volume was that there might be systemic vasoconstriction. One idea he had that might cause this was the release of chemicals called isoprostanes that are released when the body is under oxidative stress.
He also stated that if you could normalize blood flow to the brain, then it may help resolve many symptoms. But there were no good treatments to restore blood volume at this time. He also stated that he had patients that had low blood volume and had blood transfusions. They had some symptom relief from the transfusions, but the benefits only lasted a couple of weeks.
Below are all Dr. Bell’s slides from the lecture: (click for larger image)