In this blog entry I will examine the likelihood of myself being XMRV positive. I am not stating that XMRV is the root cause of CFS nor do I know whether or not I am XMRV positive. Unlike previous blog entries, this one is more based upon pure speculation and hypothesises with little or no evidence. With the potentially significant news on XMRV and with little information about this retrovirus and CFS I am not able to provide many studies, mechanism or various other “criteria for a good explanation.”
Dr Judy Mikovits has stated in an interview that in unpublished data, XMRV’s expression is controlled by 3 things.
- Cortisol (the stress hormone.)
- The response to hormones
- The response to inflammatory cytokines.
I will examine each of these factors in relation to my CFS. I must state again that this is all pure speculation and I am committing the logical fallacy of confirmation bias by actively trying to fit my symptoms and illness around XMRV.
I had my cortisol levels measured via a 24 hour saliva test approximately 1 ½ years ago and they were normal. The reason for this test was the speculation that I had adrenal fatigue of some degree. Some of my symptoms fit neatly into the diagnosis of adrenal fatigue. For the past 2 years I have experienced a more severe cognitive impairment consistently during the morning. This involves my headaches being more severe, struggling to be in the same house as people and not being able to experience much stimulation (i.e. not being able to use the computer or watch TV.) It was therefore surprising to be told that I had normal cortisol levels.
Below is a graph showing normal diurnal cortisol levels (which I assume I still have) and my diurnal cognitive impairment.
The continuous line indicates what I expect my cortisol levels are. In regards to the continuous line, the X-axis is time over a 24 hour period and the Y-axis is serum cortisol in nanomoles per litre. As you can see, there is a peak in the early morning of cortisol.
The dashed line indicates an approximation of my cognitive impairment. In regards to the dashed line, the X-axis is time over a 24 hour period (the same period as the cortisol levels) and the Y axis indicates my cognitive impairment (with a higher number indicating a higher degree at cognitive impairment.)
Based on the 2 graphs, it seems that there is a correlation between my cortisol levels and cognitive impairment. With Dr Mikovits’s comments that cortisol affects XMRV, there is a possibility that my fluctuating cortisol levels may be affecting the XMRV throughout the day. This in turn may be affecting my cognitive levels. I must emphasise that this is merely a possibility to explain why I have morning severe cognitive impairment. It may be and is most likely just a spurious similarity in regards to cortisol levels.
Many people with CFS claim that a stressful event may have triggered there illness. This fits nicely in with the cortisol-XMRV study that Dr Mikovits is yet to publish. In regards to my CFS onset, I was completing my final year of high school and was training for the national athletics championships. I didn’t consider myself overly stressed and was only doing 10 minutes of homework a week, with a reduced subject load. I was however pushing my body to the extreme physically through running training. High VO2 max or prolonged physical exercise can stimulate cortisol release and this is indeed a possibility for me. Around 2 months before my CFS onset, I was participating in the steeplechase and cut my leg open. I got around 6 stitches and a sizable scar on my leg. It is conceivable that this may have raised my cortisol levels which in turn reacted with the XMRV virus that may have already been present inside my body.
Stressful events also negatively affect me like many other CFS patients. I seldom got overly affected by stressful events prior to CFS and this sequence of stress raising cortisol levels, affecting XMRV in someway and then physically affecting me is plausible.
If you are interested in reading about some theories concerning XMRV and cortisol a discussion is running at the Phoenix Rising forums here: http://forums.aboutmecfs.org/showthread.php?t=785
Response to hormones
The second factor that XMRV’s expression is controlled by, according the Dr Mikovits, is its response to hormones. I took the hormone T3 for over a month during January of 2008 and my CFS got significantly worse. Nothing else has affected me more directly and severely throughout the past 4 years than the T3. This fits in with the possibility of me being XMRV positive due to XMRV’s response to hormones. I must stress again that this is merely speculation and I would like to hear further comments from Dr Mikovits and read the study she alludes to before being more certain of things.
The response to inflammatory cytokines
The third factor that Dr Mikovits refers to is XMRV and its response to inflammatory cytokines. CFS can be considered an inflammatory disease however is unique in the sense that other inflammatory diseases tend to have high levels of inflammatory cytokines while CFS has increased levels of the ‘receptors’ for the inflammatory cytokines. Studies show that CFS patients have normal levels for the cytokines IL-6 and TNF. Despite this they have increased levels of the receptors for IL-6 and TNF. The inflammatory cytokines IL-6 is exercise induced and hence the corresponding receptors high levels show that CFS patients should be and indeed are sensitive to exercise.
I am unsure how the inflammatory cytokines relate to XMRV however Dr Mikovits may be referring to the inflammatory cytokine receptors which would link in with what I have written here as well as my post-exertional malaise.
Other noteworthy factors
Dr Mikovits has also suggested that immunisations may trigger XMRV and CFS in some way. My last immunisation was 2 months prior to my CFS onset. I had a tetanus vaccine due to injuring my leg while competing in the steeplechase.
It has been reported that XMRV may be passed on through bodily fluids and hence a family connection is possible. This may be through the medium of breast milk, blood ie shaving or saliva (unlikely yet possible.)
There is an unusually high incidence of CFS on my mother’s side of the family. On this side of the family, my aunties, uncles and cousins total approximately 26 (including my immediate family.) Including me, 6 of the 26 have been diagnosed with CFS. This means that it’s plausible that my family has a genetic susceptibility to XMRV or are carriers of XMRV. This high incidence of CFS within my family therefore has a possible explanatory mechanism, XMRV.
Although the XMRV-CFS study was only preliminary, it did look promising. This is why I have tried to fit my illness around it, to see how plausible it is that I have XMRV. Ideally I would be tested for it however the test isn’t available at present in Australia. I am reluctant to draw too many conclusions here as I have purposely committed the confirmation bias fallacy. Despite this I must conclude that I wouldn’t be overly surprised if I was XMRV positive as it seems to fit in within the framework of my CFS. Also the fact that premature studies show approximately 95% of the CFS cohort to be XMRV positive means odds are I’ve got it.