| XMRV and ME/CFS: What do we know so far? And what don't we know? (version 3) |
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Version 3 clarifies some of the points and queries raised in the previous two summaries. It also updates the situation on XMRV research in the UK, testing for XMRV and refers to our letter to the Chief Medical Officer regarding blood supplies and blood donation. This summary is intended to be a balanced account which not only raises questions but is also very cautious when it comes to drawing any firm conclusions about the role of XMRV in ME/CFS at this very early stage in the research. BACKGROUND
Until these research findings have been properly replicated, and we have the answers to some of the above questions, there is no point in asking your doctor to be tested for XMRV. This is because the NHS does not currently have the facilities to do so and the testing procedures are only being used in a research capacity at present. But, if it does turn out that there is a consistent and strong association with ME/CFS, then testing for XMRV would almost certainly have to be made available on the NHS. We are not aware of any private pathology laboratories here in the UK that are able to test for XMRV, or are intending to start offering to carry out testing. Dr Vincent Lombardi, primary investigator and lead author of the Science paper is Director of Operations for XMRV testing at Viral Immune Pathology Diagnostics (VIPDx) - a commercial laboratory in America. VIPDx website This testing facility is not available to people living outside the US. VIRAL TRANSMISSION We know that some people with ME/CFS are now very concerned about the possibility of transmission of XMRV through what are termed body fluids (ie blood, saliva, semen). However, until we know more about what this virus does in the body it would be premature to start arriving at firm conclusions and recommending all kinds of restrictions to normal daily living. Remember: we still do not know for certain whether this is a disease-causing virus in humans and whether it plays a role in causing or maintaining ME/CFS. And if this virus was behaving as an 'ME virus' in the way that HIV, another retrovirus, causes and transmits HIV infection, often leading to AIDS, there would be a significant number of sexual partners of people with ME/CFS developing ME/CFS. But this is clearly not the case. One simple way of obtaining some early clues about viral transmission of XMRV would be to test for the presence of the virus in healthy partners and offspring of people who have the infection and comparing the findings to a control group of people that have no such link. PRESENCE OF XMRV IN THE HEALTHY POPULATION If this virus is also present in up to 4% of the normal healthy population here in the UK (ie around 2.4 million, or ten times the number of people who have ME/CFS), as appears to be the case in America, and it does play a significant role in diseases such as ME/CFS and prostate cancer, there will be widespread and very serious implications for public health, blood donation etc. This could also include vaccination against the virus and treating people who are XMRV positive. These are complex decisions which can only be made in the light of further research studies. BLOOD DONATION AND XMRV In relation to blood donation in the UK, current advice is that people with ME/CFS who have symptoms, or are receiving treatment, should not donate blood. It would seem sensible in the short term, until we know more about transmission and pathogenicity of XMRV, to consider extending this restriction to people who have recovered from ME/CFS. It seems strange that many overseas countries have not followed the UK lead on blood donation and ME/CFS. The MEA has now written to Sir Liam Donaldson, Chief Medical Officer at the Department of Health, regarding the possibility of XMRV being transmitted via human blood products and the implications that this has for blood donation. A copy of this letter can be read here, The CFIDS Association of America has been issued with guidance from the National Cancer Institute regarding blood donation in the US. The guidance can be read on the CFIDS website here. WHAT CAN WE LEARN ABOUT THE ROLE OF INFECTION FROM OUTBREAKS OF ME/CFS? It should be noted that unlike the retroviral infection HIV, ME/CFS is an illness that occurs both sporadically and in highly localised acute geographical outbreaks, often involving closed communities such as schools and hospitals, where there is no obvious evidence of bodily fluid transmission. This fact would obviously question the role of XMRV as a precipitating infection in the onset of the illness. In the pivotal Royal Free Hospital outbreak of ME back in 1955, far more than 4% of a previously healthy population of doctors and nurses contracted an unknown infection at roughly the same time (the hospital had to close due to lack of staff). This fact would question the role of XMRV as a key predisposing factor if it only occurs in 4% of the population. TREATMENT OF XMRV: ANTIRETROVIRAL DRUGS AND VACCINE Until we know more about the possible role of XMRV in ME/CFS there is no point in asking your doctor about antiviral drug treatment. If it turns out that the virus does play a role in causing or maintaining ME/CFS then antiviral drug treatment will need to be investigated. This will involve clinical trials to test possible drug treatments for both safety and efficacy - a process that normally takes a considerable amount of time and money. The 2007 NICE Guideline on ME/CFS specifically states that doctors should not use antiviral medication to treat ME/CFS. This dogmatic position is unlikely to change without clear evidence of benefit in good quality randomised clinical trials. We understand that the NICE guideline will be reviewed in late 2010. Vaccination against XMRV has also been raised as a possibility. ROLE OF THE MEA RAMSAY RESEARCH FUND, VOLUNTEERING FOR RESEARCH and THE MEDICAL RESEARCH COUNCIL The ME Association is keen to progress this research here in the UK through any way we can help. We have already made contact with virologists and retrovirologists who are interested in this virus here in the UK, and we are aware of at least four sound research groups who are keen to pursue this work. Funding from the Ramsay Research Fund (RRF) could be made available very quickly if we receive a good quality research proposal. However, our contacts and discussions with UK researchers so far indicate that short term funding is not an immediate problem and that initial plans can probably be covered from existing budgets. More information on the work of the RRF can be found here Since publication of these results it has become apparent that a number of international research groups outsde the US and UK are also intending to try and confirm or refute the findings. The MEA has been contacted in relation to two such groups from overseas. This is obviously good news and should help to clear up some of the immediate uncertainties. If volunteers are required for any research taking place in the UK we will place an announcement on the MEA website. The Medical Research Council's Expert Group on ME/CFS research (membership includes Dr Jonathan Kerr and Dr Charles Shepherd) will be holding a two day research workshop on 19 - 20 November where XMRV will obviously be one of the topics under discussion. SELECTING PEOPLE FOR FURTHER RESEARCH STUDIES There is an immediate need for international agreement and co-operation on the research criteria being used to select well-characterised ME/CFS patients for further research into XMRV. Otherwise, we could end up in 2010 with a collection of conflicting results on prevalence because different international research groups have been using different patient selection criteria. In the present situation, with many research groups reluctant or unwilling to use Canadian criteria, and not having stored samples from patients that meet Canadian criteria, the best way forward may be for everyone to agree to use Fukuda defined CFS. We may then be able to draw some conclusions about which people who come under the wide clinical spectrum of CFS clinical presentation have XMRV and which do not. Besides using stored blood samples, research needs to involve fresh clinical cases, as well as other disease groups (particularly inflammatory conditions with immune activation) and properly matched healthy controls. KEY FACTS ABOUT THE XMRV RESEARCH
The bottom line to this interesting research is that it currently raises more questions than answers.
We will update this summary as further information becomes available. If you want to comment on this item, please do so via our
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Dr Charles Shepherd
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