Tuesday, July 19, 2011

Research paper: CFS, the immune system and viral infection, 2 July 2011

From the M.E. Association's website, a post by Tony Britton entitled 'Research paper: CFS, the immune system and viral infection, 2 July 2011':
From Brain, Behaviour and Immunity, the official journal of the Psychoneuroimmunology Research Society (PNIRS). 2011 Jul 2. [Epub ahead of print]

Chronic fatigue syndrome, the immune system and viral infection.

Bansal AS, Bradley AS, Bishop KN, Kiani S, Ford B.
Dept. of Immunology, Epsom and St. Helier University Hospitals NHS Trust, Carshalton, Surrey, SM5 1AA and Chronic Illness Research Team, Stratford Campus, University of East London, London E15 4LZ, UK.

Abstract

The chronic fatigue syndrome (CFS), as defined by recent criteria, is a heterogeneous disorder with a common set of symptoms that often either follows a viral infection or a period of stress. Despite many years of intense investigation there is little consensus on the presence, nature and degree of immune dysfunction in this condition. However, slightly increased parameters of inflammation and pro-inflammatory cytokines such as interleukin (IL) 1, IL6 and tumour necrosis factor (TNF) α are likely present. Additionally, impaired natural killer cell function appears evident. Alterations in T cell numbers have been described by some and not others. While the prevalence of positive serology for the common herpes viruses appears no different from healthy controls, there is some evidence of viral persistence and inadequate containment of viral replication. The ability of certain herpes viruses to impair the development of T cell memory may explain this viral persistence and the continuation of symptoms. New therapies based on this understanding are more likely to produce benefit than current methods.

Copyright © 2011. Published by Elsevier Inc.

PMID: 21756995 [PubMed - as supplied by publisher]

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Thursday, July 14, 2011

What's it like to have severe ME/CFS? It's a living death and hell in solitary confinement

BEFORE a viral illness struck me down in 1999, I never imagined that such a disabling and painful illness could exist without it being taken seriously by British doctors and health care professionals.

It's a lonely feeling and tough to take when you see the scepticism in their eyes and/or hear it in their voices. When they don't take M.E. seriously how are others, family and friends, expected to understand or even believe us?

Watching the following excellent video from getwellfromme.com entitled "What is it like to have M.E.?" made me cry.

Today, my answer to the question "What is it like to have severe M.E.?" would be this: "It's a living death and hell in solitary confinement".

Tomorrow, I might be feeling worse but my answer to the question would still be the same because every day is bad.

Some days even are worse if I do too much, other days are horrendous for months on end if I get an infection or go out.

I've been too ill to sit up long enough to go out in a wheelchair and manage the basics of day to day life after I return home.

Hopefully, now that I am on painkillers which are helping me to control some of the symptoms, next year will be different.

If you, or any person you know or care for, are suffering from severe M.E., please contact the The 25% M.E. Support Group, the UK's only national support group for people severely affected by M.E. (c. 25% of M.E. sufferers are severely affected, hence the name).

There are two separate forms of Membership in order to try to provide a suitable service for as many sufferers as possible, whether severely, moderately or mildly affected by ME and, of course also provide support to carers of ME sufferers.



Credit: Video courtesy of getwellfromme.com
Hat tip: Rachel M @bluecoffeemug / YouTube http://youtu.be/qBriPTFOtmY (read comments)

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Tuesday, June 14, 2011

New study: Gene expression alterations at baseline and following moderate exercise in patients with CFS & FMS

RESEARCHERS behind a new study say they've discovered post-exercise differences in genetic expression that meet criteria for an objective biomarker for a subgroup of chronic fatigue syndrome (ME/CFS). They also say data show two distinct subgroups of ME/CFS and also differentiate fibromyalgia (FMS) from both ME/CFS and healthy controls. Further details in three reports reprinted here below.

(1) From Post Viral Fatigue Forum, 6 June 2011 www.postviralfatigue.me.uk Full copy:
New Study Claims Change in Gene Expression in CFS

Looks interesting: http://chronicfatigue.about.com/b/2011/06/06/genetic-expression-after-exercise-in-fibromyalgia-chronic-fatigue-syndrome.htm

Researchers analyzed blood samples before exercise to get a baseline, then took samples again half an hour, 8 hours, 24 hours and 48 hours after moderate exercise.

They found that:

- 71% of the ME/CFS group (34 of 48) had increased expression of 4 genes dealing with sensory and adrenergic receptors and cytokines for 48 hours after exercise; Those with the largest change in genetic expression also had the largest increase in post-exercise symptoms.

- The other 29% of the ME/CFS group (14 of 48) did not show the above changes but did have a decrease in expression of the adrenergic α-2A receptor; This group had significantly more orthostatic intolerance (dizziness upon standing) than the first group.

- Healthy controls and people with FMS had no post-exercises changes in the genes that were studied.

They [the researchers] say the data show two distinct subgroups of ME/CFS and also differentiate fibromyalgia (FMS) from both ME/CFS and healthy controls.

Seems encouraging to me.

B.
edited by Barbarian on 6/6/2011 [End]
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(2) From About.com Guide Fibromyalgia & Chronic Fatigue
6 June 2011 - http://chronicfatigue.about.com
By Adrienne Dellwo
Full copy:
Research Brief

Researchers behind a new study [full copy below, courtesy of PubMed] say they've discovered post-exercise differences in genetic expression that meet criteria for an objective biomarker for a subgroup of chronic fatigue syndrome (ME/CFS). They also say data show two distinct subgroups of ME/CFS and also differentiate fibromyalgia (FMS) from both ME/CFS and healthy controls.

Researchers analyzed blood samples before exercise to get a baseline, then took samples again half an hour, 8 hours, 24 hours and 48 hours after moderate exercise (maintaining maximum heart rate for 20 minutes.) They were looking for changes in genes that deal with sensory fatigue and muscle pain, which are common post-exercise symptoms of ME/CFS. The found that:

71% of the ME/CFS group (34 of 48) had increased expression of 4 genes dealing with sensory and adrenergic receptors and cytokines for 48 hours after exercise;
Those with the largest change in genetic expression also had the largest increase in post-exercise symptoms;

The other 29% of the ME/CFS group (14 of 48) did not show the above changes but did have a decrease in expression of the adrenergic α-2A receptor;
This group had significantly more orthostatic intolerance (dizziness upon standing) than the first group;

Healthy controls and people with FMS had no post-exercises changes in the genes that were studied;
However, those with FMS had baseline elevations in 3 genes -- 2 sensory ion channels and 1 cytokine -- that were not found in the other groups.
These differences in genetic expression could help explain post-exertional malaise (PEM), which is considered the hallmark symptom of ME/CFS. PEM causes a marked upswing in symptoms after exertion, and for some people it takes very little exertion -- such as taking a shower or walking to the mailbox -- to trigger this symptom. In the most severe cases, even sitting up for a few minutes can lead to PEM.

FMS involves a similar but generally less-severe reaction to over exertion or stressful events, and these genetic abnormalities could help shed light on this as well.

Researchers concluded that these findings could help establish an objective biomarker for diagnosing at least 1 subgroup of ME/CFS, guide treatment for both identified ME/CFS subgroups, and differentiate FMS from ME/CFS. [End]
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(3) From PubMed - May 2011 - National Center for Biotechnology Information, U.S. National Library of Medicine
http://www.ncbi.nlm.nih.gov/pubmed/21615807?forumid=331851
Full copy:
J Intern Med. 2011 May 26. doi: 10.1111/j.1365-2796.2011.02405.x. [Epub ahead of print]

Gene expression alterations at baseline and following moderate exercise in patients with Chronic Fatigue Syndrome, and Fibromyalgia Syndrome.

Light AR, Bateman L, Jo D, Hughen RW, Vanhaitsma TA, White AT, Light KC.

Source
Department of Anesthesiology, University of Utah, Salt Lake City, UT The Brain Institute, University of Utah, Salt Lake City, UT Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT Department of Exercise and Sprt Science, University of Utah, Salt Lake City, UT.

Abstract
Light AR, Bateman L, Jo D, Hughen RW, VanHaitsma TA, White AT, Light KC (University of Utah Dept. Anesthesiology, Dept. Neurobiology and Anatomy, Dept. Exercise and Sport Science) Gene expression alterations at baseline and following moderate exercise in patients with Chronic Fatigue Syndrome, and Fibromyalgia Syndrome.

Objectives: To determine mRNA expression differences in genes involved in signaling and modulating sensory fatigue, and muscle pain in patients with Chronic Fatigue Syndrome (CFS) and Fibromyalgia Syndrome (FM) at baseline, and following moderate exercise.

Design: Forty eight Patients with CFS-only, or CFS with comorbid FM, 18 Patients with FM that did not meet criteria for CFS, and 49 healthy Controls underwent moderate exercise (25 minutes at 70% maximum age predicted heart-rate). Visual-analogue measures of fatigue and pain were taken before, during, and after exercise. Blood samples were taken before, and 0.5, 8, 24, and 48 hours after exercise. Leukocytes were immediately isolated from blood, number coded for blind processing and analyses, and flash frozen. Using real-time, quantitative PCR, the amount of mRNA for 13 genes (relative to control genes) involved in sensory, adrenergic, and immune functions was compared between groups at baseline, and following exercise. Changes in amounts of mRNA were correlated with behavioral measures, and functional clinical assessments.

Results: No gene expression changes occurred following exercise in Controls. In 71% of CFS patients, moderate exercise increased most sensory and adrenergic receptor's and one cytokine gene's transcription for 48 hours. These post-exercise increases correlated with behavioral measures of fatigue and pain. In contrast, for the other 29% of CFS patients, adrenergic α-2A receptor's transcription was decreased at all time points after exercise; other genes were not altered. History of orthostatic intolerance was significantly more common in the α-2A decrease subgroup. FM only patients showed no post-exercise alterations in gene expression, but their pre-exercise baseline mRNA for two sensory ion channels and one cytokine were significantly higher than Controls.

Conclusions: At least two subgroups of CFS patients can be identified by gene expression changes following exercise. The larger subgroup showed increases in mRNA for sensory and adrenergic receptors and a cytokine. The smaller subgroup contained most of the CFS patients with orthostatic intolerance, showed no post-exercise increases in any gene, and was defined by decreases in mRNA for α-2A. FM only patients can be identified by baseline increases in 3 genes. Post-exercise increases for 4 genes meet published criteria as an objective biomarker for CFS, and could be useful in guiding treatment selection for different subgroups.

Copyright © 2011 The Association for the Publication of the Journal of Internal Medicine.

PMID: 21615807 [PubMed - as supplied by publisher] [End]
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Thursday, June 09, 2011

The US National Institutes of Health is sponsoring new studies to ascertain whether the association between XMRV and CFS can be confirmed

Dr Jonathan Stoye, a retrovirologist at the UK Medical Research Council National Institute for Medical Research, has joined in criticism of the XMRV paper by Lombardi and colleagues, despite having co-written an editorial in Science in 2009 in support of it.

Dr Stoye said it should not be forgotten that a subset of CFS patients “almost certainly” had disease triggered by a viral infection, and although efforts to explain this should continue, the viral trigger was not XMRV.

The US National Institutes of Health is sponsoring new studies to ascertain whether the association between XMRV and CFS can be confirmed.

Editor in chief of Science, Bruce Alberts, writing in the journal, said, “Science eagerly awaits the outcomes of these further studies and will take appropriate action when their results are known.”

Full story below from MEA website June 8, 2011:
‘Science asks researchers to withdraw paper on chronic fatigue syndrome and infectious retrovirus’, British Medical Journal, 6 June 2011

From the British Medical Journal, 6 June 2011 (news story by Matthew Limb)

Researchers are facing calls to retract published findings that link chronic fatigue syndrome to a retrovirus called xenotropic murine leukemia virus related virus (XMRV) after new scientific criticism of their validity.

Editors of the journal, Science, have issued an “editorial expression of concern” over a research paper it published in October 2009, saying the report is “now seriously in question.”

The study, “Detection of an infectious retrovirus, XMRV, in blood cell of patients with chronic fatigue syndrome,” was led by Vincent Lombardi and Judy Mikovits of the Whittemore Peterson Institute, Reno, Nevada (Science 2009;326:585).

It purported to show that a retrovirus XMRV was present in the blood of 67% of patients with chronic fatigue syndrome (CFS) compared with 3.7% of healthy controls.

The study caused a stir when it appeared and led to some CFS patients, believing XMRV to be a possible contributor to their condition, seeking antiretroviral treatments marketed to combat HIV.

But Science, which is the weekly journal of the American Association for the Advancement of Science, has now highlighted “flaws” in the paper.

Since 2009, it says, at least 10 studies conducted by other investigators and published elsewhere have failed to detect XMRV in independent populations of CFS patients.

Furthermore, Science has published two new reports that “strongly support the growing view that the association between XMRV and CFS described by Lombardi and colleagues likely reflects contamination of laboratories and research reagents with the virus.”

One report provides evidence that the virus originated when two mouse leukaemia viruses underwent recombination during experimental passage of a human prostate tumour xenograft in mice in the 1990s.

In their analysis, Paprotka and colleagues conclude that laboratory contamination with XMRV produced by a cell line (22Rv1) derived from these early xenograft experiments is the most likely explanation for detection of the virus in patient samples. (Science 2011 doi:10.1126/science.1205292)

“Our results suggest that the association with XMRV with human disease is due to contamination of human samples with virus originating from this recombination event,” the authors write.

In the second report, K Knox and colleagues examined blood samples from 61 CFS patients from the same medical practice that had provided patient samples to Lombardi and colleagues.

Comprehensive assays by Knox and colleagues for viral nucleic acids, infectious virus, and virus-specific antibodies showed no evidence of XMRV in any of the samples (Science 2011 doi:10.1126/science.1204963).

In February 2010, a Dutch study refuting the original US study reporting the link was published in the BMJ (2010;341:c1018; doi:10.1136/bmj.c1018).

It has emerged that editors of Science, before publishing their “editorial expression of concern,” privately requested that the authors of the original study retract it themselves.

Dr Judy Mikovits has written to the editors warning that Science’s action could be “disastrous” for future research in this field while insisting the study is accurate.

She wrote that she and her co-authors shared the “deep concern” over the number of studies that had not been able to replicate their findings.

She said other scientists had not replicated their work faithfully and there were no data to support claims of laboratory contamination.

Since the study was published there have been calls in the US for people with CFS to be barred from donating blood in case blood supplies might be contaminated by the “contagious” retrovirus.

The US National Institutes of Health is sponsoring new studies to ascertain whether the association between XMRV and CFS can be confirmed.

Editor in chief of Science, Bruce Alberts, writing in the journal, said, “Science eagerly awaits the outcomes of these further studies and will take appropriate action when their results are known.”

Jonathan Stoye, a retrovirologist at the UK Medical Research Council National Institute for Medical Research, has joined in criticism of the paper by Lombardi and colleagues, despite having co-written an editorial in Science in 2009 in support of it.

He told the BMJ that there was strong evidence that contamination explained the findings and therefore the suggested the link between XMRV and CFS was “wrong.”

He said, “Nobody has reproduced the original results and that is very unsatisfactory.” I don’t see any reasons for the scientific community to spend any more time and effort on this.”

He told the BMJ he had no plans to do further research himself in this area, adding, “I believe the scientific argument is done, but the political argument may not be.”

He said although requests to withdraw a published research paper were “unusual, it does happen.

“In football terms, it’s somewhere between a yellow and a red card,” he said.

Dr Stoye said it should not be forgotten that a subset of CFS patients “almost certainly” had disease triggered by a viral infection, and although efforts to explain this should continue, the viral trigger was not XMRV.

Charles Shepherd, medical adviser to the UK based ME Association, a national charity supporting people affected by myalgic encephalopathy (ME), CFS, and post viral fatigue syndrome, said the failure of many leading experts to support the findings of Lombardi and colleagues “must be taken seriously.”

He said the charity was waiting to hear the results of ongoing US research, including a multicentre study of CFS patients by virologist Ian Lipkin, which might provide “definitive” results.

Dr Shepherd told the BMJ, “I am trying to take a balanced view although it will be a tremendous disappointment to many patients if it turns out that XMRV is a red herring.”

He said, given the current uncertainty, it would be “unethical” for doctors to prescribe antiretrovirals for CFS patients, and there was no evidence for this happening in the UK.

Peter Spencer, chief executive of the charity Action for ME, said, “Like many patients, we were excited when the original study was published in 2009, and hoped that further studies would lead to independent and substantive confirmation of a link between XMRV and ME. Unfortunately, it seems that it is now time to move on. But it’s imperative that this very disappointing news does not overshadow the continuing importance of rigorous scientific study into the biology of ME. There is still a long way to go.”

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Thursday, April 07, 2011

Viral Encephalomyelitis - Academic review

ENCEPHALOMYELITIS is an unusual complication of infection with encephalitic viruses.

The term encephalomyelitis refers to inflammation in the brain and spinal cord that results from the immune response to virus infection. In humans, the viruses most commonly identified as causes of viral encephalomyelitis include herpesviruses and RNA viruses in the enterovirus, e.g., polio, enterovirus 71.

The primary target cells for most encephalitic viruses are neurons, although a few viruses attack cerebrovascular endothelial cells to cause ischemia and stroke or glial cells to cause demyelination, encephalopathy, or dementia.

Widespread infection of neurons may occur or viruses may display preferences for particular types of neurons in specific locations in the central nervous system (CNS). For instance, herpes simplex virus (HSV) type 1 often infects neurons in the hippocampus to cause behavioral changes, while poliovirus preferentially infects motor neurons in the brainstem and spinal cord to cause paralysis and Japanese encephalitis virus infects basal ganglia neurons to cause symptoms similar to those of Parkinson’s disease.

Because infections with encephalitic viruses are initiated outside the CNS (e.g., with an insect bite, skin, respiratory, or gastrointestinal infection), innate and adaptive immune responses are usually mounted rapidly enough to prevent virus entry into the CNS. Therefore, most viruses that can cause encephalitis more often cause asymptomatic infection or a febrile illness without neurologic disease, and encephalomyelitis is an uncommon complication of infection.

Full details below.

Useful academic review of encephalomyelitis: PLoS Pathogens
Source: ME Association website posted by Tony Britton
April 7, 2011. Copy in full:

From PLoS Pathogens, March 2011.

Diane E. Griffin*

W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America

Citation: Griffin DE (2011) Viral Encephalomyelitis. PLoS Pathog 7(3): e1002004. doi:10.1371/journal.ppat.1002004

Editor: Hiten D. Madhani, University of California San Francisco, United States of America

Published: March 24, 2011

Copyright: © 2011 Diane E. Griffin. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: Work from the author’s laboratory was supported by the NIH/NINDS (R01 NS038932) and the Dana Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The author has declared that no competing interests exist.

* E-mail: dgriffin@jhsph.edu

Encephalomyelitis Is an Unusual Complication of Infection with Encephalitic Viruses

Viral encephalomyelitis is an important cause of morbidity and mortality worldwide, and many encephalitic viruses are emerging and re-emerging due to changes in virulence, spread to new geographic regions, and adaptation to new hosts and vectors [1]. The term encephalomyelitis refers to inflammation in the brain and spinal cord that results from the immune response to virus infection. In humans, the viruses most commonly identified as causes of viral encephalomyelitis are herpesviruses and RNA viruses in the enterovirus (e.g., polio, enterovirus 71), rhabdovirus (e.g., rabies), alphavirus (e.g., eastern equine, Venezuelan equine, and western equine encephalitis), flavivirus (e.g., West Nile, Japanese encephalitis, Murray Valley, and tick-borne encephalitis), and bunyavirus (e.g., La Crosse) families. Other virus families with members that can cause acute encephalitis are the paramyxoviruses (e.g., Nipah, Hendra) and arenaviruses (e.g., lymphocytic choriomeningitis, Junin). However, this is certainly not a complete list, because for most cases of human viral encephalitis the etiologic agent is not identified, even when heroic attempts are made [2].

The primary target cells for most encephalitic viruses are neurons, although a few viruses attack cerebrovascular endothelial cells to cause ischemia and stroke or glial cells to cause demyelination, encephalopathy, or dementia [3]–[5]. Widespread infection of neurons may occur or viruses may display preferences for particular types of neurons in specific locations in the central nervous system (CNS). For instance, herpes simplex virus (HSV) type 1 often infects neurons in the hippocampus to cause behavioral changes, while poliovirus preferentially infects motor neurons in the brainstem and spinal cord to cause paralysis and Japanese encephalitis virus infects basal ganglia neurons to cause symptoms similar to those of Parkinson’s disease.

Because infections with encephalitic viruses are initiated outside the CNS (e.g., with an insect bite, skin, respiratory, or gastrointestinal infection), innate and adaptive immune responses are usually mounted rapidly enough to prevent virus entry into the CNS. Therefore, most viruses that can cause encephalitis more often cause asymptomatic infection or a febrile illness without neurologic disease, and encephalomyelitis is an uncommon complication of infection.

Encephalitic Viruses Can Use Neuronal or Non-Neuronal Pathways to Enter the CNS

When a virus does invade the CNS, there are several routes by which infection of neurons can occur. The most common entry point is from the blood, and the level of viremia as a result of virus replication in peripheral organs often correlates with the likelihood of CNS infection. However, the blood–brain barrier (BBB), composed of vascular endothelial cells with tight junctions in contact with the foot processes of astrocytes, inhibits direct access to the brain parenchyma and neurons. Some neurotropic viruses can replicate in cerebrovascular endothelial cells, enter with infected leukocytes, or cross directly into the cerebrospinal fluid (CSF) through the porous capillaries of the choroid plexus. A specialized CNS entry pathway used by several viruses, most notably HSV, varicella zoster, and rabies viruses, is by way of nerve terminals in peripheral organs. These viruses can enter the nerve and then use neural transport mechanisms to transport the infecting virions to the neuronal cell body where replication occurs [6], [7]. A variation on this theme is infection through the exposed end processes of neurons in the nasal olfactory epithelium, followed by transport of the virus to the olfactory lobe within the CNS. Intranasal infection is commonly used to initiate infection of the CNS in experimental animals, but in humans this pathway may be important only in rare cases of aerosol exposure to a neurotropic virus [8]–[10].

In tissue culture systems most of these viruses can infect many types of cells, in addition to neurons. Few neuron-specific virus receptors have been identified (e.g., p75NTR, NCAM, and AChR for rabies; nectin for HSV) but these do not always account for neuronotropism in vivo [11]–[13]. Recent studies with HSV suggest that receptors used to enter processes of peripheral neurons can be different from those used to infect neurons in the brain [12]. Therefore, the mechanisms by which encephalitic viruses target neurons to the exclusion of other cells within the CNS are poorly understood. Once within the nervous system, encephalitic viruses often follow synaptic pathways for spread to other neuronal populations. These viruses interact with motor proteins either directly or through accessory proteins to travel using both anterograde (kinesin motors) and retrograde (dynein-dynactin motors) neuronal microtubule transport systems [6].

Neuronal Damage Can Be Caused Directly by Virus Infection or by the Immune Response to the Infection

In addition to fever and headache, signs and symptoms of viral encephalomyelitis typically include evidence of neuronal dysfunction—seizures, cognitive impairment, ataxia, paralysis, etc. Virus replication can damage neurons directly by inducing cell death through apoptotic or necrotic mechanisms (Figure 1) [14]. Many viruses cause more severe CNS disease in the young. For these infections, immature neurons support more efficient virus replication and greater virus-induced cell death than mature neurons [15]. In humans, Venezuelan equine encephalitis and La Crosse viruses cause symptomatic neurologic disease almost exclusively in children, although adults are equally susceptible to infection [16], [17]. Conversely, for unexplained reasons, neurologic disease due to West Nile virus infection occurs primarily in people over the age of 60 years [18].
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Figure 1. Schematic diagram of the potential outcomes after virus infection of neurons.

Virus infection itself may induce death of the infected neuron, especially in young individuals. Neuronal death can also result from the local release of excitotoxic neurotransmitters (e.g., glutamate) and inflammatory mediators. Neurons can also survive infection and virus replication can be controlled through noncytolytic mechanisms such as local production of antiviral antibody and interferon (IFN)-γ. In the latter case, viral nucleic acid persists intracellularly and long-term immune control is necessary to prevent virus reactivation.
doi:10.1371/journal.ppat.1002004.g001

Although neuronal virus infection per se is necessary for, and contributes directly to, neuronal dysfunction, the inflammatory response in the CNS is also a major contributor to neuronal damage and can even result in death of nearby uninfected neurons (Figure 1) [19], [20]. The CNS inflammatory response to virus infection consists of activation and proliferation of resident astrocytes and microglial cells and of perivascular and parenchymal infiltration of activated monocytes and lymphocytes from the blood. The mechanism(s) by which the immune response causes neuronal damage are incompletely understood, but evidence exists for production of neurotoxins and reactive oxygen and nitrogen species by activated glial cells, increased levels of the excitotoxic neurotransmitter glutamate, and production of cytokines by activated lymphocytes [21]. The ability to control inflammation through induction of regulatory T cells and suppression of lymphocyte function by infected neurons can be an important determinant of outcome [22], [23]. In alphavirus encephalomyelitis, combined prevention of inflammation and glutamate excitotoxicity by treatment with glutamate receptor antagonists prevents paralysis and death despite continued virus replication [20].

Virus Clearance from Neurons Is Complicated by the Irreplaceable Nature of Neurons

The immune response to infection can contribute to fatal disease, but is also necessary for recovery and virus clearance. Elimination of virus-infected cells from tissue requires elimination of all cells in which the virus is replicating. This can occur either by virus-induced or immune-mediated cytolysis. T cells are ideal for this purpose because they recognize viral antigen as processed antigen only in the context of cell surface–expressed MHC class I (CD8+ T cells) or of MHC class II (CD4+ T cells) and can possess cytotoxic properties. Neurons are long-lived essential cells that cannot be replaced, so a noncytolytic immune mechanism for virus clearance would be advantageous to the host to avoid death of surviving cells. If the immune clearance mechanism is damaging to the infected neuron, then the function of that neuron will be lost and the outcome for the host will be the same as if the virus infection had caused neuronal death.

Because mature neurons are relatively resistant to virus-induced cell death [15], noncytolytic mechanisms for virus clearance can be employed to control or eliminate infection. If infected cells are allowed to survive, the clearance of virus must include mechanisms for inhibiting intracellular synthesis of virus nucleic acid and protein, and for removing virus genomes from cells or preventing their replacement after degradation. Alphavirus encephalitis has been most thoroughly studied, and two noncytolytic clearance mechanisms have been identified: IFN-γ and anti-viral antibody (Figure 1). However, not all types of neurons are equally responsive to virus clearance by these mechanisms. IFN-γ acts through a Jak/STAT signaling pathway to activate an antiviral response that suppresses virus replication in motor neurons without toxicity, but the relevant antiviral proteins have not been identified [24]. Antibody to the E2 viral glycoprotein present on the surface of infected neurons suppresses virus replication in all populations of neurons through a pathway that requires bivalent antibody, but does not require complement or effector cells [25], [26].

Recovery from Encephalitis Results in Virus Persistence and the Need for Long-Term Immune Control

Because the noncytolytic process for virus clearance does not completely eliminate viral RNA from neurons, a mechanism for long-term immunologic control of virus replication is needed to prevent virus reactivation or progressive disease [27], [28]. Antibody is likely to participate in control, as well as initial clearance. Maintaining adequate levels of antibody in the CNS for continued control of virus replication requires either passage of antibody from the blood into the brain parenchyma or local production by resident antibody-secreting cells. The BBB restricts the entry of proteins from the blood into the CNS, and although this function is compromised during the acute phase of infection, it is quickly repaired. Under normal conditions, levels of antibody in the brain are sustained at 1% of plasma levels that are likely to be inadequate for long-term prevention of virus reactivation. Therefore, resident long-lived antibody-secreting cells that can continue to produce antiviral antibody for a lifetime are a feature of recovery from most CNS virus infections [29]. Long-term immune control of virus replication is not always successful, leading to recurrent or progressive neurologic disease [30]–[32].

Conclusions

Encephalomyelitis resulting from virus infection of neurons is a disease that can be fatal or result in permanent disability due to irreversible damage of infected neurons. The immune response to infection can enhance neuronal damage or can control virus replication by noncytolytic mechanisms and thus determine outcome. However, noncytolytic virus clearance results in persistence of viral nucleic acid in the CNS and thus establishes a need for long-term local immune responses to prevent reactivation of infection and progressive disease. Understanding these mechanisms is necessary for development of strategies for treating and preventing neurologic disease due to viral encephalomyelitis.

References

1. Griffin DE (2010) Emergence and re-emergence of viral diseases of the central nervous system. Prog Neurobiol 91: 95–101.

2. Glaser CA, Honarmand S, Anderson LJ, Schnurr DP, Forghani B, Cossen CK, Schuster FL, Christie LJ, Tureen JH (2006) Beyond viruses: clinical profiles and etiologies associated with encephalitis. Clin Infect Dis 43: 1565–1577.

3. Gilden D, Cohrs RJ, Mahalingam R, Nagel MA (2009) Varicella zoster virus vasculopathies: diverse clinical manifestations, laboratory features, pathogenesis, and treatment. Lancet Neurol 8: 731–740.

4. Major EO (2010) Progressive multifocal leukoencephalopathy in patients on immunomodulatory therapies. Annu Rev Med 61: 35–47.

5. Takahashi K, Wesselingh S, Griffin DE, McArthur JC, Johnson RT, Glass JD (1996) Localization of HIV-1 in human brain using polymerase chain reaction/in situ hybridization and immunocytochemistry. Ann Neurol 39: 705–711.

6. Lyman MG, Enquist LW (2009) Herpesvirus interactions with the host cytoskeleton. J Virol 83: 2058–2066.

7. Ugolini G (2008) Use of rabies virus as a transneuronal tracer of neuronal connections: implications for the understanding of rabies pathogenesis. Dev Biol (Basel) 131: 493–506.

8. Thach DC, Kimura T, Griffin DE (2000) Differences between C57BL/6 and BALB/cBy mice in mortality and virus replication after intranasal infection with neuroadapted Sindbis virus. J Virol 74: 6156–6161.

9. Roy CJ, Reed DS, Wilhelmsen CL, Hartings J, Norris S, Steele KE (2009) Pathogenesis of aerosolized eastern equine encephalitis virus infection in guinea pigs. Virol J 6: 170. doi: 10.1186/1743-422X-6-170.

10. Yamada M, Nakamura K, Yoshii M, Kaku Y, Narita M (2009) Brain lesions induced by experimental intranasal infection of Japanese encephalitis virus in piglets. J Comp Pathol 141: 156–162.

11. Tuffereau C, Schmidt K, Langevin C, Lafay F, Dechant G, Koltzenburg M (2007) The rabies virus glycoprotein receptor p75NTR is not essential for rabies virus infection. J Virol 81: 13622–13630.

12. Kopp SJ, Banisadr G, Glajch K, Maurer UE, Grunewald K, Miller RJ, Osten P, Spear PG (2009) Infection of neurons and encephalitis after intracranial inoculation of herpes simplex virus requires the entry receptor nectin-1. Proc Natl Acad Sci USA 106: 17916–17920.

13. Bender SJ, Phillips JM, Scott EP, Weiss SR (2010) Murine coronavirus receptors are differentially expressed in the central nervous system and play virus strain-dependent roles in neuronal spread. J Virol 84: 11030–11044.

14. Havert MB, Schofield B, Griffin DE, Irani DN (2000) Activation of divergent neuronal cell death pathways in different target cell populations during neuroadapted Sindbis virus infection of mice. J Virol 74: 5352–5356.

15. Vernon PS, Griffin DE (2005) Characterization of an in vitro model of alphavirus infection of immature and mature neurons. J Virol 79: 3438–3447.

16. Rivas F, Diaz LA, Cardenas VM, Daza E, Bruzon L, et al. (1997) Epidemic Venezuelan equine encephalitis in La Guajira, Colombia, 1995. J Infect Dis 175: 828–832.

17. Haddow AD, Odoi A (2009) The incidence risk, clustering, and clinical presentation of La Crosse virus infections in the eastern United States, 2003-2007. PLoS ONE 4: e6145. doi: 10.1371/journal.pone.0006145.

18. Hayes EB, Komar N, Nasci RS, Montgomery SP, O’Leary DR, Campbell GL (2005) Epidemiology and transmission dynamics of West Nile virus disease. Emerg Infect Dis 11: 1167–1173.

19. Conrady CD, Drevets DA, Carr DJ (2010) Herpes simplex type I (HSV-1) infection of the nervous system: is an immune response a good thing? J Neuroimmunol 220: 1–9.

20. Greene IP, Lee E-Y, Prow NA, Ngwang B, Griffin DE (2008) Protection from fatal viral encephalomyelitis: AMPA receptor antagonists have a direct effect on the inflammatory response to infection. Proc Natl Acad Sci USA 105: 3575–3580.

21. Tilleux S, Hermans E (2007) Neuroinflammation and regulation of glial glutamate uptake in neurological disorders. J Neurosci Res 85: 2059–2070.

22. Lafon M, Megret F, Meuth SG, Simon O, Velandia Romero ML, et al. (2008) Detrimental contribution of the immuno-inhibitor B7-H1 to rabies virus encephalitis. J Immunol 180: 7506–7515.

23. Lanteri MC, O’Brien KM, Purtha WE, Cameron MJ, Lund JM, et al. (2009) Tregs control the development of symptomatic West Nile virus infection in humans and mice. J Clin Invest 119: 3266–3277.

24. Burdeinick-Kerr R, Govindarajan D, Griffin DE (2009) Noncytolytic clearance of Sindbis virus infection from neurons by gamma interferon is dependent on Jak/STAT signaling. J Virol 83: 3429–3435.

25. Ubol S, Levine B, Lee S-H, Greenspan NS, Griffin DE (1995) Roles of immunoglobulin valency and the heavy-chain constant domain in antibody-mediated downregulation of Sindbis virus replication in persistently infected neurons. J Virol 69: 1990–1993.

26. Levine B, Hardwick JM, Trapp BD, Crawford TO, Bollinger RC, Griffin DE (1991) Antibody-mediated clearance of alphavirus infection from neurons. Science 254: 856–860.

27. Dorries R (2001) The role of T-cell-mediated mechanisms in virus infections of the nervous system. Curr Top Microbiol Immunol 253: 219–245.

28. Marten NW, Stohlman SA, Bergmann CC (2000) Role of viral persistence in retaining CD8(+) T cells within the central nervous system. J Virol 74: 7903–7910.

29. Tyor WR, Wesselingh S, Levine B, Griffin DE (1992) Long term intraparenchymal Ig secretion after acute viral encephalitis in mice. J Immunol 149: 4016–4020.

30. Mansfield KL, Johnson N, Phipps LP, Stephenson JR, Fooks AR, Solomon T (2009) Tick-borne encephalitis virus – a review of an emerging zoonosis. J Gen Virol 90: 1781–1794.

31. Bellini WJ, Rota JS, Lowe LE, Katz RS, Dyken PR, et al. (2005) Subacute sclerosing panencephalitis: more cases of this fatal disease are prevented by measles immunization than was previously recognized. J Infect Dis 192: 1686–1693.

32. Levine B, Hardwick JM, Griffin DE (1994) Persistence of alphaviruses in vertebrate hosts. Trends Microbiol 2: 25–28.

Monday, March 14, 2011

Virology: Nature News Feature - XMRV could be an opportunistic infection affecting those whose immune systems are already dampened by CFS/ME

Researchers and public-health officials are scrambling to determine whether blood products could be spreading the virus XMRV (xenotropic murine leukaemia virus-related virus2), which has been linked to chronic fatigue syndrome (CFS) and prostate cancer.

Judy Mikovits, a viral immunologist at the Whittemore Peterson Institute for Neuro-Immune Disease (WPI) in Reno, Nevada, USA, says that she will not abandon the hypothesis that XMRV and related viruses cause CFS, despite a growing chorus of critics.

CFS, also known as myalgic encephalomyelitis (ME), affects an estimated 17 million people worldwide, but it is extremely difficult to diagnose. Many with the disorder are told that their symptoms — which include exhaustion, joint and muscle pain, cognitive issues, and heart and respiratory problems — are psychosomatic. "I had no idea there was that much bias against this disease," Mikovits says.

The stakes are high and many are taking the risks seriously. Several countries have barred people with chronic fatigue from donating blood in case the virus spreads. And the US government has launched a US$1.3-million study to investigate the link. Patients are already being tested for XMRV, and some are taking antiviral drugs on the assumption that the virus causes chronic fatigue by attacking their immune defences. Many say that such action is premature, but Mikovits is steadfast. "We're not changing our course," she says.

Full details below, in a copy of a news feature from Nature.com.

Note that even if a study confirms the link to chronic fatigue, it won't be able to determine whether the virus is the cause. XMRV could, for example, be an opportunistic infection affecting those whose immune systems are already dampened by chronic fatigue. Even Mikovits can only hypothesize as to how it might cause disease.

From Nature
Published online 14 March 2011
Virology: Fighting for a cause
By EWEN CALLAWAY (London)
Ref: Nature 471, 282-285 (2011) | doi:10.1038/471282a
When Judy Mikovits found links between chronic fatigue syndrome and a virus, the world took notice. Now, she's caught between the patients who believe her work and the researchers who don't.

On a sunny January afternoon in Santa Rosa, California, a small crowd waits patiently for Judy Mikovits to arrive. She is scheduled to deliver a talk on a mysterious virus called XMRV, which she believes underlies chronic fatigue syndrome. Although she's two hours late — held up by fog at San Francisco International Airport — not a single person has left. And when she arrives, they burst into applause.

To a rapt audience, she gives a chaotic and wide-ranging talk that explores viral sequences, cell-culture techniques and some of the criticisms that have been thrown at her since she published evidence1 of a link between XMRV and chronic fatigue in 2009. Afterwards, Mikovits is swarmed by attendees. A middle-aged woman who spent most of the talk in a motorized scooter stands up to snap pictures of her with a digital camera. Ann Cavanagh, who has chronic fatigue and has tested positive for XMRV, says that she came in part for information and in part to show her support for Mikovits. "I just wish there were a hundred of her," Cavanagh says.

The event was "surreal", says Mikovits, a viral immunologist at the Whittemore Peterson Institute for Neuro-Immune Disease (WPI) in Reno, Nevada. She is discomfited by the attention from patients, which at times borders on adulation. But her reception among scientists has been markedly cooler. Numerous follow-up studies have found no link between the virus and the disease; no group has published a replication of her findings; and some scientists argue that XMRV is an artefact of laboratory contamination. Now, even some of Mikovits's former collaborators are having second thoughts.

Mikovits has dug in, however, attacking her critics' methods and motives. She says that their distrust of her science stems from doubts about the legitimacy of chronic fatigue syndrome itself. Chronic fatigue, also known as myalgic encephalomyelitis, affects an estimated 17 million people worldwide, but it is extremely difficult to diagnose. Many with the disorder are told that their symptoms — which include exhaustion, joint and muscle pain, cognitive issues, and heart and respiratory problems — are psychosomatic. "I had no idea there was that much bias against this disease," Mikovits says.

The stakes are high and many are taking the risks seriously. Several countries have barred people with chronic fatigue from donating blood in case the virus spreads (see 'Something in the blood'). And the US government has launched a US$1.3-million study to investigate the link. Patients are already being tested for XMRV, and some are taking antiviral drugs on the assumption that the virus causes chronic fatigue by attacking their immune defences. Many say that such action is premature, but Mikovits is steadfast. "We're not changing our course," she says.

First findings

In October 2007, Mikovits attended a prostate-cancer meeting near Lake Tahoe, Nevada, where she met Robert Silverman, a virologist at the Cleveland Clinic in Ohio. Silverman co-discovered XMRV, which stands for xenotropic murine leukaemia virus-related virus2. While examining human prostate tumours, he and his collaborators found genetic sequences that resemble retroviruses found in the mouse genome. Like all retroviruses, XMRV rewrites its RNA genome into DNA on infection, then slips the DNA into the genomes of host cells. Ancient remnants of such viruses litter animal genomes. But the only active retroviruses conclusively linked to human disease are HTLV-1, which causes leukaemia, and HIV.

At the meeting, Silverman was presenting research linking XMRV to deficiencies in a virus-defence pathway. Mikovits recalled that the same pathway was weakened in some patients with chronic fatigue. She wondered whether the prostate-tumour virus could also be behind chronic fatigue. After the meeting, Silverman sent Mikovits reagents to test for XMRV.

The idea excited Mikovits, but she had other priorities. After stints in industry and at the US National Cancer Institute (NCI) in Maryland, she had recently joined the WPI to lead its research programme. The WPI was founded in 2006 by physician Daniel Peterson, an expert on chronic fatigue, and by Annette Whittemore, the wife of a well-connected Nevada businessman, whose daughter Andrea has had chronic fatigue for more than 20 years. The Whittemores spent $5 million establishing the WPI, and several million more to support Mikovits's research, which has attracted few other grants.

At the WPI, Mikovits established a sample collection from Peterson's patients and began screening it for signs of an infection. A litany of pathogens has been linked to chronic fatigue over the years, including Epstein-Barr virus, Borna disease virus, human herpes virus 6 and HTLV-2. None panned out. Still, the disorder bears some hallmarks of an infection. Many patients report acute illness before chronic symptoms appear, and their bodies often show signs of an immune system at war. The disease can also crop up in apparent outbreaks, including one characterized by Peterson near Lake Tahoe in the 1980s.

Just before Christmas 2008, Mikovits turned her attention to Silverman's reagents. She and her postdoc, Vincent Lombardi, known as Vinny, asked a graduate student to test for XMRV DNA in white blood cells from some of the most seriously ill people being studied at the WPI.

The first try turned up just two positives out of 20. But by tweaking the conditions of the test, Mikovits says her team found XMRV in all 20. "Vinny and I looked at each other and said, 'Well, that's interesting'," she says. They spent the next few weeks convincing themselves that they were onto something, and soon conscripted Silverman and Mikovits's former mentor at the NCI, Frank Ruscetti, to help prove that XMRV infection was behind chronic fatigue.

"We really retooled our entire programme and did nothing but focus on that," she says. They kept the effort under wraps, dubbing it 'Project X'. Even Peterson and the Whittemores weren't clued in. Mikovits says that the secrecy was necessary because her team also found XMRV in the blood of some healthy people, raising concerns about blood products. She hoped to build an airtight case because she worried that sceptical public-health officials would undermine her work.

In May 2009, the team submitted a paper to Science reporting the identification of XMRV genetic material in two-thirds of the 101 patients with chronic fatigue they had tested and in 3.7% of 218 healthy people. They also included data suggesting that infected white blood cells could pass the virus on to uninfected cells.

“They call me every single day. I spend so much time trying to understand the patients, to understand this disease.”
Reviewers wanted more evidence: a clear electron micrograph of virus-infected cells, proof that patients mounted an immune response to the virus, an evolutionary tree showing XMRV's relationship to other viruses and the locations where viral DNA was integrating into patient genomes. Mikovits's team went to work. "None of us took any time off, not even a weekend," she says. They resubmitted the paper in early July with everything the reviewers had asked for, except the DNA integration sites, which many scientists consider a gold standard in proving a retroviral infection.

Later that month, NCI officials who had learned about the work invited Mikovits to give a talk at a closed-door meeting with other XMRV researchers and government scientists. "When I finished speaking you could've heard a pin drop," she says. Mikovits says she thinks at least one of her manuscript's reviewers was at the meeting, because soon after, she got a call from a Science editor. Their paper had been accepted.

Jonathan Stoye, a retrovirologist at the MRC National Institute for Medical Research in London, wrote a commentary about the paper for Science3. He had never heard of Mikovits, but Frank Ruscetti's name on the paper gave him confidence, he says, and "if it were true, it was clearly very important". Stoye's co-author John Coffin, a retrovirologist at Tufts University in Boston, Massachusetts, says he was satisfied with the data and thought it was time to "let the field and public chew on them".

The BBC, US National Public Radio, The New York Times, The Wall Street Journal and dozens of other news outlets covered the research. "Prostate cancer pathogen may be behind the disease once dubbed 'yuppie flu'," Nature announced on its news website the day the paper came out. Phoenix Rising, a forum for patients with chronic fatigue that has become a hub for all things XMRV, called the work a "game changer", and patients flocked to learn more about a virus that they hoped would explain their condition. But others, including Britain's leading chronic fatigue patient group, urged caution until more research buttressed the link.

The first negative findings started to arrive in January 2010 — failing to find XMRV in 186 people with chronic fatigue from the United Kingdom4. A month later, a team including Stoye published a paper5 showing no evidence of XMRV in more than 500 blood samples from patients with chronic fatigue and healthy people. One day later, the British Medical Journal accepted a paper reporting more negative results in Dutch patients6. Studies began piling up so fast that Coffin made a scorecard to show at talks. "I've lost count now," he says.

Mikovits says that the discrepancies can be explained by differences in the geographical distribution of XMRV or in the methods used.

The most common way to detect XMRV is PCR, or polymerase chain reaction, which amplifies viral DNA sequences to a level at which they can be identified. Mikovits and her team used this method to detect XMRV in some of their patients, but she contends that the most sensitive way to detect the virus is to culture patients' blood cells with a cell line in which the virus replicates more quickly. This should create more copies of the virus, making it easier to detect with PCR and other techniques. She says that none of the negative studies applied this method exactly, a fact that annoys her. "Nobody's tried to rep-li-cate it," she says, sounding out each syllable for emphasis.

In summer 2010, some evidence emerged in Mikovits's corner. Harvey Alter, a hepatitis expert at the NIH's Clinical Center, and his team identified viruses similar to XMRV in 32 of 37 people with chronic fatigue and in 3 of 44 healthy people. They were preparing to publish their results in the Proceedings of the National Academy of Sciences. But scientists at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, were about to publish a negative report. The authors delayed publication of both papers7,8 for several weeks to assess discrepancies. The move agitated Mikovits as well as the chronic-fatigue community, who suspected that important data were being suppressed.

When Alter's work came out in late August7, Mikovits was ecstatic, and the WPI released a YouTube video of her touting it. For other researchers, however, the new paper had shortcomings. The viral sequences from Alter's paper differed from XMRV, says Greg Towers, a retrovirologist at University College London. "He doesn't get variation, he gets a totally different virus." Towers says that mouse DNA, which is chock-full of virus sequences like those Alter's team found, probably contaminated their samples, which were collected in the 1990s. But Alter says that his team found no contamination from mouse DNA and recovered the same viral sequences from the same patients sampled a decade later.

Contamination became a dirty word for Mikovits. Just before Christmas 2010, Retrovirology published four papers9,10,11,12 that highlighted laboratory contamination as a possible explanation for her findings. One showed, for example, that mouse DNA contaminates an enzyme from a commercial kit commonly used for PCR. Coffin, an author on two of the Retrovirology papers, urges caution against over-extrapolating. These papers do not say that contamination explains Mikovits's results, he says, just that extreme care is required to avoid it.

Towers and his colleague Paul Kellam, a virologist at the Wellcome Trust Sanger Institute near Cambridge, UK, are less charitable, however. Their study12 showed that the XMRV sequences that Mikovits and Silverman had extracted from patients lacked the diversity expected of a retrovirus that accumulates mutations as it passes between patients. "This doesn't look like an onwardly transmittable infectious virus," says Kellam. A press release for the paper issued by the Sanger Institute put it more bluntly: "Chronic fatigue syndrome is not caused by XMRV."

Mikovits is riled when the topic turns to Towers's paper over dinner one night in Reno — "Christmas garbage", she calls it. Contamination cannot explain why her team can reproduce its results both in her lab in Reno and at Ruscetti's at the NCI, she says. Her team checks for contamination in reagents and in the cells it grows the patients' samples with. She says that her team has also collected viral sequences that will address Towers's and Kellam's criticism but that it hasn't yet been able to publish them. Meanwhile, an unpublished study of patients in Britain with chronic fatigue bears out the link to XMRV, she says. "I haven't for one second seen a piece of data that convinced me they're not infected."

Jay Levy, a virologist at the Univer sity of California, San Francisco, has a window in his closet-sized office that looks out into the laboratory where, in the 1980s, he became one of the first scientists to isolate HIV. After his discovery was scooped by other researchers, Levy turned his attention to chronic fatigue and started a long but fruitless search for an infectious cause.

Now, Levy is putting the finishing touches on what could be the most thorough response yet to Mikovits's Science paper, adopting the same cell-culture techniques to detect the virus and using samples from the same patients. He's done this with the help of Daniel Peterson, who left the WPI in 2010 for what Peterson says are "personal reasons". Peterson has questioned the institute's singular pursuit of XMRV, a research direction that was pursued without his consultation.

Mikovits says that she kept the XMRV work secret from Peterson over fears he would tell his patients, and left his name off the original Science manuscript until a reviewer questioned the omission. When asked whether that episode contributed to his departure, he says, "I was surprised at the secrecy and lack of collaboration." As for his motivation to team up with Levy: "I'm just trying to get to the truth. It's my only motive, because this is such a deserving group of patients who need to know what's going on."

Others, too, are rallying for a definitive answer. Ian Lipkin, a microbial epidemiologist at Columbia University in New York, has a reputation for getting to the bottom of mysterious disease–pathogen links. His team debunked the association between Borna disease virus and chronic fatigue, for example. Now he is spearheading the $1.3-million effort funded by the US government. He is leaving the testing to three labs: Mikovits's at the WPI, Alter's at the NIH and the CDC. Each will receive coded samples of white blood cells and plasma from 150 patients with chronic fatigue and from 150 healthy controls. The labs will test for XMRV using their method of choice. Lipkin will crunch the data and unblind the samples.

But even if a study confirms the link to chronic fatigue, it won't be able to determine whether the virus is the cause. XMRV could, for example, be an opportunistic infection affecting those whose immune systems are already dampened by chronic fatigue. Even Mikovits can only hypothesize as to how it might cause disease.

The virus might not even exist as a natural infection. At a retrovirus conference this month in Boston, Massachusetts, Coffin and his colleague Vinay Pathak at the NCI in Frederick, Maryland, presented data showing that XMRV emerged in the 1990s, during the development of a prostate-tumour cell line called 22Rv1. Developing the line involved implanting a prostate-tumour sample into mice, retrieving cells that might divide indefinitely and repeating the process. But looking back at DNA samples taken throughout the cell-line's development showed that human cells became infected only after passing through several different mice. Importantly, XMRV's sequence seems to have come from two different mouse strains. "They just sort of snapped together like two puzzle pieces," says Coffin, an event extremely unlikely to have happened twice.

XMRV sequences retrieved from patients with prostate cancer and chronic fatigue — including some who have had chronic fatigue since the mid-1980s — are nearly identical to the virus from 22Rv1 cells. The implication, says Coffin, is that this virus, born in a laboratory, has probably been infecting samples for more than a decade, but not people. "Although people on the blogs aren't going to believe me, I'm afraid this is by far the most reasonable explanation for how XMRV came to be," says Coffin, who hoped that the association with chronic fatigue would pan out and still thinks some pathogen other than XMRV could explain the disease.

Silverman, who no longer works with Mikovits, says that he wasn't using 22Rv1 cells when XMRV was discovered. Nonetheless, the work has rattled his confidence in XMRV's link to both prostate cancer and chronic fatigue.

Mikovits, however, is undeterred. The WPI owns a company that charges patients up to $549 to be tested for XMRV, and Mikovits believes that patients who test positive should consult their doctors about getting antiretroviral drugs normally prescribed to those with HIV. Levy and others worry that she is overreaching. "That's scary for me. These antiretroviral drugs are not just like taking an aspirin," he says. Mikovits argues that they might be some patients' only hope. "The people who we know they're infected should have a right to get therapy," she says, "They have nothing. They have no other choice."

Context and debate

Back in her Reno laboratory two days after the talk in Santa Rosa, Mikovits examines a stack of small plastic flasks under a microscope. Some contain patient cells that she hopes will turn into cell lines and churn out XMRV. "On Wednesdays I get to take care of my cells, and that's where I'm the happiest," she says.

She has just come off the phone from a sobbing patient infected with XMRV whose symptoms had worsened. "They call me every single day," Mikovits says. "I don't do science any more. I spend so much time trying to understand the patients, to understand this disease. People have moved to Reno to be here," she says. They've left gifts: stuffed animals, and stacks of bumper stickers that say "Today's Discoveries, Tomorrow's Cures" and, more boldly, "It's the virus XMRV".

Mikovits clearly shares in the frustration of those with chronic fatigue who have been marginalized over the years and told that their disease is not real. She says that this disbelief in the disorder drives the criticism of her work. Kellam and the others say that this isn't true. They don't deny the existence of the syndrome or even the possibility of an infectious origin. "What we're trying to understand is the aetiology," Kellam says. "It's a scientific debate."

Mikovits says that she's analysed all the papers critical of her work and found flaws in each of them. Nevertheless, she's quick to endorse findings that support her work. She claims that Coffin and Pathak's study, for example, "says nothing about human infection". Yet new work presented at a different meeting that found XMRV using next-generation DNA sequencing offers "no doubt it's not contamination — that the whole story's real", she says.

Despite the growing choir of sceptics, Mikovits says that she has simply seen too many data implicating XMRV and other related viruses in chronic fatigue to change her mind. For her supporters, that steadfastness offers legitimacy and hope. "The scientists are moving forward," she announced at her talk in Santa Rosa, "and I think the politics will go away shortly." The crowd responded with vigorous applause.

Ewen Callaway writes for Nature from London.

References
Lombardi, V. C. et al. Science 326, 585-589 (2009).
Urisman, A. et al. PLoS Pathog. 2, e25 (2006).
Coffin, J. M. & Stoye, J. P. Science 326, 530-531 (2009).
Erlwein, O. et al. PLoS ONE 5, e8519 (2010).
Groom, H. C. et al. Retrovirology 7, 10 (2010).
Van Kuppeveld, F. J. et al. Br. Med. J. 340, c1018 (2010).
Lo, S. C. et al. Proc. Natl Acad. Sci. USA 107, 15874-15879 (2010).
Switzer, W. M. et al. Retrovirology 7, 57 (2010).
Robinson, M. J. et al. Retrovirology 7, 108 (2010).
Oakes, B. et al. Retrovirology 7, 109 (2010).
Sato, E. , Furuta, R. A. & Miyazawa, T. Retrovirology 7, 110 (2010).
Hué, S. et al. Retrovirology 7, 111 (2010).
[Ends]

Ewen Callaway, London
Ewen Callaway joined Nature in August 2010, after 2 years at New Scientist as Boston-based biomedical reporter. He attended the science writing program at the University of California, Santa Cruz and earned a masters degree in microbiology at the University of Washington. He spends his free time learning to bicycle on the left side of the road.
- - -

'Something in the blood'
From the article:
Virology: Fighting for a cause*

Researchers and public-health officials are scrambling to determine whether blood products could be spreading the virus XMRV, which has been linked to chronic fatigue syndrome (CFS) and prostate cancer.

2009

October
Judy Mikovits publishes a paper showing XMRV in two-thirds of patients with CFS and in 4% of healthy individuals1.

December The US Department of Health and Human Services establishes a working group and the AABB (formerly the American Association of Blood Banks) organizes a task force to assess the prevalence of XMRV in blood products and the risk of its transmission.

2010

April Australia, Canada and New Zealand ban people with a history of CFS from donating blood.

June The task force recommends that patients with CFS be discouraged from donating blood in the United States.

November Britain bans patients with CFS from donating blood, officially to protect them from a decline in health.

December The working group reports discordant results of a pilot study on XMRV blood contamination, but recommends banning patients with CFS from donating blood.

The American Red Cross bans blood donations from people with a history of CFS.

2011

March
At a retrovirology meeting in Boston, Massachusetts, researchers present data suggesting that XMRV is a laboratory artefact and not a human pathogen.

*Download a PDF of the article
Virology: Fighting for a cause*

Labels: , , ,

Tuesday, January 04, 2011

Chronic Neuroimmune Diseases - CFS: A polio by another name

From The New York Times
January 3, 2011
Exhausted by Illness, and Doubts
By DAVID TULLER
Chronic fatigue syndrome causes a host of debilitating symptoms: profound exhaustion, disordered sleep, muscle and joint pain and severe cognitive problems, among others. But what causes the syndrome itself?

Since the first cases in the United States were identified in the 1980s, scientists have been divided over that question. Some have suspected that one or more viral infections are likely to play a central role.

But many other researchers — not to mention relatives, friends, employers, doctors and insurers of the million or more Americans estimated to suffer from the illness — have dismissed it as stress-related, psychosomatic or simply imaginary.

Now recent back-to-back announcements have highlighted both the volatility of the issue and the ambiguity of the science, and have alternately heartened and dismayed patients.

On Dec. 14, an advisory panel suggested that the Food and Drug Administration ban blood donations by people with a history of C.F.S., as the illness is often called. The goal was to prevent the possible spread of viruses that two high-profile studies had linked to the condition.

But then, on Dec. 20, the journal Retrovirology published four papers suggesting that key findings in those studies could have resulted from laboratory contamination.

The F.D.A. is not required to accept the opinion of its advisory panel. Yet patients still hailed the recommendation as a sign that their illness was being taken seriously.

“When an F.D.A. panel suggests that patients with C.F.S. not donate blood, that’s going to impact the way doctors think about it,” said Mary Schweitzer, a former history professor at Villanova, who has frequently written about living with the illness. Dr. Schweitzer said she has been unable to work for 16 years because of the syndrome, which was diagnosed after she suffered from a series of flulike illnesses.

The studies that concerned the F.D.A. had reported that people with the syndrome, which is also called myalgic encephalomyelitis or myalgic encephalopathy in Europe, showed higher rates of infection with the virus XMRV or others from the same category, known as MLV-related viruses. (These viruses are all relatives of mouse leukemia viruses, some of which can infect species other than mice; their role in human disease, if any, remains poorly understood.)

But several other research teams in the last year have found no connection between chronic fatigue syndrome and these viruses, although none tried to replicate the exact methods used by researchers who reported an association.

The new papers in Retrovirology reported that contamination of tissue samples or other laboratory items with mouse DNA or viral genetic material could lead to false positive results for XMRV, and by extension other MLV-related viruses, specifically when using polymerase chain reaction technology. The technique rapidly produces millions of copies of genetic segments, so even minute traces of genetic contamination can skew results.

“Our conclusion is quite simple: XMRV is not the cause of chronic fatigue syndrome,” said the senior author of one of the studies, Greg Towers, a professor of virology at University College London, in a statement released by Wellcome Trust Sanger Institute, the British research center that co-sponsored it.

Other scientists and advocates for patients have sharply criticized such certainty as unwarranted, noting that the Retrovirology papers themselves expressed their findings in more cautious terms. The critics agree that contamination can be a serious issue when using polymerase chain reaction technology. But the new papers, said Eric Gordon, a doctor in Santa Rosa, Calif., who treats many patients with the illness, do not evaluate other strategies besides P.C.R., as the technique is known, for detecting the MLV-related viruses, like testing for an immune response and culturing the viruses in cell lines.

“The articles make the point that P.C.R. doesn’t work that well for these viruses, and then they act like that disproves the whole idea,” said Dr. Gordon.

XMRV was first identified in 2006 and has been detected in prostate cancer patients in some studies. It was linked to chronic fatigue syndrome in October 2009 in a paper in the journal Science by researchers from the Whittemore Peterson Institute for Neuro-Immune Disease at the University of Nevada, Reno, the National Cancer Institute and the Cleveland Clinic.

The researchers relied on P.C.R. technology to show that about two-thirds of patients but less than 4 percent of control subjects harbored XMRV. Using other technologies, however, they also documented an antibody response in some chronic fatigue syndrome patients, and reported that XMRV in human blood could infect other human cell lines.

In a statement responding to the new papers in Retrovirology, Judy A. Mikovits, director of research at Whittemore Peterson and the senior author of the Science study, said her team took extensive steps to rule out P.C.R. contamination and also focused on other approaches to finding XMRV. “Nothing that has been published to date refutes our data,” she said.

Even some specialists stumbled over the meaning of the new findings. Vincent Racaniello, a professor of microbiology at Columbia not involved in the research, apologized on his Virology Blog for having stated that it was likely to spell “the beginning of the end” for the proposed connection between the viruses and chronic fatigue syndrome.

After reviewing the issue more thoroughly, he wrote, he realized that the new studies “show that identification of XMRV can be fraught with contamination problems, but they do not imply that previously published studies are compromised.” He added, “If I had difficulties interpreting these papers, how would nonscientists fare?”

Federal agencies have come down on different sides of the issue. In a paper published in The Proceedings of the National Academy of Sciences in August, researchers from the National Institutes of Health and the F.D.A. found a link between the fatigue syndrome and MLV-related viruses (although not specifically XMRV). In contrast, a study from the Centers for Disease Control and Prevention was among those not reporting a link.

Federal health officials have organized two research efforts to resolve the inconsistencies, determine whether XMRV and MLV-related viruses are possible human pathogens, and identify reliable ways to detect them. Patients hope the increased attention will quickly lead to research on treatments, including clinical trials of H.I.V. drugs, some of which have been shown in lab studies to inhibit the replication of XMRV.

The unsettled situation has created a quandary for patients with chronic fatigue syndrome and the doctors who treat them. Some patients are seeking to be treated with H.I.V. drugs, which doctors can legally prescribe even though the F.D.A. has not approved them for that purpose.

Many doctors and researchers say it is too early to prescribe the drugs for chronic fatigue because of possible side effects, like bone marrow suppression, gastrointestinal problems and liver or kidney dysfunction, among others. But Michael Allen, a writer and a former psychologist in San Francisco who has been disabled for more than 15 years, said he wouldn’t hesitate to try the medications if he found out he was positive for an MLV-related virus.

“It feels patronizing when the medical establishment says the side effects are too risky and we should keep waiting,” he said. “What that says to me is they have no idea whatsoever how sick people like me have been with this disease.”
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NOTES TO SELF

Enterovirus: Coxsackie B virus
Symptoms of infection with viruses in the Coxsackie B grouping include fever, headache, sore throat, gastrointestinal distress, as well as chest and muscle pain. [...] As of 2008, there is no well-accepted treatment for the Coxsackie B group of viruses.

Coxsackie B viruses can cause mild signs and symptoms, similar to a "cold", but these viruses also can lead to more serious diseases, including myocarditis (inflammation of the heart); pericarditis (inflammation of the sac lining the heart); meningitis (inflammation of the membranes that line the brain and spinal cord); and pancreatitis (inflammation of the pancreas).
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Coxsackie_B_virus
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Poliomyelitis
The term poliomyelitis is used to identify the disease caused by any of the three serotypes of poliovirus. Two basic patterns of polio infection are described: a minor illness which does not involve the central nervous system (CNS), sometimes called abortive poliomyelitis, and a major illness involving the CNS, which may be paralytic or non-paralytic.[9] In most people with a normal immune system, a poliovirus infection is asymptomatic. Rarely the infection produces minor symptoms; these may include upper respiratory tract infection (sore throat and fever), gastrointestinal disturbances (nausea, vomiting, abdominal pain, constipation or, rarely, diarrhea), and influenza-like illness.[4]
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Poliomyelitis
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Cortisol
Cortisol can weaken the activity of the immune system. Cortisol prevents proliferation of T-cells by rendering the interleukin-2 producer T-cells unresponsive to interleukin-1 (IL-1), and unable to produce the T-cell growth factor.[32] Cortisol also has a negative feedback effect on interleukin-1.[33] IL-1 must be especially useful in combating some diseases; however, endotoxin bacteria have gained an advantage by forcing the hypothalamus to increase cortisol levels via forcing secretion of CRH hormone, thus antagonizing IL-1 in this case.
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Cortisol
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Chronic Neuroimmune Diseases
Information on CFS, FM, MCS, Lyme Disease, Thyroid, and more...
Last updated December 18, 2009
Chronic Fatigue Syndrome
A polio by another name
Read more at:
http://www.anapsid.org/cnd/diffdx/polio1.html
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Ampligen
Ampligen was first synthesized in the 1970s and has been proposed and tested as a treatment for illnesses including chronic fatigue syndrome (CFS) and acquired immunodeficiency syndrome (AIDS).
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Ampligen
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Co-codamol
Co-codamol (BAN) is a non-proprietary name used to denote a compound analgesic, a combination of codeine phosphate and paracetamol (acetaminophen). Co-codamol tablets are used for the relief of mild to severe pain.
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Co-codamol
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Nabilone
Nabilone is a synthetic cannabinoid with therapeutic use as an antiemetic and as an adjunct analgesic for neuropathic pain. It is a synthetic cannabinoid, which mimics the main ingredient of cannabis (THC). Chemically, nabilone is similar to the active ingredient found in naturally occurring Cannabis sativa L. [1]
In Canada, the United States, the United Kingdom and Mexico, nabilone is marketed as Cesamet. It was approved in 1985 by the U.S. Food and Drug Administration (FDA) for treatment of chemotherapy-induced nausea and vomiting that has not responded to conventional antiemetics. Though it was approved by the FDA in 1985, the drug only began marketing in the United States in 2006. It is also approved for use in treatment of anorexia and weight loss in patients with AIDS.
Although it doesn't have the official indication (except in Mexico), nabilone is widely used as an adjunct therapy for chronic pain management. Numerous trials and case studies have demonstrated various benefits for condition such as fibromyalgia[2] and multiple sclerosis.[3]
Read more at Wikipedia:
http://en.wikipedia.org/wiki/Nabilone
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