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Detection of an infectious retrovirus, XMRV, in blood cells of patients with chronic fatigue syndrome


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In October 2009, we reported the first direct isolation of infectious xenotropic murine leukemia virus-related virus (XMRV). In that study, we used a combination of biological amplification and molecular enhancement techniques to detect XMRV in more than 75% of 101 patients with chronic fatigue syndrome (CFS). Since our report, controversy arose after the publication of several studies that failed to detect XMRV infection in their CFS patient populations. In this addenda, we further detail the multiple detection methods we used in order to observe XMRV infection in our CFS cohort. Our results indicate that PCR from DNA of unstimulated peripheral blood mononuclear cells is the least sensitive method for detection of XMRV in subjects' blood. We advocate the use of more than one type of assay in order to determine the frequency of XMRV infection in patient cohorts in future studies of the relevance of XMRV to human disease.
Content may be subject to copyright.
Virulence 1:5, 386-390; September/October 2010; © 2010 Landes Bioscience
386 Virulence Volume 1 Issue 5
Key words: biological amplification,
molecular amplification, XMRV, myalgic
encephalomyelitis/chronic fatigue
Submitted: 02/26/10
Revised: 05/20/10
Accepted: 05/24/10
Previously published online:
*Correspondence to: Judy A. Mikovits;
In October 2009, we reported the first
direct isolation of infectious xenotro-
pic murine leukemia virus-related virus
(XMRV). In that study, we used a com-
bination of biological amplification and
molecular enhancement techniques to
detect XMRV in more than 75% of 101
patients with chronic fatigue syndrome
(CFS). Since our report, controversy
arose after the publication of several
studies that failed to detect XMRV infec-
tion in their CFS patient populations. In
this addenda, we further detail the mul-
tiple detection methods we used in order
to observe XMRV infection in our CFS
cohort. Our results indicate that PCR
from DNA of unstimulated peripheral
blood mononuclear cells is the least sen-
sitive method for detection of XMRV in
subjects’ blood. We advocate the use of
more than one type of assay in order to
determine the frequency of XMRV infec-
tion in patient cohorts in future studies
of the relevance of XMRV to human
Patient selection poses a challenge to
any study of myalgic encephalomyelitis/
chronic fatigue syndrome (ME/CFS). In
our October 2009 paper, samples banked
from 2006 to 2008 were selected for our
study from severely disabled patients who
fulfilled the 1994 CDC Fukuda Criteria
for chronic fatigue syndrome1 as well as
the 2003 Canadian Consensus Criteria
(CCC) for ME/CFS.2 The CCC requires
Detection of an infectious retrovirus, XMRV, in blood cells of patients
with chronic fatigue syndrome
Judy A. Mikovits,1,* Vincent C. Lombardi,1 Max A. Pfost,1 Kathryn S. Hagen1 and Francis W. Ruscetti2
1Whittemore Peterson Institute; Reno, NV USA; 2Laboratory of Experimental Immunology; Cancer and Inflammation Program;
National Cancer Institute-Frederick; Frederick, MD USA
post-exertional malaise, which many cli-
nicians feel is the sine qua non of ME/
CFS. Furthermore the CCC further
requires that patients exhibit post exer-
tional fatigue, unrefreshing sleep, pain
and neurological/cognitive manifesta-
tions, rather than these being optional
symptoms.3 Many clinicians interested in
CFS are switching to the Canadian crite-
ria because they feel it is more descriptive
of the clinical entity being defined. The
Fukuda criteria have the advantage of a
longer period of usage and existence of
many publications that have added modi-
fications. Suffice it to say that the clinician
author of the Science paper elected to use
both criteria, thus bypassing the argument
of which criteria were better. Moreover,
the emphasis in the Science paper was
directed toward the virology, not the clini-
cal description of ME/CFS.
In our October 2009 publication, we
established XMRV infection in the blood
products of our patient population by five
different methods. Of these methods,
single-round PCR on DNA from periph-
eral blood mononuclear cells (PBMCs),
the least sensitive method, required us to
use samples from a subset of chronically ill
patients we had observed to have persis-
tent viremia. In Figure 1A of our Science
paper, we showed that DNA of 7 of 11
patients exhibited the expected gag and
env PCR amplification products from sin-
gle-round PCR with XMRV primers. We
included this figure to demonstrate that
Addendum to: Lombardi VC, Ruscetti FW, Das
Gupta J, Pfost MA, Hagen KS, Peterson DL, et al.
Detection of an infectious retrovirus, XMRV, in
blood cells of patients with chronic fatigue syn-
drome. Science 2009; 326:585–9; PMID: 19815723;
DOI: 10.1126/science.1179052. Virulence 387
samples exhibited gag products upon
nested PCR, though PCR with nested env
primers did not result in detectable prod-
ucts from these samples (Table 1).
Samples that are negative for XMRV
by one of our PCR assays are sometimes
positive by other assays. For example, in
Figure 1A of the Science paper, patient
1118 was negative by single round PCR
on DNA from unstimulated PBMCs, but
positive in other assays (Science Figs. 2A
and D, 4A and S5). Of the 34 patients
whose PBMCs were negative for XMRV
by DNA or cDNA PCR, 17 were posi-
tive for infectious virus when co-cultured
with the LNCaP indicator cell line, as
XMRV gag and env PCR products were
detected in the cell line following their
infection with XMRV from the patient
PBMCs (Tab le 2 ). Both gag and env prod-
ucts obtained from either single-round or
nested PCR were sequenced and shown to
be 99% identical to XMRV VP62.
Subsequent to our October 2009
publication, two papers from the United
Kingdom4,5 and a paper from the
Netherlands6 have appeared in which
the authors report the lack of detection
of XMRV PCR products from DNA of
unstimulated PBMCs, using patient pop-
ulations selected by only the Fukuda crite-
ria or the Oxford criteria rather than both
Fukuda and CCC criteria. We regret that
these authors did not request positive con-
trol samples of our patients who exhibit
XMRV PCR products even when assayed
by the least sensitive detection method,
namely PCR of DNA from unstimulated
PBMCs. Given that only 7% of our 101
patients’ PBMCs exhibit products upon
DNA PCR (Table 3 and 4), and that a
number of patients were included in the
UK studies who do not fulfill the CCC
criteria, very few, if any, of the samples
would be expected to be positive by DNA
PCR. We also note that both studies fol-
lowed different methods than ours for
blood collection, DNA quantities and
isolation and PCR, possible sources of
the disparate results. The XMRV detec-
tion results of the 101 patients are listed
in Table 4.
The negative reports of PCR tests for
XMRV has raised questions whether our
findings could be due to contamination of
our PCR experiments by mouse genomic
XMRV-gag specific PCR products and no
env specific PCR products following single
round DNA PCR of DNA of unstimu-
lated PBMCs. In contrast, when cDNA
was prepared from PBMCs, 67% of the
nested PCR, which inevitably raises ques-
tions of contamination, is not essential
to detect XMRV in highly viremic ME/
CFS patients. The remaining 90 samples
described in the paper exhibited very few
Tab le 1. XMRV detection using cDNA from 22 unstimulated PBMCs
gag gene env gene
Sample 1st 2nd Sample 1st 2nd
1 - - Normal 1 - - Normal
2 - + 1104 2 - - 110 4
3 + + 1110 3 - - 1110
4 - - 1113 4 - - 1113
5 - - 1114 5 - - 1114
6 - + 1115 6 - + 1115
7 - - 1117 7 - - 1117
8 - + 1125 8 - - 112 5
9 - + 1130 9 - - 113 0
10 + + 1135 10 - - 1135
11 - - 11 42 11 - - 1142
12 + + 1150 12 - - 115 0
13 - - 1155 13 - - 115 5
14 - + 1161 14 - - 1161
15 - + 1165 15 - - 116 5
16 - + 1166 16 - - 116 6
17 + + 1168 17 - - 116 8
18 - + 1169 18 - - 116 9
19 - + 1177 19 - - 117 7
20 - + 1178 20 - - 1178
21 - - 1182 21 - - 118 2
22 - - 1199 22 - - 119 9
Tab le 2 . Co-culture with LNCaP of PBMCs from 12 patients PCR negative for env
gag gene env gene
Sample 1st 2nd Sample 1st 2nd Typ e
1 - - Normal 1 - - Normal cDNA
2 - + 116 9 2 + + 1169 cDNA
3 + + 1221 3 + + 1221 cDNA
4 - + 1150 4 + + 1150 cDNA
5 - + 119 9 5 - + 119 9 cDNA
6 + + 1220 6 + + 1220 cDNA
7 - - LNCaP 7 - - LNCaP cDNA
8 - + 118 6 8 - + 118 6 cDNA
9 - + 1132 9 - + 1132 DNA
10 - + 1111 10 - - 1111 DNA
11 - + 1189 11 + + 118 9 DNA
12 - + 1172 12 + + 117 2 DNA
13 - + 1173 13 - + 117 3 DNA
14 - + 1103 14 + + 1103 DNA
388 Virulence Volume 1 Issue 5
Tab le 4. XMRV detec tion results of 101 patients
Patient ID cDNA nested PCR DNA nested PCR LNCaP co-culture with
Antibody in
LNCaP culture with
110 3 + + + + +
110 4 + + + + +
110 5 + - + + +
110 6 + + + + +
1107 + - - NT*NT
110 8 + - - - -
110 9 + - NT NT NT
1110 + - + + +
1111 + + + - +
1112 + - NT NT NT
1113 + - + NT NT
1114 + - NT NT +
1115 + - + + +
1116 - - NT NT +
1117 - - NT NT NT
1118 + - + + +
1119 + - NT NT NT
1120 - - NT NT NT
1121 + - NT NT NT
1124 + - - - -
1125 + - + + +
1126 + - NT NT NT
1127 + - NT NT NT
1128 + - NT NT NT
1129 + - NT -NT
1130 + - NT NT NT
1131 + - NT NT NT
1132 + + + NT NT
1133 + + NT NT NT
113 4 - - NT NT NT
1135 + + NT NT NT
1136 + + - + +
1137 + + - + +
1265 + - + + +
1138 + - NT NT NT
1335 + - NT + +
1139 - - - - -
*NT, not tested. Note not all assays were run on all samples and/or patients.
Tab le 3. Summary of multiple viral assays from a group of 57 patients
Unstimulated PBMC Stimulated PBMC Co-Cultured LNCaP Serology Unstimulated PBMC
Nested gag Nested gag Nested gag Env antibody Single round gag
31/57 44/205*41/57 -51/57 -47/57 4/57
54% 21% 72% -89% -82% 7%
*multiple DNA samples taken from some of the 57 patients on different dates. Virulence 389
Tab le 4. XMRV detec tion results of 101 patients
114 0 + - NT - +
1141 + - + + +
1142 - - NT NT +
120 6 + - NT - +
114 4 + - NT NT NT
1145 - - NT NT NT
114 8 - - NT NT NT
1149 + - NT NT NT
1150 + + + + +
1151 + - NT NT NT
123 0 + - + NT NT
1237 + - + NT NT
115 4 - - NT NT NT
1155 - - NT NT NT
1156 - - NT NT +
1157 + + NT NT NT
1158 + - - + +
1159 + - NT NT NT
1231 + - + NT NT
1161 + - - + +
1220 + - + NT NT
1221 + - + NT +
116 4 - - NT NT NT
116 5 + - + + +
116 6 + - - + +
1167 - - NT NT NT
116 8 + - NT NT NT
116 9 + - + + +
1170 - - NT NT NT
1235 - - + NT NT
1281 + - + + +
1172 + + + + +
1282 + - - - +
1173 + + + + +
1174 + - NT NT NT
1175 - - NT NT NT
1176 - - NT NT NT
1177 + - + + +
1178 + - + + +
1179 + - NT - +
118 0 - - NT + +
1181 + - NT NT NT
118 2 - - NT + +
118 3 + - - - +
123 6 + - + NT NT
1224 + - NT NT +
118 6 + + + + +
*NT, not tested. Note not all assays were run on all samples and/or patients.
390 Virulence Volume 1 Issue 5
unless PCR primers are designed with this
possibility in mind.
We have not claimed in our October
2009 publication or in other venues that
XMRV is the cause of CFS, only that its
detection in the majority of our ME/CFS
patient cohort allows us to form a testable
hypothesis as to an infectious basis for this
devastating disease. Future work should
establish what role XMRV may play in
development of prostate cancer, ME/CFS
and other diseases.
1. Fukuda K , Straus S, Hickie I, Sharpe MC, Dobbins
JG, Komaroff A. The chronic fatigue syndrome: A
comprehensive approach to its definition and study.
Ann Intern Med 1994; 121:953-9.
2. Carrut hers B, Jain A, DeMeirlier K, Peterson DL ,
Klimas NG, Lerner AM, et a l. Myalgic encephalo-
myelitis/chronic fatigue syndrome: Clinical work ing
case definition. diagnostic and t reatment protocols. J
Chronic Fatigue Syndrome 2003; 11:1-12.
3. Jason L, Torres-Harding S, Jurgens A, Helgerson
J. Comparing the Fukuda et al. criteria and the
Canadian def inition for chronic fatigue sy ndrome. J
Chronic Fatigue S 2004; 12:37-52.
4. Erlwein O, Kaye S, McClure MO, Weber J, Wills G,
Collier D, et al. Failure to detect the novel retrovirus
XMRV in chronic fatigue syndrome. PLoS One
5: 8519.
5. Groom HC, Boucherit VC, Makinson K, Randal
E, Baptista S, Hagan S, et al. Absence of xenotropic
murine leu kaemia virus-related virus in UK patients
with chronic fatigue syndrome. Retrov irology 7.
6. van Kuppeveld FJ, de Jong AS, La nke KH, Verhaegh
GW, Melchers WJ, Swanink CM ,et al. Prevalence of
xenotropic murine leukaemia virus-related virus in
patients with chronic fatigue syndrome in t he
Netherlands: retrospective ana lysis of samples from
an established cohort. BMJ 340:1018.
7. Ratner L, Philpott T, Towbridge DB. Nucleotide
sequence a nalysis of isolates of Human
T-lymphotropic virus type 1 of diverse georgraphical
regions. AIDS Rs Hum Retroviruses 1991; 7:923-41.
8. Verdonck K, Gonzalez E, Van Dooren S, Vandamme
AM, Vanh am G, Gotuzz o E. Human T-lymphotro pic
viru s 1: Recent knowled ge about an ancient i nfection.
Lancet Infect Dis 2007; 7:266-81.
9. Yan Y, Liu Q, Kozak C A. Six host range variants of
the xenotropic/polytropic gammaretroviruses def ine
determinants for entry in the XPR1 cell surface
receptor. Retrovirology 2009; 6: 87.
In our experience from performing the
multiple methods on the same 57 blood
samples, the most sensitive blood-based
assays for detection of XMRV in decreas-
ing order (Tabl e 3) are: (1) perform-
ing nested PCR for gag sequences from
LNCaP cells that have been co-cultured
with subject’s plasma or activated PBMCs,
(2) the presence of antibodies to XMRV
Env in subject’s plasma, (3) presence of
gag products by nested PCR on stimu-
lated PBMCs or detection of viral pro-
teins expressed by activated PBMCs with
appropriate antisera, (4) nested RT-PCR
of plasma nucleic acid or PCR from cDNA
from unactivated PBMCs and (5) PCR of
DNA from unactivated PBMC prepared
from subject’s blood.
Despite association with both prostate
cancer and CFS, many questions remain
regarding the prevalence of XMRV in
the human population, the incidence
of XMRV in disease, and the extent of
genetic variation between XMRV isolates.
The genetic variation between XMRV
isolates currently identified is only 0.03%,
despite the fact that the viral sequences
were obtained from isolates from two
vastly different diseases in patients from
geographically distinct areas. This varia-
tion is smaller than the variation observed
between HTLV-1 isolates.7 As in the case
with HTLV, the lack of diversity implies
that XMRV recently descended from a
common ancestor.8 The high degree of
similarity to xenotropic murine leukemia
virus suggests that a cross-species trans-
mission event was likely involved in the
evolution of XMRV.9 Further examina-
tion of XMRV from human subjects may
reveal more extensive sequence variation,
which also may confound its detection
DNA, which contain gag and env sequences
highly similar to XMRV. Positive PCR
results for XMRV were obtained inde-
pendently in multiple laboratories led by
co-authors of the Science paper. In the sum-
mer of 2006, prior to work on XMRV at
the Reno Whittemore-Peterson Institute
(WPI), 30 mL of heparinized peripheral
blood were obtained from patients resid-
ing in the US, Canada and Europe com-
ing to be treated at the well-known Sierra
Internal Medicine practice, located in
Incline Village, NV. Once collected, 48 of
these blood samples were shipped directly
to NCI where cDNA was prepared for
planned microarray experiments. After the
WPI observed an XMRV PCR product
from a patient sample in 2009, the NCI
began testing these stored samples by PCR.
cDNA from 42 of the 48 samples sent to
the NCI lab in February 2007 tested posi-
tive for XMRV gag by nested PCR. Neither
the WPI nor NCI labs where PCR was per-
formed had ever worked with mouse tissues
or had been exposed to XMRV from other
sources. The env sequences amplified from
LNCaP cells infected by patient PBMCs
exhibit less similarity to mouse genomic
DNA than to XMRV VP62, further indi-
cating the presence of XMRV infection
rather than mouse genomic DNA contami-
nation. After we developed a sensitive cell
culture assay for detection of XMRV, we
assayed our cell lines and patient material
with a highly sensitive assay (developed and
kindly provided by Bill Switzer, CDC) to
detect the presence of mouse tissue con-
tamination by the identification of murine
mitochrondial cytochrome oxidase by real
time PCR. All of the cell lines and 101
patient materials tested negative for mouse
Tab le 4. XMRV detec tion results of 101 patients
1187 - - NT + +
118 8 + - + + +
118 9 + + + + +
119 0 + - + + +
1191 + - + + +
1192 + + NT + +
1193 + + NT + +
119 4 + - NT - +
123 8 + - + + +
*NT, not tested. Note not all assays were run on all samples and/or patients.
... Viral etiologies have been speculated to be involved in various complex human diseases [1][2][3][4][5][6][7][8][9]. Many viruses are able to insert their genetic materials into host chromosomes [10][11][12][13], and the resulting viral integrations, i.e., human-virus-human sequences, may play roles in the pathogenesis and development of some diseases via different mechanisms, such as expressing viral proteins, dysregulating host gene functions, and influencing genomic instability. ...
Viral sequence integrations in the human genome have been implicated in various human diseases. Viral integrations remain among the most challenging-to-detect structural changes of the human genome. No studies have systematically analyzed how molecular and bioinformatics factors affect the power (sensitivity) to detect viral integrations using high-throughput sequencing (HTS). We selected a wide-range of molecular and bioinformatics factors covering genome sequence characteristics, HTS features, and viral integration detection. We designed a fast simulation-based framework to model the process of detecting variable viral integration events in the human genome. We then examined the associations of selected factors with viral integration detection power. We identified six factors that significantly affected viral integration detection power (P < 2 × 10⁻¹⁶). The strongest factors associated with detection power included proportion of sample cells with clonal viral integrations (Pearson's ρ = 0.64), sequencing depth (ρ = 0.37), length of viral integration (ρ = 0.37), paired-end read insert size (ρ = 0.23), user-defined threshold (number of supporting reads) to claim successful identification of integrations (ρ = −0.19), and read length (when sequence volume was fixed) (ρ = −0.09). As the first tool of its kind, VIpower incorporates all these factors, which can be manipulated in concert with each other to optimize the detection power. This tool may be used to estimate viral integration detection power for various combinations of sequencing or analytic parameters. It may also be used to estimate the parameters required to achieve a specific power when designing new sequencing experiments.
... However, XMRV related xenotropic-MLV (X-MLV) is known to infect other species including cats, mice, and non- human primates causing leukemias, lymphomas, neurological diseases and immunodeficiencies in these species suggesting a plausible role for XMRV in PCa (Rezaei et al., 2013; Schlaberg et al., 2009). The detection of XMRV in human bio specimens is controversial being associated with two major human diseases, PCa (Qiu et al., 2010; Urisman et al., 2006) and chronic fatigue syndrome (Lombardi et al., 2009; Mikovits et al., 2010). Several previous studies had revealed the infection of XMRV in PCa. ...
Presently, the known gamma-retroviruses, Xenotropic Murine Leukemia virus (MLV) -related Virus (XMRV) is imminent as a cancer causing infectious virus in prostate cancer. This study has been designed on retrovirus (XMRV) infection in Indian PCa patient and its co-relation with clinical pathological and demographic parameters of prostate cancer cases and Benign Prostate hyperplasia (BPH) as controls. A total of 235 prostate samples including 105 confirmed prostate cancer cases and 130 benign prostate hyperplasia (BPH) as controls were analyzed for XMRV infection. We have used Nested –PCR method for XMRV detection followed by sequencing. Statistical analysis was done by Graphpad Instat version 3.3 for co-relation between XMRV status and clinical pathological parameters of prostate cancer cases and BPH controls. Out of 235 prostate samples, XMRV was detected 5.4% (7/130) in BPH tissue samples and 7.6% (8/105) in PCa tissue samples. Patients with higher PSA level were found to prone for XMRV infection in both PCa as well as BPH samples with non significant statistical correlation (p˃0.05). We found no significant correlation with other clinical parameter like Gleason score (p=0.72), histological grading (p=0.82) and tumor stages I-IV (p=0.31). This study does not support the evidence of XMRV infection in prostate cancer initiation and development in Indian population. Clearly, decision of this discrepancy will require more information and investigation with larger sample size.
... In 2009, Lombardi et al. published a report of XMRV DNA detection in 68 (67%) of 101 patients with CFS but in only 8 (3.7%) of 218 of healthy controls (18). They reported the ability to detect the virus in unstimulated peripheral blood mononuclear cells (18)(19)(20) and demonstrated the virus's ability to infect human lymphocytes in vitro (18,21). Electron microscopy demonstrated actual viral particles budding from infected cells in culture. ...
In 2006, a new virus, xenotropic murine leukemia virus-related virus (XMRV), was discovered in a cohort of U.S. men with prostate cancer. Soon after this initial finding, XMRV was also detected in samples from patients with chronic fatigue syndrome (CFS). The blood community, which is highly sensitive to the threat of emerging infectious diseases since the HIV/AIDS crisis, recommended indefinite deferral of all blood donors with a history of CFS. As XMRV research progressed, conflicting results emerged regarding the importance of this virus in the pathophysiology of prostate cancer and/or CFS. Molecular biologists traced the development of XMRV to a recombination event in a laboratory mouse that likely occurred circa 1993. The virus was propagated via cell lines derived from a tumor present in this mouse and spread through contamination of laboratory samples. Well-controlled experiments showed that detection of XMRV was due to contaminated samples and was not a marker of or a causal factor in prostate cancer or CFS. This paper traces the development of XMRV in the prostate and CFS scientific communities and explores the effect it had on the blood community.
... For the tumor virus identification, the Virochip was used to screen RNA samples from prostate tumors. A novel gammaretrovirus, Xenotropic murine leukemia virus-related virus (XMRV), which is closely related to the xenotropic murine leukemia viruses (MuLVs), was found in patients with prostate cancers (Urisman et al., 2006), and chronic fatigue syndrome (Lombardi et al., 2009). XMRV is detected in malignant prostate epithelium by using quantitative PCR assay and immunohistochemistry with an anti- XMRV specific antiserum, raising the possibility of the virus may indirectly support tumorigenesis (Schlaberg et al., 2009). ...
Full-text available
Over 20% of human cancers worldwide are associated with infectious agents, including viruses, bacteria, and parasites. Various methods have been used to identify human tumor viruses, including electron microscopic observations of viral particles, immunologic screening, cDNA library screening, nucleic acid hybridization, consensus PCR, viral DNA array chip, and representational difference analysis (RDA). With the Human Genome Project, a large amount of genetic information from humans and other organisms has accumulated over the last decade. Utilizing the available genetic databases, Patrick S. Moore, Yuan Chang, and colleagues developed digital transcriptome subtraction (DTS), an in silico method to sequentially subtract human sequences from tissue or cellular transcriptome, and discovered Merkel cell polyomavirus (MCV) from Merkel cell carcinoma (MCC). Here we review the background and methods underlying the human tumor virus discoveries and explain how DTS was developed and used for the discovery of MCV.
... Исследование образцов крови 101 пациента с СХУ показало, что у 68 (67%) из них присутствует XMRV. В крови здоровых людей этот вирус встречается только у 3,8% (у 8 из 218) [36]. В исследованиях, проведенных в других странах, таких феноменальных данных высокой распространенности вируса XMRV у пациентов с СХУ получено не было. ...
Full-text available
Chronic fatigue syndrome is a disease of unexplained feeling of profound fatigue lasting for more than 6 months. This fatigue is not relieved even after prolonged rest and is exacerbated after physical or mental work. More than 3000 scientific studies had proved that chronic fatigue syndrome is not a form of depression or hypochondria. It is a real somatic illness that results in professional, social and individual desadaptation. This article summarizes the contemporary etiological conceptions of this condition.
... A widely reported recent example concerns the possibility that chronic fatigue syndrome may be caused by the XMRV virus. There was considerable media coverage of the results of a study by Lombardi et al. (2009) suggesting that maybe as many as 95% of sufferers had the XMRV virus compared to about 4% of the general population. A few months later, a study by Erlwein et al. (2010) found that none of the patients with chronic fatigue syndrome they tested had the XMRV virus. ...
Objective Bu Zhong Yi Qi (BZYQ) decoction is a classic prescription in Chinese history that has an obvious effect on improving fatigue symptoms. The objective was to investigate the substance basis and mechanism of BZYQ in the treatment of chronic fatigue syndrome (CFS) at the molecular level based on network pharmacology and molecular docking technology. Method The active components and their targets of Huangqi, Baizhu, Renshen, Gancao, Danggui, Chaihu, Chenpi, Shenma in BZYQ were screened by the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database and the Encyclopedia of Traditional Chinese Medicine (ETCM). The UniProt database was used to calibrate the target information in BZYQ. CFS target genes were obtained from the GeneCards and DisGeNET databases. Cytoscape 3.7.2 software and the STRING 11.0 database were used to construct a protein–protein interaction (PPI) network and screen core targets. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the the Database for Annotation, Visualization and Integrated Discovery (DAVID) database. Subsequently, the binding affinity of BZYQ with key target receptors was assessed by molecular docking analysis. Result BZYQ consists of 329 active components, 198 targets, and 6490 CFS-related targets. There were 180 common targets of BZYQ and CFS, including nitric oxide synthase Ⅱ (NOS2), estrogen receptor beta (ESR2), interleukin-2 (IL2), interleukin-6 (IL6), interleukin-1 beta (IL1B), MAP kinase-activated protein kinase 3 (MAPK3), vascular endothelial growth factor A (VEGFA), nitric oxide synthase Ⅲ (NOS3), and matrix metallopeptidase 2 (MMP2). More than 600 GO terms were obtained (Biological Process 630; Cellular Component: 95; Molecular Function:152) and 185 related signaling pathways, involving the AGE-RAGE signaling pathway in diabetic complications, pathways in cancer, TNF signaling pathway, lipid and atherosclerosis, cAMP signaling pathway, VEGF signaling pathway, calcium signaling pathway, and NF-kappa B signaling pathway. Conclusion BZYQ achieves the purpose of treating CFS through the interaction mechanism of multiple components, multiple targets and multiple pathways. It advances the study of BZYQ to the clinical stage, expounds the effective mechanism of Traditional Chinese Medicine from an overall perspective, and provides ideas at the molecular level for future experimental study.
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The previous chapter presented the voice of experience to which the present chapter responds with the voice of scientific knowledge. The objective here is not to present a single canonical account of a medical condition. Chapter merely illustrates the way mainstream biomedical literature represents CFS/ ME, and the kinds of questions is addresses.
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Purpose: We hypothesized that chronic fatigue syndrome (CFS) may be caused by single or multiple Epstein-Barr virus (EBV), cytomegalovirus (HCMV), or human herpesvirus 6 (HHV6) infection. To determine if CFS life-altering fatigue and associated findings including muscle aches, tachycardia at rest, chest aches, left ventricular dysfunction, syncope, and elevated herpesvirus serum antibody titers are reversed by long-term subset-directed valacyclovir and/or valganciclovir. Patients and methods: Data were collected at physician visits every 4-6 weeks from 142 CFS patients at one clinic from 2001 to 2007. To be included in this study, patients had to be followed for at least six months. The data captured included over 7000 patient visits and over 35,000 fields of information. Severity of fatigue was monitored by a validated Energy Index Point Score® (EIPS®). Baseline and follow-up serum antibody titers to EBV, HCMV, and HHV6, as well as coinfections with Borrelia burgdorferi, Anaplasma phagocytophila, Babesia microti, and antistreptolysin O, 24-hour ECG Holter monitors, 2D echocardiograms, cardiac dynamic studies, symptoms, and toxicity were captured and monitored. International criteria for CFS plus a specifically designed CFS diagnostic panel were used. Results and conclusions: The Group A herpesvirus CFS patients (no coinfections) returned to a near-normal to normal life (P = 0.0001). The long-term EIPS value increased (primary endpoint, P < 0.0001) with subset-directed long-term valacyclovir and/or valganciclovir therapy. Secondary endpoints (cardiac, immunologic, and neurocognitive abnormalities) improved or disappeared. Group B CFS patients (herpesvirus plus coinfections) continued to have CFS. © Lerner et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited.
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The human genome is composed of viral DNA: Viral homologues of the protein products cause Alzheimer's disease and others via autoimmune mechanisms.
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Recent years have brought growing recognition of the need for clinical criteria for myalgic encephalomyelitis (ME), which is also called chronic fatigue syndrome (CFS). An Expert Subcommittee of Health Canada established the Terms of Reference, and selected an Expert Medical Consensus Panel representing treating physicians, teaching faculty and researchers. A Consensus Workshop was held on March 30 to April 1,2001 to culminate the review process and establish consensus for a clinical working case definition, diagnostic protocols and treatment protocols. We present a systematic clinical working case definition that encourages a diagnosis based on characteristic patterns of symptom clusters, which reflect specific areas of pathogenesis. Diagnostic and treatment protocols, and a short overview of research are given to facilitate a comprehensive and integrated approach to this illness. Throughout this paper, “myalgic encephalomyelitis” and “chronic fatigue syndrome” are used interchangeably and this illness is referred to as “ME/CFS.”
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• The complexities of the chronic fatigue syndrome and the methodologic problems associated with its study indicate the need for a comprehensive, system­ atic, and integrated approach to the evaluation, classi­ fication, and study of persons with this condition and other fatiguing illnesses. We propose a conceptual framework and a set of guidelines that provide such an approach. Our guidelines include recommendations for the clinical evaluation of fatigued persons, a revised case definition of the chronic fatigue syndrome, and a strategy for subgrouping fatigued persons in formal investigations.
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Because the pathogenesis of Chronic Fatigue Syndrome (CFS) has yet to be determined, case definitions have relied on clinical observation in classifying signs and symptoms for diagnosis. The selec-tion of diagnostic signs and symptoms has major implications for which individuals are diagnosed with CFS and how seriously the illness is viewed by health care providers, disability insurers and rehabilitation planners, and patients and their families and friends. Diagnostic criteria also have implications for whether research based on varying definitions can be synthesized. The current investigation examined differences be-tween CFS as defined by Fukuda et al. (1994) and a set of criteria that has been proposed for a clinical Canadian Case definition. There were twenty-three participants who met the Canadian criteria, 12 in the CFS (Fukuda et al. (7) criteria) group and the 33 from the chronic fatigue (CF)-psychiatric group. Dependent measures included: work status, psychiatric comorbidity, symptoms, and functional impairment (measured by the Medical Outcomes Study). People meeting the Fukuda et al. and Canadian criteria were compared with people who had a chronically fatiguing illness explained by a psychiatric condition. Statistical tests used included binomial logistic regression and analysis of variance. The Canadian criteria group, in contrast to the Fukuda et al. criteria group, had more variables that statistically significantly differentiated them from the psychiatric comparison group. Overall, there were 17 symptom differences between the Canadian and CF-psychiatric group, but only 7 symptom differences between the CFS and CF-psychiatric group. The findings suggest that both the Canadian and Fukuda et al. case definitions select individuals who are statistically significantly different from psychiatric controls with chronic fatigue, with the Canadian criteria selecting cases with less psychiatric co-morbidity, more physical functional impairment, and more fatigue/weakness, neuropsychiatric, and neurological symptoms.
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The presence of the retrovirus xenotropic murine leukaemia virus-related virus (XMRV) has been reported in peripheral blood mononuclear cells of patients with chronic fatigue syndrome. Considering the potentially great medical and social relevance of such a discovery, we investigated whether this finding could be confirmed in an independent European cohort of patients with chronic fatigue syndrome. Analysis of a well defined cohort of patients and matched neighbourhood controls by polymerase chain reaction. Certified (ISO 15189) laboratory of clinical virology in a university hospital in the Netherlands. Population Between December 1991 and April 1992, peripheral blood mononuclear cells were isolated from 76 patients and 69 matched neighbourhood controls. In this study we tested cells from 32 patients and 43 controls from whom original cryopreserved phials were still available. Detection of XMRV in peripheral blood mononuclear cells by real time polymerase chain reaction assay targeting the XMRV integrase gene and/or a nested polymerase chain reaction assay targeting the XMRV gag gene. We detected no XMRV sequences in any of the patients or controls in either of the assays, in which relevant positive and negative isolation controls and polymerase chain reaction controls were included. Spiking experiments showed that we were able to detect at least 10 copies of XMRV sequences per 10(5) peripheral blood mononuclear cells by real time as well as by nested polymerase chain reaction, demonstrating high sensitivity of both assays. This study failed to show the presence of XMRV in peripheral blood mononuclear cells of patients with chronic fatigue syndrome from a Dutch cohort. These data cast doubt on the claim that XMRV is associated with chronic fatigue syndrome in the majority of patients.
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Detection of a retrovirus, xenotropic murine leukaemia virus-related virus (XMRV), has recently been reported in 67% of patients with chronic fatigue syndrome. We have studied a total of 170 samples from chronic fatigue syndrome patients from two UK cohorts and 395 controls for evidence of XMRV infection by looking either for the presence of viral nucleic acids using quantitative PCR (limit of detection <16 viral copies) or for the presence of serological responses using a virus neutralisation assay. We have not identified XMRV DNA in any samples by PCR (0/299). Some serum samples showed XMRV neutralising activity (26/565) but only one of these positive sera came from a CFS patient. Most of the positive sera were also able to neutralise MLV particles pseudotyped with envelope proteins from other viruses, including vesicular stomatitis virus, indicating significant cross-reactivity in serological responses. Four positive samples were specific for XMRV. No association between XMRV infection and CFS was observed in the samples tested, either by PCR or serological methodologies. The non-specific neutralisation observed in multiple serum samples suggests that it is unlikely that these responses were elicited by XMRV and highlights the danger of over-estimating XMRV frequency based on serological assays. In spite of this, we believe that the detection of neutralising activity that did not inhibit VSV-G pseudotyped MLV in at least four human serum samples indicates that XMRV infection may occur in the general population, although with currently uncertain outcomes.
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In October 2009 it was reported that 68 of 101 patients with chronic fatigue syndrome (CFS) in the US were infected with a novel gamma retrovirus, xenotropic murine leukaemia virus-related virus (XMRV), a virus previously linked to prostate cancer. This finding, if confirmed, would have a profound effect on the understanding and treatment of an incapacitating disease affecting millions worldwide. We have investigated CFS sufferers in the UK to determine if they are carriers of XMRV. Patients in our CFS cohort had undergone medical screening to exclude detectable organic illness and met the CDC criteria for CFS. DNA extracted from blood samples of 186 CFS patients were screened for XMRV provirus and for the closely related murine leukaemia virus by nested PCR using specific oligonucleotide primers. To control for the integrity of the DNA, the cellular beta-globin gene was amplified. Negative controls (water) and a positive control (XMRV infectious molecular clone DNA) were included. While the beta-globin gene was amplified in all 186 samples, neither XMRV nor MLV sequences were detected. XMRV or MLV sequences were not amplified from DNA originating from CFS patients in the UK. Although we found no evidence that XMRV is associated with CFS in the UK, this may be a result of population differences between North America and Europe regarding the general prevalence of XMRV infection, and might also explain the fact that two US groups found XMRV in prostate cancer tissue, while two European studies did not.
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Chronic fatigue syndrome (CFS) is a debilitating disease of unknown etiology that is estimated to affect 17 million people worldwide. Studying peripheral blood mononuclear cells (PBMCs) from CFS patients, we identified DNA from a human gammaretrovirus, xenotropic murine leukemia virus–related virus (XMRV), in 68 of 101 patients (67%) as compared to 8 of 218 (3.7%) healthy controls. Cell culture experiments revealed that patient-derived XMRV is infectious and that both cell-associated and cell-free transmission of the virus are possible. Secondary viral infections were established in uninfected primary lymphocytes and indicator cell lines after their exposure to activated PBMCs, B cells, T cells, or plasma derived from CFS patients. These findings raise the possibility that XMRV may be a contributing factor in the pathogenesis of CFS.
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The evolutionary interactions between retroviruses and their receptors result in adaptive selection of restriction variants that can allow natural populations to evade retrovirus infection. The mouse xenotropic/polytropic (X/PMV) gammaretroviruses rely on the XPR1 cell surface receptor for entry into host cells, and polymorphic variants of this receptor have been identified in different rodent species. We screened a panel of X/PMVs for infectivity on rodent cells carrying 6 different XPR1 receptor variants. The X/PMVs included 5 well-characterized laboratory and wild mouse virus isolates as well as a novel cytopathic XMV-related virus, termed Cz524, isolated from an Eastern European wild mouse-derived strain, and XMRV, a xenotropic-like virus isolated from human prostate cancer. The 7 viruses define 6 distinct tropisms. Cz524 and another wild mouse isolate, CasE#1, have unique species tropisms. Among the PMVs, one Friend isolate is restricted by rat cells. Among the XMVs, two isolates, XMRV and AKR6, differ from other XMVs in their PMV-like restriction in hamster cells. We generated a set of Xpr1 mutants and chimeras, and identified critical amino acids in two extracellular loops (ECLs) that mediate entry of these different viruses, including 3 residues in ECL3 that are involved in PMV entry (E500, T507, and V508) and can also influence infectivity by AKR6 and Cz524. We used a set of natural variants and mutants of Xpr1 to define 6 distinct host range variants among naturally occurring X/PMVs (2 XMV variants, 2 PMVs, 2 different wild mouse variants). We identified critical amino acids in XPR1 that mediate entry of these viruses. These gammaretroviruses and their XPR1 receptor are thus highly functionally polymorphic, a consequence of the evolutionary pressures that favor both host resistance and virus escape mutants. This variation accounts for multiple naturally occurring virus resistance phenotypes and perhaps contributes to the widespread distribution of these viruses in rodent and non-rodent species.
Recent years have brought growing recognition of the need for clinical criteria for myalgic encephalomyelitis (ME), which is also called chronic fatigue syndrome (CFS). An Expert Subcommittee of Health Canada established the Terms of Reference, and selected an Ex- pert Medical Consensus Panel representing treating physicians, teaching faculty and researchers. A Consensus Workshop was held on March 30 to April 1, 2001 to culminate the review process and establish consensus for a clinical working case definition, diagnostic protocols and treatment protocols. We present a systematic clinical working case definition that